Document and Entity Information - shares	9 Months Ended
Document and Entity Information - shares	Sep. 30, 2018	Nov. 01, 2018
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2018
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	Q3
Trading Symbol	DCP
Entity Registrant Name	DCP MIDSTREAM, LP
Entity Central Index Key	0001338065
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		143,317,328

Consolidated Balance Sheets - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 1	$ 156
Accounts receivable:
Trade, net of allowance for doubtful accounts of $6 and $8 million, respectively	989	773
Affiliates	227	191
Other	18	17
Inventories	77	68
Unrealized gains on derivative instruments	57	30
Collateral cash deposits	140	75
Other	17	12
Total current assets	1,526	1,322
Property, plant and equipment, net	9,163	8,983
Goodwill	231	231
Intangible assets, net	99	106
Investments in unconsolidated affiliates	3,277	3,050
Unrealized gains on derivative instruments	19	3
Other long-term assets	170	183
Total assets	14,485	13,878
Accounts payable:
Trade	1,176	989
Affiliates	106	68
Other	40	19
Current debt	525	0
Unrealized losses on derivative instruments	157	76
Accrued interest	68	71
Accrued taxes	81	58
Accrued wages and benefits	52	65
Capital spending accrual	49	39
Other	79	103
Total current liabilities	2,333	1,488
Long-term debt	4,575	4,707
Unrealized losses on derivative instruments	37	15
Deferred income taxes	29	29
Other long-term liabilities	235	201
Total liabilities	7,209	6,440
Commitments and contingent liabilities (see note 14)
Equity:
Limited partners (143,317,328 and 143,309,828 common units authorized, issued and outstanding, respectively)	6,491	6,772
General partner	109	154
Accumulated other comprehensive loss	(8)	(9)
Total partners’ equity	7,246	7,408
Noncontrolling interests	30	30
Total equity	7,276	7,438
Total liabilities and equity	14,485	13,878
Series A Preferred Limited Partners [Member]
Equity:
Preferred Units, Preferred Partners' Capital Accounts	498	491
Total equity	498	491
Series B Preferred Limited Partners [Member]
Equity:
Preferred Units, Preferred Partners' Capital Accounts	156	0
Total equity	$ 156	$ 0

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Condensed Balance Sheet Statements, Captions [Line Items]
Allowance for Doubtful Accounts Receivable, Current	$ 6	$ 8
Common unitholders, units issued (in shares)	143,317,328	143,309,828
Common unitholders, units outstanding (in shares)	143,317,328	143,309,828
Series A Preferred Limited Partners [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Preferred Units, Issued	500,000	500,000
Preferred Units, Outstanding	500,000	500,000
Series B Preferred Limited Partners [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Preferred Units, Issued	6,450,000	0
Preferred Units, Outstanding	6,450,000	0

Consolidated Statements of Operations - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Operating revenues:
Sales of natural gas, NGLs and condensate	$ 2,682	$ 1,936	$ 7,008	$ 5,641
Transportation, processing and other	133	162	371	474
Trading and marketing (losses) gains, net	(56)	(43)	(164)	10
Total operating revenues	2,759	2,055	7,215	6,125
Operating costs and expenses:
Purchases and related costs	2,327	1,695	6,024	4,939
Operating and maintenance expense	196	168	543	513
Depreciation and amortization expense	98	94	289	282
General and administrative expense	70	69	199	202
Other expense, net	2	0	7	15
Total operating costs and expenses	2,693	2,074	7,062	5,965
Operating income (loss)	66	(19)	153	160
Loss from financing activities	(19)	0	(19)	0
Earnings from unconsolidated affiliates	104	74	278	234
Interest expense, net	(69)	(73)	(203)	(219)
Income (loss) before income taxes	82	(18)	209	175
Income tax expense	0	(2)	(2)	(5)
Net income (loss)	82	(20)	207	170
Net income attributable to noncontrolling interests	(1)	0	(3)	(1)
Net income (loss) attributable to partners	81	(20)	204	169
Series A preferred limited partners' interest in net income	(10)	0	(28)	0
Series B preferred limited partners' interest in net income	(3)	0	(5)	0
General partner’s interest in net income	(42)	(39)	(123)	(122)
Net income (loss) allocable to limited partners	$ 26	$ (59)	$ 48	$ 47
Net income (loss) per limited partner unit — basic and diluted	$ 0.18	$ (0.41)	$ 0.33	$ 0.33
Weighted Average Limited Partnership Units Outstanding, Basic	143.3	143.3	143.3	143.3
Affiliated Entity
Operating revenues:
Sales of natural gas, NGLs and condensate	$ 491	$ 318	$ 1,224	$ 885
Operating costs and expenses:
Purchases and related costs	253	145	643	411
Third Party
Operating revenues:
Sales of natural gas, NGLs and condensate	2,191	1,618	5,784	4,756
Operating costs and expenses:
Purchases and related costs	$ 2,074	$ 1,550	$ 5,381	$ 4,528

Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 82	$ (20)	$ 207	$ 170
Other comprehensive income:
Reclassification of cash flow hedge losses into earnings	0	0	1	1
Total other comprehensive income	0	0	1	1
Total comprehensive income (loss)	82	(20)	208	171
Total comprehensive income attributable to noncontrolling interests	(1)	0	(3)	(1)
Total comprehensive income attributable to partners	$ 81	$ (20)	$ 205	$ 170

Consolidated Statements of Cash Flows - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
OPERATING ACTIVITIES:
Net income	$ 207	$ 170
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization expense	289	282
Earnings from unconsolidated affiliates	(278)	(234)
Distributions from unconsolidated affiliates	325	270
Net unrealized losses (gains) on derivative instruments	79	(1)
Asset impairments	0	48
Loss from financing activities	(19)	0
Other, net	13	29
Change in operating assets and liabilities, which provided (used) cash, net of effects of acquisitions:
Accounts receivable	(256)	(59)
Inventories	(9)	10
Accounts payable	255	179
Increase (Decrease) in Other Operating Assets and Liabilities, Net	(103)	24
Net cash provided by operating activities	541	684
INVESTING ACTIVITIES:
Capital expenditures	(428)	(258)
Investments in unconsolidated affiliates, net	(265)	(70)
Proceeds from sale of assets	3	130
Net cash used in investing activities	(690)	(198)
FINANCING ACTIVITIES:
Proceeds from long-term debt	3,620	0
Payments of long-term debt	(3,225)	(195)
Costs incurred to redeem senior notes	18	0
Proceeds from issuance of preferred limited partner units, net of offering costs	155	0
Distributions to preferred limited partners	25	0
Net change in advances to predecessor from DCP Midstream, LLC	0	418
Distributions to limited partners and general partner	(503)	(390)
Distributions to noncontrolling interests	(3)	(6)
Other	(7)	(2)
Net cash used in financing activities	(6)	(175)
Net change in cash and cash equivalents	(155)	311
Cash and cash equivalents, beginning of period	156	1
Cash and cash equivalents, end of period	$ 1	$ 312

Consolidated Statements of Changes in Equity - USD ($) $ in Millions	Total	Series A Preferred Limited Partners [Member]	Series B Preferred Limited Partners [Member]	General Partner	Limited Partners	Accumulated Other Comprehensive (Loss) Income	Noncontrolling Interests
Beginning balance (Predecessor) at Dec. 31, 2016	$ 4,220
Beginning balance at Dec. 31, 2016	6,853			$ 18	$ 2,591	$ (8)	$ 32
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income \| Predecessor	0
Net income	170			122	47		1
Other comprehensive income	1					1
Net change in parent advances	(418)				(418)
Acquisition of the DCP Midstream Business \| Predecessor	(4,220)
Acquisition of the DCP Midstream Business	(4,220)
Deficit purchase price under carrying value of the Transaction	3,092				3,094	(2)
Proceeds from Issuance of Preferred Limited Partners Units	0
Proceeds from issuance of common units, net of offering costs	1,125			92	1,033
Distributions to unitholders	(390)			(77)	(313)
Distributions to noncontrolling interests	(6)						(6)
Ending balance (Predecessor) at Sep. 30, 2017	0
Ending balance at Sep. 30, 2017	7,043			155	6,870	(9)	27
Beginning balance at Dec. 31, 2017	7,438	$ 491	$ 0	154	6,772	(9)	30
Increase (Decrease) in Partners' Capital [Roll Forward]
Cumulative effect adjustment for Adoption of ASC 606	6	0	0	0	6	0	0
Net income	207	28	5	123	48		3
Other comprehensive income	1					(1)
Proceeds from Issuance of Preferred Limited Partners Units	155	0	155		0
Distributions to unitholders	(528)	21	4	(168)	(335)
Distributions to noncontrolling interests	(3)	0	0	0	0	0	(3)
Ending balance at Sep. 30, 2018	$ 7,276	$ 498	$ 156	$ 109	$ 6,491	$ (8)	$ 30

Consolidated Statements of Changes in Equity (Parenthetical)	9 Months Ended
	Sep. 30, 2018 shares	Sep. 30, 2017 shares
Issuance of 6,450,000 Series B Preferred Units [Member] \| Series B Preferred Limited Partners [Member]
Sale of Preferred Limited Partnership Units	6,450,000
Issuance of 28,552,480 common units and 2,550,644 general partner units to DCP Midstream, LLC and affiliates [Member] \| Limited Partners
Issuance of common units (in shares)		28,552,480
Issuance of 28,552,480 common units and 2,550,644 general partner units to DCP Midstream, LLC and affiliates [Member] \| General Partner
Issuance of common units (in shares)		2,550,644

Description of Business and Basis of Presentation	9 Months Ended
Description of Business and Basis of Presentation	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business and Basis of Presentation	1. Description of Business and Basis of Presentation DCP Midstream, LP, with its consolidated subsidiaries, or "us", "we", "our" or the "Partnership" is a Delaware limited partnership formed in 2005 by DCP Midstream, LLC to own, operate, acquire and develop a diversified portfolio of complementary midstream energy assets. Our Partnership includes our Gathering and Processing and Logistics and Marketing segments. For additional information regarding these segments, see Note 16 - Business Segments. Our operations and activities are managed by our general partner, DCP Midstream GP, LP, which in turn is managed by its general partner, DCP Midstream GP, LLC, which we refer to as the General Partner, and which is 100% owned by DCP Midstream, LLC. DCP Midstream, LLC and its subsidiaries and affiliates, collectively referred to as DCP Midstream, LLC, is owned 50% by Phillips 66 and 50% by Enbridge Inc. and its affiliates, or Enbridge. DCP Midstream, LLC directs our business operations through its ownership and control of the General Partner. As of September 30, 2018, DCP Midstream, LLC owned approximately 38.1% of us, including limited partner and general partner interests. The condensed consolidated financial statements include the accounts of the Partnership and all majority-owned subsidiaries where we have the ability to exercise control. Investments in greater than 20% owned affiliates that are not variable interest entities and where we do not have the ability to exercise control, and investments in less than 20% owned affiliates where we have the ability to exercise significant influence, are accounted for using the equity method. The condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America, or GAAP. Conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the condensed consolidated financial statements and notes. Although these estimates are based on management’s knowledge of current and expected future events, actual results could differ from those estimates. All intercompany balances and transactions have been eliminated in consolidation. The accompanying unaudited condensed consolidated financial statements in this Quarterly Report on Form 10-Q have been prepared pursuant to the rules and regulations of the U.S. Securities and Exchange Commission ("SEC"). Accordingly, these condensed consolidated financial statements reflect all adjustments, consisting of normal recurring adjustments, that are, in the opinion of management, necessary to present fairly the financial position and results of operations for the respective interim periods. Certain information and note disclosures normally included in our annual financial statements prepared in accordance with GAAP have been condensed or omitted from these interim financial statements pursuant to such rules and regulations, although we believe that the disclosures made are adequate to make the information presented not misleading. Results of operations for the three and nine months ended September 30, 2018 are not necessarily indicative of the results that may be expected for the year ending December 31, 2018. These unaudited condensed consolidated financial statements and other information included in this Quarterly Report on Form 10-Q should be read in conjunction with the 2017 audited consolidated financial statements and notes thereto included in our Annual Report on Form 10-K for the year ended December 31, 2017.

New Accounting Pronouncements

9 Months Ended

Sep. 30, 2018

New Accounting Pronouncements, Policy [Abstract]

New Accounting Pronouncements

Financial Accounting Standards Board, or FASB, Accounting Standards Update, or ASU, 2016-15 “Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments,” or ASU 2016-15 - In August 2016, the FASB issued ASU 2016-15, which amends certain cash flow statement classification guidance. We adopted the ASU on January 1, 2018 and it has not had any impact on our condensed consolidated results of operations, cash flows and financial position.

FASB ASU, 2016-02 “Leases (Topic 842),” or ASU 2016-02 - In February 2016, the FASB issued ASU 2016-02, which requires lessees to recognize a lease liability on a discounted basis and the right of use of a specified asset at the commencement date for all leases. This ASU is effective for interim and annual reporting periods beginning after December 15, 2018, with the option to early adopt for financial statements that have not been issued.

We will adopt Topic 842 on January 1, 2019, and intend to elect the land easement practical expedient. In addition, we intend to elect the package of practical expedients permitted under the transition guidance within the new standard. We are currently in the process of gathering a complete population of our lease arrangements, implementing a software solution, and evaluating the impact of the new standard on our consolidated financial statements. Based on our evaluation to-date and from the perspective as the lessee, our leasing activity primarily consists of transportation agreements, office space, vehicles and equipment. Though the evaluation process is still in progress, we currently anticipate that this new lease guidance will result in changes to the way we recognize, present and disclose our operating leases in our consolidated financial statements, including the recognition of a lease liability and an offsetting right-of-use asset in our consolidated balance sheets for our operating leases (with the exception of short-term leases excluded by practical expedient).

FASB ASU 2014-09 “Revenue from Contracts with Customers (Topic 606),” or ASU 2014-09 and related interpretations and amendments - In May 2014, the FASB issued ASU 2014-09, which supersedes the revenue recognition requirements of Accounting Standards Codification Topic 605 “Revenue Recognition.” We adopted this ASU on January 1, 2018 using the modified retrospective method for contracts that were not completed as of the date of adoption. Under this method, the comparative information has not been restated and continues to be reported under the accounting standards in effect for those prior periods. Under the new standard, revenue is recognized when a customer obtains control of promised goods or services in an amount that reflects the consideration the entity expects to receive in exchange for those goods or services. We recognized the initial cumulative effect of applying this ASU as an adjustment to the opening balance of total partners’ equity.

In accordance with the new revenue standard requirements, the impact of adoption on our consolidated statement of operations was as follows:



	Three Months Ended September 30, 2018						Nine Months Ended September 30, 2018
	As Reported		Effect of Change		Presentation Without Adoption of ASC 606		As Reported		Effect of Change		Presentation Without Adoption of ASC 606
	(millions)
Statement of Operations
Operating revenues
Sales of natural gas, NGLs and condensate	$	2,191	$	41	$	2,232	$	5,784	$	116	$	5,900
Transportation, processing and other	$	133	$	43	$	176	$	371	$	122	$	493

Costs and expenses
Purchases and related costs	$	2,074	$	84	$	2,158	$	5,381	$	238	$	5,619

Net income	$	82	$	—	$	82	$	207	$	—	$	207

Revenue Recognition

9 Months Ended

Sep. 30, 2018

Revenue Recognition [Abstract]

Revenue from External Customers by Products and Services [Table Text Block]

Revenue Recognition

Our operating revenues are primarily derived from the following activities:


•	sales of natural gas, NGLs, and condensate;


•	services related to gathering, compressing, treating and processing NGLs and natural gas; and


•	services related to transportation and storage of natural gas and NGLs.

Sales of natural gas, NGLs and condensate - We sell our commodities to a variety of customers ranging from large, multi-national petrochemical and refining companies to regional retail propane distributors. We recognize revenue from commodity sales at the point in time when the product is delivered to the customer. Generally, the transaction price is determined at the time of each delivery as the uncertainty of commodity pricing is resolved. Customers usually pay monthly based on the products purchased that month.

Sales of natural gas, NGLs and condensate include physical sales contracts which qualify as financial derivative instruments, and buy-sell and exchange transactions which involve purchases and sales of inventory with the same counterparty that are legally contingent or in contemplation of one another as a single transaction on a combined net basis. Neither of these types of arrangements are contracts with customers within the scope of Topic 606.

Gathering, compressing, treating and processing natural gas - For natural gas gathering and processing activities, we receive either fees and/or a percentage of proceeds from commodity sales as payment for these services, depending on the type of contract. For gathering and processing agreements within the scope of Topic 606, we recognize the revenue associated with our services when the gas is gathered, treated or processed at our facilities. Under fee-based contracts, we receive a fee for our services based on throughput volumes. Under percent-of-proceeds contracts, we receive either an agreed upon percentage of the actual proceeds received from our sale of the residue natural gas and NGLs or an agreed upon percentage based on index related prices for the natural gas and NGLs. Our percent-of-proceeds contracts may also include a fee-based component.

Transportation and storage - Revenue from transportation and storage agreements is recognized based on contracted volumes transported and stored in the period the services are provided.

Our service contracts generally have terms that extend beyond one year, and are recognized over time. The performance obligation for most of our service contracts encompasses a series of distinct services performed on discrete daily quantities of natural gas or NGLs for purposes of allocating variable consideration and recognizing revenue while the customer simultaneously receives and consumes the benefits of the services provided. Revenue is recognized over time consistent with the transfer of good or service over time to the customer based on daily volumes delivered. Consideration is generally variable, and the transaction price cannot be determined at the inception of the contract, because the volume of natural gas or NGLs for which the service is provided is only specified on a daily or monthly basis. The transaction price is determined at the time the service is provided and the uncertainty is resolved. Customers usually pay monthly based on the services performed that month.

Purchase arrangements - Under purchase arrangements, we purchase natural gas at either the wellhead or the tailgate of a plant. These purchase arrangements represent an arrangement with a supplier and are recorded in “Purchases and related costs”. Often, we earn fees for services performed prior to taking control of the product in these arrangements and service revenue is recorded for these fees. Revenue generated from the sale of product obtained in these purchase arrangements are reported as “Sales of natural gas, NGLs and condensate” on the consolidated statements of operations and are recognized on a gross basis as we purchase and take control of the product prior to sale and are the principal in the transaction.

Practical expedients - We apply the practical expedients in Topic 606 and do not disclose information about transaction prices allocated to remaining performance obligations that have original expected durations of one year or less, nor do we disclose information about transaction prices allocated to remaining performance obligations if the variable consideration is allocated entirely to a wholly unsatisfied performance obligation.

We disaggregate our revenue from contracts with customers by type for each of our reportable segments, as we believe it best depicts the nature, timing and uncertainty of our revenue and cash flows. The following tables set forth our revenue by those categories:

Revenue by type was as follows:



	Three Months Ended September 30, 2018
	Gathering and Processing			Logistics and Marketing		Eliminations			Total
	(millions)
Sales of natural gas	$	469		$	530	$	(410	)	$	589
Sales of NGLs and condensate (a)	1,053			2,040		(1,000		)	2,093
Transportation, processing and other	118			15		—			133
Trading and marketing losses, net (c)	(61		)	5		—			(56		)
Total operating revenues	$	1,579		$	2,590	$	(1,410	)	$	2,759



	Nine Months Ended September 30, 2018
	Gathering and Processing			Logistics and Marketing			Eliminations			Total
	(millions)
Sales of natural gas	$	1,313		$	1,546		$	(1,182	)	$	1,677
Sales of NGLs and condensate (b)	2,663			5,210			(2,542		)	5,331
Transportation, processing and other	327			45			(1		)	371
Trading and marketing losses, net (c)	(124		)	(40		)	—			(164		)
Total operating revenues	$	4,179		$	6,761		$	(3,725	)	$	7,215

(a) Includes $1,379 million of revenues from physical sales contracts and buy-sell exchange transactions in our logistics and marketing segment, which are not within the scope of Topic 606.

(b) Includes $3,280 million of revenues from physical sales contracts and buy-sell exchange transactions in our logistics and marketing segment, which are not within the scope of Topic 606.

Contract Liabilities

9 Months Ended

Sep. 30, 2018

Contract Assets and Liabilities [Abstract]

Contract Assets and Liabilities [Text Block]

Contract Liabilities

We have contracts with customers whereby the customer reimburses us for costs to construct certain connections to our operating assets. These agreements are typically entered into in contemplation with gathering and processing agreements and transportation agreements with customers, and are part of the consideration of the contract. Prior to the adoption of Topic 606, we accounted for these arrangements as a reduction to the cost basis of our long-lived assets which were amortized as a reduction to depreciation expense over the estimated useful life of the related assets. Under Topic 606, we record these payments as deferred revenue which will be amortized into revenue over the expected contract term. The noncurrent portion of deferred revenue is included in other long-term liabilities on our condensed consolidated balance sheet.

The following table summarizes changes in contract liabilities included in our condensed consolidated balance sheet:



	September 30,
	2018
	(millions)
Balance, beginning of period	$	—
Cumulative effect of implementation of Topic 606	36
Revenue recognized (a)	(2		)
Balance, end of period	$	34
Current contract liabilities	—
Long-term contract liabilities	$	34

(a) Deferred revenue recognized is included in transportation, processing and other on the condensed consolidated statement of operations.

The contract liabilities disclosed in the table above will be recognized as revenue as the obligations are satisfied over the next 35 years as of September 30, 2018.

Agreements and Transactions with Affiliates

9 Months Ended

Sep. 30, 2018

Agreements and Transactions with Affiliates

DCP Midstream, LLC

Services Agreement and Other General and Administrative Charges

Under the Services and Employee Secondment Agreement (the “Services Agreement”), we are required to reimburse DCP Midstream, LLC for costs, expenses, and expenditures incurred or payments made on our behalf for general and administrative functions including, but not limited to, legal, accounting, compliance, treasury, insurance administration and claims processing, risk management, health, safety and environmental, information technology, human resources, benefit plan maintenance and administration, credit, payroll, internal audit, taxes and engineering, as well as salaries and benefits of seconded employees, insurance coverage and claims, capital expenditures, maintenance and repair costs and taxes. There is no limit on the reimbursements we make to DCP Midstream, LLC under the Services Agreement for costs, expenses and expenditures incurred or payments made on our behalf. The following table summarizes employee related costs that were charged by DCP Midstream, LLC to the Partnership that are included in the condensed consolidated statements of operations:



	Three Months Ended September 30,				Nine Months Ended September 30,
	2018		2017		2018		2017
	(millions)
Employee related costs charged by DCP Midstream, LLC
Operating and maintenance expense	$	54	$	50	$	156	$	149
General and administrative expense	$	51	$	46	$	136	$	116

Phillips 66 and its Affiliates

We sell a portion of our residue gas and NGLs to Phillips 66 and Chevron Phillips Chemical LLC, or CPChem. CPChem is owned 50% by Phillips 66, and is considered a related party. Approximately 18% of our NGL production was committed to Phillips 66 and CPChem as of September 30, 2018. The primary production commitment on certain contracts began a ratable wind down period in December 2014 which expires in January 2019. We anticipate continuing to purchase and sell commodities with Phillips 66 and CPChem in the ordinary course of business.

Enbridge and its Affiliates

We sell NGLs to and purchase NGLs from Enbridge and its affiliates. We anticipate continuing to sell commodities to and purchase commodities from Enbridge and its affiliates in the ordinary course of business.

Unconsolidated Affiliates

We sell a portion of our residue gas and NGLs to, purchase natural gas and other NGL products from, and provide gathering and transportation services to other unconsolidated affiliates. We anticipate continuing to purchase and sell commodities and provide services to unconsolidated affiliates in the ordinary course of business.

Summary of Transactions with Affiliates

The following table summarizes our transactions with affiliates:



	Three Months Ended September 30,					Nine Months Ended September 30,
	2018			2017		2018		2017
	(millions)
Phillips 66 (including its affiliates):
Sales of natural gas, NGLs and condensate to affiliates	$	483		$	289	$	1,166	$	814
Purchases and related costs from affiliates	$	57		$	7	$	95	$	22
Operating and maintenance and general administrative expenses	$	4		$	—	$	10	$	1
Enbridge (including its affiliates):
Sales of natural gas, NGLs and condensate to affiliates	$	(13	)	$	14	$	12	$	34
Purchases and related costs from affiliates	$	(2	)	$	12	$	26	$	31
Operating and maintenance and general administrative expenses	$	—		$	1	$	—	$	2
Unconsolidated affiliates:
Sales of natural gas, NGLs and condensate to affiliates	$	21		$	15	$	46	$	37
Transportation, processing, and other to affiliates	$	2		$	1	$	5	$	4
Purchases and related costs from affiliates	$	198		$	126	$	522	$	358

We had balances with affiliates as follows:



	September 30, 2018		December 31, 2017
	(millions)
Phillips 66 (including its affiliates):
Accounts receivable	$	198	$	156
Accounts payable	$	25	$	6
Other assets	$	1	$	—
Enbridge (including its affiliates):
Accounts receivable	$	1	$	11
Accounts payable	$	5	$	9
Unconsolidated affiliates:
Accounts receivable	$	28	$	24
Accounts payable	$	76	$	53
Other assets	$	1	$	4

Inventories

9 Months Ended

Sep. 30, 2018

Inventory Disclosure [Abstract]

Inventories

Inventories were as follows:



	September 30, 2018		December 31, 2017
	(millions)
Natural gas	$	16	$	30
NGLs	61		38
Total inventories	$	77	$	68

We recognize lower of cost or market adjustments when the carrying value of our inventories exceeds their estimated market value. These non-cash charges are a component of purchases and related costs in the condensed consolidated statements of operations. We recognized no lower of cost or net realizable value adjustments during the three and nine months ended September 30, 2018 and September 30, 2017, respectively.

Property, Plant and Equipment

9 Months Ended

Sep. 30, 2018

Property, Plant and Equipment [Abstract]

Property, Plant and Equipment

A summary of property, plant and equipment by classification is as follows:



	Depreciable Life	September 30, 2018			December 31, 2017
		(millions)
Gathering and transmission systems	20 — 50 Years	$	8,737		$	8,473
Processing, storage and terminal facilities	35 — 60 Years	5,317			5,128
Other	3 — 30 Years	564			557
Construction work in progress		382			374
Property, plant and equipment		15,000			14,532
Accumulated depreciation		(5,837		)	(5,549		)
Property, plant and equipment, net		$	9,163		$	8,983

Interest capitalized on construction projects was $4 million and $2 million for the three months ended September 30, 2018 and 2017, respectively, and $15 million and $4 million for the nine months ended September 30, 2018 and 2017, respectively.

Depreciation expense was $95 million and $90 million for the three months ended September 30, 2018 and 2017, respectively, and $281 million and $272 million for the nine months ended September 30, 2018 and 2017, respectively.

Goodwill

9 Months Ended

Sep. 30, 2018

Goodwill and Intangible Assets Disclosure [Abstract]

Goodwill

We performed our annual goodwill assessment during the third quarter of 2018 at the reporting unit level, which is conducted by assessing whether (i) the components of our operating segments constitute businesses for which discrete financial information is available, (ii) segment management regularly reviews the operating results of those components and (iii) whether the economic and regulatory characteristics are similar. As a result of our assessment, we concluded that the fair value of goodwill substantially exceeded its carrying value in our North reporting unit, the only reporting unit allocated goodwill included within our Gathering and Processing reportable segment, and in our Marysville reporting unit included within our Logistics and Marketing reportable segment. For our Wholesale Propane reporting unit, which is included in our Logistics and Marketing reportable segment, the fair value exceeded the carrying value (including approximately $37 million of allocated goodwill) by approximately 10%. We concluded that the entire amount of goodwill disclosed on the condensed consolidated balance sheet is recoverable.

We primarily used a discounted cash flow analysis, supplemented by a market approach analysis, to perform our goodwill assessment. Key assumptions in the analysis include the use of an appropriate discount rate, terminal year multiples, and estimated future cash flows, including an estimate of operating and general and administrative costs. In estimating cash flows, we incorporate current market information (including forecasted volumes and commodity prices), as well as historical and other factors. If actual results are not consistent with our assumptions and estimates, or our assumptions and estimates change due to new information, we may be exposed to goodwill impairment charges, which would be recognized in the period in which the carrying value exceeds fair value.

We expect that the fair value of our Wholesale Propane reporting unit will continue to exceed its carrying value so long as our estimate of future cash flows and the market valuation remain consistent with current levels. A continued period of volatile propane prices could result in further deterioration of market multiples, comparable sales transactions prices, weighted average costs of capital, and our cash flow estimates. Changes to any one or combination of these factors, would result in changes to the reporting unit fair values discussed above which could lead to future impairment charges. Such potential impairment could have a material effect on our results of operations.

During the three and nine months ended September 30, 2018, we had no additions to or dispositions from the carrying amount of goodwill in each of our reportable segments. The carrying amount of goodwill in each of our reportable segments was as follows:




	September 30, 2018
	(millions)
	Gathering and Processing		Logistics and Marketing		Total
Balance, end of period	$	159	$	72	$	231

Investments in Unconsolidated Affiliates

9 Months Ended

Sep. 30, 2018

Equity Method Investments and Joint Ventures [Abstract]

Investments in Unconsolidated Affiliates

The following table summarizes our investments in unconsolidated affiliates:



		Carrying Value as of
	Percentage Ownership	September 30, 2018		December 31, 2017
		(millions)
DCP Sand Hills Pipeline, LLC	66.67%	$	1,774	$	1,633
DCP Southern Hills Pipeline, LLC	66.67%	733		739
Discovery Producer Services LLC	40.00%	350		362
Front Range Pipeline LLC	33.33%	175		165
Texas Express Pipeline LLC	10.00%	92		90
Gulf Coast Express Pipeline LLC	25.00%	89		—
Mont Belvieu Enterprise Fractionator	12.50%	27		23
Panola Pipeline Company, LLC	15.00%	23		24
Mont Belvieu 1 Fractionator	20.00%	10		10
Other	Various	4		4
Total investments in unconsolidated affiliates		$	3,277	$	3,050

Earnings from investments in unconsolidated affiliates were as follows:



	Three Months Ended September 30,					Nine Months Ended September 30,
	2018		2017			2018		2017
	(millions)
DCP Sand Hills Pipeline, LLC	$	64	$	37		$	170	$	105
DCP Southern Hills Pipeline, LLC	21		10			50		34
Discovery Producer Services LLC	1		14			4		59
Front Range Pipeline LLC	6		5			16		12
Texas Express Pipeline LLC	4		4			14		7
Mont Belvieu Enterprise Fractionator	3		3			10		10
Mont Belvieu 1 Fractionator	4		2			12		6
Other	1		(1		)	2		1
Total earnings from unconsolidated affiliates	$	104	$	74		$	278	$	234

The following tables summarize the combined financial information of our investments in unconsolidated affiliates:



	Three Months Ended September 30,				Nine Months Ended September 30,
	2018		2017		2018		2017
	(millions)
Statements of operations:
Operating revenue	$	407	$	358	$	1,149	$	1,063
Operating expenses	$	157	$	164	$	443	$	464
Net income	$	250	$	194	$	704	$	598



	September 30, 2018			December 31, 2017
	(millions)
Balance sheets:
Current assets	$	557		$	244
Long-term assets	5,937			5,319
Current liabilities	(412		)	(196		)
Long-term liabilities	(237		)	(200		)
Net assets	$	5,845		$	5,167

Fair Value Measurement

9 Months Ended

Sep. 30, 2018

Fair Value Disclosures [Abstract]

Fair Value Measurement

Determination of Fair Value

Below is a general description of our valuation methodologies for derivative financial assets and liabilities which are measured at fair value. Fair values are generally based upon quoted market prices or prices obtained through external sources, where available. If listed market prices or quotes are not available, we determine fair value based upon a market quote, adjusted by other market-based or independently sourced market data such as historical commodity volatilities, crude oil future yield curves, and/or counterparty specific considerations. These adjustments result in a fair value for each asset or liability under an “exit price” methodology, in line with how we believe a marketplace participant would value that asset or liability. Fair values are adjusted to reflect the credit risk inherent in the transaction as well as the potential impact of liquidating open positions in an orderly manner over a reasonable time period under current conditions. These adjustments may include amounts to reflect counterparty credit quality, the effect of our own creditworthiness, and/or the liquidity of the market.

•

Counterparty credit valuation adjustments are necessary when the market price of an instrument is not indicative of the fair value as a result of the credit quality of the counterparty. Generally, market quotes assume that all counterparties have near zero, or low, default rates and have equal credit quality. Therefore, an adjustment may be necessary to reflect the credit quality of a specific counterparty to determine the fair value of the instrument. We record counterparty credit valuation adjustments on all derivatives that are in a net asset position as of the measurement date in accordance with our established counterparty credit policy, which takes into account any collateral margin that a counterparty may have posted with us as well as any letters of credit that they have provided.

•

Entity valuation adjustments are necessary to reflect the effect of our own credit quality on the fair value of our net liability positions with each counterparty. This adjustment takes into account any credit enhancements, such as collateral margin we may have posted with a counterparty, as well as any letters of credit that we have provided. The methodology to determine this adjustment is consistent with how we evaluate counterparty credit risk, taking into account our own credit rating, current credit spreads, as well as any change in such spreads since the last measurement date.

•

Liquidity valuation adjustments are necessary when we are not able to observe a recent market price for financial instruments that trade in less active markets for the fair value to reflect the cost of exiting the position. Exchange traded contracts are valued at market value without making any additional valuation adjustments and, therefore, no liquidity reserve is applied. For contracts other than exchange traded instruments, we mark our positions to the midpoint of the bid/ask spread, and record a liquidity reserve based upon our total net position. We believe that such practice results in the most reliable fair value measurement as viewed by a market participant.

We manage our derivative instruments on a portfolio basis and the valuation adjustments described above are calculated on this basis. We believe that the portfolio level approach represents the highest and best use for these assets as there are benefits inherent in naturally offsetting positions within the portfolio at any given time, and this approach is consistent with how a market participant would view and value the assets and liabilities. Although we take a portfolio approach to managing these assets/liabilities, in order to reflect the fair value of any one individual contract within the portfolio, we allocate all valuation adjustments down to the contract level, to the extent deemed necessary, based upon either the notional contract volume, or the contract value, whichever is more applicable.

The methods described above may produce a fair value calculation that may not be indicative of net realizable value or reflective of future fair values. While we believe that our valuation methods are appropriate and consistent with other market participants, we recognize that the use of different methodologies or assumptions to determine the fair value of certain financial instruments could result in a different estimate of fair value at the reporting date. We review our fair value policies on a regular basis taking into consideration changes in the marketplace and, if necessary, will adjust our policies accordingly. See Note 12 - Risk Management and Hedging Activities.

Valuation Hierarchy

Our fair value measurements are grouped into a three-level valuation hierarchy and are categorized in their entirety in the same level of the fair value hierarchy as the lowest level input that is significant to the entire measurement. The valuation hierarchy is based upon the transparency of inputs to the valuation of an asset or liability as of the measurement date. The three levels are defined as follows.


•	Level 1 — inputs are unadjusted quoted prices for identical assets or liabilities in active markets.


•	Level 2 — inputs include quoted prices for similar assets and liabilities in active markets, and inputs that are observable for the asset or liability, either directly or indirectly, for substantially the full term of the financial instrument.


•	Level 3 — inputs are unobservable and considered significant to the fair value measurement.

A financial instrument’s categorization within the hierarchy is based upon the level of judgment involved in the most significant input in the determination of the instrument’s fair value. Following is a description of the valuation methodologies used as well as the general classification of such instruments pursuant to the hierarchy.

Commodity Derivative Assets and Liabilities

We enter into a variety of derivative financial instruments, which may include exchange traded instruments (such as New York Mercantile Exchange, or NYMEX, crude oil or natural gas futures) or over-the-counter, or OTC, instruments (such as natural gas contracts, crude oil or NGL swaps). The exchange traded instruments are generally executed with a highly rated broker dealer serving as the clearinghouse for individual transactions.

Our activities expose us to varying degrees of commodity price risk. To mitigate a portion of this risk and to manage commodity price risk related primarily to owned natural gas storage and pipeline assets, we engage in natural gas asset based trading and marketing, and we may enter into natural gas and crude oil derivatives to lock in a specific margin when market conditions are favorable. A portion of this may be accomplished through the use of exchange traded derivative contracts. Such instruments are generally classified as Level 1 since the value is equal to the quoted market price of the exchange traded instrument as of our balance sheet date, and no adjustments are required. Depending upon market conditions and our strategy we may enter into exchange traded derivative positions with a significant time horizon to maturity. Although such instruments are exchange traded, market prices may only be readily observable for a portion of the duration of the instrument. In order to calculate the fair value of these instruments, readily observable market information is utilized to the extent it is available; however, in the event that readily observable market data is not available, we may interpolate or extrapolate based upon observable data. In instances where we utilize an interpolated or extrapolated value, and it is considered significant to the valuation of the contract as a whole, we would classify the instrument within Level 3.

We also engage in the business of trading energy related products and services, which exposes us to market variables and commodity price risk. We may enter into physical contracts or financial instruments with the objective of realizing a positive margin from the purchase and sale of these commodity-based instruments. We may enter into derivative instruments for NGLs or other energy related products, primarily using the OTC derivative instrument markets, which are not as active and liquid as exchange traded instruments. Market quotes for such contracts may only be available for short dated positions (up to six months), and an active market itself may not exist beyond such time horizon. Contracts entered into with a relatively short time horizon for which prices are readily observable in the OTC market are generally classified within Level 2. Contracts with a longer time horizon, for which we internally generate a forward curve to value such instruments, are generally classified within Level 3. The internally generated curve may utilize a variety of assumptions including, but not limited to, data obtained from third-party pricing services, historical and future expected relationship of NGL prices to crude oil prices, the knowledge of expected supply sources coming online, expected weather trends within certain regions of the United States, and the future expected demand for NGLs.

Each instrument is assigned to a level within the hierarchy at the end of each financial quarter depending upon the extent to which the valuation inputs are observable. Generally, an instrument will move toward a level within the hierarchy that requires a lower degree of judgment as the time to maturity approaches, and as the markets in which the asset trades will likely become more liquid and prices more readily available in the market, thus reducing the need to rely upon our internally developed assumptions. However, the level of a given instrument may change, in either direction, depending upon market conditions and the availability of market observable data.

Nonfinancial Assets and Liabilities

We utilize fair value to perform impairment tests as required on our property, plant and equipment, goodwill, equity investments, and other long-lived intangible assets. Assets and liabilities acquired in third party business combinations are recorded at their fair value as of the date of acquisition. The inputs used to determine such fair value are primarily based upon internally developed cash flow models and would generally be classified within Level 3 in the event that we were required to measure and record such assets at fair value within our condensed consolidated financial statements. Additionally, we use fair value to determine the inception value of our asset retirement obligations. The inputs used to determine such fair value are primarily based upon costs incurred historically for similar work, as well as estimates from independent third parties for costs that would be incurred to restore leased property to the contractually stipulated condition, and would generally be classified within Level 3.

During the nine months ended September 30, 2018, we recognized no impairments of property, plant and equipment, intangible assets and investment in unconsolidated affiliates. During the nine months ended September 30, 2017, we recognized impairments of property, plant and equipment, intangible assets and investment in unconsolidated affiliates of $48 million in our condensed consolidated statement of operations as summarized in the table below. Our impairment determinations involved significant assumptions and judgments. Differing assumptions regarding any of these inputs could have a significant effect on the various valuations. As such, the fair value measurements utilized within these models are classified as non-recurring Level 3 measurements in the fair value hierarchy because they are not observable from objective sources.

The following tables present the carrying value of assets measured at fair value on a non-recurring basis, by condensed consolidated balance sheet caption and by valuation hierarchy, as of and for the nine months ended September 30, 2017:



	Net Carrying Value		Fair Value Measurements Using						Asset Impairments
	Net Carrying Value		Level 1		Level 2		Level 3		Asset Impairments
	(millions)

Property, plant and equipment	$	14	$	—	$	—	$	14	$	26
Intangible assets	11		—		—		11		21
Investment in unconsolidated affiliates	1		—		—		1		1
Total impairments	$	26	$	—	$	—	$	26	$	48

The following table presents the financial instruments carried at fair value as of September 30, 2018 and December 31, 2017, by condensed consolidated balance sheet caption and by valuation hierarchy, as described above:



	September 30, 2018												December 31, 2017
	Level 1			Level 2			Level 3			Total Carrying Value			Level 1			Level 2			Level 3			Total Carrying Value
	(millions)
Current assets:
Commodity derivatives (a)	$	44		$	9		$	4		$	57		$	10		$	17		$	3		$	30
Short-term investments (b)	$	—		$	—		$	—		$	—		$	156		$	—		$	—		$	156
Long-term assets:
Commodity derivatives (c)	$	15		$	2		$	2		$	19		$	1		$	1		$	1		$	3
Current liabilities:
Commodity derivatives (d)	$	(82	)	$	(57	)	$	(18	)	$	(157	)	$	(29	)	$	(34	)	$	(13	)	$	(76	)
Long-term liabilities:
Commodity derivatives (e)	$	(25	)	$	(7	)	$	(5	)	$	(37	)	$	(3	)	$	(11	)	$	(1	)	$	(15	)


(a)	Included in current unrealized gains on derivative instruments in our condensed consolidated balance sheets.


(b)	Includes short-term money market securities included in cash and cash equivalents in our condensed consolidated balance sheets.


(c)	Included in long-term unrealized gains on derivative instruments in our condensed consolidated balance sheets.


(d)	Included in current unrealized losses on derivative instruments in our condensed consolidated balance sheets.


(e)	Included in long-term unrealized losses on derivative instruments in our condensed consolidated balance sheets.

Changes in Levels 1 and 2 Fair Value Measurements

The determination to classify a financial instrument within Level 1 or Level 2 is based upon the availability of quoted prices for identical or similar assets and liabilities in active markets. Depending upon the information readily observable in the market, and/or the use of identical or similar quoted prices, which are significant to the overall valuation, the classification of any individual financial instrument may differ from one measurement date to the next. To qualify as a transfer, the asset or liability must have existed in the previous reporting period and moved into a different level during the current period. In the event that there is a movement between the classification of an instrument as Level 1 or 2, the transfer would be reflected in a table as “Transfers into or out of Level 1 and Level 2”. During the nine months ended September 30, 2018 and 2017, there were no transfers between Level 1 and Level 2 of the fair value hierarchy.

Changes in Level 3 Fair Value Measurements

The tables below illustrate a rollforward of the amounts included in our condensed consolidated balance sheets for derivative financial instruments that we have classified within Level 3. Since financial instruments classified as Level 3 typically include a combination of observable components (that is, components that are actively quoted and can be validated to external sources) and unobservable components, the gains and losses in the table below may include changes in fair value due in part to observable market factors, or changes to our assumptions on the unobservable components. Depending upon the information readily observable in the market, and/or the use of unobservable inputs, which are significant to the overall valuation, the classification of any individual financial instrument may differ from one measurement date to the next. The significant unobservable inputs used in determining fair value include adjustments by other market-based or independently sourced market data such as historical commodity volatilities, crude oil future yield curves, and/or counterparty specific considerations. In the event that there is a movement to/from the classification of an instrument as Level 3, we would reflect such items in the table below within the “Transfers into/out of Level 3” captions.

We manage our overall risk at the portfolio level and in the execution of our strategy, we may use a combination of financial instruments, which may be classified within any level. Since Level 1 and Level 2 risk management instruments are not included in the rollforward below, the gains or losses in the table do not reflect the effect of our total risk management activities.



	Commodity Derivative Instruments
	Current Assets			Long-Term Assets			Current Liabilities			Long-Term Liabilities
	(millions)
Three months ended September 30, 2018 (a):
Beginning balance	$	1		$	1		$	(10	)	$	(7	)
Net unrealized gains (losses) included in earnings (b)	4			1			(20		)	2
Transfers out of Level 3 (c)	(1		)	—			5			—
Settlements	—			—			7			—
Ending balance	$	4		$	2		$	(18	)	$	(5	)
Net unrealized gains (losses) on derivatives still held included in earnings (b)	$	3		$	1		$	(15	)	$	2
Three months ended September 30, 2017 (a):
Beginning balance	$	7		$	2		$	(2	)	$	(3	)
Net unrealized gains (losses) included in earnings (b)	—			2			(26		)	—
Transfers out of Level 3 (c)	—			—			2			—
Settlements	—			—			2			—
CME Rule 814 adjustment	(5		)	(3		)	16			1
Ending balance	$	2		$	1		$	(8	)	$	(2	)
Net unrealized gains on derivatives still held included in earnings (b)	$	3		$	2		$	(22	)	$	—



	Commodity Derivative Instruments
	Current Assets			Long-Term Assets			Current Liabilities			Long-Term Liabilities
	(millions)
Nine months ended September 30, 2018 (a):
Beginning balance	$	3		$	1		$	(13	)	$	(1	)
Net unrealized gains (losses) included in earnings (b)	2			1			(28		)	(4		)
Transfers out of Level 3 (c)	(1		)	—			10			—
Settlements	—			—			13			—
Ending balance	$	4		$	2		$	(18	)	$	(5	)
Net unrealized gains (losses) on derivatives still held included in earnings (b)	$	4		$	1		$	(17	)	$	(4	)
Nine months ended September 30, 2017 (a):
Beginning balance	$	9		$	5		$	(23	)	$	—
Net unrealized gains (losses) included in earnings (b)	4			(1		)	(20		)	(3		)
Transfers out of Level 3 (c)	(4		)	—			12			—
Settlements	(2		)	—			7			—
CME Rule 814 adjustment	$	(5	)	$	(3	)	$	16		$	1
Ending balance	$	2		$	1		$	(8	)	$	(2	)
Net unrealized gains (losses) on derivatives still held included in earnings (b)	$	7		$	(1	)	$	(21	)	$	(2	)


(a)	There were no purchases, issuances or sales of derivatives or transfers into Level 3 for the three and nine months ended September 30, 2018 and 2017.


(b)	Represents the amount of unrealized gains or losses for the period, included in trading and marketing gains (losses), net.


(c)	Amounts transferred out of Level 3 are reflected at fair value at the end of the period.

Quantitative Information and Fair Value Sensitivities Related to Level 3 Unobservable Inputs

We utilize the market approach to measure the fair value of our commodity contracts. The significant unobservable inputs used in this approach to fair value are longer dated price quotes. Our sensitivity to these longer dated forward curve prices are presented in the table below. Significant changes in any of those inputs in isolation would result in significantly different fair value measurements, depending on our short or long position in contracts.



	September 30, 2018
Product Group	Fair Value			Forward Curve Range
	(millions)
Assets
NGLs	$	4		$0.38-$1.29	Per gallon
Natural gas	$	2		$1.87-$2.43	Per MMBtu
Liabilities
NGLs	$	(22	)	$0.15-$1.29	Per gallon
Natural gas	$	(1	)	$2.37-$2.80	Per MMBtu

Estimated Fair Value of Financial Instruments

Valuation of a contract’s fair value is validated by an internal group independent of the marketing group. While common industry practices are used to develop valuation techniques, changes in pricing methodologies or the underlying assumptions could result in significantly different fair values and income recognition. When available, quoted market prices or prices obtained through external sources are used to determine a contract’s fair value. For contracts with a delivery location or duration for which quoted market prices are not available, fair value is determined based on pricing models developed primarily from historical and expected relationships with quoted market prices.

Values are adjusted to reflect the credit risk inherent in the transaction as well as the potential impact of liquidating open positions in an orderly manner over a reasonable time period under current conditions. Changes in market prices and management estimates directly affect the estimated fair value of these contracts. Accordingly, it is reasonably possible that such estimates may change in the near term.

The fair value of our interest rate swaps, if any, and commodity non-trading derivatives is based on prices supported by quoted market prices and other external sources and prices based on models and other valuation methods. The “prices supported by quoted market prices and other external sources” category includes our interest rate swaps, if any, our NGL and crude oil swaps and our NYMEX positions in natural gas. In addition, this category includes our forward positions in natural gas for which our forward price curves are obtained from a third party pricing service and then validated through an internal process which includes the use of independent broker quotes. This category also includes our forward positions in NGLs at points for which OTC broker quotes for similar assets or liabilities are available for the full term of the instrument. This category also includes “strip” transactions whose pricing inputs are directly or indirectly observable from external sources and then modeled to daily or monthly prices as appropriate. The “prices based on models and other valuation methods” category includes the value of transactions for which inputs to the fair value of the instrument are unobservable in the marketplace and are considered significant to the overall fair value of the instrument. The fair value of these instruments may be based upon an internally developed price curve, which was constructed as a result of the long dated nature of the transaction or the illiquidity of the specific market point.

We have determined fair value amounts using available market information and appropriate valuation methodologies. However, considerable judgment is required in interpreting market data to develop the estimates of fair value. Accordingly, the estimates presented herein are not necessarily indicative of the amounts that we could realize in a current market exchange. The use of different market assumptions and/or estimation methods may have a material effect on the estimated fair value amounts.

The fair value of accounts receivable and accounts payable are not materially different from their carrying amounts because of the short-term nature of these instruments or the stated rates approximating market rates. Derivative instruments are carried at fair value.

We determine the fair value of our fixed-rate senior notes and junior subordinated notes based on quotes obtained from bond dealers. The fair value of borrowings under the Credit Agreement and our Accounts Receivable Securitization Facility (the "Securitization Facility") are based on carrying value, which approximates fair value as their interest rates are based on prevailing market interest rates. We classify the fair values of our outstanding debt balances within Level 2 of the valuation hierarchy. As of September 30, 2018 and December 31, 2017, the carrying value and fair value of our total debt, including current maturities, were as follows:



		September 30, 2018				December 31, 2017
		Carrying Value (a)		Fair Value		Carrying Value (a)		Fair Value
	(millions)

Total debt		$	5,131	$	5,199	$	4,736	$	4,885

(a) Excludes unamortized issuance costs.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Debt

9 Months Ended

Sep. 30, 2018

Debt Disclosure [Abstract]

Debt



	September 30, 2018			December 31, 2017
	(millions)
Senior notes:
Issued February 2009, interest at 9.750% payable semiannually, due March 2019	$	—		$	450
Issued March 2014, interest at 2.700% payable semi-annually, due April 2019	325			325
Issued March 2010, interest at 5.350% payable semiannually, due March 2020 (a)	600			600
Issued September 2011, interest at 4.750% payable semiannually, due September 2021	500			500
Issued March 2012, interest at 4.950% payable semi-annually, due April 2022	350			350
Issued March 2013, interest at 3.875% payable semi-annually, due March 2023	500			500
Issued July 2018, interest at 5.375% payable semi-annually, due July 2025	500			—
Issued August 2000, interest at 8.125% payable semi-annually, due August 2030 (a)	300			300
Issued October 2006, interest at 6.450% payable semi-annually, due November 2036	300			300
Issued September 2007, interest at 6.750% payable semi-annually, due September 2037	450			450
Issued March 2014, interest at 5.600% payable semi-annually, due April 2044	400			400
Junior subordinated notes:
Issued May 2013, interest at 5.850% payable semi-annually, due May 2043	550			550
Credit agreement:
Revolving credit facility, weighted-average variable interest rate of 3.650%, as of September 30, 2018, due December 2022	145			—
Accounts Receivable Securitization Facility:
Accounts receivable securitization facility, weighted-average variable interest rate of 3.061% as of September 30, 2018, due August 2019	200			—
Fair value adjustments related to interest rate swap fair value hedges (a)	21			23
Unamortized issuance costs	(31		)	(29		)
Unamortized discount	(10		)	(12		)
Total debt	5,100			4,707
Current debt	525			—
Total long-term debt	$	4,575		$	4,707

(a) The swaps associated with this debt were previously terminated. The remaining long-term fair value of approximately

$21 million related to the swaps is being amortized as a reduction to interest expense through 2020 and 2030, the original maturity dates of the debt.

Accounts Receivable Securitization Facility

In August 2018, we entered into our Securitization Facility that provides up to $200 million of borrowing capacity through August 2019 at LIBOR market index rates plus a margin. Under this Securitization Facility, certain of the Partnership’s wholly owned subsidiaries sell or contribute receivables to another of the Partnership’s consolidated subsidiaries, DCP Receivables LLC (“DCP Receivables”), a bankruptcy-remote special purpose entity created for the sole purpose of this Securitization Facility.

DCP Receivables’ sole activity consists of purchasing receivables from the Partnership’s wholly owned subsidiaries that participate in the Securitization Facility and providing these receivables as collateral for DCP Receivables’ borrowings under the Securitization Facility. DCP Receivables is a separate legal entity and the accounts receivable of DCP Receivables, up to the amount of the outstanding debt under the Securitization Facility, are not available to satisfy the claims of creditors of the Partnership, its subsidiaries selling receivables under the Securitization Facility, or their affiliates. Any excess receivables are eligible to satisfy the claims of creditors of the Partnership, its subsidiaries selling receivables under the Securitization Facility, or their affiliates. The amount available for borrowing is based on the availability of eligible receivables and other customary factors and conditions. As of September 30, 2018, DCP Receivables had $838 million of our accounts receivable under its Securitization Facility. Borrowings under the Securitization Facility are included in “Current debt” on the condensed consolidated balance sheet.

Senior Notes Redemption

In August 2018, we redeemed our outstanding $450 million 9.750% Senior Notes due March 2019, totaling $468 million in aggregate principal and make-whole payments, at a price of 104.008% plus accrued interest through the redemption date. The redemption resulted in a $19 million loss, which is reflected as loss from financing activities on the condensed consolidated statements of operations.

Senior Notes Issuance

On July 17, 2018, we issued $500 million of 5.375% Senior Notes due July 2025, unless redeemed prior to maturity. We received proceeds of $495 million, net of underwriters’ fees, related expenses and unamortized discounts which we used to redeem our $450 million 9.750% Senior Notes due March 2019. Interest on the notes will be paid semi-annually in arrears on January 15 and July 15 of each year, commencing January 15, 2019.

Credit Agreement

We are a party to a $1.4 billion unsecured revolving Credit Agreement (the "Credit Agreement") which matures on December 6, 2022. The Credit Agreement also grants us the option to increase the revolving loan commitment by an aggregate principal amount of up to $500 million, subject to requisite lender approval. The Credit Agreement may be extended for up to two additional one-year periods subject to requisite lender approval. Loans under the Credit Agreement may be used for working capital and other general partnership purposes including acquisitions.

The Credit Agreement allows for unrestricted cash and cash equivalents to be netted against consolidated indebtedness for purposes of calculating the Partnership’s Consolidated Leverage Ratio (as defined in the Credit Agreement). Additionally, under the Credit Agreement, the Consolidated Leverage Ratio of the Partnership as of the end of any fiscal quarter shall not exceed 5.00 to 1.0 for each fiscal quarter ending after September 30, 2018; provided that, if there is a Qualified Acquisition (as defined in the Credit Agreement) during any fiscal quarter ending September 30, 2018 or thereafter, the maximum Consolidated Leverage Ratio shall not exceed 5.50 to 1.0 at the end of the three consecutive fiscal quarters, including the fiscal quarter in which the Qualified Acquisition occurs.

Our cost of borrowing under the Credit Agreement is determined by a ratings-based pricing grid. Indebtedness under the Credit Agreement bears interest at either: (1) LIBOR, plus an applicable margin of 1.45% based on our current credit rating; or (2) (a) the base rate which shall be the higher of the prime rate, the Federal Funds rate plus 0.50% or the LIBOR Market Index rate plus 1%, plus (b) an applicable margin of 0.45% based on our current credit rating. The Credit Agreement incurs an annual facility fee of 0.30% based on our current credit rating. This fee is paid on drawn and undrawn portions of the $1.4 billion revolving credit facility.

As of September 30, 2018, we had unused borrowing capacity of $1,242 million, net of $13 million of letters of credit, under the Credit Agreement. Our borrowing capacity may be limited by financial covenants set forth in the Credit Agreement. The financial covenants set forth in the Credit Agreement limit the Partnership's ability to incur incremental debt by the unused borrowing capacity of $1,242 million as of September 30, 2018. Except in the case of a default, amounts borrowed under our Credit Agreement will not become due prior to the December 6, 2022 maturity date.

Senior Notes and Junior Subordinated Notes

Our senior notes and junior subordinated notes, collectively referred to as our debt securities, mature and become payable on their respective due dates, and are not subject to any sinking fund or mandatory redemption provisions. The senior notes are senior unsecured obligations that are guaranteed by the Partnership and rank equally in a right of payment with our other senior unsecured indebtedness, including indebtedness under our Credit Agreement, and the junior subordinated notes are unsecured and rank subordinate in right of payment to all of our existing and future senior indebtedness. The debt securities include an optional redemption whereby we may elect to redeem the notes, in whole or in part from time-to-time for a premium. Additionally, we may defer the payment of all or part of the interest on the junior subordinated notes for one or more periods up to five consecutive years. The underwriters’ fees and related expenses are recorded in our condensed consolidated balance sheets within the carrying amount of long-term debt and will be amortized over the term of the notes.

The maturities of our debt as of September 30, 2018 are as follows:



	Debt Maturities
	(millions)
2018	$	—
2019	525
2020	600
2021	500
2022	495
Thereafter	3,000
Total debt	$	5,120

Risk Management and Hedging Activities

9 Months Ended

Sep. 30, 2018

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Risk Management and Hedging Activities

Our operations expose us to a variety of risks including but not limited to changes in the prices of commodities that we buy or sell, changes in interest rates, and the creditworthiness of each of our counterparties. We manage certain of these exposures with either physical or financial transactions. We have established a comprehensive risk management policy and a risk management committee, or the Risk Management Committee, to monitor and manage market risks associated with commodity prices and counterparty credit. The Risk Management Committee is composed of senior executives who receive regular briefings on positions and exposures, credit exposures and overall risk management in the context of market activities. The Risk Management Committee is responsible for the overall management of credit risk and commodity price risk, including monitoring exposure limits. The following describes each of the risks that we manage.

Commodity Price Risk

Our portfolio of commodity derivative activity is primarily accounted for using the mark-to-market method of accounting; however, depending upon our risk profile and objectives, in certain limited cases, we may execute transactions that qualify for the hedge method of accounting. The risks, strategies and instruments used to mitigate such risks, as well as the method of accounting are discussed and summarized below.

Natural Gas Asset Based Trading and Marketing

Our natural gas storage and pipeline assets are exposed to certain risks including changes in commodity prices. We manage commodity price risk related to our natural gas storage and pipeline assets through our commodity derivative program. The commercial activities related to our natural gas storage and pipeline assets primarily consist of the purchase and sale of gas and associated time spreads and basis spreads.

A time spread transaction is executed by establishing a long gas position at one point in time and establishing an equal short gas position at a different point in time. Time spread transactions allow us to lock in a margin supported by the injection, withdrawal, and storage capacity of our natural gas storage assets. We may execute basis spread transactions to mitigate the risk of sale and purchase price differentials across our system. A basis spread transaction allows us to lock in a margin on our physical purchases and sales of gas, including injections and withdrawals from storage. We typically use swaps to execute these transactions, which are not designated as hedging instruments and are recorded at fair value with changes in fair value recorded in the current period condensed consolidated statements of operations. While gas held in our storage locations is recorded at the lower of average cost or market, the derivative instruments that are used to manage our storage facilities are recorded at fair value and any changes in fair value are currently recorded in our condensed consolidated statements of operations. Even though we may have economically hedged our exposure and locked in a future margin, the use of lower-of-cost-or-market accounting for our physical inventory and the use of mark-to-market accounting for our derivative instruments may subject our earnings to market volatility.

Commodity Cash Flow Hedges

In order for our natural gas storage facility to remain operational, a minimum level of base gas must be maintained in each storage cavern, which is capitalized on our condensed consolidated balance sheets as a component of property, plant and equipment, net. During construction or expansion of our storage caverns, we may execute a series of derivative financial instruments to mitigate a portion of the risk associated with the forecasted purchase of natural gas when we bring the storage caverns into operation. These derivative financial instruments may be designated as cash flow hedges. While the cash paid upon settlement of these hedges economically fixes the cash required to purchase base gas, the deferred losses or gains would remain in accumulated other comprehensive income, or AOCI, until the cavern is emptied and the base gas is sold. The balance in AOCI of our previously settled base gas cash flow hedges was in a loss position of $6 million as of September 30, 2018.

Commodity Cash Flow Protection Activities

We are exposed to the impact of market fluctuations in the prices of natural gas, NGLs and condensate as a result of our gathering, processing, sales and storage activities. For gathering, processing and storage services, we may receive cash or commodities as payment for these services, depending on the contract type. We may enter into derivative financial instruments to mitigate a portion of the risk of weakening natural gas, NGL and condensate prices associated with our gathering, processing and sales activities, thereby stabilizing our cash flows. As of September 30, 2018 our derivative financial instruments used to mitigate a portion of the risk of weakening natural gas, NGL and condensate prices extend through the first quarter of 2020. The commodity derivative instruments used for our hedging programs are a combination of direct NGL product, crude oil and natural gas hedges. Crude oil and NGL transactions are primarily accomplished through the use of forward contracts that effectively exchange floating price risk for a fixed price. The type of instrument used to mitigate a portion of the risk may vary depending on our risk management objectives. These transactions are not designated as hedging instruments for accounting purposes and the change in fair value is reflected in the current period within our condensed consolidated statements of operations as trading and marketing gains and (losses), net.

NGL Proprietary Trading

Our NGL proprietary trading activity includes trading energy related products and services. We undertake these activities through the use of fixed forward sales and purchases, basis and spread trades, storage opportunities, put/call options, term contracts and spot market trading. These energy trading operations are exposed to market variables and commodity price risk with respect to these products and services, and these operations may enter into physical contracts and financial instruments with the objective of realizing a positive margin from the purchase and sale of commodity-based instruments. These physical and financial instruments are not designated as hedging instruments and are recorded at fair value with changes in fair value recorded in the current period condensed consolidated statements of operations.

We employ established risk limits, policies and procedures to manage risks associated with our natural gas asset based trading and marketing and NGL proprietary trading.

Credit Risk

Our principal customers range from large, natural gas marketers to industrial end-users for our natural gas products and services, as well as large multi-national petrochemical and refining companies, to small regional propane distributors for our NGL products and services. Substantially all of our natural gas and NGL sales are made at market-based prices. Approximately 18% of our NGL production was committed to Phillips 66 and CPChem as of September 30, 2018. This concentration of credit risk may affect our overall credit risk, in that these customers may be similarly affected by changes in economic, regulatory or other factors. Where exposed to credit risk, we analyze the counterparties’ financial condition prior to entering into an agreement, establish credit limits and monitor the appropriateness of these limits on an ongoing basis. We may use various master agreements that include language giving us the right to request collateral to mitigate credit exposure. The collateral language provides for a counterparty to post cash or letters of credit for exposure in excess of the established threshold. The threshold amount represents an open credit limit, determined in accordance with our credit policy. The collateral language also provides that the inability to post collateral is sufficient cause to terminate a contract and liquidate all positions. In addition, our master agreements and our standard gas and NGL sales contracts contain adequate assurance provisions, which allow us to suspend deliveries and cancel agreements, or continue deliveries to the buyer after the buyer provides acceptable security for payment.

Contingent Credit Features

Each of the above risks is managed through the execution of individual contracts with a variety of counterparties. Certain of our derivative contracts may contain credit-risk related contingent provisions that may require us to take certain actions in certain circumstances.

We have International Swaps and Derivatives Association, or ISDA, contracts which are standardized master legal arrangements that establish key terms and conditions which govern certain derivative transactions. These ISDA contracts contain standard credit-risk related contingent provisions. Some of the provisions we are subject to are outlined below.


•	If we were to have an effective event of default under our Credit Agreement that occurs and is continuing, our ISDA counterparties may have the right to request early termination and net settlement of any outstanding derivative liability positions.


•	Our ISDA counterparties generally have collateral thresholds of zero, requiring us to fully collateralize any commodity contracts in a net liability position, when our credit rating is below investment grade.

•

Additionally, in some cases, our ISDA contracts contain cross-default provisions that could constitute a credit-risk related contingent feature. These provisions apply if we default in making timely payments under other credit arrangements and the amount of the default is above certain predefined thresholds, which are significantly high and are generally consistent with the terms of our Credit Agreement. As of September 30, 2018, we were not a party to any agreements that would trigger the cross-default provisions.

Our commodity derivative contracts that are not governed by ISDA contracts do not have any credit-risk related contingent features. Depending upon the movement of commodity prices and interest rates, each of our individual contracts with counterparties to our commodity derivative instruments or interest rate swap instruments are in either a net asset or net liability position. As of September 30, 2018, we had less than $1 million of individual commodity derivative contracts that contain credit-risk related contingent features that were in a net liability position. If we were required to net settle our position with an individual counterparty, due to a credit-risk related event, our ISDA contracts may permit us to net all outstanding contracts with that counterparty, whether in a net asset or net liability position, as well as any cash collateral already posted. As of September 30, 2018, we have not been required to post additional collateral.

Collateral

As of September 30, 2018, we had cash deposits of $140 million, included in collateral cash deposits in our condensed consolidated balance sheets. Additionally, as of September 30, 2018, we held cash of $3 million, included in other current liabilities in our condensed consolidated balance sheet, related to cash postings by third parties and letters of credit of $73 million from counterparties to secure their future performance under financial or physical contracts. Collateral amounts held or posted may be fixed or may vary, depending on the value of the underlying contracts, and could cover normal purchases and sales, services, trading and hedging contracts. In many cases, we and our counterparties have publicly disclosed credit ratings, which may impact the amounts of collateral requirements.

Physical forward contracts and financial derivatives are generally cash settled at the expiration of the contract term. These transactions are generally subject to specific credit provisions within the contracts that would allow the seller, at its discretion, to suspend deliveries, cancel agreements or continue deliveries to the buyer after the buyer provides security for payment satisfactory to the seller.

Offsetting

Certain of our derivative instruments are subject to a master netting or similar arrangement, whereby we may elect to settle multiple positions with an individual counterparty through a single net payment. Each of our individual derivative instruments are presented on a gross basis on the condensed consolidated balance sheets, regardless of our ability to net settle our positions. Instruments that are governed by agreements that include net settle provisions allow final settlement, when presented with a termination event, of outstanding amounts by extinguishing the mutual debts owed between the parties in exchange for a net amount due. We have trade receivables and payables associated with derivative instruments, subject to master netting or similar agreements, which are not included in the table below. The following summarizes the gross and net amounts of our derivative instruments:



	September 30, 2018								December 31, 2017
	Gross Amounts of Assets and (Liabilities) Presented in the Balance Sheet			Amounts Not Offset in the Balance Sheet - Financial Instruments		Net Amount			Gross Amounts of Assets and (Liabilities) Presented in the Balance Sheet			Amounts Not Offset in the Balance Sheet - Financial Instruments		Net Amount
	(millions)
Assets:
Commodity derivatives	$	76		$	—	$	76		$	33		$	—	$	33
Liabilities:
Commodity derivatives	$	(194	)	$	—	$	(194	)	$	(91	)	$	—	$	(91	)

Summarized Derivative Information

The fair value of our derivative instruments that are marked-to-market each period, as well as the location of each within our condensed consolidated balance sheets, by major category, is summarized below. We have no derivative instruments that are designated as hedging instruments for accounting purposes as of September 30, 2018 and December 31, 2017.



Balance Sheet Line Item	September 30, 2018		December 31, 2017		Balance Sheet Line Item	September 30, 2018			December 31, 2017
	(millions)					(millions)
Derivative Assets Not Designated as Hedging Instruments:					Derivative Liabilities Not Designated as Hedging Instruments:
Commodity derivatives:					Commodity derivatives:
Unrealized gains on derivative instruments — current	$	57	$	30	Unrealized losses on derivative instruments — current	$	(157	)	$	(76	)
Unrealized gains on derivative instruments — long-term	19		3		Unrealized losses on derivative instruments — long-term	(37		)	(15		)
Total	$	76	$	33	Total	$	(194	)	$	(91	)

The following summarizes the balance and activity within AOCI relative to our interest rate, commodity and foreign currency cash flow hedges as of and for the three months ended September 30, 2018:



	Interest Rate Cash Flow Hedges			Commodity Cash Flow Hedges			Foreign Currency Cash Flow Hedges (a)		Total
	(millions)
Net deferred (losses) gains in AOCI (beginning balance)	$	(3	)	$	(6	)	$	1	$	(8	)
Losses reclassified from AOCI to earnings — effective portion	—			—			—		—
Net deferred (losses) gains in AOCI (ending balance)	$	(3	)	$	(6	)	$	1	$	(8	)
Deferred losses in AOCI expected to be reclassified into earnings over the next 12 months	$	—		$	—		$	—	$	—

The following summarizes the balance and activity within AOCI relative to our interest rate, commodity and foreign currency cash flow hedges as of and for the nine months ended September 30, 2018:



	Interest Rate Cash Flow Hedges			Commodity Cash Flow Hedges			Foreign Currency Cash Flow Hedges (a)		Total
	(millions)
Net deferred (losses) gains in AOCI (beginning balance)	$	(4	)	$	(6	)	$	1	$	(9	)
Losses reclassified from AOCI to earnings — effective portion	1			—			—		1
Net deferred (losses) gains in AOCI (ending balance)	$	(3	)	$	(6	)	$	1	$	(8	)
Deferred losses in AOCI expected to be reclassified into earnings over the next 12 months	$	(1	)	$	—		$	—	$	(1	)

(a)Relates to Discovery Producer Services LLC ("Discovery"), an unconsolidated affiliate.

The following summarizes the balance and activity within AOCI relative to our interest rate, commodity and foreign currency cash flow hedges as of and for the three months ended September 30, 2017:



	Interest Rate Cash Flow Hedges			Commodity Cash Flow Hedges			Foreign Currency Cash Flow Hedges (a)		Total
	(millions)
Net deferred (losses) gains in AOCI (beginning balance)	$	(4	)	$	(6	)	$	1	$	(9	)
Net deferred (losses) gains in AOCI (ending balance)	$	(4	)	$	(6	)	$	1	$	(9	)

The following summarizes the balance and activity within AOCI relative to our interest rate, commodity and foreign currency cash flow hedges as of and for the nine months ended September 30, 2017:



	Interest Rate Cash Flow Hedges			Commodity Cash Flow Hedges			Foreign Currency Cash Flow Hedges (a)		Total
	(millions)
Net deferred (losses) gains in AOCI (beginning balance)	$	(3	)	$	(6	)	$	1	$	(8	)
Losses reclassified from AOCI to earnings — effective portion	1			—			—		1
Deficit purchase price under carrying value	(2		)	—			—		(2		)
Net deferred (losses) gains in AOCI (ending balance)	$	(4	)	$	(6	)	$	1	$	(9	)


(a)	Relates to Discovery, an unconsolidated affiliate.

For the three and nine months ended September 30, 2018 and 2017, no derivative losses attributable to the ineffective portion or to amounts excluded from effectiveness testing were recognized in trading and marketing gains or losses, net or interest expense in our condensed consolidated statements of operations. For the three and nine months ended September 30, 2018 and 2017, no derivative losses were reclassified from AOCI to trading and marketing gains or losses, net or interest expense as a result of the discontinuance of cash flow hedges related to certain forecasted transactions that are not probable of occurring.

Changes in the value of derivative instruments, for which the hedge method of accounting has not been elected from one period to the next, are recorded in the condensed consolidated statements of operations. The following summarizes these amounts and the location within the condensed consolidated statements of operations that such amounts are reflected:



Commodity Derivatives: Statements of Operations Line Item	Three Months Ended September 30,						Nine Months Ended September 30,
	2018			2017			2018			2017
	(millions)
Realized (losses) gains	$	(43	)	$	16		$	(85	)	$	9
Unrealized (losses) gains	(13		)	(59		)	(79		)	1
Trading and marketing (losses) gains, net	$	(56	)	$	(43	)	$	(164	)	$	10

We do not have any derivative financial instruments that qualify as a hedge of a net investment.

The following tables represent, by commodity type, our net long or short positions that are expected to partially or entirely settle in each respective year. To the extent that we have long dated derivative positions that span multiple calendar years, the contract will appear in more than one line item in the tables below.



	September 30, 2018
	Crude Oil		Natural Gas		Natural Gas Liquids		Natural Gas Basis Swaps
Year of Expiration	Net Short Position (Bbls)		Net Short Position (MMBtu)		Net Short Position (Bbls)		Net (Short) Long Position (MMBtu)
2018	(721,000	)	(9,938,000	)	(13,436,719	)	(1,652,500	)
2019	(1,994,000	)	(16,508,750	)	(21,595,027	)	(4,532,500	)
2020	(189,000	)	—		(13,601,378	)	3,660,000
2021	—		—		(5,754,322	)	—

	September 30, 2017
	Crude Oil		Natural Gas		Natural Gas Liquids		Natural Gas Basis Swaps
Year of Expiration	Net Short Position (Bbls)		Net Short Position (MMBtu)		Net (Short) Long Position (Bbls)		Net Long Position (MMBtu)
2017	(81,000	)	(20,888,000	)	(9,288,558	)	2,680,000
2018	(1,803,000	)	(29,277,400	)	(13,417,484	)	9,190,000
2019	(367,000	)	—		(2,353,300	)	9,317,500
2020	(50,000	)	—		238,548		3,660,000

Partnership Equity and Distributions

9 Months Ended

Sep. 30, 2018

Equity [Abstract]

Partnership Equity and Distributions

Common Units — During the nine months ended September 30, 2018 and 2017, we issued no common units pursuant to our at-the-market program. As of September 30, 2018, $750 million of common units remained available for sale pursuant to our at-the-market program.

Distributions — The following table presents our cash distributions paid in 2018 and 2017:



Payment Date	Per Unit Distribution		Total Cash Distribution
			(millions)
Distributions to common unitholders
August 14, 2018	$	0.7800	$	154
May 15, 2018	$	0.7800	$	155
February 14, 2018	$	0.7800	$	194
November 14, 2017	$	0.7800	$	155
August 14, 2017	$	0.7800	$	134
May 15, 2017	$	0.7800	$	135
February 14, 2017	$	0.7800	$	121

Distributions to Series A Preferred unitholders
June 15, 2018	$	41.9965	$	21

Distributions to Series B Preferred unitholders
September 17, 2018	$	0.6781	$	4

Net Income or Loss per Limited Partner Unit	9 Months Ended
Net Income or Loss per Limited Partner Unit	Sep. 30, 2018
Earnings Per Share [Abstract]
Net Income or Loss per Limited Partner Unit	Net Income or Loss per Limited Partner Unit Basic and diluted net income or loss per Limited Partner Unit ("LPU") is calculated by dividing net income or loss allocable to limited partners, by the weighted-average number of LPUs outstanding during the period. Diluted net income or loss per LPU is computed based on the weighted average number of units plus the effect of potential dilutive units outstanding during the period using the two-class method.

Commitments and Contingent Liabilities

9 Months Ended

Sep. 30, 2018

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingent Liabilities

Litigation — We are not a party to any significant legal proceedings, but are a party to various administrative and regulatory proceedings and commercial disputes that have arisen in the ordinary course of our business. Management currently believes that the ultimate resolution of the foregoing matters, taken as a whole, and after consideration of amounts accrued, insurance coverage or other indemnification arrangements, will not have a material adverse effect on our results of operations, financial position, or cash flow.

Insurance — Our insurance coverage is carried with third-party insurers and with an affiliate of Phillips 66. Our insurance coverage includes: (i) general liability insurance covering third-party exposures; (ii) statutory workers’ compensation insurance; (iii) automobile liability insurance for all owned, non-owned and hired vehicles; (iv) excess liability insurance above the established primary limits for general liability and automobile liability insurance; (v) property insurance, which covers the replacement value of real and personal property and includes business interruption; and (vi) insurance covering our directors and officers for acts related to our business activities. All coverage is subject to certain limits and deductibles, the terms and conditions of which are common for companies with similar types of operations.

Environmental — The operation of pipelines, plants and other facilities for gathering, transporting, processing, treating, fractionating, or storing natural gas, NGLs and other products is subject to stringent and complex laws and regulations pertaining to health, safety and the environment. As an owner or operator of these facilities, we must comply with laws and regulations at the federal, state and, in some cases, local levels that relate to worker safety, air and water quality, solid and hazardous waste management and disposal, and other environmental matters. The cost of planning, designing, constructing and operating pipelines, plants, and other facilities incorporates compliance with environmental laws and regulations, worker safety standards, and safety standards applicable to our various facilities. In addition, there is increasing focus from (i) city, state and federal regulatory officials and through litigation, on hydraulic fracturing and the real or perceived environmental impacts of this technique, which indirectly presents some risk to our available supply of natural gas and the resulting supply of NGLs, (ii) federal regulatory agencies regarding pipeline system safety which could impose additional regulatory burdens and increase the cost of our operations, (iii) state and federal regulatory officials regarding the emission of greenhouse gases, which could impose regulatory burdens and increase the cost of our operations, and (iv) regulatory bodies and communities that could prevent or delay the development of fossil fuel energy infrastructure such as pipelines, plants, and other facilities used in our business. Failure to comply with these various health, safety and environmental laws and regulations may trigger a variety of administrative, civil and potentially criminal enforcement measures, including citizen suits, which can include the assessment of monetary penalties, the imposition of remedial requirements, and the issuance of injunctions or restrictions on operation. Management believes that, based on currently known information, compliance with these existing laws and regulations will not have a material adverse effect on our results of operations, financial position or cash flows.

In June 2017, we were issued a Compliance Advisory by the Colorado Department of Public Health and Environment (CDPHE) regarding alleged noncompliance with various terms and requirements of the air permit for our Lucerne 2 natural gas processing plant. Following information exchanges and discussions with CDPHE, on November 1, 2018, we entered into a Compliance Order on Consent to resolve the alleged noncompliance. The Compliance Order provides for our payment of a $46,200 administrative penalty and to fund Supplemental Environmental Projects in the amount of $184,800 to offset administrative penalties.

Business Segments

9 Months Ended

Sep. 30, 2018

Segment Reporting [Abstract]

Business Segments

Our operations are organized into two reportable segments: (i) Gathering and Processing and (ii) Logistics and Marketing. These segments are monitored separately by management for performance against our internal forecast and are consistent with internal financial reporting. These segments have been identified based on the differing products and services, regulatory environment and the expertise required for these operations. Our Gathering and Processing reportable segment includes operating segments that have been aggregated based on the nature of the products and services provided. Gross margin is a performance measure utilized by management to monitor the operations of each segment. The accounting policies of the reportable segments are the same as those described in the summary of significant accounting policies included in Note 2 of the Notes to Consolidated Financial Statements in “Financial Statements and Supplementary Data” included as Item 8 in our Annual Report on Form 10-K for the year ended December 31, 2017.

Our Gathering and Processing segment consists of gathering, compressing, treating, processing natural gas, producing and fractionating NGLs, and recovering condensate. Our Logistics and Marketing segment includes transporting, trading, marketing, and storing natural gas and NGLs, fractionating NGLs, and wholesale propane logistics. The remainder of our business operations is presented as “Other,” and consists of unallocated corporate costs. Elimination of inter-segment transactions are reflected in the eliminations column.

The following tables set forth our segment information:

Three Months Ended September 30, 2018



	Gathering and Processing			Logistics and Marketing			Other			Eliminations			Total
	(millions)
Total operating revenue	$	1,579		$	2,590		$	—		$	(1,410	)	$	2,759
Gross margin (a)	$	364		$	68		$	—		$	—		$	432
Operating and maintenance expense	(175		)	(14		)	(7		)	—			(196		)
Depreciation and amortization expense	(87		)	(5		)	(6		)	—			(98		)
General and administrative expense	(6		)	(3		)	(61		)	—			(70		)
Other expense	(1		)	—			(1		)	—			(2		)
Loss from financing activities	—			—			(19		)	—			(19		)
Earnings from unconsolidated affiliates	2			102			—			—			104
Interest expense	—			—			(69		)	—			(69		)
Net income (loss)	$	97		$	148		$	(163	)	$	—		$	82
Net income attributable to noncontrolling interests	(1		)	—			—			—			(1		)
Net income (loss) attributable to partners	$	96		$	148		$	(163	)	$	—		$	81
Non-cash derivative mark-to-market (b)	$	(21	)	$	8		$	—		$	—		$	(13	)
Capital expenditures	$	152		$	3		$	5		$	—		$	160
Investments in unconsolidated affiliates, net	$	3		$	136		$	—		$	—		$	139

Three Months Ended September 30, 2017:



	Gathering and Processing			Logistics and Marketing			Other			Eliminations			Total
	(millions)
Total operating revenue	$	1,337		$	1,913		$	—		$	(1,195	)	$	2,055
Gross margin (a)	$	303		$	57		$	—		$	—		$	360
Operating and maintenance expense	(154		)	(9		)	(5		)	—			(168		)
Depreciation and amortization expense	(85		)	(4		)	(5		)	—			(94		)
General and administrative expense	(2		)	(3		)	(64		)	—			(69		)
Asset impairment	(48		)	—			—			—			(48		)
Other (expense) income	—			(1		)	1			—			—
Earnings from unconsolidated affiliates	15			59			—			—			74
Interest expense	—			—			(73		)	—			(73		)
Income tax expense	—			—			(2		)	—			(2		)
Net income (loss)	$	29		$	99		$	(148	)	$	—		$	(20	)
Net income attributable to noncontrolling interests	—			—			—			—			—
Net income (loss) attributable to partners	$	29		$	99		$	(148	)	$	—		$	(20	)
Non-cash derivative mark-to-market (b)	$	(51	)	$	(8	)	$	—		$	—		$	(59	)
Capital expenditures	$	91		$	1		$	7		$	—		$	99
Investments in unconsolidated affiliates, net	$	1		$	28		$	—		$	—		$	29

Nine Months Ended September 30, 2018:



	Gathering and Processing			Logistics and Marketing			Other			Eliminations			Total
	(millions)
Total operating revenue	$	4,179		$	6,761		$	—		$	(3,725	)	$	7,215
Gross margin (a)	$	1,049		$	142		$	—		$	—		$	1,191
Operating and maintenance expense	(492		)	(36		)	(15		)	—			(543		)
Depreciation and amortization expense	(258		)	(11		)	(20		)	—			(289		)
General and administrative expense	(12		)	(9		)	(178		)	—			(199		)
Other expense, net	(4		)	(2		)	(1		)	—			(7		)
Loss from financing activities	—			—			(19		)	—			(19		)
Earnings from unconsolidated affiliates	5			273			—			—			278
Interest expense	—			—			(203		)	—			(203		)
Income tax expense	—			—			(2		)	—			(2		)
Net income (loss)	$	288		$	357		$	(438	)	$	—		$	207
Net income attributable to noncontrolling interests	(3		)	—			—			—			(3		)
Net income (loss) attributable to partners	$	285		$	357		$	(438	)	$	—		$	204
Non-cash derivative mark-to-market (b)	$	(49	)	$	(30	)	$	—		$	—		$	(79	)
Capital expenditures	$	412		$	4		$	12		$	—		$	428
Investments in unconsolidated affiliates, net	$	4		$	261		$	—		$	—		$	265

Nine Months Ended September 30, 2017:



	Gathering and Processing			Logistics and Marketing			Other			Eliminations			Total
	(millions)
Total operating revenue	$	3,965		$	5,596		$	—		$	(3,436	)	$	6,125
Gross margin (a)	$	1,021		$	165		$	—		$	—		$	1,186
Operating and maintenance expense	(469		)	(31		)	(13		)	—			(513		)
Depreciation and amortization expense	(256		)	(11		)	(15		)	—			(282		)
General and administrative expense	(15		)	(8		)	(179		)	—			(202		)
Asset impairment	(48		)	—			—			—			(48		)
Other expense	(3		)	(12		)	—			—			(15		)
Gain on sale of assets, net	34			—			—			—			34
Earnings from unconsolidated affiliates	59			175			—			—			234
Interest expense	—			—			(219		)	—			(219		)
Income tax expense	—			—			(5		)	—			(5		)
Net income (loss)	$	323		$	278		$	(431	)	$	—		$	170
Net income attributable to noncontrolling interests	(1		)	—			—			—			(1		)
Net income (loss) attributable to partners	$	322		$	278		$	(431	)	$	—		$	169
Non-cash derivative mark-to-market (b)	$	(4	)	$	5		$	—		$	—		$	1
Capital expenditures	$	237		$	2		$	19		$	—		$	258
Investments in unconsolidated affiliates, net	$	1		$	69		$	—		$	—		$	70



	September 30,		December 31,
	2018		2017
	(millions)
Segment long-term assets:
Gathering and Processing	$	9,098	$	8,943
Logistics and Marketing	3,584		3,348
Other (c)	277		265
Total long-term assets	12,959		12,556
Current assets	1,526		1,322
Total assets	$	14,485	$	13,878

(a)

Gross margin consists of total operating revenues, including commodity derivative activity, less purchases and related costs. Gross margin is viewed as a non-GAAP financial measure under the rules of the SEC, but is included as a supplemental disclosure because it is a primary performance measure used by management as it represents the results of product sales versus product purchases. As an indicator of our operating performance, gross margin should not be considered an alternative to, or more meaningful than, net income or net cash provided by operating activities as determined in accordance with GAAP. Our gross margin may not be comparable to a similarly titled measure of another company because other entities may not calculate gross margin in the same manner.


(b)	Non-cash commodity derivative mark-to-market is included in gross margin, along with cash settlements for our commodity derivative contracts.


(c)	Other long-term assets not allocable to segments consist of corporate leasehold improvements and other long-term assets.

Supplemental Cash Flow Information

9 Months Ended

Sep. 30, 2018

Additional Cash Flow Elements and Supplemental Cash Flow Information [Abstract]

Supplemental Cash Flow Information



	Nine Months Ended September 30,
	2018		2017
	(millions)
Cash paid for interest:
Cash paid for interest, net of amounts capitalized	$	192	$	218
Cash paid for income taxes, net of income tax refunds	$	3	$	2
Non-cash investing and financing activities:
Property, plant and equipment acquired with accounts payable and accrued liabilities	$	58	$	27
Other non-cash changes in property, plant and equipment	$	—	$	(1	)
Issuance of common and general partner units	$	—	$	1,125
Deficit purchase price	$	—	$	3,094

Condensed Consolidating Financial Information

9 Months Ended

Sep. 30, 2018

Condensed Financial Information of Parent Company Only Disclosure [Abstract]

Condensed Consolidating Financial Information

The following condensed consolidating financial information presents the results of operations, financial position and cash flows of DCP Midstream, LP, or parent guarantor, DCP Midstream Operating LP, or subsidiary issuer, which is a 100% owned subsidiary, and non-guarantor subsidiaries, as well as the consolidating adjustments necessary to present DCP Midstream, LP’s results on a consolidated basis. The parent guarantor has agreed to fully and unconditionally guarantee debt securities of the subsidiary issuer. For the purpose of the following financial information, investments in subsidiaries are reflected in accordance with the equity method of accounting. The financial information may not necessarily be indicative of results of operations, cash flows, or financial position had the subsidiaries operated as independent entities.



	Condensed Consolidating Balance Sheets
	September 30, 2018
	Parent Guarantor		Subsidiary Issuer			Non-Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
	(millions)
ASSETS
Current assets:
Cash and cash equivalents	$	—	$	—		$	1		$	—		$	1
Accounts receivable, net	—		—			1,234			—			1,234
Inventories	—		—			77			—			77
Other	—		—			214			—			214
Total current assets	—		—			1,526			—			1,526
Property, plant and equipment, net	—		—			9,163			—			9,163
Goodwill and intangible assets, net	—		—			330			—			330
Advances receivable — consolidated subsidiaries	2,522		1,739			—			(4,261		)	—
Investments in consolidated subsidiaries	4,724		7,953			—			(12,677		)	—
Investments in unconsolidated affiliates	—		—			3,277			—			3,277
Other long-term assets	—		—			189			—			189
Total assets	$	7,246	$	9,692		$	14,485		$	(16,938	)	$	14,485
LIABILITIES AND EQUITY
Accounts payable and other current liabilities	$	—	$	68		$	1,740		$	—		$	1,808
Current maturities of long-term debt	—		325			200			—			525
Advances payable — consolidated subsidiaries	—		—			4,261			(4,261		)	—
Long-term debt	—		4,575			—			—			4,575
Other long-term liabilities	—		—			301			—			301
Total liabilities	—		4,968			6,502			(4,261		)	7,209
Commitments and contingent liabilities
Equity:
Partners’ equity:
Net equity	7,246		4,727			7,958			(12,677		)	7,254
Accumulated other comprehensive loss	—		(3		)	(5		)	—			(8		)
Total partners’ equity	7,246		4,724			7,953			(12,677		)	7,246
Noncontrolling interests	—		—			30			—			30
Total equity	7,246		4,724			7,983			(12,677		)	7,276
Total liabilities and equity	$	7,246	$	9,692		$	14,485		$	(16,938	)	$	14,485



	Condensed Consolidating Balance Sheets
	December 31, 2017
	Parent Guarantor		Subsidiary Issuer			Non-Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
	(millions)
ASSETS
Current assets:
Cash and cash equivalents	$	—	$	155		$	1		$	—		$	156
Accounts receivable, net	—		—			981			—			981
Inventories	—		—			68			—			68
Other	—		—			117			—			117
Total current assets	—		155			1,167			—			1,322
Property, plant and equipment, net	—		—			8,983			—			8,983
Goodwill and intangible assets, net	—		—			337			—			337
Advances receivable — consolidated subsidiaries	2,895		1,614			—			(4,509		)	—
Investments in consolidated subsidiaries	4,513		7,522			—			(12,035		)	—
Investments in unconsolidated affiliates	—		—			3,050			—			3,050
Other long-term assets	—		—			186			—			186
Total assets	$	7,408	$	9,291		$	13,723		$	(16,544	)	$	13,878
LIABILITIES AND EQUITY
Accounts payable and other current liabilities	$	—	$	71		$	1,417		$	—		$	1,488
Advances payable — consolidated subsidiaries	—		—			4,509			(4,509		)	—
Long-term debt	—		4,707			—			—			4,707
Other long-term liabilities	—		—			245			—			245
Total liabilities	—		4,778			6,171			(4,509		)	6,440
Commitments and contingent liabilities
Equity:
Partners’ equity:
Net equity	7,408		4,517			7,527			(12,035		)	7,417
Accumulated other comprehensive loss	—		(4		)	(5		)	—			(9		)
Total partners’ equity	7,408		4,513			7,522			(12,035		)	7,408
Noncontrolling interests	—		—			30			—			30
Total equity	7,408		4,513			7,552			(12,035		)	7,438
Total liabilities and equity	$	7,408	$	9,291		$	13,723		$	(16,544	)	$	13,878



	Condensed Consolidating Statement of Operations
	Three Months Ended September 30, 2018
	Parent Guarantor		Subsidiary Issuer			Non- Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
	(millions)
Operating revenues:
Sales of natural gas, NGLs and condensate	$	—	$	—		$	2,682		$	—		$	2,682
Transportation, processing and other	—		—			133			—			133
Trading and marketing losses, net	—		—			(56		)	—			(56		)
Total operating revenues	—		—			2,759			—			2,759
Operating costs and expenses:
Purchases and related costs	—		—			2,327			—			2,327
Operating and maintenance expense	—		—			196			—			196
Depreciation and amortization expense	—		—			98			—			98
General and administrative expense	—		—			70			—			70
Other expense, net	—		—			2			—			2
Total operating costs and expenses	—		—			2,693			—			2,693
Operating income	—		—			66			—			66
Loss from financing activities	—		(19		)	—			—			(19		)
Interest expense, net	—		(68		)	(1		)	—			(69		)
Income from consolidated subsidiaries	81		168			—			(249		)	—
Earnings from unconsolidated affiliates	—		—			104			—			104
Income before income taxes	81		81			169			(249		)	82
Income tax expense	—		—			—			—			—
Net income	81		81			169			(249		)	82
Net income attributable to noncontrolling interests	—		—			(1		)	—			(1		)
Net income attributable to partners	$	81	$	81		$	168		$	(249	)	$	81



	Condensed Consolidating Statement of Comprehensive Income
	Three Months Ended September 30, 2018
	Parent Guarantor		Subsidiary Issuer		Non-Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
	(millions)
Net income	$	81	$	81	$	169		$	(249	)	$	82
Total other comprehensive income	—		—		—			—			—
Total comprehensive income	81		81		169			(249		)	82
Total comprehensive income attributable to noncontrolling interests	—		—		(1		)	—			(1		)
Total comprehensive income attributable to partners	$	81	$	81	$	168		$	(249	)	$	81



	Condensed Consolidating Statement of Operations
	Three Months Ended September 30, 2017
	Parent Guarantor			Subsidiary Issuer			Non-Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
	(millions)
Operating revenues:
Sales of natural gas, NGLs and condensate	$	—		$	—		$	1,936		$	—		$	1,936
Transportation, processing and other	—			—			162			—			162
Trading and marketing losses, net	—			—			(43		)	—			(43		)
Total operating revenues	—			—			2,055			—			2,055
Operating costs and expenses:
Purchases of natural gas and NGLs	—			—			1,695			—			1,695
Operating and maintenance expense	—			—			168			—			168
Depreciation and amortization expense	—			—			94			—			94
General and administrative expense	—			—			69			—			69
Asset impairment	—			—			48			—			48
Total operating costs and expenses	—			—			2,074			—			2,074
Operating loss	—			—			(19		)	—			(19		)
Interest expense, net	—			(73		)	—			—			(73		)
(Loss) income from consolidated subsidiaries	(20		)	53			—			(33		)	—
Earnings from unconsolidated affiliates	—			—			74			—			74
(Loss) income before income taxes	(20		)	(20		)	55			(33		)	(18		)
Income tax expense	—			—			(2		)	—			(2		)
Net (loss) income	(20		)	(20		)	53			(33		)	(20		)
Net income attributable to noncontrolling interests	—			—			—			—			—
Net (loss) income attributable to partners	$	(20	)	$	(20	)	$	53		$	(33	)	$	(20	)



	Condensed Consolidating Statement of Comprehensive Income
	Three Months Ended September 30, 2017
	Parent Guarantor			Subsidiary Issuer			Non-Guarantor Subsidiaries		Consolidating Adjustments			Consolidated
	(millions)
Net (loss) income	$	(20	)	$	(20	)	$	53	$	(33	)	$	(20	)
Total other comprehensive income	—			—			—		—			—
Total comprehensive (loss) income	(20		)	(20		)	53		(33		)	(20		)
Total comprehensive income attributable to noncontrolling interests	—			—			—		—			—
Total comprehensive (loss) income attributable to partners	$	(20	)	$	(20	)	$	53	$	(33	)	$	(20	)



	Condensed Consolidating Statement of Operations
	Nine Months Ended September 30, 2018
	Parent Guarantor		Subsidiary Issuer			Non- Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
	(millions)
Operating revenues:
Sales of natural gas, NGLs and condensate	$	—	$	—		$	7,008		$	—		$	7,008
Transportation, processing and other	—		—			371			—			371
Trading and marketing losses, net	—		—			(164		)	—			(164		)
Total operating revenues	—		—			7,215			—			7,215
Operating costs and expenses:
Purchases and related costs	—		—			6,024			—			6,024
Operating and maintenance expense	—		—			543			—			543
Depreciation and amortization expense	—		—			289			—			289
General and administrative expense	—		—			199			—			199
Other expense, net	—		—			7			—			7
Total operating costs and expenses	—		—			7,062			—			7,062
Operating income	—		—			153			—			153
Loss from financing activities	—		(19		)	—			—			(19		)
Interest expense, net	—		(202		)	(1		)	—			(203		)
Income from consolidated subsidiaries	204		425			—			(629		)	—
Earnings from unconsolidated affiliates	—		—			278			—			278
Income before income taxes	204		204			430			(629		)	209
Income tax expense	—		—			(2		)	—			(2		)
Net income	204		204			428			(629		)	207
Net income attributable to noncontrolling interests	—		—			(3		)	—			(3		)
Net income attributable to partners	$	204	$	204		$	425		$	(629	)	$	204



	Condensed Consolidating Statement of Comprehensive Income
	Nine Months Ended September 30, 2018
	Parent Guarantor		Subsidiary Issuer		Non-Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
	(millions)
Net income	$	204	$	204	$	428		$	(629	)	$	207
Other comprehensive income:
Reclassification of cash flow hedge losses into earnings	—		1		—			—			1
Other comprehensive income from consolidated subsidiaries	1		—		—			(1		)	—
Total other comprehensive income	1		1		—			(1		)	1
Total comprehensive income	205		205		428			(630		)	208
Total comprehensive income attributable to noncontrolling interests	—		—		(3		)	—			(3		)
Total comprehensive income attributable to partners	$	205	$	205	$	425		$	(630	)	$	205



	Condensed Consolidating Statement of Operations
	Nine Months Ended September 30, 2017
	Parent Guarantor		Subsidiary Issuer			Non- Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
	(millions)
Operating revenues:
Sales of natural gas, NGLs and condensate	$	—	$	—		$	5,641		$	—		$	5,641
Transportation, processing and other	—		—			474			—			474
Trading and marketing gains, net	—		—			10			—			10
Total operating revenues	—		—			6,125			—			6,125
Operating costs and expenses:
Purchases and related costs	—		—			4,939			—			4,939
Operating and maintenance expense	—		—			513			—			513
Depreciation and amortization expense	—		—			282			—			282
General and administrative expense	—		—			202			—			202
Asset impairment	—		—			48			—			48
Gain on sale of assets, net	—		—			(34		)	—			(34		)
Other expense, net	—		—			15			—			15
Total operating costs and expenses	—		—			5,965			—			5,965
Operating income	—		—			160			—			160
Interest expense, net	—		(219		)	—			—			(219		)
Income from consolidated subsidiaries	169		388			—			(557		)	—
Earnings from unconsolidated affiliates	—		—			234			—			234
Income before income taxes	169		169			394			(557		)	175
Income tax expense	—		—			(5		)	—			(5		)
Net income	169		169			389			(557		)	170
Net income attributable to noncontrolling interests	—		—			(1		)	—			(1		)
Net income attributable to partners	$	169	$	169		$	388		$	(557	)	$	169



	Condensed Consolidating Statement of Comprehensive Income
	Nine Months Ended September 30, 2017
	Parent Guarantor		Subsidiary Issuer		Non-Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
	(millions)
Net income	$	169	$	169	$	389		$	(557	)	$	170
Other comprehensive income:
Reclassification of cash flow hedge losses into earnings	—		1		—			—			1
Other comprehensive income from consolidated subsidiaries	1		—		—			(1		)	—
Total other comprehensive income	1		1		—			(1		)	1
Total comprehensive income	170		170		389			(558		)	171
Total comprehensive income attributable to noncontrolling interests	—		—		(1		)	—			(1		)
Total comprehensive income attributable to partners	$	170	$	170	$	388		$	(558	)	$	170



	Condensed Consolidating Statement of Cash Flows
	Nine Months Ended September 30, 2018
	Parent Guarantor			Subsidiary Issuer			Non-Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
	(millions)
OPERATING ACTIVITIES
Net cash (used in) provided by operating activities	$	—		$	(201	)	$	742		$	—		$	541
INVESTING ACTIVITIES:
Intercompany transfers	373			(125		)	—			(248		)	—
Capital expenditures	—			—			(428		)	—			(428		)
Investments in unconsolidated affiliates, net	—			—			(265		)	—			(265		)
Proceeds from sale of assets	—			—			3			—			3
Net cash provided by (used in) investing activities	373			(125		)	(690		)	(248		)	(690		)
FINANCING ACTIVITIES:
Intercompany transfers	—			—			(248		)	248			—
Proceeds from debt	—			3,420			200			—			3,620
Payments of debt	—			(3,225		)	—			—			(3,225		)
Costs incurred to redeem senior notes	—			(18		)	—			—			(18		)
Proceeds from issuance of preferred limited partner units, net of offering costs	155			—			—			—			155
Distributions to preferred limited partners	(25		)	—			—			—			(25		)
Distributions to limited partners and general partner	(503		)	—			—			—			(503		)
Distributions to noncontrolling interests	—			—			(3		)	—			(3		)
Other	—			(6		)	(1		)	—			(7		)
Net cash (used in) provided by financing activities	(373		)	171			(52		)	248			(6		)
Net change in cash and cash equivalents	—			(155		)	—			—			(155		)
Cash and cash equivalents, beginning of period	—			155			1			—			156
Cash and cash equivalents, end of period	$	—		$	—		$	1		$	—		$	1



	Condensed Consolidating Statements of Cash Flows
	Nine Months Ended September 30, 2017
	Parent Guarantor			Subsidiary Issuer			Non-Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
	(millions)
OPERATING ACTIVITIES
Net cash (used in) provided by operating activities	$	—		$	(217	)	$	901		$	—		$	684
INVESTING ACTIVITIES:
Intercompany transfers	390			724			—			(1,114		)	—
Capital expenditures	—			—			(258		)	—			(258		)
Investments in unconsolidated affiliates, net	—			—			(70		)	—			(70		)
Proceeds from sale of assets	—			—			130			—			130
Net cash provided by (used in) investing activities	390			724			(198		)	(1,114		)	(198		)
FINANCING ACTIVITIES:
Intercompany transfers	—			—			(1,114		)	1,114			—
Payments of debt	—			(195		)	—			—			(195		)
Net change in advances to predecessor from DCP Midstream, LLC	—			—			418			—			418
Distributions to limited partners and general partner	(390		)	—			—			—			(390		)
Distributions to noncontrolling interests	—			—			(6		)	—			(6		)
Other	—			(2		)	—			—			(2		)
Net cash used in financing activities	(390		)	(197		)	(702		)	1,114			(175		)
Net change in cash and cash equivalents	—			310			1			—			311
Cash and cash equivalents, beginning of period	—			—			1			—			1
Cash and cash equivalents, end of period	$	—		$	310		$	2		$	—		$	312

- Definition

The entire disclosure for condensed financial information, including the financial position, cash flows, and the results of operations of the registrant (parent company) as of the same dates or for the same periods for which audited consolidated financial statements are being presented. Alternatively, the details of this disclosure can be reported by the specific parent company taxonomy elements, indicating the appropriate date and period contexts in an instance document.

+ References + Details

Subsequent Events	9 Months Ended
Subsequent Events	Sep. 30, 2018
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events On October 4, 2018, we issued 4,000,000 of our Series C Preferred Units representing limited partnership interests at a price of $25 per unit. On October 19, 2018, we issued an additional 400,000 Series C Preferred Units which represented the partial exercise of the underwriters’ option to purchase additional Series C Preferred Units. We used the net proceeds of $106 million from the issuance of the Series C Preferred Units for general partnership purposes including funding capital expenditures and the repayment of outstanding indebtedness under the Credit Agreement. Distributions of the Series C Preferred Units are payable out of available cash, accrue and are cumulative from the date of original issuance of the Series C Preferred Units and are payable quarterly in arrears on January 15th, April 15th, July 15th and October 15th of each year to holders of record as of the close of business on the first business day of the month in which the distribution will be made. The initial distribution rate will be 7.95% per year of the $25 liquidation preference per unit (equal to $1.9875 per unit). On and after October 15, 2023, distributions will accumulate at a percentage of the $25 liquidation preference equal to an annual floating rate of the three-month LIBOR plus a spread of 4.882%. The Series C Preferred Units rank senior to our common units with respect to distribution rights and rights upon liquidation. On October 23, 2018, we announced that the board of directors of the General Partner declared a quarterly distribution on our common units of $0.78 per common unit. The distribution will be paid on November 14, 2018 to unitholders of record on November 2, 2018. On the same date, we announced that the board of directors of the General Partner declared a semi-annual and quarterly distribution on our Series A Preferred Units and B Preferred Units of $36.8750 and $0.4922 per unit, respectively. The distributions will be paid on December 17, 2018 to unitholders of record on December 3, 2018. On the same date, we announced that the board of directors of the General Partner declared an initial quarterly distribution on our Series C Preferred Units of $0.5576 per Series C Preferred Unit, which includes the distribution attributable to the partial-period from and including the original issue date of October 4, 2018. The distribution will be paid on January 15, 2019 to unitholders of record on January 2, 2019.

Description of Business and Basis of Presentation (Policies)	9 Months Ended
	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation and Significant Accounting Policies [Text Block]	The condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America, or GAAP.
Equity Method Investments	Investments in greater than 20% owned affiliates that are not variable interest entities and where we do not have the ability to exercise control, and investments in less than 20% owned affiliates where we have the ability to exercise significant influence, are accounted for using the equity method.

New Accounting Pronouncements New Accounting Pronouncements (Tables)

9 Months Ended

Sep. 30, 2018

Item Effected [Line Items]

Schedule of Cumulative Impact of Prospective Adoption of Accounting Policy [Table Text Block]



	Three Months Ended September 30, 2018						Nine Months Ended September 30, 2018
	As Reported		Effect of Change		Presentation Without Adoption of ASC 606		As Reported		Effect of Change		Presentation Without Adoption of ASC 606
	(millions)
Statement of Operations
Operating revenues
Sales of natural gas, NGLs and condensate	$	2,191	$	41	$	2,232	$	5,784	$	116	$	5,900
Transportation, processing and other	$	133	$	43	$	176	$	371	$	122	$	493

Costs and expenses
Purchases and related costs	$	2,074	$	84	$	2,158	$	5,381	$	238	$	5,619

Net income	$	82	$	—	$	82	$	207	$	—	$	207

Revenue Recognition (Tables)

9 Months Ended

Sep. 30, 2018

Disaggregation of Revenue [Line Items]

Disaggregation of Revenue [Table Text Block]



	Three Months Ended September 30, 2018
	Gathering and Processing			Logistics and Marketing		Eliminations			Total
	(millions)
Sales of natural gas	$	469		$	530	$	(410	)	$	589
Sales of NGLs and condensate (a)	1,053			2,040		(1,000		)	2,093
Transportation, processing and other	118			15		—			133
Trading and marketing losses, net (c)	(61		)	5		—			(56		)
Total operating revenues	$	1,579		$	2,590	$	(1,410	)	$	2,759



	Nine Months Ended September 30, 2018
	Gathering and Processing			Logistics and Marketing			Eliminations			Total
	(millions)
Sales of natural gas	$	1,313		$	1,546		$	(1,182	)	$	1,677
Sales of NGLs and condensate (b)	2,663			5,210			(2,542		)	5,331
Transportation, processing and other	327			45			(1		)	371
Trading and marketing losses, net (c)	(124		)	(40		)	—			(164		)
Total operating revenues	$	4,179		$	6,761		$	(3,725	)	$	7,215

Contract Liabilities (Tables)

9 Months Ended

Sep. 30, 2018

Contract Assets and Liabilities [Abstract]

Contract with Customer, Asset and Liability [Table Text Block]



	September 30,
	2018
	(millions)
Balance, beginning of period	$	—
Cumulative effect of implementation of Topic 606	36
Revenue recognized (a)	(2		)
Balance, end of period	$	34
Current contract liabilities	—
Long-term contract liabilities	$	34

Agreements and Transactions with Affiliates (Tables)

9 Months Ended

Sep. 30, 2018

Schedule of Fees Incurred and Other Fees Paid

The following table summarizes employee related costs that were charged by DCP Midstream, LLC to the Partnership that are included in the condensed consolidated statements of operations:



	Three Months Ended September 30,				Nine Months Ended September 30,
	2018		2017		2018		2017
	(millions)
Employee related costs charged by DCP Midstream, LLC
Operating and maintenance expense	$	54	$	50	$	156	$	149
General and administrative expense	$	51	$	46	$	136	$	116

Summary of Transactions with Affiliates

The following table summarizes our transactions with affiliates:



	Three Months Ended September 30,					Nine Months Ended September 30,
	2018			2017		2018		2017
	(millions)
Phillips 66 (including its affiliates):
Sales of natural gas, NGLs and condensate to affiliates	$	483		$	289	$	1,166	$	814
Purchases and related costs from affiliates	$	57		$	7	$	95	$	22
Operating and maintenance and general administrative expenses	$	4		$	—	$	10	$	1
Enbridge (including its affiliates):
Sales of natural gas, NGLs and condensate to affiliates	$	(13	)	$	14	$	12	$	34
Purchases and related costs from affiliates	$	(2	)	$	12	$	26	$	31
Operating and maintenance and general administrative expenses	$	—		$	1	$	—	$	2
Unconsolidated affiliates:
Sales of natural gas, NGLs and condensate to affiliates	$	21		$	15	$	46	$	37
Transportation, processing, and other to affiliates	$	2		$	1	$	5	$	4
Purchases and related costs from affiliates	$	198		$	126	$	522	$	358

We had balances with affiliates as follows:



	September 30, 2018		December 31, 2017
	(millions)
Phillips 66 (including its affiliates):
Accounts receivable	$	198	$	156
Accounts payable	$	25	$	6
Other assets	$	1	$	—
Enbridge (including its affiliates):
Accounts receivable	$	1	$	11
Accounts payable	$	5	$	9
Unconsolidated affiliates:
Accounts receivable	$	28	$	24
Accounts payable	$	76	$	53
Other assets	$	1	$	4

Inventories (Tables)

9 Months Ended

Sep. 30, 2018

Inventory Disclosure [Abstract]

Schedule of Inventories

Inventories were as follows:



	September 30, 2018		December 31, 2017
	(millions)
Natural gas	$	16	$	30
NGLs	61		38
Total inventories	$	77	$	68

Property, Plant and Equipment (Tables)

9 Months Ended

Sep. 30, 2018

Property, Plant and Equipment [Abstract]

Classification of Property, Plant and Equipment

A summary of property, plant and equipment by classification is as follows:



	Depreciable Life	September 30, 2018			December 31, 2017
		(millions)
Gathering and transmission systems	20 — 50 Years	$	8,737		$	8,473
Processing, storage and terminal facilities	35 — 60 Years	5,317			5,128
Other	3 — 30 Years	564			557
Construction work in progress		382			374
Property, plant and equipment		15,000			14,532
Accumulated depreciation		(5,837		)	(5,549		)
Property, plant and equipment, net		$	9,163		$	8,983

Goodwill (Tables)

9 Months Ended

Sep. 30, 2018

Goodwill [Line Items]

Schedule of Goodwill [Table Text Block]




	September 30, 2018
	(millions)
	Gathering and Processing		Logistics and Marketing		Total
Balance, end of period	$	159	$	72	$	231

Investments in Unconsolidated Affiliates (Tables)

9 Months Ended

Sep. 30, 2018

Equity Method Investments and Joint Ventures [Abstract]

Investments in Unconsolidated Affiliates

The following table summarizes our investments in unconsolidated affiliates:



		Carrying Value as of
	Percentage Ownership	September 30, 2018		December 31, 2017
		(millions)
DCP Sand Hills Pipeline, LLC	66.67%	$	1,774	$	1,633
DCP Southern Hills Pipeline, LLC	66.67%	733		739
Discovery Producer Services LLC	40.00%	350		362
Front Range Pipeline LLC	33.33%	175		165
Texas Express Pipeline LLC	10.00%	92		90
Gulf Coast Express Pipeline LLC	25.00%	89		—
Mont Belvieu Enterprise Fractionator	12.50%	27		23
Panola Pipeline Company, LLC	15.00%	23		24
Mont Belvieu 1 Fractionator	20.00%	10		10
Other	Various	4		4
Total investments in unconsolidated affiliates		$	3,277	$	3,050

Schedule Of Earnings From Investment In Unconsolidated Affiliates [Table Text Block]

Earnings from investments in unconsolidated affiliates were as follows:



	Three Months Ended September 30,					Nine Months Ended September 30,
	2018		2017			2018		2017
	(millions)
DCP Sand Hills Pipeline, LLC	$	64	$	37		$	170	$	105
DCP Southern Hills Pipeline, LLC	21		10			50		34
Discovery Producer Services LLC	1		14			4		59
Front Range Pipeline LLC	6		5			16		12
Texas Express Pipeline LLC	4		4			14		7
Mont Belvieu Enterprise Fractionator	3		3			10		10
Mont Belvieu 1 Fractionator	4		2			12		6
Other	1		(1		)	2		1
Total earnings from unconsolidated affiliates	$	104	$	74		$	278	$	234

Equity Method Investment Summarized Financial Information, Statement of Operations [Table Text Block]

The following tables summarize the combined financial information of our investments in unconsolidated affiliates:



	Three Months Ended September 30,				Nine Months Ended September 30,
	2018		2017		2018		2017
	(millions)
Statements of operations:
Operating revenue	$	407	$	358	$	1,149	$	1,063
Operating expenses	$	157	$	164	$	443	$	464
Net income	$	250	$	194	$	704	$	598

Equity Method Investment Summarized Financial Information Balance Sheet Table [Table Text Block]



	September 30, 2018			December 31, 2017
	(millions)
Balance sheets:
Current assets	$	557		$	244
Long-term assets	5,937			5,319
Current liabilities	(412		)	(196		)
Long-term liabilities	(237		)	(200		)
Net assets	$	5,845		$	5,167

Fair Value Measurement (Tables)

9 Months Ended

Sep. 30, 2018

Fair Value Disclosures [Abstract]

Schedule of Impaired Assets



	Net Carrying Value		Fair Value Measurements Using						Asset Impairments
	Net Carrying Value		Level 1		Level 2		Level 3		Asset Impairments
	(millions)

Property, plant and equipment	$	14	$	—	$	—	$	14	$	26
Intangible assets	11		—		—		11		21
Investment in unconsolidated affiliates	1		—		—		1		1
Total impairments	$	26	$	—	$	—	$	26	$	48

The following table presents the financial instruments carried at fair value as of

Financial Instruments Carried at Fair Value



	September 30, 2018												December 31, 2017
	Level 1			Level 2			Level 3			Total Carrying Value			Level 1			Level 2			Level 3			Total Carrying Value
	(millions)
Current assets:
Commodity derivatives (a)	$	44		$	9		$	4		$	57		$	10		$	17		$	3		$	30
Short-term investments (b)	$	—		$	—		$	—		$	—		$	156		$	—		$	—		$	156
Long-term assets:
Commodity derivatives (c)	$	15		$	2		$	2		$	19		$	1		$	1		$	1		$	3
Current liabilities:
Commodity derivatives (d)	$	(82	)	$	(57	)	$	(18	)	$	(157	)	$	(29	)	$	(34	)	$	(13	)	$	(76	)
Long-term liabilities:
Commodity derivatives (e)	$	(25	)	$	(7	)	$	(5	)	$	(37	)	$	(3	)	$	(11	)	$	(1	)	$	(15	)


(a)	Included in current unrealized gains on derivative instruments in our condensed consolidated balance sheets.


(b)	Includes short-term money market securities included in cash and cash equivalents in our condensed consolidated balance sheets.


(c)	Included in long-term unrealized gains on derivative instruments in our condensed consolidated balance sheets.


(d)	Included in current unrealized losses on derivative instruments in our condensed consolidated balance sheets.


(e)	Included in long-term unrealized losses on derivative instruments in our condensed consolidated balance sheets.

Fair Value Assets and Liabilities Measured On Recurring Basis Unobservable Input Reconciliation



	Commodity Derivative Instruments
	Current Assets			Long-Term Assets			Current Liabilities			Long-Term Liabilities
	(millions)
Three months ended September 30, 2018 (a):
Beginning balance	$	1		$	1		$	(10	)	$	(7	)
Net unrealized gains (losses) included in earnings (b)	4			1			(20		)	2
Transfers out of Level 3 (c)	(1		)	—			5			—
Settlements	—			—			7			—
Ending balance	$	4		$	2		$	(18	)	$	(5	)
Net unrealized gains (losses) on derivatives still held included in earnings (b)	$	3		$	1		$	(15	)	$	2
Three months ended September 30, 2017 (a):
Beginning balance	$	7		$	2		$	(2	)	$	(3	)
Net unrealized gains (losses) included in earnings (b)	—			2			(26		)	—
Transfers out of Level 3 (c)	—			—			2			—
Settlements	—			—			2			—
CME Rule 814 adjustment	(5		)	(3		)	16			1
Ending balance	$	2		$	1		$	(8	)	$	(2	)
Net unrealized gains on derivatives still held included in earnings (b)	$	3		$	2		$	(22	)	$	—



	Commodity Derivative Instruments
	Current Assets			Long-Term Assets			Current Liabilities			Long-Term Liabilities
	(millions)
Nine months ended September 30, 2018 (a):
Beginning balance	$	3		$	1		$	(13	)	$	(1	)
Net unrealized gains (losses) included in earnings (b)	2			1			(28		)	(4		)
Transfers out of Level 3 (c)	(1		)	—			10			—
Settlements	—			—			13			—
Ending balance	$	4		$	2		$	(18	)	$	(5	)
Net unrealized gains (losses) on derivatives still held included in earnings (b)	$	4		$	1		$	(17	)	$	(4	)
Nine months ended September 30, 2017 (a):
Beginning balance	$	9		$	5		$	(23	)	$	—
Net unrealized gains (losses) included in earnings (b)	4			(1		)	(20		)	(3		)
Transfers out of Level 3 (c)	(4		)	—			12			—
Settlements	(2		)	—			7			—
CME Rule 814 adjustment	$	(5	)	$	(3	)	$	16		$	1
Ending balance	$	2		$	1		$	(8	)	$	(2	)
Net unrealized gains (losses) on derivatives still held included in earnings (b)	$	7		$	(1	)	$	(21	)	$	(2	)


(a)	There were no purchases, issuances or sales of derivatives or transfers into Level 3 for the three and nine months ended September 30, 2018 and 2017.


(b)	Represents the amount of unrealized gains or losses for the period, included in trading and marketing gains (losses), net.


(c)	Amounts transferred out of Level 3 are reflected at fair value at the end of the period.

Schedule of Valuation Processes



	September 30, 2018
Product Group	Fair Value			Forward Curve Range
	(millions)
Assets
NGLs	$	4		$0.38-$1.29	Per gallon
Natural gas	$	2		$1.87-$2.43	Per MMBtu
Liabilities
NGLs	$	(22	)	$0.15-$1.29	Per gallon
Natural gas	$	(1	)	$2.37-$2.80	Per MMBtu

Schedule of Carrying Values and Estimated Fair Values of Debt Instruments [Table Text Block]



		September 30, 2018				December 31, 2017
		Carrying Value (a)		Fair Value		Carrying Value (a)		Fair Value
	(millions)

Total debt		$	5,131	$	5,199	$	4,736	$	4,885

(a) Excludes unamortized issuance costs.

Debt (Tables)

9 Months Ended

Sep. 30, 2018

Debt Disclosure [Abstract]

Schedule of Debt



	September 30, 2018			December 31, 2017
	(millions)
Senior notes:
Issued February 2009, interest at 9.750% payable semiannually, due March 2019	$	—		$	450
Issued March 2014, interest at 2.700% payable semi-annually, due April 2019	325			325
Issued March 2010, interest at 5.350% payable semiannually, due March 2020 (a)	600			600
Issued September 2011, interest at 4.750% payable semiannually, due September 2021	500			500
Issued March 2012, interest at 4.950% payable semi-annually, due April 2022	350			350
Issued March 2013, interest at 3.875% payable semi-annually, due March 2023	500			500
Issued July 2018, interest at 5.375% payable semi-annually, due July 2025	500			—
Issued August 2000, interest at 8.125% payable semi-annually, due August 2030 (a)	300			300
Issued October 2006, interest at 6.450% payable semi-annually, due November 2036	300			300
Issued September 2007, interest at 6.750% payable semi-annually, due September 2037	450			450
Issued March 2014, interest at 5.600% payable semi-annually, due April 2044	400			400
Junior subordinated notes:
Issued May 2013, interest at 5.850% payable semi-annually, due May 2043	550			550
Credit agreement:
Revolving credit facility, weighted-average variable interest rate of 3.650%, as of September 30, 2018, due December 2022	145			—
Accounts Receivable Securitization Facility:
Accounts receivable securitization facility, weighted-average variable interest rate of 3.061% as of September 30, 2018, due August 2019	200			—
Fair value adjustments related to interest rate swap fair value hedges (a)	21			23
Unamortized issuance costs	(31		)	(29		)
Unamortized discount	(10		)	(12		)
Total debt	5,100			4,707
Current debt	525			—
Total long-term debt	$	4,575		$	4,707

(a) The swaps associated with this debt were previously terminated. The remaining long-term fair value of approximately

$21 million related to the swaps is being amortized as a reduction to interest expense through 2020 and 2030, the original maturity dates of the debt.

Future Maturities of Long-Term Debt

The maturities of our debt as of September 30, 2018 are as follows:



	Debt Maturities
	(millions)
2018	$	—
2019	525
2020	600
2021	500
2022	495
Thereafter	3,000
Total debt	$	5,120

Risk Management and Hedging Activities (Tables)

9 Months Ended

Sep. 30, 2018

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Summary of Gross and Net Amounts of Derivative Instruments



	September 30, 2018								December 31, 2017
	Gross Amounts of Assets and (Liabilities) Presented in the Balance Sheet			Amounts Not Offset in the Balance Sheet - Financial Instruments		Net Amount			Gross Amounts of Assets and (Liabilities) Presented in the Balance Sheet			Amounts Not Offset in the Balance Sheet - Financial Instruments		Net Amount
	(millions)
Assets:
Commodity derivatives	$	76		$	—	$	76		$	33		$	—	$	33
Liabilities:
Commodity derivatives	$	(194	)	$	—	$	(194	)	$	(91	)	$	—	$	(91	)

Schedule of Designated and Non-Designated Derivative Instruments in Statement of Financial Position, Fair Value

September 30, 2018 and December 31, 2017.



Balance Sheet Line Item	September 30, 2018		December 31, 2017		Balance Sheet Line Item	September 30, 2018			December 31, 2017
	(millions)					(millions)
Derivative Assets Not Designated as Hedging Instruments:					Derivative Liabilities Not Designated as Hedging Instruments:
Commodity derivatives:					Commodity derivatives:
Unrealized gains on derivative instruments — current	$	57	$	30	Unrealized losses on derivative instruments — current	$	(157	)	$	(76	)
Unrealized gains on derivative instruments — long-term	19		3		Unrealized losses on derivative instruments — long-term	(37		)	(15		)
Total	$	76	$	33	Total	$	(194	)	$	(91	)

Schedule of Cash Flow Hedges Included in Accumulated Other Comprehensive Income (Loss) [Table Text Block]

The following summarizes the balance and activity within AOCI relative to our interest rate, commodity and foreign currency cash flow hedges as of and for the three months ended September 30, 2018:



	Interest Rate Cash Flow Hedges			Commodity Cash Flow Hedges			Foreign Currency Cash Flow Hedges (a)		Total
	(millions)
Net deferred (losses) gains in AOCI (beginning balance)	$	(3	)	$	(6	)	$	1	$	(8	)
Losses reclassified from AOCI to earnings — effective portion	—			—			—		—
Net deferred (losses) gains in AOCI (ending balance)	$	(3	)	$	(6	)	$	1	$	(8	)
Deferred losses in AOCI expected to be reclassified into earnings over the next 12 months	$	—		$	—		$	—	$	—

The following summarizes the balance and activity within AOCI relative to our interest rate, commodity and foreign currency cash flow hedges as of and for the nine months ended September 30, 2018:



	Interest Rate Cash Flow Hedges			Commodity Cash Flow Hedges			Foreign Currency Cash Flow Hedges (a)		Total
	(millions)
Net deferred (losses) gains in AOCI (beginning balance)	$	(4	)	$	(6	)	$	1	$	(9	)
Losses reclassified from AOCI to earnings — effective portion	1			—			—		1
Net deferred (losses) gains in AOCI (ending balance)	$	(3	)	$	(6	)	$	1	$	(8	)
Deferred losses in AOCI expected to be reclassified into earnings over the next 12 months	$	(1	)	$	—		$	—	$	(1	)

(a)Relates to Discovery Producer Services LLC ("Discovery"), an unconsolidated affiliate.

The following summarizes the balance and activity within AOCI relative to our interest rate, commodity and foreign currency cash flow hedges as of and for the three months ended September 30, 2017:



	Interest Rate Cash Flow Hedges			Commodity Cash Flow Hedges			Foreign Currency Cash Flow Hedges (a)		Total
	(millions)
Net deferred (losses) gains in AOCI (beginning balance)	$	(4	)	$	(6	)	$	1	$	(9	)
Net deferred (losses) gains in AOCI (ending balance)	$	(4	)	$	(6	)	$	1	$	(9	)

The following summarizes the balance and activity within AOCI relative to our interest rate, commodity and foreign currency cash flow hedges as of and for the nine months ended September 30, 2017:



	Interest Rate Cash Flow Hedges			Commodity Cash Flow Hedges			Foreign Currency Cash Flow Hedges (a)		Total
	(millions)
Net deferred (losses) gains in AOCI (beginning balance)	$	(3	)	$	(6	)	$	1	$	(8	)
Losses reclassified from AOCI to earnings — effective portion	1			—			—		1
Deficit purchase price under carrying value	(2		)	—			—		(2		)
Net deferred (losses) gains in AOCI (ending balance)	$	(4	)	$	(6	)	$	1	$	(9	)


(a)	Relates to Discovery, an unconsolidated affiliate.

Schedule of Changes in Derivative Instruments Not Designated as Hedging Instruments



Commodity Derivatives: Statements of Operations Line Item	Three Months Ended September 30,						Nine Months Ended September 30,
	2018			2017			2018			2017
	(millions)
Realized (losses) gains	$	(43	)	$	16		$	(85	)	$	9
Unrealized (losses) gains	(13		)	(59		)	(79		)	1
Trading and marketing (losses) gains, net	$	(56	)	$	(43	)	$	(164	)	$	10

Schedule of Net Long or Short Positions Expected to be Realized



	September 30, 2018
	Crude Oil		Natural Gas		Natural Gas Liquids		Natural Gas Basis Swaps
Year of Expiration	Net Short Position (Bbls)		Net Short Position (MMBtu)		Net Short Position (Bbls)		Net (Short) Long Position (MMBtu)
2018	(721,000	)	(9,938,000	)	(13,436,719	)	(1,652,500	)
2019	(1,994,000	)	(16,508,750	)	(21,595,027	)	(4,532,500	)
2020	(189,000	)	—		(13,601,378	)	3,660,000
2021	—		—		(5,754,322	)	—

	September 30, 2017
	Crude Oil		Natural Gas		Natural Gas Liquids		Natural Gas Basis Swaps
Year of Expiration	Net Short Position (Bbls)		Net Short Position (MMBtu)		Net (Short) Long Position (Bbls)		Net Long Position (MMBtu)
2017	(81,000	)	(20,888,000	)	(9,288,558	)	2,680,000
2018	(1,803,000	)	(29,277,400	)	(13,417,484	)	9,190,000
2019	(367,000	)	—		(2,353,300	)	9,317,500
2020	(50,000	)	—		238,548		3,660,000

Partnership Equity and Distributions (Tables)

9 Months Ended

Sep. 30, 2018

Equity [Abstract]

Cash Distribution

The following table presents our cash distributions paid in 2018 and 2017:



Payment Date	Per Unit Distribution		Total Cash Distribution
			(millions)
Distributions to common unitholders
August 14, 2018	$	0.7800	$	154
May 15, 2018	$	0.7800	$	155
February 14, 2018	$	0.7800	$	194
November 14, 2017	$	0.7800	$	155
August 14, 2017	$	0.7800	$	134
May 15, 2017	$	0.7800	$	135
February 14, 2017	$	0.7800	$	121

Distributions to Series A Preferred unitholders
June 15, 2018	$	41.9965	$	21

Distributions to Series B Preferred unitholders
September 17, 2018	$	0.6781	$	4

Business Segments (Tables)

9 Months Ended

Sep. 30, 2018

Segment Reporting [Abstract]

Segment Information

Three Months Ended September 30, 2018



	Gathering and Processing			Logistics and Marketing			Other			Eliminations			Total
	(millions)
Total operating revenue	$	1,579		$	2,590		$	—		$	(1,410	)	$	2,759
Gross margin (a)	$	364		$	68		$	—		$	—		$	432
Operating and maintenance expense	(175		)	(14		)	(7		)	—			(196		)
Depreciation and amortization expense	(87		)	(5		)	(6		)	—			(98		)
General and administrative expense	(6		)	(3		)	(61		)	—			(70		)
Other expense	(1		)	—			(1		)	—			(2		)
Loss from financing activities	—			—			(19		)	—			(19		)
Earnings from unconsolidated affiliates	2			102			—			—			104
Interest expense	—			—			(69		)	—			(69		)
Net income (loss)	$	97		$	148		$	(163	)	$	—		$	82
Net income attributable to noncontrolling interests	(1		)	—			—			—			(1		)
Net income (loss) attributable to partners	$	96		$	148		$	(163	)	$	—		$	81
Non-cash derivative mark-to-market (b)	$	(21	)	$	8		$	—		$	—		$	(13	)
Capital expenditures	$	152		$	3		$	5		$	—		$	160
Investments in unconsolidated affiliates, net	$	3		$	136		$	—		$	—		$	139

Three Months Ended September 30, 2017:



	Gathering and Processing			Logistics and Marketing			Other			Eliminations			Total
	(millions)
Total operating revenue	$	1,337		$	1,913		$	—		$	(1,195	)	$	2,055
Gross margin (a)	$	303		$	57		$	—		$	—		$	360
Operating and maintenance expense	(154		)	(9		)	(5		)	—			(168		)
Depreciation and amortization expense	(85		)	(4		)	(5		)	—			(94		)
General and administrative expense	(2		)	(3		)	(64		)	—			(69		)
Asset impairment	(48		)	—			—			—			(48		)
Other (expense) income	—			(1		)	1			—			—
Earnings from unconsolidated affiliates	15			59			—			—			74
Interest expense	—			—			(73		)	—			(73		)
Income tax expense	—			—			(2		)	—			(2		)
Net income (loss)	$	29		$	99		$	(148	)	$	—		$	(20	)
Net income attributable to noncontrolling interests	—			—			—			—			—
Net income (loss) attributable to partners	$	29		$	99		$	(148	)	$	—		$	(20	)
Non-cash derivative mark-to-market (b)	$	(51	)	$	(8	)	$	—		$	—		$	(59	)
Capital expenditures	$	91		$	1		$	7		$	—		$	99
Investments in unconsolidated affiliates, net	$	1		$	28		$	—		$	—		$	29

Nine Months Ended September 30, 2018:



	Gathering and Processing			Logistics and Marketing			Other			Eliminations			Total
	(millions)
Total operating revenue	$	4,179		$	6,761		$	—		$	(3,725	)	$	7,215
Gross margin (a)	$	1,049		$	142		$	—		$	—		$	1,191
Operating and maintenance expense	(492		)	(36		)	(15		)	—			(543		)
Depreciation and amortization expense	(258		)	(11		)	(20		)	—			(289		)
General and administrative expense	(12		)	(9		)	(178		)	—			(199		)
Other expense, net	(4		)	(2		)	(1		)	—			(7		)
Loss from financing activities	—			—			(19		)	—			(19		)
Earnings from unconsolidated affiliates	5			273			—			—			278
Interest expense	—			—			(203		)	—			(203		)
Income tax expense	—			—			(2		)	—			(2		)
Net income (loss)	$	288		$	357		$	(438	)	$	—		$	207
Net income attributable to noncontrolling interests	(3		)	—			—			—			(3		)
Net income (loss) attributable to partners	$	285		$	357		$	(438	)	$	—		$	204
Non-cash derivative mark-to-market (b)	$	(49	)	$	(30	)	$	—		$	—		$	(79	)
Capital expenditures	$	412		$	4		$	12		$	—		$	428
Investments in unconsolidated affiliates, net	$	4		$	261		$	—		$	—		$	265

Nine Months Ended September 30, 2017:



	Gathering and Processing			Logistics and Marketing			Other			Eliminations			Total
	(millions)
Total operating revenue	$	3,965		$	5,596		$	—		$	(3,436	)	$	6,125
Gross margin (a)	$	1,021		$	165		$	—		$	—		$	1,186
Operating and maintenance expense	(469		)	(31		)	(13		)	—			(513		)
Depreciation and amortization expense	(256		)	(11		)	(15		)	—			(282		)
General and administrative expense	(15		)	(8		)	(179		)	—			(202		)
Asset impairment	(48		)	—			—			—			(48		)
Other expense	(3		)	(12		)	—			—			(15		)
Gain on sale of assets, net	34			—			—			—			34
Earnings from unconsolidated affiliates	59			175			—			—			234
Interest expense	—			—			(219		)	—			(219		)
Income tax expense	—			—			(5		)	—			(5		)
Net income (loss)	$	323		$	278		$	(431	)	$	—		$	170
Net income attributable to noncontrolling interests	(1		)	—			—			—			(1		)
Net income (loss) attributable to partners	$	322		$	278		$	(431	)	$	—		$	169
Non-cash derivative mark-to-market (b)	$	(4	)	$	5		$	—		$	—		$	1
Capital expenditures	$	237		$	2		$	19		$	—		$	258
Investments in unconsolidated affiliates, net	$	1		$	69		$	—		$	—		$	70



	September 30,		December 31,
	2018		2017
	(millions)
Segment long-term assets:
Gathering and Processing	$	9,098	$	8,943
Logistics and Marketing	3,584		3,348
Other (c)	277		265
Total long-term assets	12,959		12,556
Current assets	1,526		1,322
Total assets	$	14,485	$	13,878

(a)


(b)	Non-cash commodity derivative mark-to-market is included in gross margin, along with cash settlements for our commodity derivative contracts.


(c)	Other long-term assets not allocable to segments consist of corporate leasehold improvements and other long-term assets.

Supplemental Cash Flow Information (Tables)

9 Months Ended

Sep. 30, 2018

Additional Cash Flow Elements and Supplemental Cash Flow Information [Abstract]

Summary of Supplemental Cash Flow Information



	Nine Months Ended September 30,
	2018		2017
	(millions)
Cash paid for interest:
Cash paid for interest, net of amounts capitalized	$	192	$	218
Cash paid for income taxes, net of income tax refunds	$	3	$	2
Non-cash investing and financing activities:
Property, plant and equipment acquired with accounts payable and accrued liabilities	$	58	$	27
Other non-cash changes in property, plant and equipment	$	—	$	(1	)
Issuance of common and general partner units	$	—	$	1,125
Deficit purchase price	$	—	$	3,094

Condensed Consolidating Financial Information (Tables)

9 Months Ended

Sep. 30, 2018

Condensed Financial Information of Parent Company Only Disclosure [Abstract]

Condensed Consolidating Balance Sheets



	Condensed Consolidating Balance Sheets
	September 30, 2018
	Parent Guarantor		Subsidiary Issuer			Non-Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
	(millions)
ASSETS
Current assets:
Cash and cash equivalents	$	—	$	—		$	1		$	—		$	1
Accounts receivable, net	—		—			1,234			—			1,234
Inventories	—		—			77			—			77
Other	—		—			214			—			214
Total current assets	—		—			1,526			—			1,526
Property, plant and equipment, net	—		—			9,163			—			9,163
Goodwill and intangible assets, net	—		—			330			—			330
Advances receivable — consolidated subsidiaries	2,522		1,739			—			(4,261		)	—
Investments in consolidated subsidiaries	4,724		7,953			—			(12,677		)	—
Investments in unconsolidated affiliates	—		—			3,277			—			3,277
Other long-term assets	—		—			189			—			189
Total assets	$	7,246	$	9,692		$	14,485		$	(16,938	)	$	14,485
LIABILITIES AND EQUITY
Accounts payable and other current liabilities	$	—	$	68		$	1,740		$	—		$	1,808
Current maturities of long-term debt	—		325			200			—			525
Advances payable — consolidated subsidiaries	—		—			4,261			(4,261		)	—
Long-term debt	—		4,575			—			—			4,575
Other long-term liabilities	—		—			301			—			301
Total liabilities	—		4,968			6,502			(4,261		)	7,209
Commitments and contingent liabilities
Equity:
Partners’ equity:
Net equity	7,246		4,727			7,958			(12,677		)	7,254
Accumulated other comprehensive loss	—		(3		)	(5		)	—			(8		)
Total partners’ equity	7,246		4,724			7,953			(12,677		)	7,246
Noncontrolling interests	—		—			30			—			30
Total equity	7,246		4,724			7,983			(12,677		)	7,276
Total liabilities and equity	$	7,246	$	9,692		$	14,485		$	(16,938	)	$	14,485



	Condensed Consolidating Balance Sheets
	December 31, 2017
	Parent Guarantor		Subsidiary Issuer			Non-Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
	(millions)
ASSETS
Current assets:
Cash and cash equivalents	$	—	$	155		$	1		$	—		$	156
Accounts receivable, net	—		—			981			—			981
Inventories	—		—			68			—			68
Other	—		—			117			—			117
Total current assets	—		155			1,167			—			1,322
Property, plant and equipment, net	—		—			8,983			—			8,983
Goodwill and intangible assets, net	—		—			337			—			337
Advances receivable — consolidated subsidiaries	2,895		1,614			—			(4,509		)	—
Investments in consolidated subsidiaries	4,513		7,522			—			(12,035		)	—
Investments in unconsolidated affiliates	—		—			3,050			—			3,050
Other long-term assets	—		—			186			—			186
Total assets	$	7,408	$	9,291		$	13,723		$	(16,544	)	$	13,878
LIABILITIES AND EQUITY
Accounts payable and other current liabilities	$	—	$	71		$	1,417		$	—		$	1,488
Advances payable — consolidated subsidiaries	—		—			4,509			(4,509		)	—
Long-term debt	—		4,707			—			—			4,707
Other long-term liabilities	—		—			245			—			245
Total liabilities	—		4,778			6,171			(4,509		)	6,440
Commitments and contingent liabilities
Equity:
Partners’ equity:
Net equity	7,408		4,517			7,527			(12,035		)	7,417
Accumulated other comprehensive loss	—		(4		)	(5		)	—			(9		)
Total partners’ equity	7,408		4,513			7,522			(12,035		)	7,408
Noncontrolling interests	—		—			30			—			30
Total equity	7,408		4,513			7,552			(12,035		)	7,438
Total liabilities and equity	$	7,408	$	9,291		$	13,723		$	(16,544	)	$	13,878

Condensed Income Statement



	Condensed Consolidating Statement of Operations
	Nine Months Ended September 30, 2018
	Parent Guarantor		Subsidiary Issuer			Non- Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
	(millions)
Operating revenues:
Sales of natural gas, NGLs and condensate	$	—	$	—		$	7,008		$	—		$	7,008
Transportation, processing and other	—		—			371			—			371
Trading and marketing losses, net	—		—			(164		)	—			(164		)
Total operating revenues	—		—			7,215			—			7,215
Operating costs and expenses:
Purchases and related costs	—		—			6,024			—			6,024
Operating and maintenance expense	—		—			543			—			543
Depreciation and amortization expense	—		—			289			—			289
General and administrative expense	—		—			199			—			199
Other expense, net	—		—			7			—			7
Total operating costs and expenses	—		—			7,062			—			7,062
Operating income	—		—			153			—			153
Loss from financing activities	—		(19		)	—			—			(19		)
Interest expense, net	—		(202		)	(1		)	—			(203		)
Income from consolidated subsidiaries	204		425			—			(629		)	—
Earnings from unconsolidated affiliates	—		—			278			—			278
Income before income taxes	204		204			430			(629		)	209
Income tax expense	—		—			(2		)	—			(2		)
Net income	204		204			428			(629		)	207
Net income attributable to noncontrolling interests	—		—			(3		)	—			(3		)
Net income attributable to partners	$	204	$	204		$	425		$	(629	)	$	204



	Condensed Consolidating Statement of Operations
	Nine Months Ended September 30, 2017
	Parent Guarantor		Subsidiary Issuer			Non- Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
	(millions)
Operating revenues:
Sales of natural gas, NGLs and condensate	$	—	$	—		$	5,641		$	—		$	5,641
Transportation, processing and other	—		—			474			—			474
Trading and marketing gains, net	—		—			10			—			10
Total operating revenues	—		—			6,125			—			6,125
Operating costs and expenses:
Purchases and related costs	—		—			4,939			—			4,939
Operating and maintenance expense	—		—			513			—			513
Depreciation and amortization expense	—		—			282			—			282
General and administrative expense	—		—			202			—			202
Asset impairment	—		—			48			—			48
Gain on sale of assets, net	—		—			(34		)	—			(34		)
Other expense, net	—		—			15			—			15
Total operating costs and expenses	—		—			5,965			—			5,965
Operating income	—		—			160			—			160
Interest expense, net	—		(219		)	—			—			(219		)
Income from consolidated subsidiaries	169		388			—			(557		)	—
Earnings from unconsolidated affiliates	—		—			234			—			234
Income before income taxes	169		169			394			(557		)	175
Income tax expense	—		—			(5		)	—			(5		)
Net income	169		169			389			(557		)	170
Net income attributable to noncontrolling interests	—		—			(1		)	—			(1		)
Net income attributable to partners	$	169	$	169		$	388		$	(557	)	$	169

Condensed Statement of Comprehensive Income



	Condensed Consolidating Statement of Comprehensive Income
	Nine Months Ended September 30, 2018
	Parent Guarantor		Subsidiary Issuer		Non-Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
	(millions)
Net income	$	204	$	204	$	428		$	(629	)	$	207
Other comprehensive income:
Reclassification of cash flow hedge losses into earnings	—		1		—			—			1
Other comprehensive income from consolidated subsidiaries	1		—		—			(1		)	—
Total other comprehensive income	1		1		—			(1		)	1
Total comprehensive income	205		205		428			(630		)	208
Total comprehensive income attributable to noncontrolling interests	—		—		(3		)	—			(3		)
Total comprehensive income attributable to partners	$	205	$	205	$	425		$	(630	)	$	205



	Condensed Consolidating Statement of Comprehensive Income
	Nine Months Ended September 30, 2017
	Parent Guarantor		Subsidiary Issuer		Non-Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
	(millions)
Net income	$	169	$	169	$	389		$	(557	)	$	170
Other comprehensive income:
Reclassification of cash flow hedge losses into earnings	—		1		—			—			1
Other comprehensive income from consolidated subsidiaries	1		—		—			(1		)	—
Total other comprehensive income	1		1		—			(1		)	1
Total comprehensive income	170		170		389			(558		)	171
Total comprehensive income attributable to noncontrolling interests	—		—		(1		)	—			(1		)
Total comprehensive income attributable to partners	$	170	$	170	$	388		$	(558	)	$	170

Condensed Consolidating Statements of Cash Flows



	Condensed Consolidating Statement of Cash Flows
	Nine Months Ended September 30, 2018
	Parent Guarantor			Subsidiary Issuer			Non-Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
	(millions)
OPERATING ACTIVITIES
Net cash (used in) provided by operating activities	$	—		$	(201	)	$	742		$	—		$	541
INVESTING ACTIVITIES:
Intercompany transfers	373			(125		)	—			(248		)	—
Capital expenditures	—			—			(428		)	—			(428		)
Investments in unconsolidated affiliates, net	—			—			(265		)	—			(265		)
Proceeds from sale of assets	—			—			3			—			3
Net cash provided by (used in) investing activities	373			(125		)	(690		)	(248		)	(690		)
FINANCING ACTIVITIES:
Intercompany transfers	—			—			(248		)	248			—
Proceeds from debt	—			3,420			200			—			3,620
Payments of debt	—			(3,225		)	—			—			(3,225		)
Costs incurred to redeem senior notes	—			(18		)	—			—			(18		)
Proceeds from issuance of preferred limited partner units, net of offering costs	155			—			—			—			155
Distributions to preferred limited partners	(25		)	—			—			—			(25		)
Distributions to limited partners and general partner	(503		)	—			—			—			(503		)
Distributions to noncontrolling interests	—			—			(3		)	—			(3		)
Other	—			(6		)	(1		)	—			(7		)
Net cash (used in) provided by financing activities	(373		)	171			(52		)	248			(6		)
Net change in cash and cash equivalents	—			(155		)	—			—			(155		)
Cash and cash equivalents, beginning of period	—			155			1			—			156
Cash and cash equivalents, end of period	$	—		$	—		$	1		$	—		$	1



	Condensed Consolidating Statements of Cash Flows
	Nine Months Ended September 30, 2017
	Parent Guarantor			Subsidiary Issuer			Non-Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
	(millions)
OPERATING ACTIVITIES
Net cash (used in) provided by operating activities	$	—		$	(217	)	$	901		$	—		$	684
INVESTING ACTIVITIES:
Intercompany transfers	390			724			—			(1,114		)	—
Capital expenditures	—			—			(258		)	—			(258		)
Investments in unconsolidated affiliates, net	—			—			(70		)	—			(70		)
Proceeds from sale of assets	—			—			130			—			130
Net cash provided by (used in) investing activities	390			724			(198		)	(1,114		)	(198		)
FINANCING ACTIVITIES:
Intercompany transfers	—			—			(1,114		)	1,114			—
Payments of debt	—			(195		)	—			—			(195		)
Net change in advances to predecessor from DCP Midstream, LLC	—			—			418			—			418
Distributions to limited partners and general partner	(390		)	—			—			—			(390		)
Distributions to noncontrolling interests	—			—			(6		)	—			(6		)
Other	—			(2		)	—			—			(2		)
Net cash used in financing activities	(390		)	(197		)	(702		)	1,114			(175		)
Net change in cash and cash equivalents	—			310			1			—			311
Cash and cash equivalents, beginning of period	—			—			1			—			1
Cash and cash equivalents, end of period	$	—		$	310		$	2		$	—		$	312

Description of Business and Basis of Presentation - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2018
Investments in Greater Than 20%
Business Acquisition [Line Items]
Equity method ownership investment (as percent)	20.00%
Investments in Less Than 20%
Business Acquisition [Line Items]
Equity method ownership investment (as percent)	20.00%
DCP Midstream, LLC \| DCP Midstream GP, LLC
Business Acquisition [Line Items]
Ownership interest percentage by parent	100.00%
DCP Midstream, LLC \| DCP Midstream LP
Business Acquisition [Line Items]
Ownership interest percentage by parent	38.10%
Phillips 66 \| DCP Midstream, LLC
Business Acquisition [Line Items]
Ownership interest percentage by parent	50.00%
Enbridge \| DCP Midstream, LLC
Business Acquisition [Line Items]
Ownership interest percentage by parent	50.00%

Revenue Impact of Adoption (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Item Effected [Line Items]
Sales Revenue, Goods, Net	$ 2,682	$ 1,936	$ 7,008	$ 5,641
Transportation, processing and other	133	162	371	474
Purchases and related costs	2,327	1,695	6,024	4,939
Net income	82	(20)	207	170
Third Party
Item Effected [Line Items]
Sales Revenue, Goods, Net	2,191	1,618	5,784	4,756
Purchases and related costs	2,074	$ 1,550	5,381	$ 4,528
Calculated under Revenue Guidance in Effect before Topic 606 [Member]
Item Effected [Line Items]
Transportation, processing and other	43		122
Net income	0		0
Calculated under Revenue Guidance in Effect before Topic 606 [Member] \| Third Party
Item Effected [Line Items]
Sales Revenue, Goods, Net	41		116
Purchases and related costs	84		238
Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
Item Effected [Line Items]
Transportation, processing and other	176		493
Net income	82		207
Difference between Revenue Guidance in Effect before and after Topic 606 [Member] \| Third Party
Item Effected [Line Items]
Sales Revenue, Goods, Net	2,232		5,900
Purchases and related costs	$ 2,158		$ 5,619

Revenue Recognition (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
Revenue Recognition (Details) - USD ($) $ in Millions	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Disaggregation of Revenue [Line Items]
Sales of natural gas, NGLs and condensate	$ 2,682	$ 1,936	$ 7,008	$ 5,641
Transportation, processing and other	133	162	371	474
Trading and marketing (losses) gains, net	(56)	(43)	(164)	10
Total operating revenues	2,759	2,055	7,215	6,125
Revenue from contract with customer not within the scope of Topic 606	1,379		3,280
Natural Gas
Disaggregation of Revenue [Line Items]
Sales of natural gas, NGLs and condensate	589		1,677
NGLs and Condensate [Member]
Disaggregation of Revenue [Line Items]
Sales of natural gas, NGLs and condensate	2,093		5,331
Logistics and Marketing
Disaggregation of Revenue [Line Items]
Transportation, processing and other	15		45
Trading and marketing (losses) gains, net	5		(40)
Total operating revenues	2,590		6,761
Logistics and Marketing \| Natural Gas
Disaggregation of Revenue [Line Items]
Sales of natural gas, NGLs and condensate	530		1,546
Logistics and Marketing \| NGLs and Condensate [Member]
Disaggregation of Revenue [Line Items]
Sales of natural gas, NGLs and condensate	2,040		5,210
Eliminations
Disaggregation of Revenue [Line Items]
Transportation, processing and other	0		(1)
Trading and marketing (losses) gains, net	0		0
Total operating revenues	(1,410)		(3,725)
Eliminations \| Natural Gas
Disaggregation of Revenue [Line Items]
Sales of natural gas, NGLs and condensate	(410)		(1,182)
Eliminations \| NGLs and Condensate [Member]
Disaggregation of Revenue [Line Items]
Sales of natural gas, NGLs and condensate	(1,000)		(2,542)
Gathering and Processing
Disaggregation of Revenue [Line Items]
Transportation, processing and other	118		327
Trading and marketing (losses) gains, net	(61)		(124)
Total operating revenues	1,579		4,179
Gathering and Processing \| Natural Gas
Disaggregation of Revenue [Line Items]
Sales of natural gas, NGLs and condensate	469		1,313
Gathering and Processing \| NGLs and Condensate [Member]
Disaggregation of Revenue [Line Items]
Sales of natural gas, NGLs and condensate	1,053		2,663
Calculated under Revenue Guidance in Effect before Topic 606 [Member]
Disaggregation of Revenue [Line Items]
Transportation, processing and other	43		122
Third Party
Disaggregation of Revenue [Line Items]
Sales of natural gas, NGLs and condensate	2,191	$ 1,618	5,784	$ 4,756
Third Party \| Calculated under Revenue Guidance in Effect before Topic 606 [Member]
Disaggregation of Revenue [Line Items]
Sales of natural gas, NGLs and condensate	$ 41		$ 116

Contract Liabilities (Details) - USD ($) $ in Millions	9 Months Ended
Contract Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2018	Jan. 01, 2018	Dec. 31, 2017
Contract Assets and Liabilities [Abstract]
Contract with Customer, Liability	$ 34		$ 0
Cumulative effect of implementation of Topic 606		$ 36
Contract with Customer, Liability, Revenue Recognized	(2)
Contract with Customer, Liability, Current	0
Contract with Customer, Liability, Noncurrent	$ 34
Revenue, Performance Obligation, Recognition Period in Years	35 years

Agreements and Transactions with Affiliates - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Affiliated Entity \| Natural Gas Liquids
Related Party Transaction [Line Items]
Production Committed To Related Parties, Percent	18.00%		18.00%
Affiliated Entity \| Phillips 66 \| Chevron Phillips Chemical LLC
Related Party Transaction [Line Items]
Equity method ownership investment (as percent)	50.00%		50.00%
Operating Expense
Related Party Transaction [Line Items]
Labor and related expense	$ 54	$ 50	$ 156	$ 149
General and Administrative Expense
Related Party Transaction [Line Items]
Labor and related expense	$ 51	$ 46	$ 136	$ 116

Agreements and Transactions with Affiliates - Transactions with Affiliates (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Related Party Transaction [Line Items]
Sales of natural gas, NGLs and condensate	$ 2,682	$ 1,936	$ 7,008	$ 5,641
Transportation, processing and other	133	162	371	474
Purchases and related costs	2,327	1,695	6,024	4,939
Operating and maintenance expense	196	168	543	513
Affiliated Entity \| Unconsolidated Affiliates
Related Party Transaction [Line Items]
Sales of natural gas, NGLs and condensate	21	15	46	37
Transportation, processing and other	2	1	5	4
Purchases and related costs	198	126	522	358
Affiliated Entity \| Phillips 66
Related Party Transaction [Line Items]
Sales of natural gas, NGLs and condensate	483	289	1,166	814
Purchases and related costs	57	7	95	22
Operating and maintenance expense	4	0	10	1
Affiliated Entity \| Enbridge
Related Party Transaction [Line Items]
Sales of natural gas, NGLs and condensate	(13)	14	12	34
Purchases and related costs	(2)	12	26	31
Operating and maintenance expense	$ 0	$ 1	$ 0	$ 2
Natural Gas Liquids \| Affiliated Entity
Related Party Transaction [Line Items]
Production Committed To Related Parties, Percent	18.00%		18.00%

Agreements and Transactions with Affiliates - Balances with Affiliates (Detail) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Related Party Transaction [Line Items]
Accounts receivable	$ 227	$ 191
Accounts payable	106	68
Unconsolidated Affiliates
Related Party Transaction [Line Items]
Accounts receivable	28	24
Accounts payable	76	53
Other assets	1	4
Phillips 66
Related Party Transaction [Line Items]
Accounts receivable	198	156
Accounts payable	25	6
Other assets	1	0
Enbridge
Related Party Transaction [Line Items]
Accounts receivable	1	11
Accounts payable	$ 5	$ 9

Inventories - Schedule of Inventories (Detail) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Components Of Inventory [Line Items]
Total inventories	$ 77	$ 68
Natural Gas
Components Of Inventory [Line Items]
Total inventories	16	30
Natural Gas Liquids
Components Of Inventory [Line Items]
Total inventories	$ 61	$ 38

Inventories - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Inventory Disclosure [Abstract]
Lower of cost or market adjustment	$ 0	$ 0	$ 0	$ 0

Property, Plant and Equipment - Classification of Property, Plant and Equipment (Detail) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 15,000	$ 14,532
Accumulated depreciation	(5,837)	(5,549)
Property, plant and equipment, net	9,163	8,983
Gathering and transmission systems
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 8,737	8,473
Gathering and transmission systems \| Minimum
Property, Plant and Equipment [Line Items]
Depreciable life of property, plant and equipment	20 years
Gathering and transmission systems \| Maximum
Property, Plant and Equipment [Line Items]
Depreciable life of property, plant and equipment	50 years
Processing, storage and terminal facilities
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 5,317	5,128
Processing, storage and terminal facilities \| Minimum
Property, Plant and Equipment [Line Items]
Depreciable life of property, plant and equipment	35 years
Processing, storage and terminal facilities \| Maximum
Property, Plant and Equipment [Line Items]
Depreciable life of property, plant and equipment	60 years
Other
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 564	557
Other \| Minimum
Property, Plant and Equipment [Line Items]
Depreciable life of property, plant and equipment	3 years
Other \| Maximum
Property, Plant and Equipment [Line Items]
Depreciable life of property, plant and equipment	30 years
Construction work in progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 382	$ 374

Property, Plant and Equipment - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Property, Plant and Equipment [Abstract]
Interest capitalized on construction projects	$ 4	$ 2	$ 15	$ 4
Depreciation expense	$ 95	$ 90	$ 281	$ 272

Goodwill (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Goodwill [Line Items]
Balance, end of period	$ 231	$ 231
Gathering and Processing
Goodwill [Line Items]
Balance, end of period	159
Logistics and Marketing
Goodwill [Line Items]
Balance, end of period	$ 72
Wholesale Propane Logistics [Member]
Goodwill [Line Items]
Reporting Unit, Percentage of Fair Value in Excess of Carrying Amount	10.00%
Balance, end of period	$ 37

Investments In Unconsolidated Affiliates - Investments In Unconsolidated Affiliates (Detail) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Schedule of Equity Method Investments [Line Items]
Investments in unconsolidated affiliates	$ 3,277	$ 3,050
DCP Sand Hills Pipeline, LLC
Schedule of Equity Method Investments [Line Items]
Equity method ownership investment (as percent)	66.67%
Investments in unconsolidated affiliates	$ 1,774	1,633
DCP Southern Hills Pipeline, LLC
Schedule of Equity Method Investments [Line Items]
Equity method ownership investment (as percent)	66.67%
Investments in unconsolidated affiliates	$ 733	739
Discovery Producer Services LLC
Schedule of Equity Method Investments [Line Items]
Equity method ownership investment (as percent)	40.00%
Investments in unconsolidated affiliates	$ 350	362
Front Range Pipeline LLC
Schedule of Equity Method Investments [Line Items]
Equity method ownership investment (as percent)	33.33%
Investments in unconsolidated affiliates	$ 175	165
Texas Express Pipeline LLC
Schedule of Equity Method Investments [Line Items]
Equity method ownership investment (as percent)	10.00%
Investments in unconsolidated affiliates	$ 92	90
Panola Pipeline Company, LLC
Schedule of Equity Method Investments [Line Items]
Equity method ownership investment (as percent)	15.00%
Investments in unconsolidated affiliates	$ 23	24
Mont Belvieu Enterprise Fractionator
Schedule of Equity Method Investments [Line Items]
Equity method ownership investment (as percent)	12.50%
Investments in unconsolidated affiliates	$ 27	23
Gulf Coast Express [Member]
Schedule of Equity Method Investments [Line Items]
Equity method ownership investment (as percent)	25.00%
Investments in unconsolidated affiliates	$ 89	0
Mont Belvieu 1 Fractionator
Schedule of Equity Method Investments [Line Items]
Equity method ownership investment (as percent)	20.00%
Investments in unconsolidated affiliates	$ 10	10
Other
Schedule of Equity Method Investments [Line Items]
Investments in unconsolidated affiliates	$ 4	$ 4

Investments in Unconsolidated Affiliates - Earnings from Investments in Unconsolidated Affiliates (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Schedule of Equity Method Investments [Line Items]
Earnings from unconsolidated affiliates	$ 104	$ 74	$ 278	$ 234
DCP Sand Hills Pipeline, LLC
Schedule of Equity Method Investments [Line Items]
Earnings from unconsolidated affiliates	64	37	170	105
DCP Southern Hills Pipeline, LLC
Schedule of Equity Method Investments [Line Items]
Earnings from unconsolidated affiliates	21	10	50	34
Discovery Producer Services LLC
Schedule of Equity Method Investments [Line Items]
Earnings from unconsolidated affiliates	1	14	4	59
Front Range Pipeline LLC
Schedule of Equity Method Investments [Line Items]
Earnings from unconsolidated affiliates	6	5	16	12
Texas Express Pipeline LLC
Schedule of Equity Method Investments [Line Items]
Earnings from unconsolidated affiliates	4	4	14	7
Mont Belvieu Enterprise Fractionator
Schedule of Equity Method Investments [Line Items]
Earnings from unconsolidated affiliates	3	3	10	10
Mont Belvieu 1 Fractionator
Schedule of Equity Method Investments [Line Items]
Earnings from unconsolidated affiliates	4	2	12	6
Other
Schedule of Equity Method Investments [Line Items]
Earnings from unconsolidated affiliates	$ 1	$ (1)	$ 2	$ 1

Investments in Unconsolidated Affiliates - Equity Method Investment Summarized Financial Information, Statement of Operations (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Equity Method Investments and Joint Ventures [Abstract]
Operating revenue	$ 407	$ 358	$ 1,149	$ 1,063
Operating expenses	157	164	443	464
Net income	$ 250	$ 194	$ 704	$ 598

Investments in Unconsolidated Affiliates - Equity Method Investment Summarized Financial Information, Balance Sheet (Detail) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Equity Method Investments and Joint Ventures [Abstract]
Current assets	$ 557	$ 244
Long-term assets	5,937	5,319
Current liabilities	(412)	(196)
Long-term liabilities	(237)	(200)
Net assets	$ 5,845	$ 5,167

Fair Value Measurement - Financial Instruments Carried at Fair Value (Detail) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Current Assets
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term investments	$ 0	$ 156
Current Assets \| Commodity derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives	57	30
Long- Term Assets \| Commodity derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives	19	3
Current Liabilities \| Commodity derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives	(157)	(76)
Long- Term Liabilities \| Commodity derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives	(37)	(15)
Level 1 \| Current Assets
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term investments	0	156
Level 1 \| Current Assets \| Commodity derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives	44	10
Level 1 \| Long- Term Assets \| Commodity derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives	15	1
Level 1 \| Current Liabilities \| Commodity derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives	(82)	(29)
Level 1 \| Long- Term Liabilities \| Commodity derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives	(25)	(3)
Level 2 \| Current Assets
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term investments	0	0
Level 2 \| Current Assets \| Commodity derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives	9	17
Level 2 \| Long- Term Assets \| Commodity derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives	2	1
Level 2 \| Current Liabilities \| Commodity derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives	(57)	(34)
Level 2 \| Long- Term Liabilities \| Commodity derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives	(7)	(11)
Level 3 \| Current Assets
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term investments	0	0
Level 3 \| Current Assets \| Commodity derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives	4	3
Level 3 \| Long- Term Assets \| Commodity derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives	2	1
Level 3 \| Current Liabilities \| Commodity derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives	(18)	(13)
Level 3 \| Long- Term Liabilities \| Commodity derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives	$ (5)	$ 1

Fair Value Measurement - Condensed Consolidated Balance Sheets for Derivative Financial Instruments (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Current Assets
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 1	$ 7	$ 3	$ 9
Net realized and unrealized gains (losses) included in earnings	4	0	2	4
Transfers out of Level 3	(1)	0	(1)	(4)
Settlements	0	0	0	(2)
Ending balance	4	2	4	2
Net unrealized gains (losses) on derivatives still held included in earnings	3	3	4	7
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Assets, CME Rule 814 adjustments		(5)		(5)
Long- Term Assets
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	1	2	1	5
Net realized and unrealized gains (losses) included in earnings	1	2	1	(1)
Transfers out of Level 3	0	0	0	0
Settlements	0	0	0	0
Ending balance	2	1	2	1
Net unrealized gains (losses) on derivatives still held included in earnings	1	2	1	(1)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Assets, CME Rule 814 adjustments		(3)		(3)
Current Liabilities
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	(10)	(2)	(13)	(23)
Net realized and unrealized (losses) gains included in earnings	(20)	(26)	(28)	(20)
Transfers out of Level 3	5	2	10	12
Settlements	7	2	13	7
Ending balance	(18)	(8)	(18)	(8)
Net unrealized gains (losses) on derivatives still held included in earnings	(15)	(22)	(17)	(21)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liabilities, CME Rule 814 adjustments		(16)		(16)
Long- Term Liabilities
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	(7)	(3)	(1)	0
Net realized and unrealized (losses) gains included in earnings	2	0	(4)	(3)
Transfers out of Level 3	0	0	0	0
Settlements	0	0	0	0
Ending balance	(5)	(2)	(5)	(2)
Net unrealized gains (losses) on derivatives still held included in earnings	$ 2	0	$ (4)	(2)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liabilities, CME Rule 814 adjustments		$ (1)		$ (1)

Fair Value Measurement Schedule of Valuation Processes (Detail) - Level 3 - Market Approach Valuation Technique $ in Millions	Sep. 30, 2018 USD ($) $ / gal
Derivative Liabilities \| Natural Gas Liquids
Fair Value Inputs Assets And Liabilities Quantitative Information [Line Items]
Liabilities, fair value \| $	$ (22)
Derivative Liabilities \| Natural Gas Liquids \| Minimum
Fair Value Inputs Assets And Liabilities Quantitative Information [Line Items]
Forward Curve Range	0.15
Derivative Liabilities \| Natural Gas Liquids \| Maximum
Fair Value Inputs Assets And Liabilities Quantitative Information [Line Items]
Forward Curve Range	1.29
Derivative Liabilities \| Natural Gas
Fair Value Inputs Assets And Liabilities Quantitative Information [Line Items]
Liabilities, fair value \| $	$ (1)
Derivative Liabilities \| Natural Gas \| Minimum
Fair Value Inputs Assets And Liabilities Quantitative Information [Line Items]
Forward Curve Range	2.37
Derivative Liabilities \| Natural Gas \| Maximum
Fair Value Inputs Assets And Liabilities Quantitative Information [Line Items]
Forward Curve Range	2.80
Derivative Assets \| Natural Gas Liquids
Fair Value Inputs Assets And Liabilities Quantitative Information [Line Items]
Assets, fair value \| $	$ 4
Derivative Assets \| Natural Gas Liquids \| Minimum
Fair Value Inputs Assets And Liabilities Quantitative Information [Line Items]
Forward Curve Range	0.38
Derivative Assets \| Natural Gas Liquids \| Maximum
Fair Value Inputs Assets And Liabilities Quantitative Information [Line Items]
Forward Curve Range	1.29
Derivative Assets \| Natural Gas
Fair Value Inputs Assets And Liabilities Quantitative Information [Line Items]
Assets, fair value \| $	$ 2
Derivative Assets \| Natural Gas \| Minimum
Fair Value Inputs Assets And Liabilities Quantitative Information [Line Items]
Forward Curve Range	1.87
Derivative Assets \| Natural Gas \| Maximum
Fair Value Inputs Assets And Liabilities Quantitative Information [Line Items]
Forward Curve Range	2.43

Fair Value Measurement Carrying Value and Fair Value of Debt (Detail) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Total Debt, Carrying Value	$ 5,131	$ 4,736
Total Debt, Fair Value	$ 5,199	$ 4,885

Fair Value Measurement Schedule of Assets Measured at Fair Value (Details) - Fair Value, Measurements, Nonrecurring [Member] $ in Millions	9 Months Ended
	Sep. 30, 2017 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in Affiliates, Subsidiaries, Associates, and Joint Ventures, Fair Value Disclosure	$ 1
Indefinite-lived Intangible Assets (Excluding Goodwill), Fair Value Disclosure	11
Property, Plant, and Equipment, Fair Value Disclosure	14
Asset Impairments	48
Assets, Fair Value Disclosure, Nonrecurring	26
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in Affiliates, Subsidiaries, Associates, and Joint Ventures, Fair Value Disclosure	0
Indefinite-lived Intangible Assets (Excluding Goodwill), Fair Value Disclosure	0
Property, Plant, and Equipment, Fair Value Disclosure	0
Assets, Fair Value Disclosure, Nonrecurring	0
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in Affiliates, Subsidiaries, Associates, and Joint Ventures, Fair Value Disclosure	0
Indefinite-lived Intangible Assets (Excluding Goodwill), Fair Value Disclosure	0
Property, Plant, and Equipment, Fair Value Disclosure	0
Assets, Fair Value Disclosure, Nonrecurring	0
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in Affiliates, Subsidiaries, Associates, and Joint Ventures, Fair Value Disclosure	1
Indefinite-lived Intangible Assets (Excluding Goodwill), Fair Value Disclosure	11
Property, Plant, and Equipment, Fair Value Disclosure	14
Assets, Fair Value Disclosure, Nonrecurring	26
Property, Plant and Equipment [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset Impairments	26
Intangible Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset Impairments	21
Investment in unconsolidated affiliate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset Impairments	$ 1

Debt - Schedule of Debt (Detail) - USD ($) $ in Millions	Sep. 30, 2018	Aug. 01, 2018	Dec. 31, 2017
Facility [Line Items]
Fair value adjustments related to interest rate swap fair value hedges	$ 21		$ 23
Unamortized issuance costs	(31)		(29)
Unamortized discount	(10)		(12)
Total debt	5,100		4,707
Current debt	525		0
Long-term debt	4,575		4,707
Credit Agreement
Facility [Line Items]
Credit Facility	$ 145		0
Weighted-average variable interest rate	3.452%
Line of Credit Facility, Maximum Borrowing Capacity	$ 1,400
Accounts Receivable Securitization Facility
Facility [Line Items]
Accounts Receivable Securitization Agreement	$ 200		0
Weighted-average variable interest rate	3.061%
Line of Credit Facility, Maximum Borrowing Capacity	$ 200
Accounts Recievable included in the Securitization Transaction	$ 838
Senior Notes \| Issued November 2012, interest at 2.500% payable semi-annually, due December 2017
Facility [Line Items]
Debt interest rate percentage	2.50%
Senior Notes \| Senior Notes Issued February 2009, interest at 9.750% payable semiannually, due March 2019
Facility [Line Items]
Senior Notes	$ 0	$ 450	450
Debt interest rate percentage	9.75%	9.75%
Senior Notes \| Issued March 2014, interest at 2.700% payable semi-annually, due April 2019
Facility [Line Items]
Senior Notes	$ 325		325
Debt interest rate percentage	2.70%
Senior Notes \| Issued March 2010, interest at 5.350% payable semiannually, due March 2020
Facility [Line Items]
Senior Notes	$ 600		600
Debt interest rate percentage	5.35%
Senior Notes \| Issued September 2011, interest at 4.750% payable semiannually, due September 2021
Facility [Line Items]
Senior Notes	$ 500		500
Debt interest rate percentage	4.75%
Senior Notes \| Issued March 2012, interest at 4.950% payable semi-annually, due April 2022
Facility [Line Items]
Senior Notes	$ 350		350
Debt interest rate percentage	4.95%
Senior Notes \| Issued March 2013, interest at 3.875% payable semi-annually, due March 2023
Facility [Line Items]
Senior Notes	$ 500		500
Debt interest rate percentage	3.875%
Senior Notes \| Issued July 2018, interest at 5.375% payable semi-annually, due July 2025
Facility [Line Items]
Senior Notes	$ 500		0
Debt interest rate percentage	5.375%
Senior Notes \| Issued August 2000, interest at 8.125% payable semi-annually, due August 2030
Facility [Line Items]
Senior Notes	$ 300		300
Debt interest rate percentage	8.125%
Senior Notes \| Issued October 2006, interest at 6.450% payable semi-annually, due November 2036
Facility [Line Items]
Senior Notes	$ 300		300
Debt interest rate percentage	6.45%
Senior Notes \| Issued September 2007, interest at 6.750% payable semi-annually, due September 2037
Facility [Line Items]
Senior Notes	$ 450		450
Debt interest rate percentage	6.75%
Senior Notes \| Issued March 2014, interest at 5.600% payable semi-annually, due April 2044
Facility [Line Items]
Senior Notes	$ 400		400
Debt interest rate percentage	5.60%
Junior subordinated notes \| Issued May 2013, interest at 5.850% payable semi-annually, due May 2043
Facility [Line Items]
Senior Notes	$ 550		$ 550
Debt interest rate percentage	5.85%

Debt - Additional Information (Detail) $ in Millions			3 Months Ended		9 Months Ended
Debt - Additional Information (Detail) $ in Millions	Aug. 01, 2018 USD ($)	Jul. 17, 2018 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Dec. 31, 2017 USD ($)
Debt Instrument [Line Items]
Loss on Redemption of Debt			$ (19)	$ 0	$ (19)	$ 0
Line of Credit Facility, Borrowing Capacity, Description			500		$ 500
Interest deferment period					5 years
Accounts Receivable Securitization Facility
Debt Instrument [Line Items]
Accounts Recievable included in the Securitization Transaction			838		$ 838
Line of Credit Facility, Maximum Borrowing Capacity			200		200
Credit Agreement
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity			1,400		$ 1,400
Basis spread determined by credit rating					0.45%
Commitment fee percentage					0.30%
Unused capacity under the credit agreement			1,242		$ 1,242
Letter of credit amount outstanding			13		13
Debt covenants, maximum borrowing amount			1,242		$ 1,242
Credit Agreement \| LIBOR
Debt Instrument [Line Items]
Variable rate basis spread					1.45%
Credit Agreement \| Federal Funds Rate
Debt Instrument [Line Items]
Variable rate basis spread					0.50%
Credit Agreement \| LIBOR Market Index
Debt Instrument [Line Items]
Variable rate basis spread					1.00%
Credit Agreement \| Maximum
Debt Instrument [Line Items]
Maximum leverage ratio in event of acquisition							5.50
Credit Agreement \| Quarters After June 30, 2018 \| Maximum
Debt Instrument [Line Items]
Maximum leverage ratio							5.00
Senior Notes Issued February 2009, interest at 9.750% payable semiannually, due March 2019 \| Senior Notes
Debt Instrument [Line Items]
Debt Instrument, Face Amount	$ 450		$ 0		$ 0		$ 450
Gross Redemption Payment	$ 468
Debt Instrument, Redemption Price, Percentage	104.00831%
Loss on Redemption of Debt	$ (19)
Debt Instrument, Interest Rate, Stated Percentage	9.75%		9.75%		9.75%
Senior Notes Issued July 2018, interest at 5.375% payable semiannually, due July 2025 \| Senior Notes
Debt Instrument [Line Items]
Debt Instrument, Face Amount		$ 500
Debt Instrument, Interest Rate, Stated Percentage		5.375%
Proceeds from Issuance of Senior Long-term Debt		$ 495

Debt - Future Maturities of Long-Term Debt (Detail) $ in Millions	Sep. 30, 2018 USD ($)
Maturities of Long-term Debt [Abstract]
2018	$ 0
2019	525
2020	600
2021	500
2022	495
Thereafter	3,000
Total debt	$ 5,120

Risk Management and Hedging Activities - Additional Information (Detail) - USD ($) $ in Millions	Sep. 30, 2018	Jun. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2016
Derivative [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	$ (8)		$ (9)
Collateral, cash deposits	140
Collateral, cash held	3
Letters of credit received	73
Commodity derivatives
Derivative [Line Items]
Derivative contracts that contain credit-risk related contingent features that were in a net liability position (less than)	$ 1
Affiliated Entity \| Natural Gas Liquids
Derivative [Line Items]
Percent of NGL production committed	18.00%
Accumulated Net Gain (Loss) from Cash Flow Hedges
Derivative [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	$ (8)	$ (8)	(9)	$ (9)	$ (9)	$ (8)
Accumulated Net Gain (Loss) from Cash Flow Hedges \| Commodity derivatives
Derivative [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	$ (6)	$ (6)	$ (6)	$ (6)	$ (6)	$ (6)

Risk Management and Hedging Activities - Summary of Gross and Net Amounts of Derivative Instruments (Detail) - Commodity derivatives - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Offsetting Assets [Line Items]
Gross Amounts of Assets Presented in the Balance Sheet	$ 76	$ 33
Amounts Not Offset in the Balance Sheet - Financial Instruments	0	0
Net Amount	76	33
Offsetting Liabilities [Line Items]
Gross Amounts of Liabilities Presented in the Balance Sheet	(194)	(91)
Amounts Not Offset in the Balance Sheet - Financial Instruments	0	0
Net Amount	$ (194)	$ (91)

Risk Management and Hedging Activities - Schedule of Designated and Non-Designated Derivative Instruments in Statement of Financial Position, Fair Value (Detail) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Derivative Asset [Abstract]
Derivative Instruments and Hedges, Current Assets	$ 57	$ 30
Derivative Instruments and Hedges, Assets, Noncurrent	19	3
Derivative Liability [Abstract]
Derivative Instruments and Hedges, Current Liabilities	157	76
Derivative Instruments and Hedges, Liabilities, Noncurrent	37	15
Commodity derivatives \| Derivative Asset Not Designated As Hedging Instruments [Member]
Derivative Asset [Abstract]
Derivative Instruments and Hedges, Current Assets	57	30
Derivative Instruments and Hedges, Assets, Noncurrent	19	3
Derivative Instruments Not Designated as Hedging Instruments, Total Assets, at Fair Value	76	33
Commodity derivatives \| Derivative Liabilities Not Designated As Hedging Instruments [Member]
Derivative Liability [Abstract]
Derivative Instruments and Hedges, Current Liabilities	157	76
Derivative Instruments and Hedges, Liabilities, Noncurrent	37	15
Derivative Instruments Not Designated as Hedging Instruments, Total Liabilities, at Fair Value	$ 194	$ 91

Risk Management and Hedging Activities - Schedule of Cash Flow Hedges Included in Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2018	Sep. 30, 2017	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017	Dec. 31, 2016
Derivative [Line Items]
Accumulated other comprehensive loss	$ (8)	$ (8)			$ (9)
Accumulated Net Gain (Loss) from Cash Flow Hedges
Derivative [Line Items]
Accumulated other comprehensive loss	(8)	(8)	$ (9)	$ (8)	(9)	$ (9)	$ (8)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0	1
Accumulated Net Gain (Loss) from Cash Flow Hedges \| Interest Rate Derivatives
Derivative [Line Items]
Accumulated other comprehensive loss	(3)	(3)	(4)	(3)	(4)	(4)	(3)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0	1
Accumulated Net Gain (Loss) from Cash Flow Hedges \| Commodity derivatives
Derivative [Line Items]
Accumulated other comprehensive loss	(6)	(6)	(6)	(6)	(6)	(6)	(6)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0	0
Accumulated Net Gain (Loss) from Cash Flow Hedges \| Foreign Currency Derivatives
Derivative [Line Items]
Accumulated other comprehensive loss	1	1	1	$ 1	$ 1	$ 1	$ 1
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0	0
Cash Flow Hedging [Member]
Derivative [Line Items]
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months	0	(1)
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net			1
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net			(2)
Cash Flow Hedging [Member] \| Interest Rate Derivatives
Derivative [Line Items]
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months	0	(1)
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net			1
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net			(2)
Cash Flow Hedging [Member] \| Commodity derivatives
Derivative [Line Items]
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months	0	0
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net			0
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net			0
Cash Flow Hedging [Member] \| Foreign Currency Derivatives
Derivative [Line Items]
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months	$ 0	$ 0
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net			0
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net			$ 0

Risk Management and Hedging Activities - Schedule of Changes in Derivative Instruments not Designated as Hedging Instruments (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Derivative [Line Items]
Trading and marketing gains, net	$ (56)	$ (43)	$ (164)	$ 10
Derivative Assets Not Designated As Hedging Instruments \| Third Party \| Commodity derivatives
Derivative [Line Items]
Realized (losses) gains	(43)	16	(85)	9
Unrealized (losses) gains	(13)	(59)	(79)	1
Trading and marketing gains, net	$ (56)	$ (43)	$ (164)	$ 10

Risk Management and Hedging Activities - Schedule of Net Long or Short Positions Expected to be Realized (Detail)	9 Months Ended
	Sep. 30, 2018 MMBTU bbl	Sep. 30, 2017 MMBTU bbl
Crude Oil
Net (Short) Position, Volume [Abstract]
Net (Short) Position (Bbls), Year One \| bbl	(721,000)	(81,000)
Net (Short) Position (Bbls), Year Two \| bbl	(1,994,000)	(1,803,000)
Net (Short) Position (Bbls), Year Three \| bbl	(189,000)	(367,000)
Net (Short) Position (Bbls), Year Four \| bbl	0	(50,000)
Natural Gas
Net Long (Short) Position, MMBtu [Abstract]
Net Long (Short) Position (MMBtu), Year One \| MMBTU	(9,938,000)	(20,888,000)
Net Long (Short) Position (MMBtu), Year Two \| MMBTU	(16,508,750)	(29,277,400)
Net Long (Short) Position (MMBtu), Year Three \| MMBTU	0	0
Net Long (Short) Position (MMBtu), Year Four \| MMBTU	0	0
Natural Gas Liquids
Net (Short) Position, Volume [Abstract]
Net (Short) Position (Bbls), Year One \| bbl	(13,436,719)	(9,288,558)
Net (Short) Position (Bbls), Year Two \| bbl	(21,595,027)	(13,417,484)
Net (Short) Position (Bbls), Year Three \| bbl	(13,601,378)	(2,353,300)
Net (Short) Position (Bbls), Year Four \| bbl	(5,754,322)	238,548
Natural Gas Basis Swaps
Net Long (Short) Position, MMBtu [Abstract]
Net Long (Short) Position (MMBtu), Year One \| MMBTU	(1,652,500)	2,680,000
Net Long (Short) Position (MMBtu), Year Two \| MMBTU	(4,532,500)	9,190,000
Net Long (Short) Position (MMBtu), Year Three \| MMBTU	3,660,000	9,317,500
Net Long (Short) Position (MMBtu), Year Four \| MMBTU	0	3,660,000

Partnership Equity and Distributions - Additional Information (Detail) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Partnership Equity And Distribution [Line Items]
Common unitholders, units issued (in shares)	143,317,328	143,309,828
2014 Equity Distribution Agreement
Partnership Equity And Distribution [Line Items]
Common unitholders, units issued (in shares)	0
Equity Distribution Agreement [Member]
Partnership Equity And Distribution [Line Items]
Offer Value Of Common Stock Unit Remaining Available For Sale	$ 750

Partnership Equity and Distributions - Cash Distribution (Detail) - USD ($)										9 Months Ended
	Sep. 17, 2018	Aug. 14, 2018	Jun. 15, 2018	May 15, 2018	Feb. 14, 2018	Nov. 14, 2017	Aug. 14, 2017	May 15, 2017	Feb. 14, 2017	Sep. 30, 2018	Sep. 30, 2017
Distribution Made to Limited Partner [Line Items]
Per Unit Distribution (in dollars per share)								$ 0.78	$ 0.78
Total Cash Distribution								$ 135,000,000	$ 121,000,000	$ 528,000,000	$ 390,000,000
Limited Partners
Distribution Made to Limited Partner [Line Items]
Per Unit Distribution (in dollars per share)		$ 0.78		$ 0.78	$ 0.78	$ 0.78	$ 0.78
Total Cash Distribution		$ 154,000,000		$ 155,000,000	$ 194,000,000	$ 155,000,000	$ 134,000,000			335,000,000	$ 313,000,000
Series A Preferred Limited Partners [Member]
Distribution Made to Limited Partner [Line Items]
Total Cash Distribution			$ 21,000,000							(21,000,000)
Preferred Limited Partnership Distribution; Distribution Amount Paid			$ 41.9965
Series B Preferred Limited Partners [Member]
Distribution Made to Limited Partner [Line Items]
Total Cash Distribution	$ 4,000,000									$ (4,000,000)
Preferred Limited Partnership Distribution; Distribution Amount Paid	$ 0.6781

Partnership Equity and Distributions Partnership Equity and Distributions Preferred Series B Distributions (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Preferred Units [Line Items]
Proceeds from Issuance of Preferred Limited Partners Units	$ 155	$ 0
Series B Preferred Limited Partners [Member]
Preferred Units [Line Items]
Preferred Units, Issued	6,450,000		0
Proceeds from Issuance of Preferred Limited Partners Units	$ 155

Commitments and Contingent Liabilities Commitments and Contingent Liabilities (Details)	9 Months Ended
	Sep. 30, 2018 USD ($)
Amount Paid for Administrative Penalty [Member]
Other Commitments [Line Items]
Litigation Settlement, Expense	$ 46,200
Amount Paid to Fund Supplemental Environmental Projects [Member]
Other Commitments [Line Items]
Litigation Settlement, Expense	$ 184,800

Business Segments - Segment Information (Detail) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2018 USD ($) Segment	Sep. 30, 2017 USD ($)
Segment Reporting [Abstract]
Number of reportable segments \| Segment			2
Segment Reporting Information [Line Items]
Total operating revenues	$ 2,759	$ 2,055	$ 7,215	$ 6,125
Gross margin	432	360	1,191	1,186
Operating and maintenance expense	(196)	(168)	(543)	(513)
Depreciation and amortization expense	(98)	(94)	(289)	(282)
General and administrative expense	(70)	(69)	(199)	(202)
Asset impairments		(48)	0	(48)
Other income (expense)	(2)	0	(7)	(15)
Loss from financing activities	(19)	0	(19)	0
Gain on sale of assets, net	0	0	0	34
Earnings from unconsolidated affiliates	104	74	278	234
Interest expense, net	(69)	(73)	(203)	(219)
Income tax expense	0	(2)	(2)	(5)
Net income (loss)	82	(20)	207	170
Net income attributable to noncontrolling interests	(1)	0	(3)	(1)
Net income (loss) attributable to partners	81	(20)	204	169
Non-cash derivative mark-to-market	(13)	(59)	(79)	1
Non-cash lower of cost or market adjustment	0	0	0	0
Capital expenditures	160	99	428	258
Investments in unconsolidated affiliates, net	139	29	265	70
Gathering and Processing
Segment Reporting Information [Line Items]
Total operating revenues	1,579		4,179
Logistics and Marketing
Segment Reporting Information [Line Items]
Total operating revenues	2,590		6,761
Operating Segments \| Gathering and Processing
Segment Reporting Information [Line Items]
Total operating revenues	1,579	1,337	4,179	3,965
Gross margin	364	303	1,049	1,021
Operating and maintenance expense	(175)	(154)	(492)	(469)
Depreciation and amortization expense	(87)	(85)	(258)	(256)
General and administrative expense	(6)	(2)	(12)	(15)
Asset impairments		(48)		(48)
Other income (expense)	(1)	0	(4)	(3)
Loss from financing activities	0		0
Gain on sale of assets, net				34
Earnings from unconsolidated affiliates	2	15	5	59
Interest expense, net	0	0	0	0
Income tax expense		0	0	0
Net income (loss)	97	29	288	323
Net income attributable to noncontrolling interests	(1)	0	(3)	(1)
Net income (loss) attributable to partners	96	29	285	322
Non-cash derivative mark-to-market	(21)	(51)	(49)	(4)
Capital expenditures	152	91	412	237
Investments in unconsolidated affiliates, net	3	1	4	1
Operating Segments \| Logistics and Marketing
Segment Reporting Information [Line Items]
Total operating revenues	2,590	1,913	6,761	5,596
Gross margin	68	57	142	165
Operating and maintenance expense	(14)	(9)	(36)	(31)
Depreciation and amortization expense	(5)	(4)	(11)	(11)
General and administrative expense	(3)	(3)	(9)	(8)
Asset impairments		0		0
Other income (expense)	0	(1)	(2)	(12)
Loss from financing activities	0		0
Gain on sale of assets, net				0
Earnings from unconsolidated affiliates	102	59	273	175
Interest expense, net	0	0	0	0
Income tax expense		0	0	0
Net income (loss)	148	99	357	278
Net income attributable to noncontrolling interests	0	0	0	0
Net income (loss) attributable to partners	148	99	357	278
Non-cash derivative mark-to-market	8	(8)	(30)	5
Capital expenditures	3	1	4	2
Investments in unconsolidated affiliates, net	136	28	261	69
Other
Segment Reporting Information [Line Items]
Total operating revenues	0	0	0	0
Gross margin	0	0	0	0
Operating and maintenance expense	(7)	(5)	(15)	(13)
Depreciation and amortization expense	(6)	(5)	(20)	(15)
General and administrative expense	(61)	(64)	(178)	(179)
Asset impairments		0		0
Other income (expense)	(1)	1	(1)	0
Loss from financing activities	(19)		(19)
Gain on sale of assets, net				0
Earnings from unconsolidated affiliates	0	0	0	0
Interest expense, net	(69)	(73)	(203)	(219)
Income tax expense		(2)	(2)	(5)
Net income (loss)	(163)	(148)	(438)	(431)
Net income attributable to noncontrolling interests	0	0	0	0
Net income (loss) attributable to partners	(163)	(148)	(438)	(431)
Non-cash derivative mark-to-market	0	0	0	0
Capital expenditures	5	7	12	19
Investments in unconsolidated affiliates, net	0	0	0	0
Eliminations
Segment Reporting Information [Line Items]
Total operating revenues	(1,410)	(1,195)	(3,725)	(3,436)
Gross margin	0	0	0	0
Operating and maintenance expense	0	0		0
Depreciation and amortization expense	0	0	0	0
General and administrative expense	0	0	0	0
Asset impairments		0		0
Other income (expense)	0	0		0
Loss from financing activities	0		0
Gain on sale of assets, net			0	0
Earnings from unconsolidated affiliates	0	0	0	0
Interest expense, net	0	0	0	0
Income tax expense		0	0	0
Net income (loss)	0	0	0	0
Net income attributable to noncontrolling interests	0	0	0	0
Net income (loss) attributable to partners	0	0	0	0
Non-cash derivative mark-to-market	0	0		0
Non-cash lower of cost or market adjustment			0
Capital expenditures	0	0	0	0
Investments in unconsolidated affiliates, net	$ 0	$ 0	$ 0	$ 0

Business Segments - Segment Assets (Detail) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Segment Reporting, Asset Reconciling Item [Line Items]
Segment long-term assets	$ 12,959	$ 12,556
Current assets	1,526	1,322
Total assets	14,485	13,878
Operating Segments \| Gathering and Processing
Segment Reporting, Asset Reconciling Item [Line Items]
Segment long-term assets	9,098	8,943
Operating Segments \| Logistics and Marketing
Segment Reporting, Asset Reconciling Item [Line Items]
Segment long-term assets	3,584	3,348
Other
Segment Reporting, Asset Reconciling Item [Line Items]
Segment long-term assets	$ 277	$ 265

- Definition

Sum of the carrying amounts as of the balance sheet date of all assets that are expected to be realized in cash, sold or consumed after one year or beyond the normal operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(14))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(10))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(12))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(15))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(11))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(13))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(17))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(16))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Supplemental Cash Flow Information - Summary of Supplemental Cash Flow Information (Detail) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Supplemental Cash Flow Information [Abstract]
Cash paid for interest, net of amounts capitalized	$ 192	$ 218
Income Taxes Paid, Net	3	2
Noncash Investing and Financing Items [Abstract]
Property, plant and equipment acquired with accounts payable and accrued liabilities	58	27
Property, Plant and Equipment, Other Increase (Decrease)	0	(1)
Stock Issued	0	1,125
Non Cash Excess Purchase Price	$ 0	$ 3,094

Condensed Consolidating Financial Information - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2018
Parent Guarantor
Condensed Financial Statements, Captions [Line Items]
Ownership interest percentage in subsidiary	100.00%

Condensed Consolidating Financial Information - Condensed Consolidating Balance Sheets (Detail) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2016
ASSETS
Cash and cash equivalents	$ 1	$ 156	$ 312	$ 1
Accounts receivable, net	1,234	981
Inventories	77	68
Other	214	117
Total current assets	1,526	1,322
Property, plant and equipment, net	9,163	8,983
Goodwill and intangible assets, net	330	337
Advances receivable — consolidated subsidiaries	0	0
Investments in unconsolidated affiliates	0	0
Investments in unconsolidated affiliates	3,277	3,050
Other long-term assets	189	186
Total assets	14,485	13,878
LIABILITIES AND EQUITY
Accounts payable and other current liabilities	1,808	1,488
Current debt	525	0
Advances payable — consolidated subsidiaries	0	0
Long-term debt	4,575	4,707
Other long-term liabilities	301	245
Total liabilities	7,209	6,440
Commitments and contingent liabilities (see note 14)
Equity:
Net equity	7,254	7,417
Accumulated other comprehensive loss	(8)	(9)
Total partners’ equity	7,246	7,408
Noncontrolling interests	30	30
Total equity	7,276	7,438	7,043	6,853
Total liabilities and equity	14,485	13,878
Reportable Legal Entities \| Parent Guarantor
ASSETS
Cash and cash equivalents	0	0	0	0
Accounts receivable, net	0	0
Inventories	0	0
Other	0	0
Total current assets	0	0
Property, plant and equipment, net	0	0
Goodwill and intangible assets, net	0	0
Advances receivable — consolidated subsidiaries	2,522	2,895
Investments in unconsolidated affiliates	4,724	4,513
Investments in unconsolidated affiliates	0	0
Other long-term assets	0	0
Total assets	7,246	7,408
LIABILITIES AND EQUITY
Accounts payable and other current liabilities	0	0
Current debt	0
Advances payable — consolidated subsidiaries	0	0
Long-term debt	0	0
Other long-term liabilities	0	0
Total liabilities	0	0
Commitments and contingent liabilities (see note 14)
Equity:
Net equity	7,246	7,408
Accumulated other comprehensive loss	0	0
Total partners’ equity	7,246	7,408
Noncontrolling interests	0	0
Total equity	7,246	7,408
Total liabilities and equity	7,246	7,408
Reportable Legal Entities \| Subsidiary Issuer
ASSETS
Cash and cash equivalents	0	155	310	0
Accounts receivable, net	0	0
Inventories	0	0
Other	0	0
Total current assets	0	155
Property, plant and equipment, net	0	0
Goodwill and intangible assets, net	0	0
Advances receivable — consolidated subsidiaries	1,739	1,614
Investments in unconsolidated affiliates	7,953	7,522
Investments in unconsolidated affiliates	0	0
Other long-term assets	0	0
Total assets	9,692	9,291
LIABILITIES AND EQUITY
Accounts payable and other current liabilities	68	71
Current debt	325
Advances payable — consolidated subsidiaries	0	0
Long-term debt	4,575	4,707
Other long-term liabilities	0	0
Total liabilities	4,968	4,778
Commitments and contingent liabilities (see note 14)
Equity:
Net equity	4,727	4,517
Accumulated other comprehensive loss	(3)	(4)
Total partners’ equity	4,724	4,513
Noncontrolling interests	0	0
Total equity	4,724	4,513
Total liabilities and equity	9,692	9,291
Reportable Legal Entities \| Non-Guarantor Subsidiaries
ASSETS
Cash and cash equivalents	1	1	2	1
Accounts receivable, net	1,234	981
Inventories	77	68
Other	214	117
Total current assets	1,526	1,167
Property, plant and equipment, net	9,163	8,983
Goodwill and intangible assets, net	330	337
Advances receivable — consolidated subsidiaries	0	0
Investments in unconsolidated affiliates	0	0
Investments in unconsolidated affiliates	3,277	3,050
Other long-term assets	189	186
Total assets	14,485	13,723
LIABILITIES AND EQUITY
Accounts payable and other current liabilities	1,740	1,417
Current debt	200
Advances payable — consolidated subsidiaries	4,261	4,509
Long-term debt	0	0
Other long-term liabilities	301	245
Total liabilities	6,502	6,171
Commitments and contingent liabilities (see note 14)
Equity:
Net equity	7,958	7,527
Accumulated other comprehensive loss	(5)	(5)
Total partners’ equity	7,953	7,522
Noncontrolling interests	30	30
Total equity	7,983	7,552
Total liabilities and equity	14,485	13,723
Consolidating Adjustments
ASSETS
Cash and cash equivalents	0	0	$ 0	$ 0
Accounts receivable, net	0	0
Inventories	0	0
Other	0	0
Total current assets	0	0
Property, plant and equipment, net	0	0
Goodwill and intangible assets, net	0	0
Advances receivable — consolidated subsidiaries	(4,261)	(4,509)
Investments in unconsolidated affiliates	(12,677)	(12,035)
Investments in unconsolidated affiliates	0	0
Other long-term assets	0	0
Total assets	(16,938)	(16,544)
LIABILITIES AND EQUITY
Accounts payable and other current liabilities	0	0
Current debt	0
Advances payable — consolidated subsidiaries	(4,261)	(4,509)
Long-term debt	0	0
Other long-term liabilities	0	0
Total liabilities	(4,261)	(4,509)
Commitments and contingent liabilities (see note 14)
Equity:
Net equity	(12,677)	(12,035)
Accumulated other comprehensive loss	0	0
Total partners’ equity	(12,677)	(12,035)
Noncontrolling interests	0	0
Total equity	(12,677)	(12,035)
Total liabilities and equity	$ (16,938)	$ (16,544)

Condensed Consolidating Financial Information - Condensed Consolidating Statements of Operations (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Operating revenues:
Sales of natural gas, NGLs and condensate	$ 2,682	$ 1,936	$ 7,008	$ 5,641
Transportation, processing and other	133	162	371	474
Trading and marketing (losses) gains, net	(56)	(43)	(164)	10
Total operating revenues	2,759	2,055	7,215	6,125
Purchases and related costs	2,327	1,695	6,024	4,939
Operating and maintenance expense	196	168	543	513
Depreciation and amortization expense	98	94	289	282
General and administrative expense	70	69	199	202
Asset impairments		48	0	48
Gain on sale of assets, net	0	0	0	34
Other income (expense)	(2)	0	(7)	(15)
Costs and Expenses	2,693	2,074	7,062	5,965
Operating income (loss)	66	(19)	153	160
Loss from financing activities	(19)	0	(19)	0
Interest expense, net	(69)	(73)	(203)	(219)
Income from consolidated subsidiaries	0	0	0	0
Earnings from unconsolidated affiliates	104	74	278	234
Income (loss) before income taxes	82	(18)	209	175
Income tax expense	0	(2)	(2)	(5)
Net income (loss)	82	(20)	207	170
Net income attributable to noncontrolling interests	(1)	0	(3)	(1)
Net income (loss) attributable to partners	81	(20)	204	169
Reportable Legal Entities \| Parent Guarantor
Operating revenues:
Sales of natural gas, NGLs and condensate	0	0	0	0
Transportation, processing and other	0	0	0	0
Trading and marketing (losses) gains, net	0	0	0	0
Total operating revenues	0	0	0	0
Purchases and related costs	0	0	0	0
Operating and maintenance expense	0	0	0	0
Depreciation and amortization expense	0	0	0	0
General and administrative expense	0	0	0	0
Asset impairments		0		0
Gain on sale of assets, net				0
Other income (expense)	0		0	0
Costs and Expenses	0	0	0	0
Operating income (loss)	0	0	0	0
Loss from financing activities	0		0
Interest expense, net	0	0	0	0
Income from consolidated subsidiaries	81	(20)	204	169
Earnings from unconsolidated affiliates	0	0	0	0
Income (loss) before income taxes	81	(20)	204	169
Income tax expense	0	0	0	0
Net income (loss)	81	(20)	204	169
Net income attributable to noncontrolling interests	0	0	0	0
Net income (loss) attributable to partners	81	(20)	204	169
Reportable Legal Entities \| Subsidiary Issuer
Operating revenues:
Sales of natural gas, NGLs and condensate	0	0	0	0
Transportation, processing and other	0	0	0	0
Trading and marketing (losses) gains, net	0	0	0	0
Total operating revenues	0	0	0	0
Purchases and related costs	0	0	0	0
Operating and maintenance expense	0	0	0	0
Depreciation and amortization expense	0	0	0	0
General and administrative expense	0	0	0	0
Asset impairments		0		0
Gain on sale of assets, net				0
Other income (expense)	0		0	0
Costs and Expenses	0	0	0	0
Operating income (loss)	0	0	0	0
Loss from financing activities	(19)		(19)
Interest expense, net	(68)	(73)	(202)	(219)
Income from consolidated subsidiaries	168	53	425	388
Earnings from unconsolidated affiliates	0	0	0	0
Income (loss) before income taxes	81	(20)	204	169
Income tax expense	0	0	0	0
Net income (loss)	81	(20)	204	169
Net income attributable to noncontrolling interests	0	0	0	0
Net income (loss) attributable to partners	81	(20)	204	169
Reportable Legal Entities \| Non-Guarantor Subsidiaries
Operating revenues:
Sales of natural gas, NGLs and condensate	2,682	1,936	7,008	5,641
Transportation, processing and other	133	162	371	474
Trading and marketing (losses) gains, net	(56)	(43)	(164)	10
Total operating revenues	2,759	2,055	7,215	6,125
Purchases and related costs	2,327	1,695	6,024	4,939
Operating and maintenance expense	196	168	543	513
Depreciation and amortization expense	98	94	289	282
General and administrative expense	70	69	199	202
Asset impairments		48		48
Gain on sale of assets, net				34
Other income (expense)	(2)		(7)	(15)
Costs and Expenses	2,693	2,074	7,062	5,965
Operating income (loss)	66	(19)	153	160
Loss from financing activities	0		0
Interest expense, net	(1)	0	(1)	0
Income from consolidated subsidiaries	0	0	0	0
Earnings from unconsolidated affiliates	104	74	278	234
Income (loss) before income taxes	169	55	430	394
Income tax expense	0	(2)	(2)	(5)
Net income (loss)	169	53	428	389
Net income attributable to noncontrolling interests	(1)	0	(3)	(1)
Net income (loss) attributable to partners	168	53	425	388
Consolidating Adjustments
Operating revenues:
Sales of natural gas, NGLs and condensate	0	0	0	0
Transportation, processing and other	0	0	0	0
Trading and marketing (losses) gains, net	0	0	0	0
Total operating revenues	0	0	0	0
Purchases and related costs	0	0	0	0
Operating and maintenance expense	0	0	0	0
Depreciation and amortization expense	0	0	0	0
General and administrative expense	0	0	0	0
Asset impairments		0		0
Gain on sale of assets, net				0
Other income (expense)	0		0	0
Costs and Expenses	0	0	0	0
Operating income (loss)	0	0	0	0
Loss from financing activities	0		0
Interest expense, net	0	0	0	0
Income from consolidated subsidiaries	(249)	(33)	(629)	(557)
Earnings from unconsolidated affiliates	0	0	0	0
Income (loss) before income taxes	(249)	(33)	(629)	(557)
Income tax expense	0	0	0	0
Net income (loss)	(249)	(33)	(629)	(557)
Net income attributable to noncontrolling interests	0	0	0	0
Net income (loss) attributable to partners	(249)	(33)	(629)	(557)
Eliminations
Operating revenues:
Total operating revenues	(1,410)	(1,195)	(3,725)	(3,436)
Operating and maintenance expense	0	0		0
Depreciation and amortization expense	0	0	0	0
General and administrative expense	0	0	0	0
Asset impairments		0		0
Gain on sale of assets, net			0	0
Other income (expense)	0	0		0
Loss from financing activities	0		0
Interest expense, net	0	0	0	0
Earnings from unconsolidated affiliates	0	0	0	0
Income tax expense		0	0	0
Net income (loss)	0	0	0	0
Net income attributable to noncontrolling interests	0	0	0	0
Net income (loss) attributable to partners	$ 0	$ 0	$ 0	$ 0

Condensed Consolidating Financial Information - Condensed Consolidating Statement of Comprehensive Income (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Condensed Financial Statements, Captions [Line Items]
Net income	$ 82	$ (20)	$ 207	$ 170
Other comprehensive income (loss):
Reclassification of cash flow hedge losses into earnings	0	0	1	1
Other comprehensive income from consolidated subsidiaries			0	0
Total other comprehensive income	0	0	1	1
Total comprehensive income (loss)	82	(20)	208	171
Total comprehensive income attributable to noncontrolling interests	(1)	0	(3)	(1)
Total comprehensive income attributable to partners	81	(20)	205	170
Reportable Legal Entities \| Parent Guarantor
Condensed Financial Statements, Captions [Line Items]
Net income	81	(20)	204	169
Other comprehensive income (loss):
Reclassification of cash flow hedge losses into earnings			0	0
Other comprehensive income from consolidated subsidiaries			1	1
Total other comprehensive income	0	0	1	1
Total comprehensive income (loss)	81	(20)	205	170
Total comprehensive income attributable to noncontrolling interests	0	0	0	0
Total comprehensive income attributable to partners	81	(20)	205	170
Reportable Legal Entities \| Subsidiary Issuer
Condensed Financial Statements, Captions [Line Items]
Net income	81	(20)	204	169
Other comprehensive income (loss):
Reclassification of cash flow hedge losses into earnings			1	1
Other comprehensive income from consolidated subsidiaries			0	0
Total other comprehensive income	0	0	1	1
Total comprehensive income (loss)	81	(20)	205	170
Total comprehensive income attributable to noncontrolling interests	0	0	0	0
Total comprehensive income attributable to partners	81	(20)	205	170
Reportable Legal Entities \| Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Net income	169	53	428	389
Other comprehensive income (loss):
Reclassification of cash flow hedge losses into earnings			0	0
Other comprehensive income from consolidated subsidiaries			0	0
Total other comprehensive income	0	0	0	0
Total comprehensive income (loss)	169	53	428	389
Total comprehensive income attributable to noncontrolling interests	(1)	0	(3)	(1)
Total comprehensive income attributable to partners	168	53	425	388
Consolidating Adjustments
Condensed Financial Statements, Captions [Line Items]
Net income	(249)	(33)	(629)	(557)
Other comprehensive income (loss):
Reclassification of cash flow hedge losses into earnings			0	0
Other comprehensive income from consolidated subsidiaries			(1)	(1)
Total other comprehensive income	0	0	(1)	(1)
Total comprehensive income (loss)	(249)	(33)	(630)	(558)
Total comprehensive income attributable to noncontrolling interests	0	0	0	0
Total comprehensive income attributable to partners	$ (249)	$ (33)	$ (630)	$ (558)

Condensed Consolidating Financial Information - Condensed Consolidating Statements of Cash Flows (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
OPERATING ACTIVITIES
Net cash (used in) provided by operating activities			$ 541	$ 684
INVESTING ACTIVITIES:
Intercompany transfers			0	0
Capital expenditures	$ (160)	$ (99)	(428)	(258)
Investments in unconsolidated affiliates, net	(139)	(29)	(265)	(70)
Proceeds from sale of assets			3	130
Net cash used in investing activities			(690)	(198)
FINANCING ACTIVITIES:
Intercompany transfers			0	0
Proceeds from long-term debt			3,620	0
Payments of long-term debt			(3,225)	(195)
Costs incurred to redeem senior notes			(18)	0
Proceeds from Issuance of Preferred Limited Partners Units			155	0
Distribution Made to Limited Partner, Cash Distributions Paid			(25)	0
Net change in advances to predecessor from DCP Midstream, LLC			0	418
Distributions to limited partners and general partner			(503)	(390)
Distributions to noncontrolling interests			(3)	(6)
Other			(7)	(2)
Net cash used in financing activities			(6)	(175)
Net change in cash and cash equivalents			(155)	311
Cash and cash equivalents, beginning of period			156	1
Cash and cash equivalents, end of period	1	312	1	312
Parent Guarantor
FINANCING ACTIVITIES:
Costs incurred to redeem senior notes			0
Subsidiary Issuer
FINANCING ACTIVITIES:
Costs incurred to redeem senior notes			(18)
Non-Guarantor Subsidiaries
FINANCING ACTIVITIES:
Costs incurred to redeem senior notes			0
Reportable Legal Entities \| Parent Guarantor
OPERATING ACTIVITIES
Net cash (used in) provided by operating activities			0	0
INVESTING ACTIVITIES:
Intercompany transfers			373	390
Capital expenditures			0	0
Investments in unconsolidated affiliates, net			0	0
Proceeds from sale of assets			0	0
Net cash used in investing activities			373	390
FINANCING ACTIVITIES:
Intercompany transfers			0	0
Proceeds from long-term debt			0
Payments of long-term debt			0	0
Proceeds from Issuance of Preferred Limited Partners Units			155
Distribution Made to Limited Partner, Cash Distributions Paid			(25)
Net change in advances to predecessor from DCP Midstream, LLC				0
Distributions to limited partners and general partner			(503)	(390)
Distributions to noncontrolling interests			0	0
Other			0	0
Net cash used in financing activities			(373)	(390)
Net change in cash and cash equivalents			0	0
Cash and cash equivalents, beginning of period			0	0
Cash and cash equivalents, end of period	0	0	0	0
Reportable Legal Entities \| Subsidiary Issuer
OPERATING ACTIVITIES
Net cash (used in) provided by operating activities			(201)	(217)
INVESTING ACTIVITIES:
Intercompany transfers			(125)	724
Capital expenditures			0	0
Investments in unconsolidated affiliates, net			0	0
Proceeds from sale of assets			0	0
Net cash used in investing activities			(125)	724
FINANCING ACTIVITIES:
Intercompany transfers			0	0
Proceeds from long-term debt			3,420
Payments of long-term debt			(3,225)	(195)
Proceeds from Issuance of Preferred Limited Partners Units			0
Distribution Made to Limited Partner, Cash Distributions Paid			0
Net change in advances to predecessor from DCP Midstream, LLC				0
Distributions to limited partners and general partner			0	0
Distributions to noncontrolling interests			0	0
Other			(6)	(2)
Net cash used in financing activities			171	(197)
Net change in cash and cash equivalents			(155)	310
Cash and cash equivalents, beginning of period			155	0
Cash and cash equivalents, end of period	0	310	0	310
Reportable Legal Entities \| Non-Guarantor Subsidiaries
OPERATING ACTIVITIES
Net cash (used in) provided by operating activities			742	901
INVESTING ACTIVITIES:
Intercompany transfers			0	0
Capital expenditures			(428)	(258)
Investments in unconsolidated affiliates, net			(265)	(70)
Proceeds from sale of assets			3	130
Net cash used in investing activities			(690)	(198)
FINANCING ACTIVITIES:
Intercompany transfers			(248)	(1,114)
Proceeds from long-term debt			200
Payments of long-term debt			0	0
Proceeds from Issuance of Preferred Limited Partners Units			0
Distribution Made to Limited Partner, Cash Distributions Paid			0
Net change in advances to predecessor from DCP Midstream, LLC				418
Distributions to limited partners and general partner			0	0
Distributions to noncontrolling interests			(3)	(6)
Other			(1)	0
Net cash used in financing activities			(52)	(702)
Net change in cash and cash equivalents			0	1
Cash and cash equivalents, beginning of period			1	1
Cash and cash equivalents, end of period	1	2	1	2
Consolidating Adjustments
OPERATING ACTIVITIES
Net cash (used in) provided by operating activities			0	0
INVESTING ACTIVITIES:
Intercompany transfers			(248)	(1,114)
Capital expenditures			0	0
Investments in unconsolidated affiliates, net			0	0
Proceeds from sale of assets			0	0
Net cash used in investing activities			(248)	(1,114)
FINANCING ACTIVITIES:
Intercompany transfers			248	1,114
Proceeds from long-term debt			0
Payments of long-term debt			0	0
Costs incurred to redeem senior notes			0
Proceeds from Issuance of Preferred Limited Partners Units			0
Distribution Made to Limited Partner, Cash Distributions Paid			0
Net change in advances to predecessor from DCP Midstream, LLC				0
Distributions to limited partners and general partner			0	0
Distributions to noncontrolling interests			0	0
Other			0	0
Net cash used in financing activities			248	1,114
Net change in cash and cash equivalents			0	0
Cash and cash equivalents, beginning of period			0	0
Cash and cash equivalents, end of period	$ 0	$ 0	$ 0	$ 0

Subsequent Events - Additional Information (Detail) - USD ($)												9 Months Ended
	Jan. 15, 2019	Jan. 02, 2019	Dec. 17, 2018	Dec. 03, 2018	Nov. 14, 2018	Nov. 02, 2018	Oct. 23, 2018	Oct. 19, 2018	Oct. 04, 2018	Sep. 17, 2018	Jun. 15, 2018	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Subsequent Event [Line Items]
Proceeds from Issuance of Preferred Limited Partners Units												$ 155,000,000	$ 0
Subsequent Event
Subsequent Event [Line Items]
Distribution declaration date							Oct. 23, 2018
Quarterly distribution (in dollars per share)							$ 0.78
Distribution payable date					Nov. 14, 2018
Distribution record date						Nov. 02, 2018
Preferred Limited Partnership Distribution; Distribution Date			Dec. 17, 2018
Preferred Limited Partner Distribution: Record Date				Dec. 03, 2018
Series A Preferred Limited Partners [Member]
Subsequent Event [Line Items]
Preferred Units, Issued												500,000		500,000
Proceeds from Issuance of Preferred Limited Partners Units												$ 0
Preferred Limited Partnership Distribution; Distribution Amount Declared											$ 41.9965
Series A Preferred Limited Partners [Member] \| Subsequent Event
Subsequent Event [Line Items]
Preferred Limited Partnership Distribution; Distribution Amount Declared							$ 36.8750
Preferred Limited Partnership Distribution; Distribution Date			Dec. 17, 2018
Preferred Limited Partner Distribution: Record Date				Dec. 03, 2018
Preferred Limited Partnership Distribution: Declaration Date							Oct. 23, 2018
Series B Preferred Limited Partners [Member]
Subsequent Event [Line Items]
Preferred Units, Issued												6,450,000		0
Proceeds from Issuance of Preferred Limited Partners Units												$ 155,000,000
Preferred Limited Partnership Distribution; Distribution Amount Declared										$ 0.6781
Series B Preferred Limited Partners [Member] \| Subsequent Event
Subsequent Event [Line Items]
Preferred Limited Partnership Distribution; Distribution Amount Declared							$ 0.4922
Preferred Limited Partnership Distribution; Distribution Date			Dec. 17, 2018
Preferred Limited Partner Distribution: Record Date				Dec. 03, 2018
Preferred Limited Partnership Distribution: Declaration Date							Oct. 23, 2018
Series C Preferred Limited Partners [Member] [Member] \| Subsequent Event
Subsequent Event [Line Items]
Preferred Limited Partnership Units: Original Issue Date									Oct. 04, 2018
Preferred Units, Issued								400,000	4,000,000
Proceeds from Issuance of Preferred Limited Partners Units									$ 106,000,000
Preferred Limited Partnership Unit Distribution; Distribution Rate									7.95%
Units Sold Under Private Placement Price Per Unit									$ 25
Preferred Limited Partner Unit Distribution, Annual Per Unit									$ 1.9875
Preferred Limited Partnership Units: Excercise of Underwriters Option to Purchase Additional Units								Oct. 19, 2018
Preferred Limited Partnership Distribution; Distribution Amount Declared							$ 0.5576
Preferred Limited Partnership Distribution; Distribution Date	Jan. 15, 2019
Preferred Limited Partner Distribution: Record Date		Jan. 02, 2019
Preferred Limited Partnership Distribution: Declaration Date							Oct. 23, 2018
On and after October 15, 2023 [Member] \| Series C Preferred Limited Partners [Member] [Member] \| Subsequent Event
Subsequent Event [Line Items]
Preferred Limited Partnership Unit Distribution; Distribution Rate									4.88%