Document and Entity Information - shares	6 Months Ended
Document and Entity Information - shares	Jun. 30, 2019	Aug. 01, 2019
Cover page.
Entity Registrant Name	DCP MIDSTREAM, LP
Amendment Flag	false
Document Fiscal Year Focus	2019
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		143,317,328
Document Period End Date	Jun. 30, 2019
Entity Emerging Growth Company	false
Entity Small Business	false
Document Fiscal Period Focus	Q2
Entity Central Index Key	0001338065
Current Fiscal Year End Date	--12-31
Document Type	10-Q
City Area Code	(303)
Local Phone Number	595-3331
Entity Address, Postal Zip Code	80202
Entity Address, Address Line One	370 17th Street
Entity Address, Address Line Two	Suite 2500
Entity Address, City or Town	Denver
Entity Address, State or Province	CO
Entity Current Reporting Status	Yes
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	03-0567133
Document Quarterly Report	true
Document Transition Report	false
Entity File Number	001-32678
Entity Shell Company	false
Entity Interactive Data Current	Yes
Series B Preferred Limited Partners [Member]
Cover page.
Trading Symbol	DCP PRB
Title of 12(b) Security	7.875% Series B Fixed-to-Floating Rate Cumulative Redeemable Perpetual Preferred Units
Trading Symbol	DCP PRB
Security Exchange Name	NYSE
Series C Preferred Limited Partners [Member]
Cover page.
Trading Symbol	DCP PRC
Title of 12(b) Security	7.95% Series C Fixed-to-Floating Rate Cumulative Redeemable Perpetual Preferred Units
Trading Symbol	DCP PRC
Security Exchange Name	NYSE
Limited Partners
Cover page.
Trading Symbol	DCP
Title of 12(b) Security	Common units representing limited partnership interests
Trading Symbol	DCP
Security Exchange Name	NYSE

Consolidated Balance Sheets - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 1	$ 1
Accounts receivable:
Trade, net of allowance for doubtful accounts of $3 and $3 million, respectively	511	860
Affiliates	131	166
Other	18	7
Inventories	46	79
Unrealized gains on derivative instruments	66	108
Collateral cash deposits	27	34
Other	23	16
Total current assets	823	1,271
Property, plant and equipment, net	9,108	9,135
Goodwill	194	231
Intangible assets, net	65	97
Investments in unconsolidated affiliates	3,581	3,340
Unrealized gains on derivative instruments	5	8
Operating Lease, Right-of-Use Asset	69	0
Other long-term assets	188	184
Total assets	14,033	14,266
Accounts payable:
Trade	531	807
Affiliates	94	96
Other	29	23
Current debt	800	525
Unrealized losses on derivative instruments	54	91
Accrued interest	81	71
Accrued taxes	57	64
Accrued wages and benefits	31	64
Capital spending accrual	24	63
Other	102	100
Total current liabilities	1,803	1,904
Long-term debt	4,750	4,782
Unrealized losses on derivative instruments	5	8
Deferred income taxes	32	32
Operating Lease, Liability, Noncurrent	57	0
Other long-term liabilities	233	243
Total liabilities	6,880	6,969
Commitments and contingent liabilities (see note 14)
Equity:
General partner	104	107
Limited partners (143,317,328 common units authorized, issued and outstanding, respectively)	6,277	6,418
Accumulated other comprehensive loss	(8)	(8)
Total partners’ equity	7,125	7,268
Noncontrolling interests	28	29
Total equity	7,153	7,297
Total liabilities and equity	14,033	14,266
Series A Preferred Limited Partners [Member]
Equity:
Preferred Units, Preferred Partners' Capital Accounts	490	489
Total equity	490	489
Series B Preferred Limited Partners [Member]
Equity:
Preferred Units, Preferred Partners' Capital Accounts	156	156
Total equity	156	156
Series C Preferred Limited Partners [Member]
Equity:
Preferred Units, Preferred Partners' Capital Accounts	106	106
Total equity	$ 106	$ 106

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Condensed Balance Sheet Statements, Captions [Line Items]
Allowance for Doubtful Accounts Receivable, Current	$ 3	$ 3
Common unitholders, units issued (in shares)	143,317,328	143,317,328
Common unitholders, units outstanding (in shares)	143,317,328	143,317,328
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	6,450,000
Preferred Units, Outstanding	6,450,000	6,450,000
Series C Preferred Limited Partners [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Preferred Units, Issued	4,400,000	4,400,000
Preferred Units, Outstanding	4,400,000	4,400,000

Consolidated Statements of Operations - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Operating revenues:
Sales of natural gas, NGLs and condensate	$ 110	$ 127	$ 225	$ 238
Trading and marketing losses, net	29	(67)	2	(108)
Total operating revenues	1,798	2,317	3,997	4,456
Operating costs and expenses:
Purchases and related costs	1,356	(1,928)	3,160	3,697
Operating and maintenance expense	182	185	360	347
Depreciation and amortization expense	101	97	204	191
General and administrative expense	68	70	135	129
Other expense, net	(1)	(3)	(6)	(5)
Loss on sale of assets, net	5	0	14	0
Restructuring costs	9	0	9	0
Total operating costs and expenses	1,722	2,283	3,888	4,369
Operating income	76	34	109	87
Earnings from unconsolidated affiliates	117	96	230	174
Interest Expense	73	67	142	134
Income before income taxes	120	63	197	127
Income tax expense	0	1	1	2
Net income	120	62	196	125
Net income attributable to noncontrolling interests	(1)	(1)	(2)	(2)
Net income attributable to partners	119	61	194	123
Series A preferred limited partners' interest in net income	(10)	(9)	(19)	(18)
Series B preferred limited partners' interest in net income	(3)	(2)	(6)	(2)
Series C preferred limited partners' interest in net income	(2)	0	(4)	0
General partner’s interest in net income	(42)	(40)	(83)	(81)
Net income allocable to limited partners	$ 62	$ 10	$ 82	$ 22
Net income per limited partner unit — basic and diluted	$ 0.43	$ 0.07	$ 0.57	$ 0.15
Weighted Average Limited Partnership Units Outstanding, Basic	143.3	143.3	143.3	143.3
Weighted Average Limited Partnership Units Outstanding, Diluted	143.3	143.3	143.3	143.3
Natural Gas, NGLs and Condensate [Member]
Operating revenues:
Sales of natural gas, NGLs and condensate	$ 1,659	$ 2,257	$ 3,770	$ 4,326
Natural Gas, NGLs and Condensate [Member] \| Third Party
Operating revenues:
Sales of natural gas, NGLs and condensate	1,365	1,849	3,136	3,593
Operating costs and expenses:
Purchases and related costs	1,084	1,703	2,617	3,307
Transportation, Processing and Other [Member]
Operating revenues:
Sales of natural gas, NGLs and condensate	110	127	225	238
Affiliated Entity \| Natural Gas, NGLs and Condensate [Member]
Operating revenues:
Sales of natural gas, NGLs and condensate	294	408	634	733
Operating costs and expenses:
Purchases and related costs	$ 272	$ 225	$ 543	$ 390

Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 120	$ 76	$ 62	$ 63	$ 196	$ 125
Other comprehensive income:
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax	0		1		0	1
Other comprehensive income	0		1		0	1
Total comprehensive income	120		63		196	126
Total comprehensive income attributable to noncontrolling interests	(1)		(1)		(2)	(2)
Total comprehensive income attributable to partners	$ 119		$ 62		$ 194	$ 124

- Definition

The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

Consolidated Statements of Cash Flows - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
OPERATING ACTIVITIES:
Net income	$ 196	$ 125
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization expense	204	191
Earnings from unconsolidated affiliates	(230)	(174)
Distributions from unconsolidated affiliates	259	193
Net unrealized (gains) losses on derivative instruments	15	66
Loss on sale of assets, net	14	0
Other, net	6	9
Change in operating assets and liabilities, which (used) provided cash, net of effects of acquisitions:
Accounts receivable	373	(50)
Inventories	19	21
Accounts payable	(248)	42
Increase (Decrease) in Other Operating Assets and Liabilities, Net	(62)	(92)
Net cash provided by operating activities	546	331
INVESTING ACTIVITIES:
Capital expenditures	(308)	(268)
Investments in unconsolidated affiliates	(270)	(126)
Proceeds from sale of assets	132	3
Net cash used in investing activities	(446)	(391)
FINANCING ACTIVITIES:
Proceeds from debt	3,457	1,803
Payments of debt	(3,208)	(1,678)
Proceeds from Issuance of Preferred Limited Partners Units	0	155
Distributions to preferred limited partners	(28)	(21)
Distributions to limited partners and general partner	(309)	(349)
Distributions to noncontrolling interests	(3)	(2)
Other	(9)	0
Net cash provided by (used in) financing activities	(100)	(92)
Net change in cash and cash equivalents	0	(152)
Cash and cash equivalents, beginning of period	1	156
Cash and cash equivalents, end of period	$ 1	$ 4

Consolidated Statements of Changes in Equity - USD ($) $ in Millions	Total	Series A Preferred Limited Partners [Member]	Series B Preferred Limited Partners [Member]	Series C Preferred Limited Partners [Member]	General Partner	Limited Partners	Accumulated Other Comprehensive (Loss) Income	Noncontrolling Interests
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	63	9	0		41	12	0	1
Total Cash Distribution to Unitholders	(194)	0	0		83	111	0	0
Distributions to noncontrolling interests	(1)	0	0		0	0	0	1
Ending balance at Mar. 31, 2018	7,312	500	0		112	6,679	(9)	30
Beginning balance at Dec. 31, 2017	7,438	491	0		154	6,772	(9)	30
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income	125
Other comprehensive income	1
Proceeds from Issuance of Preferred Limited Partners Units	155
Ending balance at Jun. 30, 2018	7,353	488	157		109	6,577	(8)	30
Beginning balance at Mar. 31, 2018	7,312	500	0		112	6,679	(9)	30
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income	62	9	2		40	10	0	1
Other comprehensive income	1	0	0		0	0	1	0
Proceeds from Issuance of Preferred Limited Partners Units	155	0	155		0	0	0	0
Total Cash Distribution to Unitholders	176	21	0		43	112	0	0
Distributions to noncontrolling interests	1	0	0		0	0	0	1
Ending balance at Jun. 30, 2018	7,353	488	157		109	6,577	(8)	30
Beginning balance at Dec. 31, 2018	7,297	489	156	$ 106	107	6,418	(8)	29
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income	76	9	3	2	41	20	0	1
Total Cash Distribution to Unitholders	(159)	0	(3)	(2)	(43)	(111)	0	0
Distributions to noncontrolling interests	(1)	0	0	0	0	0	0	(1)
Ending balance at Mar. 31, 2019	7,213	498	156	106	105	6,327	(8)	29
Beginning balance at Dec. 31, 2018	7,297	489	156	106	107	6,418	(8)	29
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income	196
Other comprehensive income	0
Proceeds from Issuance of Preferred Limited Partners Units	0
Ending balance at Jun. 30, 2019	7,153	490	156	106	104	6,277	(8)	28
Beginning balance at Mar. 31, 2019	7,213	498	156	106	105	6,327	(8)	29
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income	120	10	3	2	42	62	0	1
Other comprehensive income	0
Total Cash Distribution to Unitholders	178	18	3	2	43	112	0	0
Distributions to noncontrolling interests	2	0	0	0	0	0	0	2
Ending balance at Jun. 30, 2019	$ 7,153	$ 490	$ 156	$ 106	$ 104	$ 6,277	$ (8)	$ 28

- Definition

The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest.

+ References

+ Details

Description of Business and Basis of Presentation (Notes)	6 Months Ended
	Jun. 30, 2019
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 Logistics and Marketing and Gathering and Processing segments. For additional information regarding these segments, see Note 20 - 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 June 30, 2019, 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. 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 (the 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 six months ended June 30, 2019 are not necessarily indicative of the results that may be expected for the year ending December 31, 2019. 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 2018 audited consolidated financial statements and notes thereto included in our Annual Report on Form 10-K for the year ended December 31, 2018.

Revenue Recognition (Notes)

6 Months Ended

Jun. 30, 2019

Revenue from Contract with Customer [Abstract]

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

. Revenue Recognition

We disaggregate our revenue from contracts with customers by type of contract 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:


	Three Months Ended June 30, 2019
	Logistics and Marketing		Gathering and Processing		Eliminations		Total
	(millions)
Sales of natural gas	$	445	$	363	$	(320)	$	488
Sales of NGLs and condensate (a)	1,155		535		(519)		1,171
Transportation, processing and other	12		98		—		110

Trading and marketing gains, net (b)	1		28		—		29
Total operating revenues	$	1,613	$	1,024	$	(839)	$	1,798


	Six Months Ended June 30, 2019
	Logistics and Marketing		Gathering and Processing		Eliminations		Total
	(millions)
Sales of natural gas	$	1,082	$	920	$	(818)	$	1,184
Sales of NGLs and condensate (a)	2,558		1,183		(1,155)		2,586
Transportation, processing and other	24		201		—		225

Trading and marketing (losses) gains, net (b)	(6)		8		—		2
Total operating revenues	$	3,658	$	2,312	$	(1,973)	$	3,997

(a) Includes $822 million and $1,680 million for the three and six months ended June 30, 2019, respectively, of revenues from physical sales contracts and buy-sell exchange transactions in our logistics and marketing segment, which are not within the scope of FASB ASU 2014-09 “Revenue from Contracts with Customers” (Topic 606).

(b) Not within the scope of Topic 606.


	Three Months Ended June 30, 2018
	Logistics and Marketing		Gathering and Processing		Eliminations		Total
	(millions)
Sales of natural gas	$	463	$	398	$	(353)	$	508
Sales of NGLs and condensate (a)	1,714		870		(835)		1,749
Transportation, processing and other	16		112		(1)		127

Trading and marketing losses, net (b)	$	(1)	$	(66)	—		(67)
Total operating revenues	$	2,192	$	1,314	$	(1,189)	$	2,317


	Six Months Ended June 30, 2018
	Logistics and Marketing		Gathering and Processing		Eliminations		Total
	(millions)
Sales of natural gas	$	1,016	$	844	$	(772)	$	1,088
Sales of NGLs and condensate (a)	3,170		1,610		(1,542)		3,238
Transportation, processing and other	30		209		(1)		238

Trading and marketing losses, net (b)	$	(45)	$	(63)	—		(108)
Total operating revenues	$	4,171	$	2,600	$	(2,315)	$	4,456

(a) Includes $1,108 million and $1,901 million for the three and six months ended June 30, 2018, respectively, 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) Not within the scope of Topic 606.

The revenue expected to be recognized in the future related to performance obligations that are not satisfied is approximately $204 million as of June 30, 2019. Our remaining performance obligations primarily consist of minimum volume commitment fee arrangements and are expected to be recognized through 2028 with a weighted average remaining life of 4 years as of June 30, 2019. As a practical expedient permitted by Topic 606, this amount excludes variable consideration as well as remaining performance obligations that have original expected durations of one year or less, as applicable. Our remaining performance obligations also exclude estimates of variable rate escalation clauses in our contracts with customers.

Agreements and Transactions with Affiliates

6 Months Ended

Jun. 30, 2019

Agreements and Transactions with Affiliates

. 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 June 30,						Six Months Ended June 30,
	2019		2018		2019		2018
	(millions)
Employee related costs charged by DCP Midstream, LLC
Operating and maintenance expense	$	50	$	53	$	99	$	102
General and administrative expense	$	44	$	47	$	91	$	85
Restructuring costs	$	9	$	—	$	9	$	—

Phillips 66 and its Affiliates

We sell a portion of our residue gas and NGLs to and purchase NGLs from Phillips 66 and its respective affiliates. We anticipate continuing to sell commodities to and purchase commodities from Phillips 66 and its affiliates in the ordinary course of business.

Enbridge and its Affiliates

We purchase NGLs from Enbridge and its affiliates. We anticipate continuing to 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 June 30,						Six Months Ended June 30,
	2019		2018		2019		2018
	(millions)
Phillips 66 (including its affiliates):
Sales of natural gas, NGLs and condensate to affiliates	$	290	$	381	$	616	$	683
Purchases and related costs from affiliates	$	64	$	28	$	109	$	38
Operating and maintenance and general administrative expenses	$	3	$	3	$	7	$	6




Enbridge (including its affiliates):
Sales of natural gas, NGLs and condensate to affiliates	$	—	$	13	$	—	$	25
Purchases and related costs from affiliates	$	7	$	18	$	14	$	28


Unconsolidated affiliates:
Sales of natural gas, NGLs and condensate to affiliates	$	4	$	14	$	18	$	25
Transportation, processing, and other to affiliates	$	—	$	2	$	1	$	3
Purchases and related costs from affiliates	$	201	$	179	$	420	$	324

We had balances with affiliates as follows:


	June 30, 2019		December 31, 2018
	(millions)







Phillips 66 (including its affiliates):
Accounts receivable	$	115	$	145
Accounts payable	$	22	$	22

Enbridge (including its affiliates):


Accounts payable	$	2	$	2


Unconsolidated affiliates:
Accounts receivable	$	16	$	21
Accounts payable	$	70	$	72

Fair Value Measurement (Notes)

6 Months Ended

Jun. 30, 2019

Fair Value Disclosures [Abstract]

Fair Value Measurement

. Fair Value Measurement

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 in unconsolidated affiliates, and 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.

The following table presents the financial instruments carried at fair value as of June 30, 2019 and December 31, 2018, by condensed consolidated balance sheet caption and by valuation hierarchy, as described above:


	June 30, 2019														December 31, 2018
	Level 1		Level 2		Level 3		Total Carrying Value		Level 1		Level 2		Level 3		Total Carrying Value
	(millions)
Current assets:
Commodity derivatives	$	31	$	27	$	8	$	66	$	62	$	32	$	14	$	108


Long-term assets:
Commodity derivatives	$	—	$	3	$	2	$	5	$	4	$	2	$	2	$	8

Current liabilities:
Commodity derivatives	$	(26)	$	(27)	$	(1)	$	(54)	$	(39)	$	(52)	$	—	$	(91)


Long-term liabilities:
Commodity derivatives	$	—	$	(5)	$	—	$	(5)	$	(1)	$	(5)	$	(2)	$	(8)

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 six months ended June 30, 2019 and 2018, 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 June 30, 2019 (a):
Beginning balance	$	5	$	1	$	(1)	$	(1)
Net unrealized gains included in earnings (b)	$	10	1		1		1

Transfers out of Level 3 (c)	(6)		—		—		—
Settlements	(1)		—		(1)		—


Ending balance	$	8	$	2	$	(1)	$	—
Net unrealized gains on derivatives still held included in earnings (b)	$	7	$	1	$	—	$	—
Three months ended June 30, 2018 (a):
Beginning balance	$	2	$	—	$	(6)	$	(3)
Net unrealized gains (losses) included in earnings (b)	1		1		(14)		(4)

Transfers out of Level 3 (c)	(2)		—		8		—
Settlements	—		—		2		—


Ending balance	$	1	$	1	$	(10)	$	(7)
Net unrealized gains (losses) on derivatives still held included in earnings (b)	$	1	$	1	$	(8)	$	(4)


	Commodity Derivative Instruments
	Current Assets		Long-Term Assets		Current Liabilities		Long-Term Liabilities
	(millions)
Six months ended June 30, 2019 (a):
Beginning balance	$	14	$	2	$	—	$	(2)
Net unrealized gains (losses) included in earnings (b)	8		2		(1)		1

Transfers out of Level 3 (c)	(8)		(2)		—		1
Settlements	(6)		—		—		—


Ending balance	$	8	$	2	$	(1)	$	—
Net unrealized gains (losses) on derivatives still held included in earnings (b)	$	7	$	1	$	(1)	$	—
Six months ended June 30, 2018 (a):
Beginning balance	$	3	$	1	$	(13)	$	(1)
Net unrealized losses included in earnings (b)	—		—		(12)		(6)

Transfers out of Level 3 (c)	(2)		—		12		—
Settlements	—		—		3		—


Ending balance	$	1	$	1	$	(10)	$	(7)
Net unrealized gains (losses) on derivatives still held included in earnings (b)	$	1	$	—	$	(7)	$	(6)

(a)There were no purchases, issuances or sales of derivatives or transfers into Level 3 for the three and six months ended June 30, 2019 and 2018.

(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.


	June 30, 2019
Product Group	Fair Value		Forward Curve Range
	(millions)
Assets
NGLs	$	8	$0.20-$1.15	Per gallon
Natural gas	$	2	$2.09-$2.73	Per MMBtu
Liabilities
NGLs	$	(1)	$0.09-$1.15	Per gallon

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.

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 (defined below) and the 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 June 30, 2019 and December 31, 2018, the carrying value and fair value of our total debt, including current maturities, were as follows:


		June 30, 2019						December 31, 2018
		Carrying Value (a)		Fair Value		Carrying Value (a)		Fair Value
	(millions)


Total debt		$	5,586	$	5,743	$	5,337	$	5,170

(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

Leases (Notes)

6 Months Ended

Jun. 30, 2019

Leases [Abstract]

Leases of Lessee Disclosure [Text Block]

13. Leases

We have operating leases for transportation agreements, office space, vehicles, compressors and field equipment. Our leases have remaining lease terms of less than 1 year to 22 years, some of which may include options to extend leases up to 20 years, and some of which may include options to terminate the leases in less than one year. Extension options on certain compressors and field equipment were included in the lease terms used to calculate our operating lease assets and liabilities as it is reasonably certain that we exercise those options. We do not have any material finance leases as of June 30, 2019. Operating leases are included in operating lease assets, other current liabilities and operating lease liabilities on our condensed consolidated balance sheet as of June 30, 2019 as follows:


	As of
	June 30, 2019
	(millions)
Operating lease assets	$	69

Operating lease liabilities	$	57
Other current liabilities	18
Total	$	75

Variable lease costs primarily consist of common area maintenance on our office spaces and variable transportation costs. The components of lease expense are as follows:


	Three Months Ended		Six Months Ended
	June 30, 2019		June 30, 2019
	(millions)
Operating lease cost	$	5	$	11
Variable lease cost	1		3
Short term lease cost	1		2
Total lease cost	$	7	$	16

Maturities of operating lease liabilities under non-cancelable leases as of June 30, 2019 are as follows:


	Future Minimum Rental Payments as of June 30, 2019
	(millions)
2019 - remainder	$	10
2020	21
2021	19
2022	14
2023	8
Thereafter	11
Total lease payments	$	83
Less imputed interest	(8)
Total operating lease liabilities	$	75

Minimum rental payments under our various operating leases in the year indicated were as follows as of December 31, 2018:


	Future Minimum Rental Payments as of December 31, 2018
	(millions)
2019	$	22
2020	18
2021	14
2022	9
2023	5
Thereafter	7
Total minimum rental payments	$	75

Consolidated rental expense totaled $9 million and $17 million, respectively for the three and six months ended June 30, 2018.

Supplemental cash flow information related to leases as follows:


	Six Months Ended
	June 30, 2019
	(millions)
Cash paid for amounts included in the measurement of operating lease liabilities:	$	12
Right-of-use assets obtained in exchange for operating lease obligations:	$	6

Other information related to operating leases as follows:
Weighted average remaining lease term	5 years
Weighted average discount rate	4.00		%

Debt (Notes)

6 Months Ended

Jun. 30, 2019

Debt Disclosure [Abstract]

Debt


	June 30, 2019		December 31, 2018
	(millions)




Senior notes:


Issued March 2014, interest at 2.700% payable semi-annually, due April 2019	—		325
Issued March 2010, interest at 5.350% payable semi-annually, due March 2020 (a)	600		600
Issued September 2011, interest at 4.750% payable semi-annually, 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 and January 2019, interest at 5.375% payable semi-annually, due July 2025	825		500
Issued May 2019, interest at 5.125% payable semi-annually, due May 2029	600		—
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 3.901%, as of December 31, 2018, due December 2022	—		351
Accounts receivable securitization facility:
Accounts receivable securitization facility, weighted-average variable interest rate of 3.20% as of June 30, 2019, due August 2019	200		200
Fair value adjustments related to interest rate swap fair value hedges (a)	20		21
Unamortized issuance costs	(36)		(30)
Unamortized discount	(9)		(10)
Total debt	5,550		5,307

Current debt	800		525
Total long-term debt	$	4,750	$	4,782

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

$20 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.

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 5 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.

Senior Notes Issuance

On May 10, 2019, we issued $600 million of aggregate principal amount of 5.125% Senior Notes due May 2029, unless redeemed prior to maturity. We received proceeds of $592 million, net of underwriters' fees, related expenses, and unamortized discounts, which we used for general partnership purposes, including the repayment of indebtedness under the Credit

Agreement (defined below) and the funding of capital expenditures. Interest on the notes will be paid semi-annually in arrears on May 15 and November 15 of each year, commencing November 15, 2019.

On January 18, 2019, we issued an additional $325 million of aggregate principal amount of our existing $500 million 5.375% Senior Notes due July 2025. We received proceeds of $324 million, net of underwriters’ fees, related expenses and issuance premiums, which we used for general partnership purposes including the funding of capital expenditures and repayment of outstanding indebtedness under the Credit Agreement. The full $825 million of our 5.375% Senior Notes due July 2025 is treated as a single series of debt. The 2025 notes will mature on July 15, 2025 unless redeemed prior to maturity. Interest on the 2025 notes is payable semi-annually in arrears on January 15 and July 15 of each year.

Senior Notes Redemption

On April 1, 2019, we repaid at maturity all $325 million aggregate principal amount outstanding of our 2.70% Senior Notes due 2019 using borrowings under our revolving credit facility.

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 provided that, if there is a Qualified Acquisition (as defined in the Credit Agreement), 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 June 30, 2019, we had unused borrowing capacity of $1,385 million, net of $15 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 $1,385 million as of June 30, 2019. 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.

Accounts Receivable Securitization Facility

We have an Accounts Receivable Securitization Facility (the “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 the 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 June 30, 2019, DCP Receivables had $658 million of our accounts receivable securing borrowings of $200 million under its Securitization Facility. Borrowings under the Securitization Facility are included in “Current debt” on the condensed consolidated balance sheet.

The maturities of our debt as of June 30, 2019 are as follows:


	Debt Maturities
	(millions)

2019	$	200
2020	600
2021	500
2022	350
2023	500
Thereafter	3,425
Total debt	$	5,575

Risk Management and Hedging Activities (Notes)

6 Months Ended

Jun. 30, 2019

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 (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.

Collateral

As of June 30, 2019, we had cash deposits of $27 million, included in collateral cash deposits in our condensed consolidated balance sheets. Additionally, as of June 30, 2019, we held letters of credit of $54 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:


	June 30, 2019										December 31, 2018
	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	$	71	$	—	$	71	$	116	$	—	$	116

Liabilities:
Commodity derivatives	$	(59)	$	—	$	(59)	$	(99)	$	—	$	(99)

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 June 30, 2019 and December 31, 2018.


Balance Sheet Line Item	June 30, 2019		December 31, 2018		Balance Sheet Line Item	June 30, 2019			December 31, 2018
	(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	$	66	$	108	Unrealized losses on derivative instruments — current	$	(54)		$	(91)
Unrealized gains on derivative instruments — long-term	5		8		Unrealized losses on derivative instruments — long-term	(5)			(8)
Total	$	71	$	116	Total	$	(59)		$	(99)

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 June 30, 2019:


	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)


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)

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 six months ended June 30, 2019:


	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)


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 June 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)

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 six months ended June 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)

(a)Relates to Discovery, an unconsolidated affiliate.

For the three and six months ended June 30, 2019 and 2018, 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 six months ended June 30, 2019 and 2018, 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 June 30,						Six Months Ended June 30,
	2019		2018		2019		2018
	(millions)
Realized (losses) gains	$	(10)	$	(30)	$	17	$	(42)
Unrealized gains (losses)	39		(37)		(15)		(66)
Trading and marketing gains (losses), net	$	29	$	(67)	$	2	$	(108)

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.


	June 30, 2019
	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 Long (Short) Position (MMBtu)
2019	(1,011,000)	(20,299,550)	(20,528,570)	2,000,000
2020	(664,000)	(3,790,000)	(14,847,743)	3,125,000
2021	(100,000)	—	(5,519,594)	(4,562,500)
2022	—	—	(689)	8,212,500
2023	—	—	—	7,300,000

	June 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 Long Position (MMBtu)

2018	(1,646,000)	(21,623,200)	(25,737,691)	2,257,500
2019	(1,900,000)	—	(19,314,335)	1,512,500
2020	(128,000)	—	(13,568,452)	3,660,000
2021	—	—	(5,750,000)	—

Commitments and Contingent Liabilities (Notes)	6 Months Ended
Commitments and Contingent Liabilities (Notes)	Jun. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingent Liabilities	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, pipeline 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) regulatory bodies and communities, and through litigation, on hydraulic fracturing and the real or perceived environmental or public health impacts of this technique, which indirectly presents some risk to our available supply of natural gas and the resulting supply of NGLs, (ii) regulatory bodies 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. The following pending proceedings involve governmental authorities under federal, state, and local laws regulating the discharge of materials into the environment. It is not possible for us to predict the final outcome of these pending proceedings; however, we do not expect the outcome of one or more of these proceedings to have a material adverse effect to our results of operations, financial position, or cash flows: •In March 2018, the New Mexico Environment Department (“NMED”) issued two separate Notices of Violation (“NOV”) relating to upset and malfunction event emissions at two of our gas processing plants. Following information exchanges and discussions with NMED regarding the events and the propriety of the alleged violations, on February 14, 2019 we entered into preliminary settlement agreements to resolve the alleged violations under each NOV for administrative penalties in the amount of $149,832 and $142,233, respectively. We intend to mitigate a portion of each administrative penalty through the implementation of environmentally beneficial projects. •In April 2018, the Colorado Department of Public Health and Environment (“CDPHE”) issued a Compliance Advisory in relation to an improperly permitted facility flare and related air emissions from flare operations at one of our gas processing plants that we self-disclosed to CDPHE in December 2017. Following information exchanges and discussions with CDPHE, during the first quarter of 2019, a resolution was proposed pursuant to which the plant's air permit would be revised to include the flare and emissions limits for such flare in addition to us paying an administrative penalty as well as an economic benefit payment generally covering the period when the flare was required to be included in the facility air permit, in a combined amount expected to be between approximately $375,000 and $420,000. We are still evaluating and holding discussions with CDPHE as to the foregoing amounts and proposed settlement terms. •In January 2019, CDPHE issued a Compliance Advisory in relation to an improperly configured facility flare meter, which failed to accurately track air emissions from the flare at one of our gas processing plants resulting in the flare exceeding its permitted emissions limits. Following information exchanges and discussions with CDPHE during the first and second quarters of 2019, a resolution was proposed that includes DCP completing a project to reduce levels of vapors directed to the flare to within existing permit limits in addition to us paying an administrative penalty of approximately $29,000 and making expenditures on an environmentally beneficial project of another $115,000. We are still holding discussions with CDPHE as to the foregoing amounts and proposed settlement terms.

Business Segments (Notes)

6 Months Ended

Jun. 30, 2019

Segment Reporting [Abstract]

Business Segments

Our operations are organized into two reportable segments: (i) Logistics and Marketing and (ii) Gathering and Processing. 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, 2018.

Our Logistics and Marketing segment includes transporting, trading, marketing, storing natural gas and NGLs, and fractionating NGLs. The operations of our wholesale propane business were included in our Logistics and Marketing segment through March 1, 2019. Our Gathering and Processing segment consists of gathering, compressing, treating, processing natural gas, producing and fractionating NGLs, and recovering condensate. 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 June 30, 2019:


	Logistics and Marketing		Gathering and Processing		Other		Eliminations		Total
	(millions)
Total operating revenue	$	1,613	$	1,024	$	—	$	(839)	1,798
Gross margin (a)	$	88	$	354	$	—	$	—	$	442
Operating and maintenance expense	(11)		(165)		(6)		—		(182)
Depreciation and amortization expense	(3)		(91)		(7)		—		(101)
General and administrative expense	(1)		(6)		(61)		—		(68)

Other expense, net	(1)		—		—		—		(1)

Loss on sale of assets, net	(1)		(4)		—		—		(5)
Restructuring costs	—		—		(9)		—		(9)
Earnings from unconsolidated affiliates	114		3		—		—		117
Interest expense	—		—		(73)		—		(73)

Net income (loss)	$	185	$	91	$	(156)	$	—	$	120
Net income attributable to noncontrolling interests	—		(1)		—		—		(1)
Net income (loss) attributable to partners	$	185	$	90	$	(156)	$	—	$	119
Non-cash derivative mark-to-market (b)	$	24	$	15	$	—	$	—	$	39
Non-cash lower of cost or market adjustments	$	3	$	—	$	—	$	—	$	3
Capital expenditures	$	11	$	111	$	4	$	—	$	126

Investments in unconsolidated affiliates, net	$	139	$	—	$	—	$	—	$	139

Three Months Ended June 30, 2018:


	Logistics and Marketing		Gathering and Processing		Other		Eliminations		Total
	(millions)
Total operating revenue	$	2,192	$	1,314	$	—	$	(1,189)	$	2,317
Gross margin (a)	$	56	$	333	$	—	$	—	$	389
Operating and maintenance expense	(11)		(169)		(5)		—		(185)
Depreciation and amortization expense	(3)		(87)		(7)		—		(97)
General and administrative expense	(3)		(2)		(65)		—		(70)

Other expense	(3)		—		—		—		(3)


Earnings from unconsolidated affiliates	94		2		—		—		96
Interest expense	—		—		(67)		—		(67)
Income tax expense	—		—		(1)		—		(1)

Net income (loss)	$	130	$	77	$	(145)	$	—	$	62
Net income attributable to noncontrolling interests	—		(1)		—		—		(1)
Net income (loss) attributable to partners	$	130	$	76	$	(145)	$	—	$	61

Non-cash derivative mark-to-market (b)	$	5	$	(42)	$	—	$	—	$	(37)

Capital expenditures	$	—	$	140	$	4	$	—	$	144

Investments in unconsolidated affiliates, net	$	66	$	—	$	—	$	—	$	66

Six Months Ended June 30, 2019:


	Logistics and Marketing		Gathering and Processing		Other		Eliminations		Total
	(millions)
Total operating revenue	$	3,658	$	2,312	$	—	$	(1,973)	$	3,997
Gross margin (a)	$	146	$	691	$	—	$	—	$	837
Operating and maintenance expense	(20)		(330)		(10)		—		(360)
Depreciation and amortization expense	(6)		(184)		(14)		—		(204)
General and administrative expense	(4)		(12)		(119)		—		(135)

Other expense, net	(1)		(5)		—		—		(6)

Loss on sale of assets, net	(10)		(4)		—		—		(14)
Restructuring costs	—		—		(9)		—		(9)
Earnings from unconsolidated affiliates	227		3		—		—		230
Interest expense	—		—		(142)		—		(142)
Income tax expense	—		—		(1)		—		(1)
Net income (loss)	$	332	$	159	$	(295)	$	—	$	196
Net income attributable to noncontrolling interests	—		(2)		—		—		(2)
Net income (loss) attributable to partners	$	332	$	157	$	(295)	$	—	$	194

Non-cash derivative mark-to-market (b)	$	6	$	(21)	$	—	$	—	$	(15)
Non-cash lower of cost or market adjustments	$	8	$	—	$	—	$	—	$	8
Capital expenditures	$	25	$	276	$	7	$	—	$	308

Investments in unconsolidated affiliates, net	$	270	$	—	$	—	$	—	$	270

Six Months Ended June 30, 2018:


	Logistics and Marketing		Gathering and Processing		Other		Eliminations		Total
	(millions)
Total operating revenue	$	4,171	$	2,600	$	—	$	(2,315)	$	4,456
Gross margin (a)	$	74	$	685	$	—	$	—	$	759
Operating and maintenance expense	(22)		(317)		(8)		—		(347)
Depreciation and amortization expense	(6)		(171)		(14)		—		(191)
General and administrative expense	(6)		(6)		(117)		—		(129)

Other expense, net	(2)		(3)		—		—		(5)


Earnings from unconsolidated affiliates	171		3		—		—		174
Interest expense	—		—		(134)		—		(134)
Income tax expense	—		—		(2)		—		(2)

Net income (loss)	$	209	$	191	$	(275)	$	—	$	125
Net income attributable to noncontrolling interests	—		(2)		—		—		(2)
Net income (loss) attributable to partners	$	209	$	189	$	(275)	$	—	$	123

Non-cash derivative mark-to-market (b)	$	(38)	$	(28)	$	—	$	—	$	(66)

Capital expenditures	$	1	$	260	$	7	$	—	$	268

Investments in unconsolidated affiliates, net	$	125	$	1	$	—	$	—	$	126


	June 30,		December 31,
	2019		2018
	(millions)
Segment long-term assets:
Gathering and Processing	$	9,100	$	9,058
Logistics and Marketing	3,823		3,661
Other (c)	287		276

Total long-term assets	13,210		12,995
Current assets	823		1,271
Total assets	$	14,033	$	14,266

(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.

Condensed Consolidating Financial Information (Notes)

6 Months Ended

Jun. 30, 2019

Condensed Financial Information Disclosure [Abstract]

Condensed Consolidating Financial Information

Condensed Consolidating Financial InformationThe 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
	June 30, 2019
	Parent Guarantor		Subsidiary Issuer		Non-Guarantor Subsidiaries		Consolidating Adjustments		Consolidated
	(millions)
ASSETS
Current assets:
Cash and cash equivalents	$	—	$	—	$	1	$	—	$	1

Accounts receivable, net	—		—		660		—		660
Inventories	—		—		46		—		46

Other	—		—		116		—		116
Total current assets	—		—		823		—		823
Property, plant and equipment, net	—		—		9,108		—		9,108
Goodwill and intangible assets, net	—		—		259		—		259
Advances receivable — consolidated subsidiaries	2,115		1,997		—		(4,112)		—
Investments in consolidated subsidiaries	5,012		8,445		—		(13,457)		—
Investments in unconsolidated affiliates	—		—		3,581		—		3,581
Other long-term assets	—		—		262		—		262
Total assets	$	7,127	$	10,442	$	14,033	$	(17,569)	$	14,033
LIABILITIES AND EQUITY
Accounts payable and other current liabilities	$	2	$	80	$	921	$	—	$	1,003
Current maturities of long-term debt	—		600		200		—		800
Advances payable — consolidated subsidiaries	—		—		4,112		(4,112)		—
Long-term debt	—		4,750		—		—		4,750
Other long-term liabilities	—		—		327		—		327
Total liabilities	2		5,430		5,560		(4,112)		6,880
Commitments and contingent liabilities
Equity:
Partners’ equity:

Net equity	7,125		5,015		8,450		(13,457)		7,133
Accumulated other comprehensive loss	—		(3)		(5)		—		(8)
Total partners’ equity	7,125		5,012		8,445		(13,457)		7,125
Noncontrolling interests	—		—		28		—		28
Total equity	7,125		5,012		8,473		(13,457)		7,153
Total liabilities and equity	$	7,127	$	10,442	$	14,033	$	(17,569)	$	14,033


	Condensed Consolidating Balance Sheets
	December 31, 2018
	Parent Guarantor		Subsidiary Issuer		Non-Guarantor Subsidiaries		Consolidating Adjustments		Consolidated
	(millions)
ASSETS
Current assets:
Cash and cash equivalents	$	—	$	—	$	1	$	—	$	1

Accounts receivable, net	—		—		1,033		—		1,033
Inventories	—		—		79		—		79

Other	—		—		158		—		158
Total current assets	—		—		1,271		—		1,271
Property, plant and equipment, net	—		—		9,135		—		9,135
Goodwill and intangible assets, net	—		—		328		—		328
Advances receivable — consolidated subsidiaries	2,452		1,883		—		(4,335)		—
Investments in consolidated subsidiaries	4,818		8,113		—		(12,931)		—
Investments in unconsolidated affiliates	—		—		3,340		—		3,340
Other long-term assets	—		—		192		—		192
Total assets	$	7,270	$	9,996	$	14,266	$	(17,266)	$	14,266
LIABILITIES AND EQUITY
Accounts payable and other current liabilities	$	2	$	71	$	1,306	$	—	$	1,379
Current maturities of long-term debt	—		325		200		—		525
Advances payable — consolidated subsidiaries	—		—		4,335		(4,335)		—
Long-term debt	—		4,782		—		—		4,782
Other long-term liabilities	—		—		283		—		283
Total liabilities	2		5,178		6,124		(4,335)		6,969
Commitments and contingent liabilities
Equity:
Partners’ equity:

Net equity	7,268		4,821		8,118		(12,931)		7,276
Accumulated other comprehensive loss	—		(3)		(5)		—		(8)
Total partners’ equity	7,268		4,818		8,113		(12,931)		7,268
Noncontrolling interests	—		—		29		—		29
Total equity	7,268		4,818		8,142		(12,931)		7,297
Total liabilities and equity	$	7,270	$	9,996	$	14,266	$	(17,266)	$	14,266


	Condensed Consolidating Statement of Operations
	Three Months Ended June 30, 2019
	Parent Guarantor		Subsidiary Issuer		Non- Guarantor Subsidiaries		Consolidating Adjustments		Consolidated
	(millions)
Operating revenues:
Sales of natural gas, NGLs and condensate	$	—	$	—	$	1,659	$	—	$	1,659
Transportation, processing and other	—		—		110		—		110
Trading and marketing gains, net	—		—		29		—		29
Total operating revenues	—		—		1,798		—		1,798
Operating costs and expenses:
Purchases and related costs	—		—		1,356		—		1,356
Operating and maintenance expense	—		—		182		—		182
Depreciation and amortization expense	—		—		101		—		101
General and administrative expense	—		—		68		—		68


Loss on sale of assets, net	—		—		5		—		5
Restructuring costs	—		—		9		—		9
Other expense, net	—		—		1		—		1
Total operating costs and expenses	—		—		1,722		—		1,722
Operating income	—		—		76		—		76

Interest expense, net	—		(71)		(2)		—		(73)
Income from consolidated subsidiaries	119		190		—		(309)		—
Earnings from unconsolidated affiliates	—		—		117		—		117
Income before income taxes	119		119		191		(309)		120
Income tax expense	—		—		—		—		—
Net income	119		119		191		(309)		120
Net income attributable to noncontrolling interests	$	—	$	—	$	(1)	$	—	$	(1)
Net income attributable to partners	119		119		190		(309)		119


	Condensed Consolidating Statement of Comprehensive Income
	Three Months Ended June 30, 2019
	Parent Guarantor		Subsidiary Issuer		Non-Guarantor Subsidiaries		Consolidating Adjustments		Consolidated
	(millions)
Net income	$	119	$	119	$	191	$	(309)	$	120
Other comprehensive income:



Total other comprehensive income	—		—		—		—		—
Total comprehensive income	119		119		191		(309)		120
Total comprehensive income attributable to noncontrolling interests	—		—		(1)		—		(1)
Total comprehensive income attributable to partners	$	119	$	119	$	190	$	(309)	$	119


	Condensed Consolidating Statement of Operations
	Three Months Ended June 30, 2018
	Parent Guarantor		Subsidiary Issuer		Non- Guarantor Subsidiaries		Consolidating Adjustments		Consolidated
	(millions)
Operating revenues:
Sales of natural gas, NGLs and condensate	$	—	$	—	$	2,257	$	—	$	2,257
Transportation, processing and other	—		—		127		—		127
Trading and marketing losses, net	—		—		(67)		—		(67)
Total operating revenues	—		—		2,317		—		2,317
Operating costs and expenses:
Purchases and related costs	—		—		1,928		—		1,928
Operating and maintenance expense	—		—		185		—		185
Depreciation and amortization expense	—		—		97		—		97
General and administrative expense	—		—		70		—		70




Other expense, net	—		—		3		—		3
Total operating costs and expenses	—		—		2,283		—		2,283
Operating income	—		—		34		—		34

Interest expense, net	—		(67)		—		—		(67)
Income from consolidated subsidiaries	61		128		—		(189)		—
Earnings from unconsolidated affiliates	—		—		96		—		96
Income before income taxes	61		61		130		(189)		63
Income tax expense	—		—		(1)		—		(1)
Net income	61		61		129		(189)		62
Net income attributable to noncontrolling interests	—		—		(1)		—		(1)
Net income attributable to partners	$	61	$	61	$	128	$	(189)	$	61


	Condensed Consolidating Statement of Comprehensive Income
	Three Months Ended June 30, 2018
	Parent Guarantor		Subsidiary Issuer		Non-Guarantor Subsidiaries		Consolidating Adjustments		Consolidated
	(millions)
Net income	$	61	$	61	$	129	$	(189)	$	62
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	62		62		129		(190)		63
Total comprehensive income attributable to noncontrolling interests	—		—		(1)		—		(1)
Total comprehensive income attributable to partners	$	62	$	62	$	128	$	(190)	$	62


	Condensed Consolidating Statement of Operations
	Six Months Ended June 30, 2019
	Parent Guarantor		Subsidiary Issuer		Non- Guarantor Subsidiaries		Consolidating Adjustments		Consolidated
	(millions)
Operating revenues:
Sales of natural gas, NGLs and condensate	$	—	$	—	$	3,770	$	—	$	3,770
Transportation, processing and other	—		—		225		—		225
Trading and marketing gains, net	—		—		2		—		2
Total operating revenues	—		—		3,997		—		3,997
Operating costs and expenses:
Purchases and related costs	—		—		3,160		—		3,160
Operating and maintenance expense	—		—		360		—		360
Depreciation and amortization expense	—		—		204		—		204
General and administrative expense	—		—		135		—		135


Loss on sale of assets, net	—		—		14		—		14
Restructuring costs	—		—		9		—		9
Other expense, net	—		—		6		—		6
Total operating costs and expenses	—		—		3,888		—		3,888
Operating income	—		—		109		—		109

Interest expense, net	—		(138)		(4)		—		(142)
Income from consolidated subsidiaries	194		332		—		(526)		—
Earnings from unconsolidated affiliates	—		—		230		—		230
Income before income taxes	194		194		335		(526)		197
Income tax expense	—		—		(1)		—		(1)
Net income	194		194		334		(526)		196
Net income attributable to noncontrolling interests	—		—		(2)		—		(2)
Net income attributable to partners	$	194	$	194	$	332	$	(526)	$	194


	Condensed Consolidating Statement of Comprehensive Income
	Six Months Ended June 30, 2019
	Parent Guarantor		Subsidiary Issuer		Non-Guarantor Subsidiaries		Consolidating Adjustments		Consolidated
	(millions)
Net income	$	194	$	194	$	334	$	(526)	$	196
Other comprehensive income:



Total other comprehensive income	—		—		—		—		—
Total comprehensive income	194		194		334		(526)		196
Total comprehensive income attributable to noncontrolling interests	—		—		(2)		—		(2)
Total comprehensive income attributable to partners	$	194	$	194	$	332	$	(526)	$	194


	Condensed Consolidating Statement of Operations
	Six Months Ended June 30, 2018
	Parent Guarantor		Subsidiary Issuer		Non- Guarantor Subsidiaries		Consolidating Adjustments		Consolidated
	(millions)
Operating revenues:
Sales of natural gas, NGLs and condensate	$	—	$	—	$	4,326	$	—	$	4,326
Transportation, processing and other	—		—		238		—		238
Trading and marketing losses, net	—		—		(108)		—		(108)
Total operating revenues	—		—		4,456		—		4,456
Operating costs and expenses:
Purchases and related costs	—		—		3,697		—		3,697
Operating and maintenance expense	—		—		347		—		347
Depreciation and amortization expense	—		—		191		—		191
General and administrative expense	—		—		129		—		129




Other expense, net	—		—		5		—		5
Total operating costs and expenses	—		—		4,369		—		4,369
Operating income	—		—		87		—		87

Interest expense, net	—		(134)		—		—		(134)
Income from consolidated subsidiaries	123		257		—		(380)		—
Earnings from unconsolidated affiliates	—		—		174		—		174
Income before income taxes	123		123		261		(380)		127
Income tax expense	—		—		(2)		—		(2)
Net income	123		123		259		(380)		125
Net income attributable to noncontrolling interests	—		—		(2)		—		(2)
Net income attributable to partners	$	123	$	123	$	257	$	(380)	$	123


	Condensed Consolidating Statement of Comprehensive Income
	Six Months Ended June 30, 2018
	Parent Guarantor		Subsidiary Issuer		Non-Guarantor Subsidiaries		Consolidating Adjustments		Consolidated
	(millions)
Net income	$	123	$	123	$	259	$	(380)	$	125
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	124		124		259		(381)		126
Total comprehensive income attributable to noncontrolling interests	—		—		(2)		—		(2)
Total comprehensive income attributable to partners	$	124	$	124	$	257	$	(381)	$	124


	Condensed Consolidating Statement of Cash Flows
	Six Months Ended June 30, 2019
	Parent Guarantor		Subsidiary Issuer		Non-Guarantor Subsidiaries		Consolidating Adjustments		Consolidated
	(millions)
OPERATING ACTIVITIES
Net cash (used in) provided by operating activities	$	—	$	(126)	$	672	$	—	$	546
INVESTING ACTIVITIES:
Intercompany transfers	337		(114)		—		(223)		—
Capital expenditures	—		—		(308)		—		(308)


Investments in unconsolidated affiliates, net	—		—		(270)		—		(270)
Proceeds from sale of assets	—		—		132		—		132
Net cash provided by (used in) investing activities	337		(114)		(446)		(223)		(446)
FINANCING ACTIVITIES:
Intercompany transfers	—		—		(223)		223		—
Proceeds from debt	—		3,457		—		—		3,457
Payments of debt	—		(3,208)		—		—		(3,208)


Distributions to preferred limited partners	(28)		—		—		—		(28)


Distributions to limited partners and general partner	(309)		—		—		—		(309)

Distributions to noncontrolling interests	—		—		(3)		—		(3)



Debt issuance costs	—		(9)		—		—		(9)
Net cash (used in) provided by financing activities	(337)		240		(226)		223		(100)
Net change in cash and cash equivalents	—		—		—		—		—
Cash and cash equivalents, beginning of period	—		—		1		—		1
Cash and cash equivalents, end of period	$	—	$	—	$	1	$	—	$	1


	Condensed Consolidating Statements of Cash Flows
	Six Months Ended June 30, 2018
	Parent Guarantor		Subsidiary Issuer		Non-Guarantor Subsidiaries		Consolidating Adjustments		Consolidated
	(millions)
OPERATING ACTIVITIES
Net cash (used in) provided by operating activities	$	—	$	(131)	$	462	$	—	$	331
INVESTING ACTIVITIES:
Intercompany transfers	215		(149)		—		(66)		—
Capital expenditures	—		—		(268)		—		(268)


Investments in unconsolidated affiliates, net	—		—		(126)		—		(126)

Proceeds from sale of assets	—		—		3		—		3

Net cash provided by (used in) investing activities	215		(149)		(391)		(66)		(391)
FINANCING ACTIVITIES:
Intercompany transfers	—		—		(66)		66		—
Proceeds from debt	—		1,803		—		—		1,803
Payments of debt	—		(1,678)		—		—		(1,678)

Proceeds from issuance of preferred limited partner units, net of offering costs	155		—		—		—		155
Distributions to preferred limited partners	(21)		—		—		—		(21)

Distributions to limited partners and general partner	(349)		—		—		—		(349)
Distributions to noncontrolling interests	—		—		(2)		—		(2)





Net cash (used in) provided by financing activities	(215)		125		(68)		66		(92)
Net change in cash and cash equivalents	—		(155)		3		—		(152)
Cash and cash equivalents, beginning of period	—		155		1		—		156
Cash and cash equivalents, end of period	$	—	$	—	$	4	$	—	$	4

Description of Business and Basis of Presentation (Policies)	6 Months Ended
	Jun. 30, 2019
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.
Business Description and Basis of Presentation [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. 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 (the 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 six months ended June 30, 2019 are not necessarily indicative of the results that may be expected for the year ending December 31, 2019. 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 2018 audited consolidated financial statements and notes thereto included in our Annual Report on Form 10-K for the year ended December 31, 2018.

Revenue Recognition (Tables)

6 Months Ended

Jun. 30, 2019

Disaggregation of Revenue [Line Items]

Disaggregation of Revenue [Table Text Block]


	Three Months Ended June 30, 2019
	Logistics and Marketing		Gathering and Processing		Eliminations		Total
	(millions)
Sales of natural gas	$	445	$	363	$	(320)	$	488
Sales of NGLs and condensate (a)	1,155		535		(519)		1,171
Transportation, processing and other	12		98		—		110

Trading and marketing gains, net (b)	1		28		—		29
Total operating revenues	$	1,613	$	1,024	$	(839)	$	1,798


	Six Months Ended June 30, 2019
	Logistics and Marketing		Gathering and Processing		Eliminations		Total
	(millions)
Sales of natural gas	$	1,082	$	920	$	(818)	$	1,184
Sales of NGLs and condensate (a)	2,558		1,183		(1,155)		2,586
Transportation, processing and other	24		201		—		225

Trading and marketing (losses) gains, net (b)	(6)		8		—		2
Total operating revenues	$	3,658	$	2,312	$	(1,973)	$	3,997

(b) Not within the scope of Topic 606.


	Three Months Ended June 30, 2018
	Logistics and Marketing		Gathering and Processing		Eliminations		Total
	(millions)
Sales of natural gas	$	463	$	398	$	(353)	$	508
Sales of NGLs and condensate (a)	1,714		870		(835)		1,749
Transportation, processing and other	16		112		(1)		127

Trading and marketing losses, net (b)	$	(1)	$	(66)	—		(67)
Total operating revenues	$	2,192	$	1,314	$	(1,189)	$	2,317


	Six Months Ended June 30, 2018
	Logistics and Marketing		Gathering and Processing		Eliminations		Total
	(millions)
Sales of natural gas	$	1,016	$	844	$	(772)	$	1,088
Sales of NGLs and condensate (a)	3,170		1,610		(1,542)		3,238
Transportation, processing and other	30		209		(1)		238

Trading and marketing losses, net (b)	$	(45)	$	(63)	—		(108)
Total operating revenues	$	4,171	$	2,600	$	(2,315)	$	4,456

(b) Not within the scope of Topic 606.

Investments in Unconsolidated Affiliates (Tables)

6 Months Ended

Jun. 30, 2019

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	June 30, 2019		December 31, 2018
		(millions)
DCP Sand Hills Pipeline, LLC	66.67%	$	1,781	$	1,791
DCP Southern Hills Pipeline, LLC	66.67%	731		728
Gulf Coast Express Pipeline LLC	25.00%	386		146
Discovery Producer Services LLC	40.00%	336		344
Front Range Pipeline LLC	33.33%	185		175
Texas Express Pipeline LLC	10.00%	101		95
Mont Belvieu Enterprise Fractionator	12.50%	27		24
Panola Pipeline Company, LLC	15.00%	21		23
Mont Belvieu 1 Fractionator	20.00%	9		10
Other	Various	4		4
Total investments in unconsolidated affiliates		$	3,581	$	3,340

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


	Three Months Ended June 30,						Six Months Ended June 30,
	2019		2018		2019		2018
	(millions)
DCP Sand Hills Pipeline, LLC	$	72	$	58	$	140	$	106
DCP Southern Hills Pipeline, LLC	22		16		45		29
Discovery Producer Services LLC	3		2		3		3
Front Range Pipeline LLC	9		5		16		10
Texas Express Pipeline LLC	4		8		9		10

Mont Belvieu Enterprise Fractionator	3		3		7		7
Mont Belvieu 1 Fractionator	4		4		8		8
Other	—		—		2		1
Total earnings from unconsolidated affiliates	$	117	$	96	$	230	$	174

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 June 30,						Six Months Ended June 30,
	2019		2018		2019		2018
	(millions)
Statements of operations:
Operating revenue	$	432	$	408	$	853	$	742
Operating expenses	$	162	$	147	$	353	$	286
Net income	$	269	$	260	$	500	$	454

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


	June 30, 2019		December 31, 2018
	(millions)
Balance sheets:
Current assets	$	409	$	411
Long-term assets	7,282		6,359
Current liabilities	(366)		(424)
Long-term liabilities	(259)		(221)
Net assets	$	7,066	$	6,125

Fair Value Measurement (Tables)

6 Months Ended

Jun. 30, 2019

Fair Value Disclosures [Abstract]

Financial Instruments Carried at Fair Value


	June 30, 2019														December 31, 2018
	Level 1		Level 2		Level 3		Total Carrying Value		Level 1		Level 2		Level 3		Total Carrying Value
	(millions)
Current assets:
Commodity derivatives	$	31	$	27	$	8	$	66	$	62	$	32	$	14	$	108


Long-term assets:
Commodity derivatives	$	—	$	3	$	2	$	5	$	4	$	2	$	2	$	8

Current liabilities:
Commodity derivatives	$	(26)	$	(27)	$	(1)	$	(54)	$	(39)	$	(52)	$	—	$	(91)


Long-term liabilities:
Commodity derivatives	$	—	$	(5)	$	—	$	(5)	$	(1)	$	(5)	$	(2)	$	(8)

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 June 30, 2019 (a):
Beginning balance	$	5	$	1	$	(1)	$	(1)
Net unrealized gains included in earnings (b)	$	10	1		1		1

Transfers out of Level 3 (c)	(6)		—		—		—
Settlements	(1)		—		(1)		—


Ending balance	$	8	$	2	$	(1)	$	—
Net unrealized gains on derivatives still held included in earnings (b)	$	7	$	1	$	—	$	—
Three months ended June 30, 2018 (a):
Beginning balance	$	2	$	—	$	(6)	$	(3)
Net unrealized gains (losses) included in earnings (b)	1		1		(14)		(4)

Transfers out of Level 3 (c)	(2)		—		8		—
Settlements	—		—		2		—


Ending balance	$	1	$	1	$	(10)	$	(7)
Net unrealized gains (losses) on derivatives still held included in earnings (b)	$	1	$	1	$	(8)	$	(4)


	Commodity Derivative Instruments
	Current Assets		Long-Term Assets		Current Liabilities		Long-Term Liabilities
	(millions)
Six months ended June 30, 2019 (a):
Beginning balance	$	14	$	2	$	—	$	(2)
Net unrealized gains (losses) included in earnings (b)	8		2		(1)		1

Transfers out of Level 3 (c)	(8)		(2)		—		1
Settlements	(6)		—		—		—


Ending balance	$	8	$	2	$	(1)	$	—
Net unrealized gains (losses) on derivatives still held included in earnings (b)	$	7	$	1	$	(1)	$	—
Six months ended June 30, 2018 (a):
Beginning balance	$	3	$	1	$	(13)	$	(1)
Net unrealized losses included in earnings (b)	—		—		(12)		(6)

Transfers out of Level 3 (c)	(2)		—		12		—
Settlements	—		—		3		—


Ending balance	$	1	$	1	$	(10)	$	(7)
Net unrealized gains (losses) on derivatives still held included in earnings (b)	$	1	$	—	$	(7)	$	(6)

(a)There were no purchases, issuances or sales of derivatives or transfers into Level 3 for the three and six months ended June 30, 2019 and 2018.

(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


	June 30, 2019
Product Group	Fair Value		Forward Curve Range
	(millions)
Assets
NGLs	$	8	$0.20-$1.15	Per gallon
Natural gas	$	2	$2.09-$2.73	Per MMBtu
Liabilities
NGLs	$	(1)	$0.09-$1.15	Per gallon

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

June 30, 2019 and December 31, 2018, the carrying value and fair value of our total debt, including current maturities, were as follows:


		June 30, 2019						December 31, 2018
		Carrying Value (a)		Fair Value		Carrying Value (a)		Fair Value
	(millions)


Total debt		$	5,586	$	5,743	$	5,337	$	5,170

(a) Excludes unamortized issuance costs.

Leases (Tables)

6 Months Ended

Jun. 30, 2019

Jun. 30, 2018

Leases [Abstract]

Schedule of Leasing Assets and Liabilities [Table Text Block]


	As of
	June 30, 2019
	(millions)
Operating lease assets	$	69

Operating lease liabilities	$	57
Other current liabilities	18
Total	$	75

Lease, Cost [Table Text Block]


	Three Months Ended		Six Months Ended
	June 30, 2019		June 30, 2019
	(millions)
Operating lease cost	$	5	$	11
Variable lease cost	1		3
Short term lease cost	1		2
Total lease cost	$	7	$	16

Lessee, Operating Lease, Liability, Maturity [Table Text Block]


	Future Minimum Rental Payments as of June 30, 2019
	(millions)
2019 - remainder	$	10
2020	21
2021	19
2022	14
2023	8
Thereafter	11
Total lease payments	$	83
Less imputed interest	(8)
Total operating lease liabilities	$	75

Leases - Other Information


	Six Months Ended
	June 30, 2019
	(millions)
Cash paid for amounts included in the measurement of operating lease liabilities:	$	12
Right-of-use assets obtained in exchange for operating lease obligations:	$	6

Other information related to operating leases as follows:
Weighted average remaining lease term	5 years
Weighted average discount rate	4.00		%

Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]

Minimum rental payments under our various operating leases in the year indicated were as follows as of December 31, 2018:


	Future Minimum Rental Payments as of December 31, 2018
	(millions)
2019	$	22
2020	18
2021	14
2022	9
2023	5
Thereafter	7
Total minimum rental payments	$	75

Debt (Tables)

6 Months Ended

Jun. 30, 2019

Debt Disclosure [Abstract]

Schedule of Debt


	June 30, 2019		December 31, 2018
	(millions)




Senior notes:


Issued March 2014, interest at 2.700% payable semi-annually, due April 2019	—		325
Issued March 2010, interest at 5.350% payable semi-annually, due March 2020 (a)	600		600
Issued September 2011, interest at 4.750% payable semi-annually, 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 and January 2019, interest at 5.375% payable semi-annually, due July 2025	825		500
Issued May 2019, interest at 5.125% payable semi-annually, due May 2029	600		—
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 3.901%, as of December 31, 2018, due December 2022	—		351
Accounts receivable securitization facility:
Accounts receivable securitization facility, weighted-average variable interest rate of 3.20% as of June 30, 2019, due August 2019	200		200
Fair value adjustments related to interest rate swap fair value hedges (a)	20		21
Unamortized issuance costs	(36)		(30)
Unamortized discount	(9)		(10)
Total debt	5,550		5,307

Current debt	800		525
Total long-term debt	$	4,750	$	4,782

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

$20 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 June 30, 2019 are as follows:


	Debt Maturities
	(millions)

2019	$	200
2020	600
2021	500
2022	350
2023	500
Thereafter	3,425
Total debt	$	5,575

Risk Management and Hedging Activities (Tables)

6 Months Ended

Jun. 30, 2019

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Summary of Gross and Net Amounts of Derivative Instruments


	June 30, 2019										December 31, 2018
	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	$	71	$	—	$	71	$	116	$	—	$	116

Liabilities:
Commodity derivatives	$	(59)	$	—	$	(59)	$	(99)	$	—	$	(99)

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


Balance Sheet Line Item	June 30, 2019		December 31, 2018		Balance Sheet Line Item	June 30, 2019			December 31, 2018
	(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	$	66	$	108	Unrealized losses on derivative instruments — current	$	(54)		$	(91)
Unrealized gains on derivative instruments — long-term	5		8		Unrealized losses on derivative instruments — long-term	(5)			(8)
Total	$	71	$	116	Total	$	(59)		$	(99)

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 June 30, 2019:


	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)


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)

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 six months ended June 30, 2019:


	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)


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 June 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)

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 six months ended June 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)

(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 June 30,						Six Months Ended June 30,
	2019		2018		2019		2018
	(millions)
Realized (losses) gains	$	(10)	$	(30)	$	17	$	(42)
Unrealized gains (losses)	39		(37)		(15)		(66)
Trading and marketing gains (losses), net	$	29	$	(67)	$	2	$	(108)

Schedule of Net Long or Short Positions Expected to be Realized


	June 30, 2019
	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 Long (Short) Position (MMBtu)
2019	(1,011,000)	(20,299,550)	(20,528,570)	2,000,000
2020	(664,000)	(3,790,000)	(14,847,743)	3,125,000
2021	(100,000)	—	(5,519,594)	(4,562,500)
2022	—	—	(689)	8,212,500
2023	—	—	—	7,300,000

	June 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 Long Position (MMBtu)

2018	(1,646,000)	(21,623,200)	(25,737,691)	2,257,500
2019	(1,900,000)	—	(19,314,335)	1,512,500
2020	(128,000)	—	(13,568,452)	3,660,000
2021	—	—	(5,750,000)	—

Business Segments (Tables)

6 Months Ended

Jun. 30, 2019

Segment Reporting [Abstract]

Segment Information

Three Months Ended June 30, 2019:


	Logistics and Marketing		Gathering and Processing		Other		Eliminations		Total
	(millions)
Total operating revenue	$	1,613	$	1,024	$	—	$	(839)	1,798
Gross margin (a)	$	88	$	354	$	—	$	—	$	442
Operating and maintenance expense	(11)		(165)		(6)		—		(182)
Depreciation and amortization expense	(3)		(91)		(7)		—		(101)
General and administrative expense	(1)		(6)		(61)		—		(68)

Other expense, net	(1)		—		—		—		(1)

Loss on sale of assets, net	(1)		(4)		—		—		(5)
Restructuring costs	—		—		(9)		—		(9)
Earnings from unconsolidated affiliates	114		3		—		—		117
Interest expense	—		—		(73)		—		(73)

Net income (loss)	$	185	$	91	$	(156)	$	—	$	120
Net income attributable to noncontrolling interests	—		(1)		—		—		(1)
Net income (loss) attributable to partners	$	185	$	90	$	(156)	$	—	$	119
Non-cash derivative mark-to-market (b)	$	24	$	15	$	—	$	—	$	39
Non-cash lower of cost or market adjustments	$	3	$	—	$	—	$	—	$	3
Capital expenditures	$	11	$	111	$	4	$	—	$	126

Investments in unconsolidated affiliates, net	$	139	$	—	$	—	$	—	$	139

Three Months Ended June 30, 2018:


	Logistics and Marketing		Gathering and Processing		Other		Eliminations		Total
	(millions)
Total operating revenue	$	2,192	$	1,314	$	—	$	(1,189)	$	2,317
Gross margin (a)	$	56	$	333	$	—	$	—	$	389
Operating and maintenance expense	(11)		(169)		(5)		—		(185)
Depreciation and amortization expense	(3)		(87)		(7)		—		(97)
General and administrative expense	(3)		(2)		(65)		—		(70)

Other expense	(3)		—		—		—		(3)


Earnings from unconsolidated affiliates	94		2		—		—		96
Interest expense	—		—		(67)		—		(67)
Income tax expense	—		—		(1)		—		(1)

Net income (loss)	$	130	$	77	$	(145)	$	—	$	62
Net income attributable to noncontrolling interests	—		(1)		—		—		(1)
Net income (loss) attributable to partners	$	130	$	76	$	(145)	$	—	$	61

Non-cash derivative mark-to-market (b)	$	5	$	(42)	$	—	$	—	$	(37)

Capital expenditures	$	—	$	140	$	4	$	—	$	144

Investments in unconsolidated affiliates, net	$	66	$	—	$	—	$	—	$	66

Six Months Ended June 30, 2019:


	Logistics and Marketing		Gathering and Processing		Other		Eliminations		Total
	(millions)
Total operating revenue	$	3,658	$	2,312	$	—	$	(1,973)	$	3,997
Gross margin (a)	$	146	$	691	$	—	$	—	$	837
Operating and maintenance expense	(20)		(330)		(10)		—		(360)
Depreciation and amortization expense	(6)		(184)		(14)		—		(204)
General and administrative expense	(4)		(12)		(119)		—		(135)

Other expense, net	(1)		(5)		—		—		(6)

Loss on sale of assets, net	(10)		(4)		—		—		(14)
Restructuring costs	—		—		(9)		—		(9)
Earnings from unconsolidated affiliates	227		3		—		—		230
Interest expense	—		—		(142)		—		(142)
Income tax expense	—		—		(1)		—		(1)
Net income (loss)	$	332	$	159	$	(295)	$	—	$	196
Net income attributable to noncontrolling interests	—		(2)		—		—		(2)
Net income (loss) attributable to partners	$	332	$	157	$	(295)	$	—	$	194

Non-cash derivative mark-to-market (b)	$	6	$	(21)	$	—	$	—	$	(15)
Non-cash lower of cost or market adjustments	$	8	$	—	$	—	$	—	$	8
Capital expenditures	$	25	$	276	$	7	$	—	$	308

Investments in unconsolidated affiliates, net	$	270	$	—	$	—	$	—	$	270

Six Months Ended June 30, 2018:


	Logistics and Marketing		Gathering and Processing		Other		Eliminations		Total
	(millions)
Total operating revenue	$	4,171	$	2,600	$	—	$	(2,315)	$	4,456
Gross margin (a)	$	74	$	685	$	—	$	—	$	759
Operating and maintenance expense	(22)		(317)		(8)		—		(347)
Depreciation and amortization expense	(6)		(171)		(14)		—		(191)
General and administrative expense	(6)		(6)		(117)		—		(129)

Other expense, net	(2)		(3)		—		—		(5)


Earnings from unconsolidated affiliates	171		3		—		—		174
Interest expense	—		—		(134)		—		(134)
Income tax expense	—		—		(2)		—		(2)

Net income (loss)	$	209	$	191	$	(275)	$	—	$	125
Net income attributable to noncontrolling interests	—		(2)		—		—		(2)
Net income (loss) attributable to partners	$	209	$	189	$	(275)	$	—	$	123

Non-cash derivative mark-to-market (b)	$	(38)	$	(28)	$	—	$	—	$	(66)

Capital expenditures	$	1	$	260	$	7	$	—	$	268

Investments in unconsolidated affiliates, net	$	125	$	1	$	—	$	—	$	126


	June 30,		December 31,
	2019		2018
	(millions)
Segment long-term assets:
Gathering and Processing	$	9,100	$	9,058
Logistics and Marketing	3,823		3,661
Other (c)	287		276

Total long-term assets	13,210		12,995
Current assets	823		1,271
Total assets	$	14,033	$	14,266

(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.

Condensed Consolidating Financial Information (Tables)

6 Months Ended

Jun. 30, 2019

Condensed Financial Information Disclosure [Abstract]

Condensed Consolidating Balance Sheets


	Condensed Consolidating Balance Sheets
	June 30, 2019
	Parent Guarantor		Subsidiary Issuer		Non-Guarantor Subsidiaries		Consolidating Adjustments		Consolidated
	(millions)
ASSETS
Current assets:
Cash and cash equivalents	$	—	$	—	$	1	$	—	$	1

Accounts receivable, net	—		—		660		—		660
Inventories	—		—		46		—		46

Other	—		—		116		—		116
Total current assets	—		—		823		—		823
Property, plant and equipment, net	—		—		9,108		—		9,108
Goodwill and intangible assets, net	—		—		259		—		259
Advances receivable — consolidated subsidiaries	2,115		1,997		—		(4,112)		—
Investments in consolidated subsidiaries	5,012		8,445		—		(13,457)		—
Investments in unconsolidated affiliates	—		—		3,581		—		3,581
Other long-term assets	—		—		262		—		262
Total assets	$	7,127	$	10,442	$	14,033	$	(17,569)	$	14,033
LIABILITIES AND EQUITY
Accounts payable and other current liabilities	$	2	$	80	$	921	$	—	$	1,003
Current maturities of long-term debt	—		600		200		—		800
Advances payable — consolidated subsidiaries	—		—		4,112		(4,112)		—
Long-term debt	—		4,750		—		—		4,750
Other long-term liabilities	—		—		327		—		327
Total liabilities	2		5,430		5,560		(4,112)		6,880
Commitments and contingent liabilities
Equity:
Partners’ equity:

Net equity	7,125		5,015		8,450		(13,457)		7,133
Accumulated other comprehensive loss	—		(3)		(5)		—		(8)
Total partners’ equity	7,125		5,012		8,445		(13,457)		7,125
Noncontrolling interests	—		—		28		—		28
Total equity	7,125		5,012		8,473		(13,457)		7,153
Total liabilities and equity	$	7,127	$	10,442	$	14,033	$	(17,569)	$	14,033


	Condensed Consolidating Balance Sheets
	December 31, 2018
	Parent Guarantor		Subsidiary Issuer		Non-Guarantor Subsidiaries		Consolidating Adjustments		Consolidated
	(millions)
ASSETS
Current assets:
Cash and cash equivalents	$	—	$	—	$	1	$	—	$	1

Accounts receivable, net	—		—		1,033		—		1,033
Inventories	—		—		79		—		79

Other	—		—		158		—		158
Total current assets	—		—		1,271		—		1,271
Property, plant and equipment, net	—		—		9,135		—		9,135
Goodwill and intangible assets, net	—		—		328		—		328
Advances receivable — consolidated subsidiaries	2,452		1,883		—		(4,335)		—
Investments in consolidated subsidiaries	4,818		8,113		—		(12,931)		—
Investments in unconsolidated affiliates	—		—		3,340		—		3,340
Other long-term assets	—		—		192		—		192
Total assets	$	7,270	$	9,996	$	14,266	$	(17,266)	$	14,266
LIABILITIES AND EQUITY
Accounts payable and other current liabilities	$	2	$	71	$	1,306	$	—	$	1,379
Current maturities of long-term debt	—		325		200		—		525
Advances payable — consolidated subsidiaries	—		—		4,335		(4,335)		—
Long-term debt	—		4,782		—		—		4,782
Other long-term liabilities	—		—		283		—		283
Total liabilities	2		5,178		6,124		(4,335)		6,969
Commitments and contingent liabilities
Equity:
Partners’ equity:

Net equity	7,268		4,821		8,118		(12,931)		7,276
Accumulated other comprehensive loss	—		(3)		(5)		—		(8)
Total partners’ equity	7,268		4,818		8,113		(12,931)		7,268
Noncontrolling interests	—		—		29		—		29
Total equity	7,268		4,818		8,142		(12,931)		7,297
Total liabilities and equity	$	7,270	$	9,996	$	14,266	$	(17,266)	$	14,266

Condensed Income Statement and Statement of Comprehensive Income


	Condensed Consolidating Statement of Operations
	Three Months Ended June 30, 2019
	Parent Guarantor		Subsidiary Issuer		Non- Guarantor Subsidiaries		Consolidating Adjustments		Consolidated
	(millions)
Operating revenues:
Sales of natural gas, NGLs and condensate	$	—	$	—	$	1,659	$	—	$	1,659
Transportation, processing and other	—		—		110		—		110
Trading and marketing gains, net	—		—		29		—		29
Total operating revenues	—		—		1,798		—		1,798
Operating costs and expenses:
Purchases and related costs	—		—		1,356		—		1,356
Operating and maintenance expense	—		—		182		—		182
Depreciation and amortization expense	—		—		101		—		101
General and administrative expense	—		—		68		—		68


Loss on sale of assets, net	—		—		5		—		5
Restructuring costs	—		—		9		—		9
Other expense, net	—		—		1		—		1
Total operating costs and expenses	—		—		1,722		—		1,722
Operating income	—		—		76		—		76

Interest expense, net	—		(71)		(2)		—		(73)
Income from consolidated subsidiaries	119		190		—		(309)		—
Earnings from unconsolidated affiliates	—		—		117		—		117
Income before income taxes	119		119		191		(309)		120
Income tax expense	—		—		—		—		—
Net income	119		119		191		(309)		120
Net income attributable to noncontrolling interests	$	—	$	—	$	(1)	$	—	$	(1)
Net income attributable to partners	119		119		190		(309)		119


	Condensed Consolidating Statement of Comprehensive Income
	Three Months Ended June 30, 2019
	Parent Guarantor		Subsidiary Issuer		Non-Guarantor Subsidiaries		Consolidating Adjustments		Consolidated
	(millions)
Net income	$	119	$	119	$	191	$	(309)	$	120
Other comprehensive income:



Total other comprehensive income	—		—		—		—		—
Total comprehensive income	119		119		191		(309)		120
Total comprehensive income attributable to noncontrolling interests	—		—		(1)		—		(1)
Total comprehensive income attributable to partners	$	119	$	119	$	190	$	(309)	$	119


	Condensed Consolidating Statement of Operations
	Three Months Ended June 30, 2018
	Parent Guarantor		Subsidiary Issuer		Non- Guarantor Subsidiaries		Consolidating Adjustments		Consolidated
	(millions)
Operating revenues:
Sales of natural gas, NGLs and condensate	$	—	$	—	$	2,257	$	—	$	2,257
Transportation, processing and other	—		—		127		—		127
Trading and marketing losses, net	—		—		(67)		—		(67)
Total operating revenues	—		—		2,317		—		2,317
Operating costs and expenses:
Purchases and related costs	—		—		1,928		—		1,928
Operating and maintenance expense	—		—		185		—		185
Depreciation and amortization expense	—		—		97		—		97
General and administrative expense	—		—		70		—		70




Other expense, net	—		—		3		—		3
Total operating costs and expenses	—		—		2,283		—		2,283
Operating income	—		—		34		—		34

Interest expense, net	—		(67)		—		—		(67)
Income from consolidated subsidiaries	61		128		—		(189)		—
Earnings from unconsolidated affiliates	—		—		96		—		96
Income before income taxes	61		61		130		(189)		63
Income tax expense	—		—		(1)		—		(1)
Net income	61		61		129		(189)		62
Net income attributable to noncontrolling interests	—		—		(1)		—		(1)
Net income attributable to partners	$	61	$	61	$	128	$	(189)	$	61


	Condensed Consolidating Statement of Comprehensive Income
	Three Months Ended June 30, 2018
	Parent Guarantor		Subsidiary Issuer		Non-Guarantor Subsidiaries		Consolidating Adjustments		Consolidated
	(millions)
Net income	$	61	$	61	$	129	$	(189)	$	62
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	62		62		129		(190)		63
Total comprehensive income attributable to noncontrolling interests	—		—		(1)		—		(1)
Total comprehensive income attributable to partners	$	62	$	62	$	128	$	(190)	$	62


	Condensed Consolidating Statement of Operations
	Six Months Ended June 30, 2019
	Parent Guarantor		Subsidiary Issuer		Non- Guarantor Subsidiaries		Consolidating Adjustments		Consolidated
	(millions)
Operating revenues:
Sales of natural gas, NGLs and condensate	$	—	$	—	$	3,770	$	—	$	3,770
Transportation, processing and other	—		—		225		—		225
Trading and marketing gains, net	—		—		2		—		2
Total operating revenues	—		—		3,997		—		3,997
Operating costs and expenses:
Purchases and related costs	—		—		3,160		—		3,160
Operating and maintenance expense	—		—		360		—		360
Depreciation and amortization expense	—		—		204		—		204
General and administrative expense	—		—		135		—		135


Loss on sale of assets, net	—		—		14		—		14
Restructuring costs	—		—		9		—		9
Other expense, net	—		—		6		—		6
Total operating costs and expenses	—		—		3,888		—		3,888
Operating income	—		—		109		—		109

Interest expense, net	—		(138)		(4)		—		(142)
Income from consolidated subsidiaries	194		332		—		(526)		—
Earnings from unconsolidated affiliates	—		—		230		—		230
Income before income taxes	194		194		335		(526)		197
Income tax expense	—		—		(1)		—		(1)
Net income	194		194		334		(526)		196
Net income attributable to noncontrolling interests	—		—		(2)		—		(2)
Net income attributable to partners	$	194	$	194	$	332	$	(526)	$	194


	Condensed Consolidating Statement of Comprehensive Income
	Six Months Ended June 30, 2019
	Parent Guarantor		Subsidiary Issuer		Non-Guarantor Subsidiaries		Consolidating Adjustments		Consolidated
	(millions)
Net income	$	194	$	194	$	334	$	(526)	$	196
Other comprehensive income:



Total other comprehensive income	—		—		—		—		—
Total comprehensive income	194		194		334		(526)		196
Total comprehensive income attributable to noncontrolling interests	—		—		(2)		—		(2)
Total comprehensive income attributable to partners	$	194	$	194	$	332	$	(526)	$	194


	Condensed Consolidating Statement of Operations
	Six Months Ended June 30, 2018
	Parent Guarantor		Subsidiary Issuer		Non- Guarantor Subsidiaries		Consolidating Adjustments		Consolidated
	(millions)
Operating revenues:
Sales of natural gas, NGLs and condensate	$	—	$	—	$	4,326	$	—	$	4,326
Transportation, processing and other	—		—		238		—		238
Trading and marketing losses, net	—		—		(108)		—		(108)
Total operating revenues	—		—		4,456		—		4,456
Operating costs and expenses:
Purchases and related costs	—		—		3,697		—		3,697
Operating and maintenance expense	—		—		347		—		347
Depreciation and amortization expense	—		—		191		—		191
General and administrative expense	—		—		129		—		129




Other expense, net	—		—		5		—		5
Total operating costs and expenses	—		—		4,369		—		4,369
Operating income	—		—		87		—		87

Interest expense, net	—		(134)		—		—		(134)
Income from consolidated subsidiaries	123		257		—		(380)		—
Earnings from unconsolidated affiliates	—		—		174		—		174
Income before income taxes	123		123		261		(380)		127
Income tax expense	—		—		(2)		—		(2)
Net income	123		123		259		(380)		125
Net income attributable to noncontrolling interests	—		—		(2)		—		(2)
Net income attributable to partners	$	123	$	123	$	257	$	(380)	$	123


	Condensed Consolidating Statement of Comprehensive Income
	Six Months Ended June 30, 2018
	Parent Guarantor		Subsidiary Issuer		Non-Guarantor Subsidiaries		Consolidating Adjustments		Consolidated
	(millions)
Net income	$	123	$	123	$	259	$	(380)	$	125
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	124		124		259		(381)		126
Total comprehensive income attributable to noncontrolling interests	—		—		(2)		—		(2)
Total comprehensive income attributable to partners	$	124	$	124	$	257	$	(381)	$	124

Condensed Consolidating Statements of Cash Flows


	Condensed Consolidating Statement of Cash Flows
	Six Months Ended June 30, 2019
	Parent Guarantor		Subsidiary Issuer		Non-Guarantor Subsidiaries		Consolidating Adjustments		Consolidated
	(millions)
OPERATING ACTIVITIES
Net cash (used in) provided by operating activities	$	—	$	(126)	$	672	$	—	$	546
INVESTING ACTIVITIES:
Intercompany transfers	337		(114)		—		(223)		—
Capital expenditures	—		—		(308)		—		(308)


Investments in unconsolidated affiliates, net	—		—		(270)		—		(270)
Proceeds from sale of assets	—		—		132		—		132
Net cash provided by (used in) investing activities	337		(114)		(446)		(223)		(446)
FINANCING ACTIVITIES:
Intercompany transfers	—		—		(223)		223		—
Proceeds from debt	—		3,457		—		—		3,457
Payments of debt	—		(3,208)		—		—		(3,208)


Distributions to preferred limited partners	(28)		—		—		—		(28)


Distributions to limited partners and general partner	(309)		—		—		—		(309)

Distributions to noncontrolling interests	—		—		(3)		—		(3)



Debt issuance costs	—		(9)		—		—		(9)
Net cash (used in) provided by financing activities	(337)		240		(226)		223		(100)
Net change in cash and cash equivalents	—		—		—		—		—
Cash and cash equivalents, beginning of period	—		—		1		—		1
Cash and cash equivalents, end of period	$	—	$	—	$	1	$	—	$	1


	Condensed Consolidating Statements of Cash Flows
	Six Months Ended June 30, 2018
	Parent Guarantor		Subsidiary Issuer		Non-Guarantor Subsidiaries		Consolidating Adjustments		Consolidated
	(millions)
OPERATING ACTIVITIES
Net cash (used in) provided by operating activities	$	—	$	(131)	$	462	$	—	$	331
INVESTING ACTIVITIES:
Intercompany transfers	215		(149)		—		(66)		—
Capital expenditures	—		—		(268)		—		(268)


Investments in unconsolidated affiliates, net	—		—		(126)		—		(126)

Proceeds from sale of assets	—		—		3		—		3

Net cash provided by (used in) investing activities	215		(149)		(391)		(66)		(391)
FINANCING ACTIVITIES:
Intercompany transfers	—		—		(66)		66		—
Proceeds from debt	—		1,803		—		—		1,803
Payments of debt	—		(1,678)		—		—		(1,678)

Proceeds from issuance of preferred limited partner units, net of offering costs	155		—		—		—		155
Distributions to preferred limited partners	(21)		—		—		—		(21)

Distributions to limited partners and general partner	(349)		—		—		—		(349)
Distributions to noncontrolling interests	—		—		(2)		—		(2)





Net cash (used in) provided by financing activities	(215)		125		(68)		66		(92)
Net change in cash and cash equivalents	—		(155)		3		—		(152)
Cash and cash equivalents, beginning of period	—		155		1		—		156
Cash and cash equivalents, end of period	$	—	$	—	$	4	$	—	$	4

Description of Business and Basis of Presentation - Additional Information (Detail)	6 Months Ended
	Jun. 30, 2019
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%

Accounting Policies (Details)	6 Months Ended
Accounting Policies (Details)	Jun. 30, 2019
Accounting Policies [Abstract]
New Accounting Pronouncement or Change in Accounting Principle, Description	Update to Significant Accounting Policies Our significant accounting policies are detailed in Note 2 - Summary of Significant Accounting Policies of our Annual Report on Form 10-K for the year ended December 31, 2018. Significant changes to our accounting policies as a result of Topic 842 (as defined below) are discussed below:Leases - Our leasing activity primarily consists of transportation agreements, office space, vehicles, compressors and field equipment. We determine if an arrangement is an operating or finance lease at inception. Right of use assets represent our right to use an underlying asset for the lease term when we control the use of the asset by obtaining substantially all of the economic benefits of the asset and direct the use of the asset. Lease liabilities represent our obligation to make lease payments arising from the lease. Operating lease right of use assets and lease liabilities are recognized at the commencement date based on the present value of lease payments over the lease term. The interest rate used to calculate the present value of lease payments is the rate implicit in the lease when determinable or our incremental borrowing rate. Our incremental borrowing rate is primarily based on our collateralized borrowing rate when such borrowings exist or an estimated collateralized borrowing rate based on independent third party quotes when such borrowings do not exist. Our lease terms may include options to extend or terminate the lease when it is reasonably certain that we will exercise that option. Operating lease expense is recognized on a straight-line basis over the lease term.

- Definition

Disclosure related to a new accounting pronouncement or a change in accounting principle, including the nature and reason for the change and the effect of the change on prior periods and the current period.

+ References + Details

Revenue Recognition (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
Revenue Recognition (Details) - USD ($) $ in Millions	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Disaggregation of Revenue [Line Items]
Sales of natural gas, NGLs and condensate	$ 110	$ 127	$ 225	$ 238
Trading and marketing losses, net	29	(67)	2	(108)
Total operating revenues	1,798	2,317	3,997	4,456
Revenue, Remaining Performance Obligation, Amount	204		204
Revenue from contract with customer not within the scope of Topic 606	822	1,108	1,680	1,901
NGLs and Condensate [Member]
Disaggregation of Revenue [Line Items]
Sales of natural gas, NGLs and condensate	1,171	1,749	2,586	3,238
Natural Gas
Disaggregation of Revenue [Line Items]
Sales of natural gas, NGLs and condensate	488	508	1,184	1,088
Gathering and Processing
Disaggregation of Revenue [Line Items]
Sales of natural gas, NGLs and condensate	98	112	201	209
Trading and marketing losses, net	28	(66)	8	(63)
Total operating revenues	1,024	1,314	2,312	2,600
Gathering and Processing \| NGLs and Condensate [Member]
Disaggregation of Revenue [Line Items]
Sales of natural gas, NGLs and condensate	535	870	1,183	1,610
Gathering and Processing \| Natural Gas
Disaggregation of Revenue [Line Items]
Sales of natural gas, NGLs and condensate	363	398	920	844
Logistics and Marketing
Disaggregation of Revenue [Line Items]
Sales of natural gas, NGLs and condensate	12	16	24	30
Trading and marketing losses, net	1	(1)	(6)	(45)
Total operating revenues	1,613	2,192	3,658	4,171
Logistics and Marketing \| NGLs and Condensate [Member]
Disaggregation of Revenue [Line Items]
Sales of natural gas, NGLs and condensate	1,155	1,714	2,558	3,170
Logistics and Marketing \| Natural Gas
Disaggregation of Revenue [Line Items]
Sales of natural gas, NGLs and condensate	445	463	1,082	1,016
Eliminations
Disaggregation of Revenue [Line Items]
Sales of natural gas, NGLs and condensate		(1)	0	(1)
Trading and marketing losses, net		0	0	0
Total operating revenues	(839)	(1,189)	(1,973)	(2,315)
Eliminations \| NGLs and Condensate [Member]
Disaggregation of Revenue [Line Items]
Sales of natural gas, NGLs and condensate	(519)	(835)	(1,155)	(1,542)
Eliminations \| Natural Gas
Disaggregation of Revenue [Line Items]
Sales of natural gas, NGLs and condensate	$ (320)	$ (353)	$ (818)	$ (772)

Agreements and Transactions with Affiliates - Transactions with Affiliates (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Related Party Transaction [Line Items]
Purchases and related costs	$ 1,356	$ (1,928)	$ 3,160	$ 3,697
Sales of natural gas, NGLs and condensate	110	127	225	238
Operating and maintenance expense	182	185	360	347
Affiliated Entity \| Unconsolidated Affiliates
Related Party Transaction [Line Items]
Purchases and related costs	201	179	420	324
Affiliated Entity \| Phillips 66
Related Party Transaction [Line Items]
Purchases and related costs	64	28	109	38
Operating and maintenance expense	3	3	7	6
Affiliated Entity \| Enbridge
Related Party Transaction [Line Items]
Purchases and related costs	7	18	14	28
Natural Gas, NGLs and Condensate [Member]
Related Party Transaction [Line Items]
Sales of natural gas, NGLs and condensate	1,659	2,257	3,770	4,326
Natural Gas, NGLs and Condensate [Member] \| Affiliated Entity \| Unconsolidated Affiliates
Related Party Transaction [Line Items]
Sales of natural gas, NGLs and condensate	4	14	18	25
Natural Gas, NGLs and Condensate [Member] \| Affiliated Entity \| Phillips 66
Related Party Transaction [Line Items]
Sales of natural gas, NGLs and condensate	290	381	616	683
Natural Gas, NGLs and Condensate [Member] \| Affiliated Entity \| Enbridge
Related Party Transaction [Line Items]
Sales of natural gas, NGLs and condensate	0	13	0	25
Transportation, Processing and Other [Member]
Related Party Transaction [Line Items]
Sales of natural gas, NGLs and condensate	110	127	225	238
Transportation, Processing and Other [Member] \| Affiliated Entity \| Unconsolidated Affiliates
Related Party Transaction [Line Items]
Sales of natural gas, NGLs and condensate	$ 0	$ 2	$ 1	$ 3

Agreements and Transactions with Affiliates - Balances with Affiliates (Detail) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Related Party Transaction [Line Items]
Accounts receivable	$ 131	$ 166
Accounts payable	94	96
Unconsolidated Affiliates
Related Party Transaction [Line Items]
Accounts receivable	16	21
Accounts payable	70	72
Phillips 66
Related Party Transaction [Line Items]
Accounts receivable	115	145
Accounts payable	22	22
Enbridge
Related Party Transaction [Line Items]
Accounts payable	$ 2	$ 2

Property, Plant and Equipment - Classification of Property, Plant and Equipment (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 14,879		$ 14,879		$ 14,724
Accumulated depreciation	(5,771)		(5,771)		(5,589)
Property, plant and equipment, net	9,108		9,108		9,135
Interest capitalized on construction projects	5	$ 6	10	$ 11
Gathering and transmission systems
Property, Plant and Equipment [Line Items]
Property, plant and equipment	8,694		$ 8,694		8,492
Gathering and transmission systems \| Minimum
Property, Plant and Equipment [Line Items]
Depreciable life of property, plant and equipment			20 years
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
Depreciable life of property, plant and equipment			50 years
Processing, storage and terminal facilities
Property, Plant and Equipment [Line Items]
Property, plant and equipment	5,384		$ 5,384		5,194
Processing, storage and terminal facilities \| Minimum
Property, Plant and Equipment [Line Items]
Depreciable life of property, plant and equipment			35 years
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
Depreciable life of property, plant and equipment			60 years
Other
Property, Plant and Equipment [Line Items]
Property, plant and equipment	584		$ 584		568
Other \| Minimum
Property, Plant and Equipment [Line Items]
Depreciable life of property, plant and equipment			3 years
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
Depreciable life of property, plant and equipment			30 years
Construction work in progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 217		$ 217		$ 470

Investments In Unconsolidated Affiliates - Investments In Unconsolidated Affiliates (Detail) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Schedule of Equity Method Investments [Line Items]
Investments in unconsolidated affiliates	$ 3,581	$ 3,340
DCP Sand Hills Pipeline, LLC
Schedule of Equity Method Investments [Line Items]
Equity method ownership investment (as percent)	66.67%
Investments in unconsolidated affiliates	$ 1,781	1,791
DCP Southern Hills Pipeline, LLC
Schedule of Equity Method Investments [Line Items]
Equity method ownership investment (as percent)	66.67%
Investments in unconsolidated affiliates	$ 731	728
Discovery Producer Services LLC
Schedule of Equity Method Investments [Line Items]
Equity method ownership investment (as percent)	40.00%
Investments in unconsolidated affiliates	$ 336	344
Front Range Pipeline LLC
Schedule of Equity Method Investments [Line Items]
Equity method ownership investment (as percent)	33.33%
Investments in unconsolidated affiliates	$ 185	175
Texas Express Pipeline LLC
Schedule of Equity Method Investments [Line Items]
Equity method ownership investment (as percent)	10.00%
Investments in unconsolidated affiliates	$ 101	95
Panola Pipeline Company, LLC
Schedule of Equity Method Investments [Line Items]
Equity method ownership investment (as percent)	15.00%
Investments in unconsolidated affiliates	$ 21	23
Mont Belvieu Enterprise Fractionator
Schedule of Equity Method Investments [Line Items]
Equity method ownership investment (as percent)	12.50%
Investments in unconsolidated affiliates	$ 27	24
Gulf Coast Express [Member]
Schedule of Equity Method Investments [Line Items]
Equity method ownership investment (as percent)	25.00%
Investments in unconsolidated affiliates	$ 386	146
Mont Belvieu 1 Fractionator
Schedule of Equity Method Investments [Line Items]
Equity method ownership investment (as percent)	20.00%
Investments in unconsolidated affiliates	$ 9	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		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Schedule of Equity Method Investments [Line Items]
Earnings from unconsolidated affiliates	$ 117	$ 96	$ 230	$ 174
DCP Sand Hills Pipeline, LLC
Schedule of Equity Method Investments [Line Items]
Earnings from unconsolidated affiliates	72	58	140	106
DCP Southern Hills Pipeline, LLC
Schedule of Equity Method Investments [Line Items]
Earnings from unconsolidated affiliates	22	16	45	29
Discovery Producer Services LLC
Schedule of Equity Method Investments [Line Items]
Earnings from unconsolidated affiliates	3	2	3	3
Front Range Pipeline LLC
Schedule of Equity Method Investments [Line Items]
Earnings from unconsolidated affiliates	9	5	16	10
Texas Express Pipeline LLC
Schedule of Equity Method Investments [Line Items]
Earnings from unconsolidated affiliates	4	8	9	10
Mont Belvieu Enterprise Fractionator
Schedule of Equity Method Investments [Line Items]
Earnings from unconsolidated affiliates	3	3	7	7
Mont Belvieu 1 Fractionator
Schedule of Equity Method Investments [Line Items]
Earnings from unconsolidated affiliates	4	4	8	8
Other
Schedule of Equity Method Investments [Line Items]
Earnings from unconsolidated affiliates	$ 0	$ 0	$ 2	$ 1

Investments in Unconsolidated Affiliates - Equity Method Investment Summarized Financial Information, Statement of Operations (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Equity Method Investments and Joint Ventures [Abstract]
Operating revenue	$ 432	$ 408	$ 853	$ 742
Operating expenses	162	147	353	286
Net income	$ 269	$ 260	$ 500	$ 454

Investments in Unconsolidated Affiliates - Equity Method Investment Summarized Financial Information, Balance Sheet (Detail) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Equity Method Investments and Joint Ventures [Abstract]
Current assets	$ 409	$ 411
Long-term assets	7,282	6,359
Current liabilities	(366)	(424)
Long-term liabilities	(259)	(221)
Net assets	$ 7,066	$ 6,125

Fair Value Measurement - Financial Instruments Carried at Fair Value (Detail) - Commodity derivatives - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Current Assets
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives	$ 66	$ 108
Long- Term Assets
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives	5	8
Current Liabilities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives	(54)	(91)
Long- Term Liabilities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives	(5)	(8)
Level 1 \| Current Assets
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives	31	62
Level 1 \| Long- Term Assets
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives	0	4
Level 1 \| Current Liabilities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives	(26)	(39)
Level 1 \| Long- Term Liabilities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives	0	(1)
Level 2 \| Current Assets
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives	27	32
Level 2 \| Long- Term Assets
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives	3	2
Level 2 \| Current Liabilities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives	(27)	(52)
Level 2 \| Long- Term Liabilities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives	(5)	(5)
Level 3 \| Current Assets
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives	8	14
Level 3 \| Long- Term Assets
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives	2	2
Level 3 \| Current Liabilities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives	(1)	0
Level 3 \| Long- Term Liabilities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives	$ 0	$ 2

Fair Value Measurement - Condensed Consolidated Balance Sheets for Derivative Financial Instruments (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Current Assets
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 5	$ 2	$ 14	$ 3
Net realized and unrealized gains (losses) included in earnings	10	1	8	0
Transfers out of Level 3	6	2	8	(2)
Settlements	1	0	(6)	0
Ending balance	8	1	8	1
Net unrealized gains (losses) on derivatives still held included in earnings	7	1	7	1
Long- Term Assets
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	1	0	2	1
Net realized and unrealized gains (losses) included in earnings	1	1	2	0
Transfers out of Level 3	0	0	2	0
Settlements	0	0	0	0
Ending balance	2	1	2	1
Net unrealized gains (losses) on derivatives still held included in earnings	1	1	1	0
Current Liabilities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Transfers out of Level 3	0	(8)	0
Settlements	1	(2)
Ending balance	(1)	(10)	(1)	(10)
Net unrealized gains (losses) on derivatives still held included in earnings	0	(8)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	(1)	6	0	(13)
Net realized and unrealized (losses) gains included in earnings	1	(14)	(1)	(12)
Transfers out of Level 3				12
Settlements			0	3
Ending balance	(1)	(10)	(1)	(10)
Net unrealized gains (losses) on derivatives still held included in earnings			(1)	(7)
Long- Term Liabilities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Transfers out of Level 3	0	0	(1)
Settlements	0	0
Ending balance	0	(7)	0	(7)
Net unrealized gains (losses) on derivatives still held included in earnings	0	(4)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	(1)	3	(2)	(1)
Net realized and unrealized (losses) gains included in earnings	1	(4)	1	(6)
Transfers out of Level 3				0
Settlements			0	0
Ending balance	$ 0	$ (7)	0	(7)
Net unrealized gains (losses) on derivatives still held included in earnings			$ 0	$ (6)

Schedule of Valuation Processes (Detail) - Level 3 - Market Approach Valuation Technique $ in Millions	Jun. 30, 2019 USD ($) $ / gal
Derivative Liabilities \| Natural Gas Liquids
Fair Value Inputs Assets And Liabilities Quantitative Information [Line Items]
Liabilities, fair value \| $	$ (1)
Derivative Liabilities \| Natural Gas Liquids \| Minimum
Fair Value Inputs Assets And Liabilities Quantitative Information [Line Items]
Forward Curve Range	0.09
Derivative Liabilities \| Natural Gas Liquids \| Maximum
Fair Value Inputs Assets And Liabilities Quantitative Information [Line Items]
Forward Curve Range	1.15
Derivative Assets \| Natural Gas Liquids
Fair Value Inputs Assets And Liabilities Quantitative Information [Line Items]
Assets, fair value \| $	$ 8
Derivative Assets \| Natural Gas Liquids \| Minimum
Fair Value Inputs Assets And Liabilities Quantitative Information [Line Items]
Forward Curve Range	0.20
Derivative Assets \| Natural Gas Liquids \| Maximum
Fair Value Inputs Assets And Liabilities Quantitative Information [Line Items]
Forward Curve Range	1.15
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	2.09
Derivative Assets \| Natural Gas \| Maximum
Fair Value Inputs Assets And Liabilities Quantitative Information [Line Items]
Forward Curve Range	2.73

Leases (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
Leases (Details) - USD ($) $ in Millions	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Leases [Abstract]
Operating Leases, Rent Expense		$ 9		$ 17
Operating Lease, Payments			$ 12
Operating Lease, Cost	$ 5		$ 11
Minimum Remaining Operating Lease Term			1 year
Operating Lease, Right-of-Use Asset	69		$ 69		$ 0
Operating Lease, Liability, Noncurrent	57		57		$ 0
Operating Lease, Liability, Current	18		$ 18
Maximum Remaining Operating Lease Term			22 years
Variable Lease, Cost	1		$ 3
Short-term Lease, Cost	1		2
Lease, Cost	$ 7		16
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability			$ 6
Operating Lease, Weighted Average Remaining Lease Term	5 years		5 years
Operating Lease, Weighted Average Discount Rate, Percent	4.00%		4.00%
Operating Lease Extension Term			20

Schedule of Maturities of Operating Lease Liabilities Under Non-Cancellable Leases (Details) $ in Millions	Jun. 30, 2019 USD ($)
Schedule of Maturities of Operating Lease Liabilities Under Non-Cancellable Leases [Abstract]
Lessee, Operating Lease, Liability, Payments, Remainder of Fiscal Year	$ 10
Lessee, Operating Lease, Liability, Payments, Due Year Two	21
Lessee, Operating Lease, Liability, Payments, Due Year Three	19
Lessee, Operating Lease, Liability, Payments, Due Year Four	14
Lessee, Operating Lease, Liability, Payments, Due Year Five	8
Lessee, Operating Lease, Liability, Payments, Due after Year Five	11
Lessee, Operating Lease, Liability, Payments, Due	83
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	8
Operating Lease, Liability	$ 75

Schedule of Future Minimum Rental Payments Under Operating Leases (Details) $ in Millions	Dec. 31, 2018 USD ($)
Schedule of Future Minimum Rental Payments Under Operating Leases [Abstract]
Operating Leases, Future Minimum Payments, Remainder of Fiscal Year	$ 22
Operating Leases, Future Minimum Payments, Due in Two Years	18
Operating Leases, Future Minimum Payments, Due in Three Years	14
Operating Leases, Future Minimum Payments, Due in Four Years	9
Operating Leases, Future Minimum Payments, Due in Five Years	5
Operating Leases, Future Minimum Payments, Due Thereafter	7
Operating Leases, Future Minimum Payments Due	$ 75

Debt - Schedule of Debt (Detail) - USD ($) $ in Millions		3 Months Ended
Debt - Schedule of Debt (Detail) - USD ($) $ in Millions	Jan. 18, 2019	Jun. 30, 2019	Dec. 31, 2018
Facility [Line Items]
Fair value adjustments related to interest rate swap fair value hedges		$ 20	$ 21
Unamortized issuance costs		(36)	(30)
Unamortized discount		(9)	(10)
Total debt		5,550	5,307
Current debt		800	525
Long-term debt		4,750	4,782
Credit Agreement
Facility [Line Items]
Credit Facility		$ 0	351
Weighted-average variable interest rate		3.901%
Line of Credit Facility, Maximum Borrowing Capacity		$ 1,400
Accounts Receivable Securitization Facility
Facility [Line Items]
Accounts Receivable Securitization Agreement		$ 200	200
Weighted-average variable interest rate		3.20%
Accounts Recievable included in the Securitization Transaction		$ 658
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 \| Issued March 2014, interest at 2.700% payable semi-annually, due April 2019
Facility [Line Items]
Senior Notes		$ 0	325
Debt interest rate percentage		2.70%
Debt Instrument, Interest Rate, Stated Percentage [Abstract]
Debt Instrument, Face Amount		$ 0	325
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%
Debt Instrument, Interest Rate, Stated Percentage [Abstract]
Debt Instrument, Face Amount		$ 600	600
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%
Debt Instrument, Interest Rate, Stated Percentage [Abstract]
Debt Instrument, Face Amount		$ 500	500
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%
Debt Instrument, Interest Rate, Stated Percentage [Abstract]
Debt Instrument, Face Amount		$ 350	350
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%
Debt Instrument, Interest Rate, Stated Percentage [Abstract]
Debt Instrument, Face Amount		$ 500	500
Senior Notes \| Issued July 2018, interest at 5.375% payable semi-annually, due July 2025
Facility [Line Items]
Senior Notes	$ 325	$ 825	500
Debt interest rate percentage		5.375%
Debt Instrument, Interest Rate, Stated Percentage [Abstract]
Proceeds from Debt, Net of Issuance Costs	324
Debt Instrument, Face Amount	$ 325	$ 825	500
Senior Notes \| Issued May 2019, interest at 5.125% payable semiannually, due May 2029
Facility [Line Items]
Senior Notes		$ 600	0
Debt interest rate percentage		5.125%
Debt Instrument, Interest Rate, Stated Percentage [Abstract]
Proceeds from Debt, Net of Issuance Costs		$ 592
Debt Instrument, Face Amount		600	0
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%
Debt Instrument, Interest Rate, Stated Percentage [Abstract]
Debt Instrument, Face Amount		$ 300	300
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%
Debt Instrument, Interest Rate, Stated Percentage [Abstract]
Debt Instrument, Face Amount		$ 300	300
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%
Debt Instrument, Interest Rate, Stated Percentage [Abstract]
Debt Instrument, Face Amount		$ 450	450
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%
Debt Instrument, Interest Rate, Stated Percentage [Abstract]
Debt Instrument, Face Amount		$ 400	400
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 Instrument, Interest Rate, Stated Percentage [Abstract]
Debt Instrument, Face Amount		$ 550	$ 550

Debt - Additional Information (Detail) - USD ($) $ in Millions		3 Months Ended	6 Months Ended
	Jan. 18, 2019	Jun. 30, 2019	Jun. 30, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Line of Credit Facility, Borrowing Capacity, Description		$ 500	$ 500
Accounts Receivable Securitization Facility
Debt Instrument [Line Items]
Accounts Recievable included in the Securitization Transaction		658	658
Credit Agreement
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		1,400	$ 1,400
Basis spread determined by credit rating			45.00%
Commitment fee percentage			30.00%
Letter of credit amount outstanding		15	$ 15
Debt covenants, maximum borrowing amount		$ 1,385	$ 1,385
Credit Agreement \| LIBOR
Debt Instrument [Line Items]
Variable rate basis spread			145.00%
Credit Agreement \| Federal Funds Rate
Debt Instrument [Line Items]
Variable rate basis spread			50.00%
Credit Agreement \| LIBOR Market Index
Debt Instrument [Line Items]
Variable rate basis spread			100.00%
Credit Agreement \| Maximum
Debt Instrument [Line Items]
Maximum leverage ratio in event of acquisition		5.50	5.50
Credit Agreement \| Quarters After June 30, 2018 \| Maximum
Debt Instrument [Line Items]
Maximum leverage ratio		5.00	5.00
Issued July 2018, interest at 5.375% payable semi-annually, due July 2025 \| Senior Notes
Debt Instrument [Line Items]
Debt Instrument, Face Amount	$ 325	$ 825	$ 825	$ 500
Proceeds from Debt, Net of Issuance Costs	$ 324
Debt Instrument, Interest Rate, Stated Percentage		5.375%	5.375%
Issued May 2019, interest at 5.125% payable semiannually, due May 2029 \| Senior Notes
Debt Instrument [Line Items]
Debt Instrument, Face Amount		$ 600	$ 600	$ 0
Proceeds from Debt, Net of Issuance Costs		$ 592
Debt Instrument, Interest Rate, Stated Percentage		5.125%	5.125%

Debt - Future Maturities of Long-Term Debt (Detail) $ in Millions	Jun. 30, 2019 USD ($)
Maturities of Long-term Debt [Abstract]
2019	$ 200
2020	600
2021	500
2022	350
2023	500
Thereafter	3,425
Long Term Debt Maturities Repayments Of Principal Total	$ 5,575

Risk Management and Hedging Activities - Additional Information (Detail) - USD ($) $ in Millions	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017
Derivative [Line Items]
Accumulated other comprehensive loss	$ (8)		$ (8)
Collateral, cash deposits	27
Letters of credit received	54
Accumulated Net Gain (Loss) from Cash Flow Hedges
Derivative [Line Items]
Accumulated other comprehensive loss	(8)	$ (8)	(8)	$ (8)	$ (9)	$ (9)
Accumulated Net Gain (Loss) from Cash Flow Hedges \| Commodity derivatives
Derivative [Line Items]
Accumulated other comprehensive loss	$ (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	Jun. 30, 2019	Dec. 31, 2018
Offsetting Assets [Line Items]
Gross Amounts of Assets Presented in the Balance Sheet	$ 71	$ 116
Amounts Not Offset in the Balance Sheet - Financial Instruments	0	0
Net Amount	71	116
Offsetting Liabilities [Line Items]
Gross Amounts of Liabilities Presented in the Balance Sheet	(59)	(99)
Amounts Not Offset in the Balance Sheet - Financial Instruments	0	0
Net Amount	$ (59)	$ (99)

Risk Management and Hedging Activities - Schedule of Designated and Non-Designated Derivative Instruments in Statement of Financial Position, Fair Value (Detail) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Derivative Asset [Abstract]
Derivative Instruments and Hedges, Current Assets	$ 66	$ 108
Derivative Instruments and Hedges, Assets, Noncurrent	5	8
Derivative Liability [Abstract]
Derivative Instruments and Hedges, Current Liabilities	54	91
Derivative Instruments and Hedges, Liabilities, Noncurrent	5	8
Commodity derivatives \| Derivative Asset Not Designated As Hedging Instruments [Member]
Derivative Asset [Abstract]
Derivative Instruments and Hedges, Current Assets	66	108
Derivative Instruments and Hedges, Assets, Noncurrent	5	8
Derivative Instruments Not Designated as Hedging Instruments, Total Assets, at Fair Value	71	116
Commodity derivatives \| Derivative Liabilities Not Designated As Hedging Instruments [Member]
Derivative Liability [Abstract]
Derivative Instruments and Hedges, Current Liabilities	54	91
Derivative Instruments and Hedges, Liabilities, Noncurrent	5	8
Derivative Instruments Not Designated as Hedging Instruments, Total Liabilities, at Fair Value	$ 59	$ 99

Risk Management and Hedging Activities - Schedule of Cash Flow Hedges Included in Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Derivative [Line Items]
Accumulated Other Comprehensive (Loss) Income	$ (8)		$ (8)			$ (8)
Accumulated Net Gain (Loss) from Cash Flow Hedges
Derivative [Line Items]
Accumulated Other Comprehensive (Loss) Income	(8)	$ (8)	(8)	$ (8)	$ (8)	(8)	$ (9)	$ (9)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		1		1
Accumulated Net Gain (Loss) from Cash Flow Hedges \| Interest Rate Derivatives
Derivative [Line Items]
Accumulated Other Comprehensive (Loss) Income	(3)	(3)	(3)	(3)	(3)	(3)	(4)	(4)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		1		1
Accumulated Net Gain (Loss) from Cash Flow Hedges \| Commodity derivatives
Derivative [Line Items]
Accumulated Other Comprehensive (Loss) Income	(6)	(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) Income	1	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	(1)		(1)
Cash Flow Hedging [Member] \| Interest Rate Derivatives
Derivative [Line Items]
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months	(1)		(1)
Cash Flow Hedging [Member] \| Commodity derivatives
Derivative [Line Items]
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months	0		0
Cash Flow Hedging [Member] \| Foreign Currency Derivatives
Derivative [Line Items]
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months	$ 0		$ 0

Risk Management and Hedging Activities - Schedule of Net Long or Short Positions Expected to be Realized (Detail)	6 Months Ended
	Jun. 30, 2019 MMBTU bbl	Jun. 30, 2018 MMBTU bbl
Crude Oil
Net (Short) Position, Volume [Abstract]
Net (Short) Position (Bbls), Year One \| bbl	(1,011,000)	(1,646,000)
Net (Short) Position (Bbls), Year Two \| bbl	(664,000)	(1,900,000)
Net (Short) Long Position (Bbls), Year Three \| bbl	(100,000)	(128,000)
Net (Short) Position (Bbls), Year Four \| bbl	0	0
Net Long (Short) Position (Bbls), Year Five \| bbl	0
Natural Gas
Net Long (Short) Position, MMBtu [Abstract]
Net (Short) Long Position (MMBtu), Year One \| MMBTU	(20,299,550)	(21,623,200)
Net Long Position (MMBtu), Year Two \| MMBTU	(3,790,000)	0
Net (Short) Long Position (MMBtu), Year Three \| MMBTU	0	0
Net Long (Short) Position (MMBtu), Year Four \| MMBTU	0	0
Net Long (Short) Position (MMBtu), Year Five \| MMBTU	0
Natural Gas Liquids
Net (Short) Position, Volume [Abstract]
Net (Short) Position (Bbls), Year One \| bbl	(20,528,570)	(25,737,691)
Net (Short) Position (Bbls), Year Two \| bbl	(14,847,743)	(19,314,335)
Net (Short) Long Position (Bbls), Year Three \| bbl	(5,519,594)	(13,568,452)
Net (Short) Position (Bbls), Year Four \| bbl	(689)	(5,750,000)
Net Long (Short) Position (Bbls), Year Five \| bbl	0
Natural Gas Basis Swaps
Net Long (Short) Position, MMBtu [Abstract]
Net (Short) Long Position (MMBtu), Year One \| MMBTU	2,000,000	2,257,500
Net Long Position (MMBtu), Year Two \| MMBTU	3,125,000	1,512,500
Net (Short) Long Position (MMBtu), Year Three \| MMBTU	(4,562,500)	3,660,000
Net Long (Short) Position (MMBtu), Year Four \| MMBTU	8,212,500	0
Net Long (Short) Position (MMBtu), Year Five \| MMBTU	7,300,000

Partnership Equity and Distributions - Cash Distribution (Detail) - USD ($) $ / shares in Units, $ in Millions													3 Months Ended
	Jun. 17, 2019	May 15, 2019	Apr. 15, 2019	Feb. 14, 2019	Jan. 15, 2019	Dec. 17, 2018	Nov. 14, 2018	Sep. 17, 2018	Aug. 14, 2018	Jun. 15, 2018	May 15, 2018	Feb. 14, 2018	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018
Distribution Made to Limited Partner [Line Items]
Total Cash Distribution													$ (178)	$ 159	$ (176)	$ 194
Series A Preferred Limited Partners [Member]
Distribution Made to Limited Partner [Line Items]
Preferred Limited Partnership Distribution; Distribution Amount Paid	$ 36.8750					$ 36.8750				$ 41.9965
Total Cash Distribution	$ 18					$ 18				$ 21			(18)	0	(21)	0
Series B Preferred Limited Partners [Member]
Distribution Made to Limited Partner [Line Items]
Preferred Limited Partnership Distribution; Distribution Amount Paid	$ 0.4922					$ 0.4922		$ 0.4922
Total Cash Distribution	$ 3					$ 3		$ 3					(3)	3	0	0
Series C Preferred Limited Partners [Member]
Distribution Made to Limited Partner [Line Items]
Preferred Limited Partnership Distribution; Distribution Amount Paid			$ 0.4969		$ 0.4969
Total Cash Distribution			$ 2		$ 2								(2)	2
Limited Partners
Distribution Made to Limited Partner [Line Items]
Per Unit Distribution (in dollars per share)		$ 0.7800		$ 0.7800			$ 0.7800		$ 0.7800		$ 0.7800	$ 0.7800
Total Cash Distribution		$ 155		$ 154			$ 155		$ 154		$ 155	$ 194	$ (112)	$ 111	$ (112)	$ (111)

Commitments and Contingent Liabilities (Details) - USD ($)	Feb. 14, 2019	Jan. 30, 2019	Jun. 30, 2019
Other Commitments [Line Items]
Administrative Settlement Penalty	$ 29,000
Amount Paid to Fund Supplemental Environmental Projects [Member]		$ 115,000
New Mexico Environment Department Notice of Violation 1 [Member]
Other Commitments [Line Items]
Administrative Settlement Penalty	149,832
New Mexico Environment Department Notice of Violation 2 [Member]
Other Commitments [Line Items]
Administrative Settlement Penalty	$ 142,233
Low end of estimate
Other Commitments [Line Items]
Estimated Litigation Liability			$ 375,000
High end of estimate
Other Commitments [Line Items]
Estimated Litigation Liability			$ 420,000

Statement of Cash Flows, Supplemental Disclosures (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Additional Cash Flow Elements and Supplemental Cash Flow Information [Abstract]
Cash paid for interest, net of amounts capitalized	$ 115	$ 129
Income Taxes Paid, Net	3	3
Property, plant and equipment acquired with accounts payable and accrued liabilities	37	42
Cumulative Effect of New Accounting Principle in Period of Adoption	$ 84	$ 0

Business Segments - Segment Information (Detail) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Jun. 30, 2019 USD ($) Segment	Jun. 30, 2018 USD ($)
Segment Reporting [Abstract]
Number of reportable segments \| Segment					2
Segment Reporting Information [Line Items]
Total operating revenues	$ 1,798		$ 2,317		$ 3,997	$ 4,456
Gross margin	442		389		837	759
Operating and maintenance expense	(182)		(185)		(360)	(347)
Depreciation and amortization expense	(101)		(97)		(204)	(191)
General and administrative expense	(68)		(70)		(135)	(129)
Other income (expense)	1		3		6	5
Loss on sale of assets, net	5		0		14	0
Restructuring costs	9		0		9	0
Earnings from unconsolidated affiliates	117		96		230	174
Interest expense, net	73		67		142	134
Income tax expense	0		1		1	2
Net income	120	$ 76	62	$ 63	196	125
Net income attributable to noncontrolling interests	(1)		(1)		(2)	(2)
Net income attributable to partners	119		61		194	123
Non-cash derivative mark-to-market	39		(37)		(15)	(66)
Non-cash lower of cost or market adjustment	(3)		0		(8)	0
Capital expenditures	126		144		308	268
Investments in unconsolidated affiliates, net	139		66		270	126
Logistics and Marketing
Segment Reporting Information [Line Items]
Total operating revenues	1,613		2,192		3,658	4,171
Gathering and Processing
Segment Reporting Information [Line Items]
Total operating revenues	1,024		1,314		2,312	2,600
Operating Segments \| Logistics and Marketing
Segment Reporting Information [Line Items]
Total operating revenues	1,613		2,192		3,658	2,600
Gross margin	88		56		146	685
Operating and maintenance expense	11		(11)		20	317
Depreciation and amortization expense	3		3		6	171
General and administrative expense	1		3		4	6
Other income (expense)	(1)		(3)		(1)	(3)
Loss on sale of assets, net	(1)				(10)
Restructuring costs	0				0
Earnings from unconsolidated affiliates	114		94		227	3
Interest expense, net	0		0		0	0
Income tax expense			0		0	0
Net income	185		130		332	209
Net income attributable to noncontrolling interests	0		0		0	(2)
Net income attributable to partners	185		130		332	209
Non-cash derivative mark-to-market	24		5		6	(28)
Non-cash lower of cost or market adjustment	(3)				(8)
Capital expenditures	11		0		25	260
Investments in unconsolidated affiliates, net	139		66		270	1
Operating Segments \| Gathering and Processing
Segment Reporting Information [Line Items]
Total operating revenues	1,024		1,314		2,312	4,171
Gross margin	354		333		691	74
Operating and maintenance expense	165		(169)		330	22
Depreciation and amortization expense	91		87		184	6
General and administrative expense	6		2		12	6
Other income (expense)	0		0		(5)	(2)
Loss on sale of assets, net	(4)				(4)
Restructuring costs	0				0
Earnings from unconsolidated affiliates	3		2		3	171
Interest expense, net	0		0		0	0
Income tax expense			0		0	0
Net income	91		77		159	191
Net income attributable to noncontrolling interests	(1)		1		2	0
Net income attributable to partners	90		76		157	189
Non-cash derivative mark-to-market	15		(42)		(21)	(38)
Non-cash lower of cost or market adjustment	0				0
Capital expenditures	111		140		276	1
Investments in unconsolidated affiliates, net	0		0		0	125
Other
Segment Reporting Information [Line Items]
Total operating revenues	0		0		0	0
Gross margin	0		0		0	0
Operating and maintenance expense	6		(5)		10	8
Depreciation and amortization expense	7		7		14	14
General and administrative expense	61		65		119	117
Other income (expense)	0		0		0	0
Loss on sale of assets, net	0				0
Restructuring costs	(9)				9
Earnings from unconsolidated affiliates	0		0		0	0
Interest expense, net	73		67		142	134
Income tax expense			1		1	2
Net income	(156)		(145)		(295)	(275)
Net income attributable to noncontrolling interests	0		0		0	0
Net income attributable to partners	(156)		(145)		(295)	(275)
Non-cash derivative mark-to-market	0		0		0
Non-cash lower of cost or market adjustment	0				0
Capital expenditures	4		4		7	7
Investments in unconsolidated affiliates, net	0		0		0	0
Eliminations
Segment Reporting Information [Line Items]
Total operating revenues	(839)		(1,189)		(1,973)	(2,315)
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
Other income (expense)	0		0			0
Loss on sale of assets, net	0				0
Restructuring costs	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	0		0		0	0
Net income attributable to noncontrolling interests	0		0			0
Net income 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				0
Capital expenditures	0		0		0
Investments in unconsolidated affiliates, net	$ 0		$ 0		$ 0	$ 0

Business Segments - Segment Assets (Detail) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Segment Reporting, Asset Reconciling Item [Line Items]
Segment long-term assets	$ 13,210	$ 12,995
Current assets	823	1,271
Total assets	14,033	14,266
Operating Segments \| Logistics and Marketing
Segment Reporting, Asset Reconciling Item [Line Items]
Segment long-term assets	3,823	3,661
Operating Segments \| Gathering and Processing
Segment Reporting, Asset Reconciling Item [Line Items]
Segment long-term assets	9,100	9,058
Other
Segment Reporting, Asset Reconciling Item [Line Items]
Segment long-term assets	$ 287	$ 276

- 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://fasb.org/us-gaap/role/ref/legacyRef
-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 2: http://fasb.org/us-gaap/role/ref/legacyRef
-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 3: http://fasb.org/us-gaap/role/ref/legacyRef
-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 4: http://fasb.org/us-gaap/role/ref/legacyRef
-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 5: http://fasb.org/us-gaap/role/ref/legacyRef
-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 6: http://fasb.org/us-gaap/role/ref/legacyRef
-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

Reference 7: http://fasb.org/us-gaap/role/ref/legacyRef
-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 8: http://fasb.org/us-gaap/role/ref/legacyRef
-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

+ Details

Condensed Consolidating Financial Information - Condensed Consolidating Balance Sheets (Detail) - USD ($) $ in Millions	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017
ASSETS
Cash and cash equivalents	$ 1		$ 1	$ 4		$ 156
Accounts receivable, net	660		1,033
Inventories	46		79
Other	116		158
Total current assets	823		1,271
Property, plant and equipment, net	9,108		9,135
Goodwill and intangible assets, net	259		328
Advances receivable — consolidated subsidiaries	0		0
Investments in unconsolidated affiliates	0		0
Investments in unconsolidated affiliates	3,581		3,340
Other long-term assets	262		192
Total assets	14,033		14,266
LIABILITIES AND EQUITY
Accounts payable and other current liabilities	1,003		1,379
Current debt	800		525
Advances payable — consolidated subsidiaries	0		0
Long-term debt	4,750		4,782
Other long-term liabilities	327		283
Total liabilities	6,880		6,969
Commitments and contingent liabilities (see note 14)
Equity:
Net equity	7,133		7,276
Accumulated other comprehensive loss	(8)		(8)
Total partners’ equity	7,125		7,268
Noncontrolling interests	28		29
Total equity	7,153	$ 7,213	7,297	7,353	$ 7,312	7,438
Total liabilities and equity	14,033		14,266
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	2,115		2,452
Investments in unconsolidated affiliates	5,012		4,818
Investments in unconsolidated affiliates	0		0
Other long-term assets	0		0
Total assets	7,127		7,270
LIABILITIES AND EQUITY
Accounts payable and other current liabilities	2		2
Current debt	0		0
Advances payable — consolidated subsidiaries	0		0
Long-term debt	0		0
Other long-term liabilities	0		0
Total liabilities	2		2
Equity:
Net equity	7,125		7,268
Accumulated other comprehensive loss	0		0
Total partners’ equity	7,125		7,268
Noncontrolling interests	0		0
Total equity	7,125		7,268
Total liabilities and equity	7,127		7,270
Reportable Legal Entities \| Subsidiary Issuer
ASSETS
Cash and cash equivalents	0		0	0		155
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	1,997		1,883
Investments in unconsolidated affiliates	8,445		8,113
Investments in unconsolidated affiliates	0		0
Other long-term assets	0		0
Total assets	10,442		9,996
LIABILITIES AND EQUITY
Accounts payable and other current liabilities	80		71
Current debt	600		325
Advances payable — consolidated subsidiaries	0		0
Long-term debt	4,750		4,782
Other long-term liabilities	0		0
Total liabilities	5,430		5,178
Equity:
Net equity	5,015		4,821
Accumulated other comprehensive loss	(3)		(3)
Total partners’ equity	5,012		4,818
Noncontrolling interests	0		0
Total equity	5,012		4,818
Total liabilities and equity	10,442		9,996
Reportable Legal Entities \| Non-Guarantor Subsidiaries
ASSETS
Cash and cash equivalents	1		1	4		1
Accounts receivable, net	660		1,033
Inventories	46		79
Other	116		158
Total current assets	823		1,271
Property, plant and equipment, net	9,108		9,135
Goodwill and intangible assets, net	259		328
Advances receivable — consolidated subsidiaries	0		0
Investments in unconsolidated affiliates	0		0
Investments in unconsolidated affiliates	3,581		3,340
Other long-term assets	262		192
Total assets	14,033		14,266
LIABILITIES AND EQUITY
Accounts payable and other current liabilities	921		1,306
Current debt	200		200
Advances payable — consolidated subsidiaries	4,112		4,335
Long-term debt	0		0
Other long-term liabilities	327		283
Total liabilities	5,560		6,124
Equity:
Net equity	8,450		8,118
Accumulated other comprehensive loss	(5)		(5)
Total partners’ equity	8,445		8,113
Noncontrolling interests	28		29
Total equity	8,473		8,142
Total liabilities and equity	14,033		14,266
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	(4,112)		(4,335)
Investments in unconsolidated affiliates	(13,457)		(12,931)
Investments in unconsolidated affiliates	0		0
Other long-term assets	0		0
Total assets	(17,569)		(17,266)
LIABILITIES AND EQUITY
Accounts payable and other current liabilities	0		0
Current debt	0		0
Advances payable — consolidated subsidiaries	(4,112)		(4,335)
Long-term debt	0		0
Other long-term liabilities	0		0
Total liabilities	(4,112)		(4,335)
Equity:
Net equity	(13,457)		(12,931)
Accumulated other comprehensive loss	0		0
Total partners’ equity	(13,457)		(12,931)
Noncontrolling interests	0		0
Total equity	(13,457)		(12,931)
Total liabilities and equity	$ (17,569)		$ (17,266)

Condensed Consolidating Financial Information - Condensed Consolidating Statements of Operations (Detail) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
Operating revenues:
Sales of natural gas, NGLs and condensate	$ 110		$ 127		$ 225	$ 238
Trading and marketing losses, net	29		(67)		2	(108)
Total operating revenues	1,798		2,317		3,997	4,456
Purchases and related costs	1,356		(1,928)		3,160	3,697
Operating and maintenance expense	182		185		360	347
Depreciation and amortization expense	101		97		204	191
General and administrative expense	68		70		135	129
Loss on sale of assets, net	5		0		14	0
Restructuring costs	9		0		9	0
Other income (expense)	1		3		6	5
Costs and Expenses	1,722		2,283		3,888	4,369
Operating income	76		34		109	87
Interest Expense	73		67		142	134
Income from consolidated subsidiaries	0		0		0	0
Earnings from unconsolidated affiliates	117		96		230	174
Income before income taxes	120		63		197	127
Income tax expense	0		1		1	2
Net income	120	$ 76	62	$ 63	196	125
Net income attributable to noncontrolling interests	(1)		(1)		(2)	(2)
Net income attributable to partners	119		61		194	123
Reportable Legal Entities \| Parent Guarantor
Operating revenues:
Trading and marketing losses, 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
Loss on sale of assets, net	0				0
Restructuring costs	0				0
Other income (expense)	0		0		0	0
Costs and Expenses	0		0		0	0
Operating income	0		0		0	0
Interest Expense	0		0		0	0
Income from consolidated subsidiaries	119		61		194	123
Earnings from unconsolidated affiliates	0		0		0	0
Income before income taxes	119		61		194	123
Income tax expense	0		0		0	0
Net income	119		61		194	123
Net income attributable to noncontrolling interests	0		0		0	0
Net income attributable to partners	119		61		194	123
Reportable Legal Entities \| Subsidiary Issuer
Operating revenues:
Trading and marketing losses, 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
Loss on sale of assets, net	0				0
Restructuring costs	0				0
Other income (expense)	0		0		0	0
Costs and Expenses	0		0		0	0
Operating income	0		0		0	0
Interest Expense	71		67		138	134
Income from consolidated subsidiaries	190		128		332	257
Earnings from unconsolidated affiliates	0		0		0	0
Income before income taxes	119		61		194	123
Income tax expense	0		0		0	0
Net income	119		61		194	123
Net income attributable to noncontrolling interests	0		0		0	0
Net income attributable to partners	119		61		194	123
Reportable Legal Entities \| Non-Guarantor Subsidiaries
Operating revenues:
Trading and marketing losses, net	29		(67)		2	(108)
Total operating revenues	1,798		2,317		3,997	4,456
Purchases and related costs	1,356		(1,928)		3,160	3,697
Operating and maintenance expense	(182)		185		360	347
Depreciation and amortization expense	(101)		97		204	191
General and administrative expense	(68)		70		135	129
Loss on sale of assets, net	(5)				14
Restructuring costs	9				9
Other income (expense)			3		6	(5)
Costs and Expenses	1,722		2,283		3,888	4,369
Operating income	76		34		109	87
Interest Expense	2		0		4	0
Income from consolidated subsidiaries	0		0		0	0
Earnings from unconsolidated affiliates	117		96		230	174
Income before income taxes	191		130		335	261
Income tax expense	0		1		1	2
Net income	191		129		334	259
Net income attributable to noncontrolling interests	(1)		(1)		2	2
Net income attributable to partners	190		128		332	257
Consolidating Adjustments
Operating revenues:
Trading and marketing losses, 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
Loss on sale of assets, net	0				0
Restructuring costs	0				0
Other income (expense)	0		0		0	0
Costs and Expenses	0		0		0	0
Operating income	0		0		0	0
Interest Expense	0		0		0	0
Income from consolidated subsidiaries	(309)		(189)		(526)	(380)
Earnings from unconsolidated affiliates	0		0		0	0
Income before income taxes	(309)		(189)		(526)	(380)
Income tax expense	0		0		0	0
Net income	(309)		(189)		(526)	(380)
Net income attributable to noncontrolling interests	0		0		0	0
Net income attributable to partners	(309)		(189)		(526)	(380)
Eliminations
Operating revenues:
Total operating revenues	(839)		(1,189)		(1,973)	(2,315)
Operating and maintenance expense	0		0			0
Depreciation and amortization expense	0		0		0	0
General and administrative expense	0		0		0	0
Loss on sale of assets, net	0				0
Restructuring costs	0				0
Other income (expense)	0		0			0
Interest Expense	0		0		0	0
Earnings from unconsolidated affiliates	0		0		0	0
Income tax expense			0		0	0
Net income	0		0		0	0
Net income attributable to noncontrolling interests	0		0			0
Net income attributable to partners	0		0		0	0
Natural Gas, NGLs and Condensate [Member]
Operating revenues:
Sales of natural gas, NGLs and condensate	1,659		2,257		3,770	4,326
Natural Gas, NGLs and Condensate [Member] \| Reportable Legal Entities \| Parent Guarantor
Operating revenues:
Sales of natural gas, NGLs and condensate	0		0		0	0
Natural Gas, NGLs and Condensate [Member] \| Reportable Legal Entities \| Subsidiary Issuer
Operating revenues:
Sales of natural gas, NGLs and condensate	0		0		0	0
Natural Gas, NGLs and Condensate [Member] \| Reportable Legal Entities \| Non-Guarantor Subsidiaries
Operating revenues:
Sales of natural gas, NGLs and condensate	1,659		2,257		3,770	4,326
Natural Gas, NGLs and Condensate [Member] \| Consolidating Adjustments
Operating revenues:
Sales of natural gas, NGLs and condensate	0		0		0	0
Transportation, Processing and Other [Member]
Operating revenues:
Sales of natural gas, NGLs and condensate	110		127		225	238
Transportation, Processing and Other [Member] \| Reportable Legal Entities \| Parent Guarantor
Operating revenues:
Sales of natural gas, NGLs and condensate	0		0		0	0
Transportation, Processing and Other [Member] \| Reportable Legal Entities \| Subsidiary Issuer
Operating revenues:
Sales of natural gas, NGLs and condensate	0		0		0	0
Transportation, Processing and Other [Member] \| Reportable Legal Entities \| Non-Guarantor Subsidiaries
Operating revenues:
Sales of natural gas, NGLs and condensate	110		127		225	238
Transportation, Processing and Other [Member] \| Consolidating Adjustments
Operating revenues:
Sales of natural gas, NGLs and condensate	$ 0		$ 0		$ 0	$ 0

Condensed Consolidating Financial Information - Condensed Consolidating Statement of Comprehensive Income (Detail) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
Condensed Financial Statements, Captions [Line Items]
Net income	$ 120	$ 76	$ 62	$ 63	$ 196	$ 125
Other comprehensive income (loss):
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax	0		1		0	1
Other comprehensive income from consolidated subsidiaries			0			0
Other comprehensive income	0		1		0	1
Total comprehensive income	120		63		196	126
Total comprehensive income attributable to noncontrolling interests	(1)		(1)		(2)	(2)
Total comprehensive income attributable to partners	119		62		194	124
Reportable Legal Entities \| Parent Guarantor
Condensed Financial Statements, Captions [Line Items]
Net income	119		61		194	123
Other comprehensive income (loss):
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax			0			0
Other comprehensive income from consolidated subsidiaries			1			1
Other comprehensive income	0		1		0	1
Total comprehensive income	119		62		194	124
Total comprehensive income attributable to noncontrolling interests	0		0		0	0
Total comprehensive income attributable to partners	119		62		194	124
Reportable Legal Entities \| Subsidiary Issuer
Condensed Financial Statements, Captions [Line Items]
Net income	119		61		194	123
Other comprehensive income (loss):
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax			1			1
Other comprehensive income from consolidated subsidiaries			0			0
Other comprehensive income	0		1		0	1
Total comprehensive income	119		62		194	124
Total comprehensive income attributable to noncontrolling interests	0		0		0	0
Total comprehensive income attributable to partners	119		62		194	124
Reportable Legal Entities \| Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Net income	191		129		334	259
Other comprehensive income (loss):
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax			0			0
Other comprehensive income from consolidated subsidiaries			0			0
Other comprehensive income	0		0		0	0
Total comprehensive income	191		129		334	259
Total comprehensive income attributable to noncontrolling interests	(1)		(1)		2	(2)
Total comprehensive income attributable to partners	190		128		332	257
Consolidating Adjustments
Condensed Financial Statements, Captions [Line Items]
Net income	(309)		(189)		(526)	(380)
Other comprehensive income (loss):
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax			0			0
Other comprehensive income from consolidated subsidiaries			(1)			(1)
Other comprehensive income	0		(1)		0	(1)
Total comprehensive income	(309)		(190)		(526)	(381)
Total comprehensive income attributable to noncontrolling interests	0		0		0	0
Total comprehensive income attributable to partners	$ (309)		$ (190)		$ (526)	$ (381)

Condensed Consolidating Financial Information - Condensed Consolidating Statements of Cash Flows (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
OPERATING ACTIVITIES
Net cash (used in) provided by operating activities			$ 546	$ 331
INVESTING ACTIVITIES:
Intercompany transfers			0	0
Capital expenditures	$ (126)	$ (144)	(308)	(268)
Investments in unconsolidated affiliates, net	(139)	(66)	(270)	(126)
Proceeds from sale of assets			132	3
Net cash used in investing activities			(446)	(391)
FINANCING ACTIVITIES:
Intercompany transfers			0	0
Proceeds from debt			3,457	1,803
Payments of debt			(3,208)	(1,678)
Proceeds from Issuance of Preferred Limited Partners Units		155	0	155
Distributions to preferred limited partners			(28)	(21)
Distributions to limited partners and general partner			(309)	(349)
Distributions to noncontrolling interests			(3)	(2)
Other			(9)	0
Net cash provided by (used in) financing activities			(100)	(92)
Net change in cash and cash equivalents			0	(152)
Cash and cash equivalents, beginning of period			1	156
Cash and cash equivalents, end of period	1	4	1	4
Reportable Legal Entities \| Parent Guarantor
OPERATING ACTIVITIES
Net cash (used in) provided by operating activities			0	0
INVESTING ACTIVITIES:
Intercompany transfers			337	215
Capital expenditures			0	0
Investments in unconsolidated affiliates, net			0	0
Proceeds from sale of assets			0	0
Net cash used in investing activities			337	215
FINANCING ACTIVITIES:
Intercompany transfers			0	0
Proceeds from debt			0	0
Payments of debt			0	0
Proceeds from Issuance of Preferred Limited Partners Units				155
Distributions to preferred limited partners			(28)	21
Distributions to limited partners and general partner			(309)	(349)
Distributions to noncontrolling interests			0	0
Other			0
Net cash provided by (used in) financing activities			(337)	(215)
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			(126)	(131)
INVESTING ACTIVITIES:
Intercompany transfers			(114)	(149)
Capital expenditures			0	0
Investments in unconsolidated affiliates, net			0	0
Proceeds from sale of assets			0	0
Net cash used in investing activities			(114)	(149)
FINANCING ACTIVITIES:
Intercompany transfers			0	0
Proceeds from debt			3,457	1,803
Payments of debt			(3,208)	(1,678)
Proceeds from Issuance of Preferred Limited Partners Units				0
Distributions to preferred limited partners			0	0
Distributions to limited partners and general partner			0	0
Distributions to noncontrolling interests			0	0
Other			(9)
Net cash provided by (used in) financing activities			240	125
Net change in cash and cash equivalents			0	(155)
Cash and cash equivalents, beginning of period			0	155
Cash and cash equivalents, end of period	0	0	0	0
Reportable Legal Entities \| Non-Guarantor Subsidiaries
OPERATING ACTIVITIES
Net cash (used in) provided by operating activities			672	462
INVESTING ACTIVITIES:
Intercompany transfers			0	0
Capital expenditures			(308)	(268)
Investments in unconsolidated affiliates, net			(270)	(126)
Proceeds from sale of assets			132	3
Net cash used in investing activities			(446)	(391)
FINANCING ACTIVITIES:
Intercompany transfers			(223)	(66)
Proceeds from debt			0	0
Payments of debt			0	0
Proceeds from Issuance of Preferred Limited Partners Units				0
Distributions to preferred limited partners			0	0
Distributions to limited partners and general partner			0	0
Distributions to noncontrolling interests			(3)	(2)
Other			0
Net cash provided by (used in) financing activities			(226)	(68)
Net change in cash and cash equivalents			0	3
Cash and cash equivalents, beginning of period			1	1
Cash and cash equivalents, end of period	1	4	1	4
Consolidating Adjustments
OPERATING ACTIVITIES
Net cash (used in) provided by operating activities			0	0
INVESTING ACTIVITIES:
Intercompany transfers			(223)	(66)
Capital expenditures			0	0
Investments in unconsolidated affiliates, net			0	0
Proceeds from sale of assets			0	0
Net cash used in investing activities			(223)	(66)
FINANCING ACTIVITIES:
Intercompany transfers			223	66
Proceeds from debt			0	0
Payments of debt			0	0
Proceeds from Issuance of Preferred Limited Partners Units				0
Distributions to preferred limited partners			0	0
Distributions to limited partners and general partner			0	0
Distributions to noncontrolling interests			0	0
Other			0
Net cash provided by (used in) financing activities			223	66
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) - $ / shares	Oct. 15, 2019	Oct. 01, 2019	Sep. 16, 2019	Sep. 03, 2019	Aug. 14, 2019	Aug. 02, 2019	Jul. 23, 2019	Jun. 17, 2019	Apr. 15, 2019	Jan. 15, 2019	Dec. 17, 2018	Sep. 17, 2018	Jun. 15, 2018
Series B Preferred Limited Partners [Member]
Subsequent Event [Line Items]
Preferred Limited Partnership Unit; Distribution Amount Declared								$ 0.4922			$ 0.4922	$ 0.4922
Series C Preferred Limited Partners [Member]
Subsequent Event [Line Items]
Preferred Limited Partnership Unit; Distribution Amount Declared									$ 0.4969	$ 0.4969
Series A Preferred Limited Partners [Member]
Subsequent Event [Line Items]
Preferred Limited Partnership Unit; Distribution Amount Declared								$ 36.8750			$ 36.8750		$ 41.9965
Subsequent Event [Member]
Subsequent Event [Line Items]
Distribution Made to Common Unitholders, Declaration Date							Jul. 23, 2019
Distribution Made to Limited Partner, Distributions Declared, Per Unit							$ 0.78
Distribution Made to Limited Partner, Distribution Date					Aug. 14, 2019
Distribution Made to Limited Partner, Date of Record						Aug. 02, 2019
Subsequent Event [Member] \| Series B Preferred Limited Partners [Member]
Subsequent Event [Line Items]
Distribution Made to Common Unitholders, Declaration Date							Jul. 23, 2019
Preferred Limited Partnership Unit; Distribution Amount Declared							$ 0.4922
Preferred Limited Partnership Distribution; Distribution Date			Sep. 16, 2019
Preferred Limited Partner Distribution: Record Date				Sep. 03, 2019
Subsequent Event [Member] \| Series C Preferred Limited Partners [Member]
Subsequent Event [Line Items]
Distribution Made to Common Unitholders, Declaration Date							Jul. 23, 2019
Preferred Limited Partnership Unit; Distribution Amount Declared							$ 0.4969
Preferred Limited Partnership Distribution; Distribution Date	Oct. 15, 2019
Preferred Limited Partner Distribution: Record Date		Oct. 01, 2019

New Accounting Pronouncements (Notes)	6 Months Ended
New Accounting Pronouncements (Notes)	Jun. 30, 2019
New Accounting Pronouncements, Policy [Abstract]
New Accounting Pronouncements	. New Accounting Pronouncements Financial Accounting Standards Board, or FASB, Accounting Standards Update, or ASU, 2016-13 “Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments” or ASU 2016-13 - In June 2016, the FASB issued ASU 2016-13, which amends current measurement techniques used to estimate credit losses for financial assets. This ASU is effective for interim and annual reporting periods beginning after December 15, 2019, with the option to early adopt for financial statements that have not been issued. We are currently evaluating the potential impact this standard will have on our consolidated financial statements and related disclosures. We do not expect this update to have a material impact on our consolidated financial statements and related disclosures. 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. We adopted this ASU on January 1, 2019 using the modified retrospective approach without application to prior periods. We implemented the following practical expedients and policy elections permitted under the new standard: (a) the package of practical expedients allowing us to not reassess whether expired or existing contracts contain a lease, the lease classification for any expired or existing leases and the treatment of initial direct costs for any expired or existing leases, (b) the land easement practical expedient, allowing us to carry forward our current accounting treatment for land easements in existing agreements, (c) not recognizing lease assets or liabilities when lease terms are less than twelve months and (d) for agreements that contain both lease and non-lease components, combining these components together and accounting for them as a single lease

Dispositions (Notes)	6 Months Ended
Dispositions (Notes)	Jun. 30, 2019
Discontinued Operations and Disposal Groups [Abstract]
Dispositions	. Dispositions On January 30, 2019, we entered into a purchase and sale agreement with NGL Energy Partners LP to sell Gas Supply Resources, our wholesale propane business primarily consisting of seven natural gas liquids terminals in the Eastern United States within our Logistics and Marketing segment for a purchase price of $90 million. Net proceeds received were approximately $103 million due to customary purchase price adjustments. The transaction closed effective March 1, 2019. We recognized a loss on sale of $9 million net of goodwill, in the first quarter of 2019. During the second quarter of 2019, we received proceeds of $29 million related to the sale of non-core assets, resulting in a loss on sale of $5 million.

Net Income or Loss per Limited Partner Unit (Notes)	6 Months Ended
Net Income or Loss per Limited Partner Unit (Notes)	Jun. 30, 2019
Earnings Per Share [Abstract]
Net Income or Loss per Limited Partner Unit	17. Net Income or Loss per Limited Partner UnitBasic 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.

Restructuring (Notes)	6 Months Ended
Restructuring (Notes)	Jun. 30, 2019
Restructuring and Related Activities [Abstract]
Restructuring and Related Activities Disclosure [Text Block]	RestructuringIn May 2019, we announced a voluntary separation program which resulted in $9 million of nonrecurring expense for the three and six months ended June 30, 2019. We expect to incur an additional $2 million of expense during the remainder of 2019 in relation to the voluntary separation program.

Subsequent Events (Notes)	6 Months Ended
Subsequent Events (Notes)	Jun. 30, 2019
Subsequent Events [Abstract]
Subsequent Events	Subsequent EventsOn July 23, 2019, 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 August 14, 2019 to unitholders of record on August 2, 2019.On the same date, the board of directors of the General Partner declared a quarterly distribution on our Series B and Series C Preferred Units of $0.4922 and $0.4969 per unit, respectively. The Series B distributions will be paid on September 16, 2019 to unitholders of record on September 3, 2019. The Series C distribution will be paid on October 15, 2019 to unitholders of record on October 1, 2019.

New Accounting Pronouncements (Details)	6 Months Ended
New Accounting Pronouncements (Details)	Jun. 30, 2019
New Accounting Pronouncements, Policy [Abstract]
New Accounting Pronouncements	. New Accounting Pronouncements Financial Accounting Standards Board, or FASB, Accounting Standards Update, or ASU, 2016-13 “Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments” or ASU 2016-13 - In June 2016, the FASB issued ASU 2016-13, which amends current measurement techniques used to estimate credit losses for financial assets. This ASU is effective for interim and annual reporting periods beginning after December 15, 2019, with the option to early adopt for financial statements that have not been issued. We are currently evaluating the potential impact this standard will have on our consolidated financial statements and related disclosures. We do not expect this update to have a material impact on our consolidated financial statements and related disclosures. 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. We adopted this ASU on January 1, 2019 using the modified retrospective approach without application to prior periods. We implemented the following practical expedients and policy elections permitted under the new standard: (a) the package of practical expedients allowing us to not reassess whether expired or existing contracts contain a lease, the lease classification for any expired or existing leases and the treatment of initial direct costs for any expired or existing leases, (b) the land easement practical expedient, allowing us to carry forward our current accounting treatment for land easements in existing agreements, (c) not recognizing lease assets or liabilities when lease terms are less than twelve months and (d) for agreements that contain both lease and non-lease components, combining these components together and accounting for them as a single lease

Dispositions (Details) - USD ($) $ in Millions		3 Months Ended
Dispositions (Details) - USD ($) $ in Millions	Jan. 30, 2019	Jun. 30, 2019
Discontinued Operations and Disposal Groups [Abstract]
Proceeds from Divestiture of Businesses	$ 90
Loss on Disposition of Business	9	$ 5
Proceeds from Sales of Business, Affiliate and Productive Assets	$ 103	$ 29

Contract Liabilities (Details) - USD ($) $ in Millions	6 Months Ended
Contract Liabilities (Details) - USD ($) $ in Millions	Jun. 30, 2019	Jan. 01, 2019
Contract Assets and Liabilities [Abstract]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	35 years
Contract with Customer, Liability	$ 33	$ 34
Contract with Customer, Liability, Revenue Recognized	$ (1)

Inventories - Schedule of Inventories (Detail) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Components Of Inventory [Line Items]
Total inventories	$ 46	$ 79
Natural Gas
Components Of Inventory [Line Items]
Total inventories	19	34
Natural Gas Liquids
Components Of Inventory [Line Items]
Total inventories	$ 27	$ 45

Goodwill (Details) - USD ($) $ in Millions	6 Months Ended
Goodwill (Details) - USD ($) $ in Millions	Jun. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Goodwill [Line Items]
Goodwill	$ 194	$ 231	$ 231
Goodwill, Written off Related to Sale of Business Unit	37
Gathering and Processing
Goodwill [Line Items]
Goodwill	159	159
Goodwill, Written off Related to Sale of Business Unit	0
Logistics and Marketing
Goodwill [Line Items]
Goodwill	35	$ 72
Goodwill, Written off Related to Sale of Business Unit	$ 37

Carrying Value and Fair Value of Debt (Detail) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Fair Value Disclosures [Abstract]
Total Debt, Carrying Value	$ 5,586	$ 5,337
Total Debt, Fair Value	$ 5,743	$ 5,170

Partnership Equity and Distributions - Additional Information (Detail) $ in Millions	Jun. 30, 2019 USD ($)
Equity Distribution Agreement [Member]
Partnership Equity And Distribution [Line Items]
Offer Value Of Common Stock Unit Remaining Available For Sale	$ 750

Restructuring (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
Restructuring (Details) - USD ($) $ in Millions	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Restructuring Cost and Reserve [Line Items]
Restructuring costs	$ 9	$ 0	$ 9	$ 0
Restructuring costs	9	$ 0	9	$ 0
Restructuring and Related Cost, Expected Cost Remaining	$ 2		$ 2

Condensed Consolidating Financial Information - Additional Information (Detail)	6 Months Ended
	Jun. 30, 2019
Parent Guarantor
Condensed Financial Statements, Captions [Line Items]
Ownership interest percentage in subsidiary	100.00%