DCP Midstream (DCP-PC) 10-Q 3 Nov 21 2021 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2021	Oct. 29, 2021
Document Type	10-Q
Current Fiscal Year End Date	--12-31
Document Period End Date	Sep. 30, 2021
Document Transition Report	false
Entity File Number	001-32678
Entity Registrant Name	DCP MIDSTREAM, LP
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	03-0567133
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 Address, Postal Zip Code	80202
City Area Code	(303)
Local Phone Number	595-3331
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Amendment Flag	false
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
Entity Central Index Key	0001338065
Entity Common Stock, Shares Outstanding		208,373,672
Document Period End Date	true
Series B Preferred Limited Partners [Member]
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]
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
Title of 12(b) Security	Common units representing limited partnership interests
Trading Symbol	DCP
Security Exchange Name	NYSE

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 3	$ 52
Accounts receivable:
Trade, net of allowance for credit losses of $2 and $2 million, respectively	1,045	572
Affiliates	484	238
Other	17	10
Inventories	58	38
Unrealized gains on derivative instruments	141	63
Collateral cash deposits	231	14
Other	22	21
Total current assets	2,001	1,008
Property, plant and equipment, net	7,775	7,993
Intangible assets, net	41	44
Investments in unconsolidated affiliates	3,577	3,641
Unrealized gains on derivative instruments	13	16
Operating lease assets	93	85
Other long-term assets	196	170
Total assets	13,696	12,957
Accounts payable:
Trade	1,037	536
Affiliates	246	161
Other	13	23
Current debt	355	505
Unrealized losses on derivative instruments	321	56
Accrued interest	72	85
Accrued taxes	71	59
Accrued wages and benefits	50	70
Capital spending accrual	3	4
Other	118	122
Total current liabilities	2,286	1,621
Long-term debt	5,325	5,119
Unrealized losses on derivative instruments	48	7
Deferred income taxes	30	30
Operating lease liabilities	81	76
Other long-term liabilities	260	243
Total liabilities	8,030	7,096
Equity:
Limited partners (208,373,672 and 208,351,528 common units authorized, issued and outstanding, respectively)	4,885	5,090
Accumulated other comprehensive loss	(6)	(7)
Total partners’ equity	5,640	5,834
Noncontrolling interests	26	27
Total equity	5,666	5,861
Total liabilities and equity	13,696	12,957
Allowance for Doubtful Accounts Receivable, Current	$ 2	$ 2
Common unitholders, units issued (in shares)	208,373,672	208,351,528
Common unitholders, units outstanding (in shares)	208,373,672	208,351,528
Series A Preferred Limited Partners [Member]
Equity:
Preferred Units, Preferred Partners' Capital Accounts	$ 499	$ 489
Total equity	$ 499	$ 489
Preferred Units, Issued	500,000	500,000
Preferred Units, Outstanding	500,000	500,000
Series B Preferred Limited Partners [Member]
Equity:
Preferred Units, Preferred Partners' Capital Accounts	$ 156	$ 156
Total equity	$ 156	$ 156
Preferred Units, Issued	6,450,000	6,450,000
Preferred Units, Outstanding	6,450,000	6,450,000
Series C Preferred Limited Partners [Member]
Equity:
Preferred Units, Preferred Partners' Capital Accounts	$ 106	$ 106
Total equity	$ 106	$ 106
Preferred Units, Issued	4,400,000	4,400,000
Preferred Units, Outstanding	4,400,000	4,400,000

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Operating revenues:
Trading and marketing gains (losses), net	$ (173)	$ 11	$ (695)	$ 156
Total operating revenues	2,827	1,586	7,230	4,517
Operating costs and expenses:
Operating and maintenance expense	168	146	482	447
Depreciation and amortization expense	89	92	273	284
General and administrative expense	63	66	158	173
Other expense (income), net	(2)	(4)	4	(12)
Asset Impairment	0	0	20	746
Loss on sale of assets, net	0	0	1	0
Restructuring costs	0	0	0	9
Total operating costs and expenses	2,833	1,526	7,317	5,009
Operating (loss) income	(6)	60	(87)	(492)
Earnings from unconsolidated affiliates	134	130	393	331
Interest expense, net	(73)	(77)	(227)	(226)
(Loss) income before income taxes	55	113	79	(387)
Income tax expense	0	1	0	2
Net income	55	112	79	(389)
Net income attributable to noncontrolling interests	(1)	(1)	(3)	(3)
Net income attributable to partners	54	111	76	(392)
Series A preferred limited partners' interest in net income	(9)	(9)	(28)	(28)
Series B preferred limited partners' interest in net income	(4)	(3)	(10)	(9)
Series C preferred limited partners' interest in net income	(3)	(3)	(7)	(7)
Net income allocable to limited partners	$ 38	$ 96	$ 31	$ (436)
Net income per limited partner unit — basic and diluted	$ 0.18	$ 0.46	$ 0.15	$ (2.09)
Weighted Average Limited Partnership Units Outstanding, Basic	208.4	208.3	208.4	208.3
Property, plant, and equipment impairment				$ 587
Weighted Average Limited Partnership Units Outstanding, Diluted	208.7	208.7	208.6	208.3
Natural Gas, NGLs and Condensate [Member] | Third Party
Operating revenues:
Sales of natural gas, NGLs and condensate	$ 1,935	$ 1,204	$ 5,395	$ 3,378
Operating costs and expenses:
Purchases and related costs	2,181	944	5,484	2,539
Transportation, Processing and Other [Member]
Operating revenues:
Sales of natural gas, NGLs and condensate	144	109	387	330
Affiliated Entity | Natural Gas, NGLs and Condensate [Member]
Operating revenues:
Sales of natural gas, NGLs and condensate	921	262	2,143	653
Operating costs and expenses:
Purchases and related costs	81	32	183	89
Affiliated Entity | Transportation Fees
Operating costs and expenses:
Purchases and related costs	$ 249	$ 242	$ 720	$ 710

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Millions	3 Months Ended						9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
Statement of Comprehensive Income [Abstract]
Net (loss) income	$ 55	$ (30)	$ 54	$ 112	$ 48	$ (549)	$ 79	$ (389)
Other comprehensive income:
Other comprehensive income	1			0			1	0
Total comprehensive income	56			112			80	(389)
Total comprehensive income attributable to noncontrolling interests	(1)			(1)			(3)	(3)
Total comprehensive income attributable to partners	$ 55			$ 111			$ 77	$ (392)

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
OPERATING ACTIVITIES:
Net (loss) income	$ 55	$ 112	$ 79	$ (389)
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization expense	89	92	273	284
Earnings from unconsolidated affiliates	(134)	(130)	(393)	(331)
Distributions from unconsolidated affiliates			462	489
Net unrealized (gains) losses on derivative instruments	107	11	296	(66)
Loss on sale of assets, net	0	0	1	0
Asset Impairment	0	0	20	746
Other, net			(13)	(27)
Change in operating assets and liabilities, which (used) provided cash, net of effects of acquisitions:
Accounts receivable			726	(185)
Inventories			20	(13)
Accounts payable			576	(230)
Decrease in Other Operating Assets and Liabilities, Net			(325)	63
Net cash provided by operating activities			255	791
INVESTING ACTIVITIES:
Capital expenditures	(28)	(23)	(69)	(125)
Investments in unconsolidated affiliates	(4)	(12)	(4)	(102)
Payments to Acquire Equity Method Investments			4	107
Proceeds from Equity Method Investment, Distribution, Return of Capital			0	5
Proceeds from sale of assets			0	2
Net cash used in investing activities			(73)	(225)
FINANCING ACTIVITIES:
Proceeds from debt			3,380	3,958
Payments of debt			3,332	4,137
Distributions to preferred limited partners			35	34
Distributions to limited partners and general partner			(244)	(325)
Payments to Noncontrolling Interests			(4)	(3)
Payments of Debt Issuance Costs			0	(8)
Proceeds from (Payments for) Other Financing Activities			0	(1)
Net cash provided by (used in) financing activities			(235)	(550)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect			(53)	16
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Beginning Balance			56	1
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Ending Balance	3	17	3	17
Cash and cash equivalents, end of period	3	14	3	14
Restricted Cash, Current	$ 0	$ 3	$ 0	$ 3

Consolidated Statements of Chan

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]	Limited Partners	Accumulated Other Comprehensive (Loss) Income	Noncontrolling Interests
Beginning balance at Dec. 31, 2019	$ 6,633	$ 489	$ 156	$ 106	$ 5,861	$ (7)	$ 28
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income (loss)	(549)	9	3	2	(564)	0	1
Total Cash Distribution to Unitholders	(167)	0	(3)	(2)	(162)	0	0
Distributions to noncontrolling interests	(1)	0	0	0	0	0	1
Ending balance at Mar. 31, 2020	5,916	498	156	106	5,135	(7)	28
Beginning balance at Dec. 31, 2019	6,633	489	156	106	5,861	(7)	28
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income (loss)	(389)
Other comprehensive income	0
Ending balance at Sep. 30, 2020	5,882	499	156	106	5,100	(7)	28
Beginning balance at Mar. 31, 2020	5,916	498	156	106	5,135	(7)	28
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income (loss)	48	10	3	2	32	0	1
Total Cash Distribution to Unitholders	(104)	(18)	(3)	(2)	(81)	0	0
Distributions to noncontrolling interests	(1)	0	0	0	0	0	(1)
Ending balance at Jun. 30, 2020	5,859	490	156	106	5,086	(7)	28
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income (loss)	112	9	3	3	96	0	1
Other comprehensive income	0
Total Cash Distribution to Unitholders	(88)	0	(3)	(3)	(82)	0	0
Distributions to noncontrolling interests	(1)	0	0	0	0	0	(1)
Ending balance at Sep. 30, 2020	5,882	499	156	106	5,100	(7)	28
Beginning balance at Dec. 31, 2020	5,861	489	156	106	5,090	(7)	27
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income (loss)	54	9	3	2	39	0	1
Total Cash Distribution to Unitholders	(86)	0	(3)	(2)	(81)	0	0
Distributions to noncontrolling interests	(1)	0	0	0	0	0	(1)
Employee Benefits and Share-based Compensation	4	0	0	0	4	0	0
Ending balance at Mar. 31, 2021	5,832	498	156	106	5,052	(7)	27
Beginning balance at Dec. 31, 2020	5,861	489	156	106	5,090	(7)	27
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income (loss)	79
Other comprehensive income	1
Ending balance at Sep. 30, 2021	5,666	499	156	106	4,885	(6)	26
Beginning balance at Mar. 31, 2021	5,832	498	156	106	5,052	(7)	27
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income (loss)	(30)	10	3	2	(46)	0	1
Total Cash Distribution to Unitholders	(105)	(18)	(3)	(2)	(82)	0	0
Distributions to noncontrolling interests	(1)	0	0	0	0	0	(1)
Employee Benefits and Share-based Compensation	1	0	0	0	1	0	0
Ending balance at Jun. 30, 2021	5,697	490	156	106	4,925	(7)	27
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income (loss)	55	9	4	3	38	0	1
Other comprehensive income	1	0	0	0	0	1	0
Total Cash Distribution to Unitholders	(88)	0	(4)	(3)	(81)	0	0
Distributions to noncontrolling interests	(2)	0	0	0	0	0	(2)
Employee Benefits and Share-based Compensation	3	0	0	0	3	0	0
Ending balance at Sep. 30, 2021	$ 5,666	$ 499	$ 156	$ 106	$ 4,885	$ (6)	$ 26

Description of Business and Bas

Description of Business and Basis of Presentation (Notes)	9 Months Ended
	Sep. 30, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
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 15 - Business Segments. Our operations and activities are managed by our general partner, DCP Midstream GP, LP, which in turn is managed by its general partner, DCP Midstream GP, LLC, which we refer to as the General Partner, and which is 100% owned by DCP Midstream, LLC. DCP Midstream, LLC and its subsidiaries and affiliates, collectively referred to as DCP Midstream, LLC, is owned 50% by Phillips 66 and 50% by Enbridge Inc. and its affiliates, or Enbridge. DCP Midstream, LLC directs our business operations through its ownership and control of the General Partner. As of September 30, 2021, DCP Midstream, LLC, together with our general partner, owned approximately 57% of us through limited 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 GAAP. Conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the condensed consolidated financial statements and notes. Although these estimates are based on management's best available knowledge of current and expected future events, actual results could differ from these estimates, which may be significantly impacted by various factors, including those outside of our control, such as the impact of a sustained deterioration in commodity prices and volumes, which would negatively impact our results of operations, financial condition and cash flows. All intercompany balances and transactions have been eliminated in consolidation. These unaudited condensed consolidated financial statements in this Quarterly Report on Form 10-Q have been prepared pursuant to the rules and regulations of 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 nine months ended September 30, 2021 are not necessarily indicative of the results that may be expected for the year ending December 31, 2021. 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 2020 audited consolidated financial statements and notes thereto included in our Annual Report on Form 10-K for the year ended December 31, 2020.

Revenue Recognition (Notes)

Revenue Recognition (Notes)	9 Months Ended
	Sep. 30, 2021
Revenue from Contract with Customer [Abstract]
Revenue from External Customers by Products and Services [Table Text Block]	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 September 30, 2021 Logistics and Marketing Gathering and Processing Eliminations Total (millions) Sales of natural gas $ 895 $ 715 $ (695) $ 915 Sales of NGLs and condensate (a) 1,768 1,139 (966) 1,941 Transportation, processing and other 19 126 (1) 144 Trading and marketing losses, net (b) (14) (159) — (173) Total operating revenues $ 2,668 $ 1,821 $ (1,662) $ 2,827 Nine Months Ended September 30, 2021 Logistics and Marketing Gathering and Processing Eliminations Total (millions) Sales of natural gas $ 2,625 $ 1,832 $ (1,673) $ 2,784 Sales of NGLs and condensate (a) 4,296 2,686 (2,228) 4,754 Transportation, processing and other 46 342 (1) 387 Trading and marketing losses, net (b) (284) (411) — (695) Total operating revenues $ 6,683 $ 4,449 $ (3,902) $ 7,230 (a) Includes $589 million and $1,473 million for the three and nine months ended September 30, 2021, respectively, of revenues from physical sales contracts and buy-sell exchange transactions in our Logistics and Marketing segment. For the three and nine months ended September 30, 2021, these revenues are net of $741 million and $1,692 million, respectively, of buy-sell purchases related to buy-sell revenues of $786 million and $1,867 million, respectively, which are not within the scope of FASB ASU 2014-09 "Revenue from Contractors with Customer" ("Topic 606"). (b) Not within the scope of Topic 606. Three Months Ended September 30, 2020 Logistics and Marketing Gathering and Processing Eliminations Total (millions) Sales of natural gas $ 437 $ 330 $ (308) $ 459 Sales of NGLs and condensate (a) 951 456 (400) 1,007 Transportation, processing and other 13 97 (1) 109 Trading and marketing gains (losses), net (b) 37 (26) — 11 Total operating revenues $ 1,438 $ 857 $ (709) $ 1,586 Nine Months Ended September 30, 2020 Logistics and Marketing Gathering and Processing Eliminations Total (millions) Sales of natural gas $ 1,203 $ 927 $ (842) $ 1,288 Sales of NGLs and condensate (a) 2,592 1,125 (974) 2,743 Transportation, processing and other 37 294 (1) 330 Trading and marketing gains, net (b) 114 42 — 156 Total operating revenues $ 3,946 $ 2,388 $ (1,817) $ 4,517 (a) Includes $303 million and $2,006 million for the three and nine months ended September 30, 2020, 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 $467 million as of September 30, 2021. Our remaining performance obligations primarily consist of minimum volume commitment fee arrangements and are expected to be recognized through 2031 with a weighted average remaining life of four years as of September 30, 2021. 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.

Contract Liabilities (Notes)

Contract Liabilities (Notes)	9 Months Ended
	Sep. 30, 2021
Contract Assets and Liabilities [Abstract]
Contract Assets and Liabilities [Text Block]	. Contract LiabilitiesOur contract liabilities consist of deferred revenue received from reimbursable projects. The noncurrent portion of deferred revenue is included in other long-term liabilities on our condensed consolidated balance sheets. The following table summarizes changes in contract liabilities included in our condensed consolidated balance sheets: September 30, 2021 (millions) Balance, beginning of period $ 35 Revenue recognized (a) (2) Balance, end of period $ 33 (a) Deferred revenue recognized is included in transportation, processing and other on the condensed consolidated statement of operations. The contract liabilities disclosed in the table above will be recognized as revenue as the obligations are satisfied over their average remaining contract life, which is 35 years as of September 30, 2021.

Agreements and Transactions wit

Agreements and Transactions with Affiliates	9 Months Ended
	Sep. 30, 2021
Related Party Transactions [Abstract]
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 September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (millions) Employee related costs charged by DCP Midstream, LLC Operating and maintenance expense $ 39 $ 39 $ 116 $ 121 General and administrative expense $ 44 $ 43 $ 109 $ 113 Restructuring costs $ — $ — $ — $ 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, provide gathering and transportation services to, and receive transportation services from unconsolidated affiliates. We anticipate continuing to purchase and sell commodities and receive and provide services to unconsolidated affiliates in the ordinary course of business. Summary of Transactions with Affiliates The following table summarizes our transactions with affiliates: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (millions) Phillips 66 (including its affiliates): Sales of natural gas, NGLs and condensate to affiliates $ 893 $ 247 $ 2,066 $ 616 Purchases and related costs from affiliates $ 45 $ 15 $ 94 $ 52 Transportation and related costs from affiliates $ 39 $ 26 $ 113 $ 70 Operating and maintenance and general administrative expenses $ 3 $ 4 $ 9 $ 10 Enbridge (including its affiliates): Sales of natural gas, NGLs and condensate to affiliates $ — $ 1 $ 4 $ 2 Purchases and related costs from affiliates $ 12 $ 2 $ 27 $ 2 Transportation and related costs from affiliates $ 1 $ 1 $ 1 $ 1 Operating and maintenance and general administrative expenses $ 1 $ — $ 1 $ 1 Unconsolidated affiliates: Sales of natural gas, NGLs and condensate to affiliates $ 28 $ 14 $ 73 $ 35 Transportation, processing, and other to affiliates $ 3 $ 3 $ 13 $ 9 Purchases and related costs from affiliates $ 24 $ 15 $ 62 $ 35 Transportation and related costs from affiliates $ 209 $ 215 $ 606 $ 639 We had balances with affiliates as follows: September 30, 2021 December 31, 2020 (millions) Phillips 66 (including its affiliates): Accounts receivable $ 457 $ 217 Accounts payable $ 158 $ 89 Other assets $ 1 $ 1 Enbridge (including its affiliates): Accounts payable $ 4 $ 2 Unconsolidated affiliates: Accounts receivable $ 27 $ 21 Accounts payable $ 84 $ 70

Inventories (Notes)

Inventories (Notes)	9 Months Ended
	Sep. 30, 2021
Inventory Disclosure [Abstract]
Inventories	Inventories Inventories were as follows: September 30, 2021 December 31, 2020 (millions) Natural gas $ 29 $ 18 NGLs 29 20 Total inventories $ 58 $ 38 We recognize lower of cost or net realizable value adjustments when the carrying value of our inventories exceeds their net realizable value. These non-cash charges are a component of purchases and related costs in the condensed consolidated statements of operations. We recognized no lower of cost or net realizable value adjustments for the three and nine months

Property, Plant and Equipment (

Property, Plant and Equipment (Notes)	9 Months Ended
	Sep. 30, 2021
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	Property, Plant and Equipment A summary of property, plant and equipment by classification is as follows: Depreciable September 30, 2021 December 31, 2020 (millions) Gathering and transmission systems 20 — 50 Years $ 7,660 $ 7,680 Processing, storage and terminal facilities 35 — 60 Years 5,059 4,986 Other 3 — 30 Years 585 585 Finance lease assets 2 — 5 Years 28 25 Construction work in progress 87 144 Property, plant and equipment 13,419 13,420 Accumulated depreciation (5,644) (5,427) Property, plant and equipment, net $ 7,775 $ 7,993 There were no construction projects with capitalized interest during the three months ended September 30, 2021. Capitalized interest on construction projects was $1 million for the three months ended September 30, 2020, and $1 million and $3 million for the nine months ended September 30, 2021 and 2020, respectively. Depreciation expense was $88 million and $90 million for the three months ended September 30, 2021 and 2020, respectively, and $269 million and $279 million for the nine months ended September 30, 2021 and 2020, respectively.

Investments in Unconsolidated A

Investments in Unconsolidated Affiliates	9 Months Ended
	Sep. 30, 2021
Equity Method Investments and Joint Ventures [Abstract]
Investments in Unconsolidated Affiliates	Investments in Unconsolidated Affiliates The following table summarizes our investments in unconsolidated affiliates: Carrying Value as of Percentage September 30, December 31, 2020 (millions) DCP Sand Hills Pipeline, LLC 66.67% $ 1,707 $ 1,723 DCP Southern Hills Pipeline, LLC 66.67% 721 734 Gulf Coast Express LLC 25.00% 425 436 Front Range Pipeline LLC 33.33% 193 198 Texas Express Pipeline LLC 10.00% 94 97 Discovery Producer Services LLC 40.00% 231 244 Mont Belvieu 1 Fractionator 20.00% 7 7 Mont Belvieu Enterprise Fractionator 12.50% 27 26 Cheyenne Connector, LLC 50.00% 149 152 Panola Pipeline Company, LLC 15.00% 20 21 Other Various 3 3 Total investments in unconsolidated affiliates $ 3,577 $ 3,641 Earnings from investments in unconsolidated affiliates were as follows: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (millions) DCP Sand Hills Pipeline, LLC $ 68 $ 73 $ 202 $ 221 DCP Southern Hills Pipeline, LLC 21 19 67 59 Gulf Coast Express LLC 16 17 46 49 Front Range Pipeline LLC 10 9 28 29 Texas Express Pipeline LLC 5 4 14 13 Discovery Producer Services LLC (a) 2 (3) 13 (63) Mont Belvieu 1 Fractionator 6 3 12 9 Mont Belvieu Enterprise Fractionator 2 4 1 10 Cheyenne Connector, LLC 4 3 8 3 Other — 1 2 1 Total earnings from unconsolidated affiliates $ 134 $ 130 $ 393 $ 331 (a) In 2020, we recognized an impairment of $61 million on our equity investment in Discovery Producer Services LLC. The following tables summarize the combined financial information of our investments in unconsolidated affiliates: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (millions) Statements of operations: Operating revenue $ 535 $ 523 $ 1,552 $ 1,560 Operating expenses $ 231 $ 196 $ 631 $ 572 Net income $ 303 $ 326 $ 917 $ 985 September 30, December 31, (millions) Balance sheets: Current assets $ 384 $ 355 Long-term assets 7,331 7,510 Current liabilities (208) (177) Long-term liabilities (253) (258) Net assets $ 7,254 $ 7,430

Fair Value Measurement (Notes)

Fair Value Measurement (Notes)	9 Months Ended
	Sep. 30, 2021
Fair Value Disclosures [Abstract]
Derivatives and Fair Value	. 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. The following table presents the financial instruments carried at fair value on a recurring basis as of September 30, 2021 and December 31, 2020, by condensed consolidated balance sheet caption and by valuation hierarchy, as described above: September 30, 2021 December 31, 2020 Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total (millions) Current assets: Commodity derivatives $ 58 $ 83 $ — $ 141 $ 21 $ 42 $ — $ 63 Short-term investments (a) $ 2 $ 1 $ — $ 3 $ — $ — $ — $ — Long-term assets: Commodity derivatives $ 3 $ 7 $ 3 $ 13 $ 1 $ 13 $ 2 $ 16 Investments in marketable securities (a) $ 31 $ — $ — $ 31 $ 22 $ 1 $ — $ 23 Current liabilities: Commodity derivatives $ (90) $ (226) $ (5) $ (321) $ (19) $ (34) $ (3) $ (56) Long-term liabilities: Commodity derivatives $ (7) $ (38) $ (3) $ (48) $ — $ (6) $ (1) $ (7) (a) $3 million and $4 million recorded within "other" current assets and $31 million and $19 million recorded within "Other long-term assets" as of September 30, 2021 and December 31, 2020, respectfully. 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. 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 Long-Term Current Long-Term (millions) Three months ended September 30, 2021 (a): Beginning balance $ 1 $ 1 $ (9) $ (5) Net unrealized gains (losses) included in earnings 1 2 (10) 2 Transfers out of Level 3 (2) — 12 — Settlements — — 2 — Ending balance $ — $ 3 $ (5) $ (3) Net unrealized gains (losses) on derivatives still held included in earnings $ — $ 2 $ (3) $ 2 Three months ended September 30, 2020 (a): Beginning balance $ 1 $ — $ (3) $ (4) Net unrealized (losses) gains included in earnings (1) 4 (1) 3 Transfers out of Level 3 — — 2 — Settlements — — 1 — Ending balance $ — $ 4 $ (1) $ (1) Net unrealized gains on derivatives still held included in earnings $ — $ 4 $ 1 $ 3 Commodity Derivative Instruments Current Long-Term Current Long-Term (millions) Nine months ended September 30, 2021 (a): Beginning balance $ — $ 2 $ (3) $ (1) Net unrealized gains (losses) included in earnings — 1 (16) (3) Transfers out of Level 3 — — 9 1 Settlements — — 5 — Ending balance $ — $ 3 $ (5) $ (3) Net unrealized gains (losses) on derivatives still held included in earnings $ — $ 1 $ (5) $ (3) Nine months ended September 30, 2020 (a): Beginning balance $ 4 $ — $ (1) $ (3) Net unrealized (losses) gains included in earnings (1) 8 8 2 Transfers out of Level 3 — (4) — — Settlements (3) — (8) — Ending balance $ — $ 4 $ (1) $ (1) Net unrealized (losses) gains on derivatives still held included in earnings $ (2) $ 4 $ (1) $ 1 (a) There were no purchases, issuances or sales of derivatives or transfers into Level 3 for the three and nine months ended September 30, 2021 and 2020. Quantitative Information and Fair Value Sensitivities Related to Level 3 Unobservable Inputs We utilize the market approach to measure the fair value of our commodity contracts. The significant unobservable inputs used in this approach to fair value are longer dated price quotes. Our sensitivity to these longer dated forward curve prices are presented in the table below. Significant changes in any of those inputs in isolation would result in significantly different fair value measurements, depending on our short or long position in contracts. September 30, 2021 Product Group Fair Value Valuation Techniques Unobservable Input Forward Weighted Average (a) (millions) Assets Natural gas $ 3 Market approach Longer dated forward curve prices $2.24-$3.40 $2.71 Per MMBtu Liabilities NGLs $ (6) Market approach Longer dated forward curve prices $0.33-$1.75 $0.92 Per gallon Natural gas $ (2) Market approach Longer dated forward curve prices $2.24-$3.30 $2.50 Per MMBtu (a) Unobservable inputs were weighted by the instrument's notional amounts. 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. The inputs used to determine such fair value are primarily based upon internally developed cash flow models and would generally be classified within Level 3 in the event that we were required to measure and record such assets at fair value within our condensed consolidated financial statements. Additionally, we use fair value to determine the inception value of our asset retirement obligations. The inputs used to determine such fair value are primarily based upon costs incurred historically for similar work, as well as estimates from independent third parties for costs that would be incurred to restore leased property to the contractually stipulated condition, and would generally be classified within Level 3. During the nine months ended September 30, 2021 we recognized a $7 million impairment associated with certain assets in the Midcontinent region of our Gathering and Processing segment that were sold in July 2021, and determined that a triggering event occurred due to a negative outlook for long-term volume forecasts for an asset in our Logistics and Marketing segment resulting in an impairment of $13 million. During the nine months ended September 30, 2020, we recognized a $587 million impairment loss associated with certain asset groups in the Permian and South regions of our Gathering and Processing segment and an impairment of $61 million of our equity investment in Discovery Producer Services LLC (“Discovery”). 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 carrying value of borrowings under the Credit Agreement and the Securitization Facility approximate fair value as their interest rates are based on prevailing market interest rates. We classify the fair values of our outstanding debt balances within Level 2 of the valuation hierarchy. As of September 30, 2021 and December 31, 2020, the carrying value and fair value of our total debt, including current maturities, were as follows: September 30, 2021 December 31, 2020 Carrying Value (a) Fair Value Carrying Value (a) Fair Value (millions) Total debt $ 5,687 $ 6,274 $ 5,635 $ 5,938

Leases (Notes)

Leases (Notes)	9 Months Ended
	Sep. 30, 2021
Leases [Abstract]
Leases of Lessee Disclosure [Text Block]	. Leases We have operating leases for transportation agreements, office space, and field equipment. We have finance leases for field equipment and vehicles. Our leases have remaining lease terms ranging from less than one year to 20 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. Operating and finance leases are included on our condensed consolidated balance sheet as follows: Location in Condensed Consolidated Balance Sheet As of September 30, 2021 December 31, 2020 (millions) Assets Operating lease assets Operating lease assets $ 93 $ 85 Finance lease assets Property, plant and equipment 28 25 Total right of use assets $ 121 $ 110 Liabilities Current liabilities Operating lease liabilities Other current liabilities $ 26 $ 24 Finance lease liabilities Current debt 5 5 Noncurrent liabilities Operating lease liabilities Operating lease liabilities $ 81 $ 76 Finance lease liabilities Long-term debt 21 22 Total lease liabilities $ 133 $ 127 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: Location in Condensed Consolidated Statement of Operations Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (millions) Operating lease cost Operating and maintenance expense $ 7 $ 7 $ 21 $ 21 Finance lease cost Amortization of right of use assets Depreciation and amortization expense 1 1 2 2 Interest on lease liabilities Interest expense 1 1 1 1 Variable lease cost Operating and maintenance expense 1 2 3 5 Short term lease cost Operating and maintenance expense 1 1 2 3 Total lease cost $ 11 $ 12 $ 29 $ 32 Maturities of operating and finance lease liabilities under non-cancelable leases as of September 30, 2021 are as follows: Future Minimum Lease Payments as of September 30, 2021 Operating Leases Finance Leases (millions) 2021 - remainder $ 7 $ 2 2022 29 6 2023 26 6 2024 17 7 2025 13 3 Thereafter 26 9 Total lease payments $ 118 $ 33 Less imputed interest (11) (7) Total lease liabilities $ 107 $ 26 As of September 30, 2021, the Company had minimum commitments related to additional operating lease contracts for which the commencement date has not yet been reached, primarily for an office lease, of approximately $19 million. Supplemental cash flow information related to leases is as follows: Nine Months Ended September 30, 2021 2020 (millions) Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 23 $ 20 Operating cash flows from finance leases 3 3 Financing cash flows from finance leases 1 1 Right-of-use assets obtained in exchange for operating lease obligations: $ 26 $ 6 Right-of-use assets obtained in exchange for finance lease obligations: $ 3 $ 5 Other information related to operating leases as follows: Weighted average remaining lease term 5 years 6 years Weighted average discount rate 4.00 % 4.00 % Other information related to finance leases as follows: Weighted average remaining lease term 4 years 5 years Weighted average discount rate 3.00 % 3.00 %

Debt (Notes)

Debt (Notes)	9 Months Ended
	Sep. 30, 2021
Debt Disclosure [Abstract]
Debt	10. Debt September 30, 2021 December 31, 2020 (millions) Senior notes: Issued September 2011, interest at 4.750% payable semi-annually, due September 2021 $ — $ 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 825 825 Issued June 2020, interest at 5.625% payable semi-annually, due July 2027 500 500 Issued May 2019, interest at 5.125% payable semi-annually, due May 2029 600 600 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, variable interest rate of 1.440% as of September 30, 2021, due December 2024 552 — Accounts receivable securitization facility: Accounts receivable securitization facility, interest at 0.980% as of September 30, 2021, due August 2024 350 350 Fair value adjustments related to interest rate swap fair value hedges (a) 16 17 Unamortized issuance costs (33) (38) Unamortized discount, net (6) (7) Finance lease liabilities 26 27 Total debt 5,680 5,624 Current finance lease liabilities 5 5 Current debt 350 500 Total long-term debt $ 5,325 $ 5,119 (a) The swaps associated with this debt were previously terminated. The remaining long-term fair value related to the swaps is being amortized as a reduction to interest expense through 2030, the original maturity date 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 Redemption On June 30, 2021, we repaid, at par, prior to maturity all $500 million aggregate principal amount outstanding of our 4.75% Senior Notes due September 2021 using borrowings under our revolving credit facility. Credit Agreement We are a party to a $1.4 billion unsecured revolving credit facility governed by the Credit Agreement, which matures on December 9, 2024. 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 1.35% 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 1.00%, plus (b) an applicable margin of 0.35% based on our current credit rating. The Credit Agreement incurs an annual facility fee of 0.275% based on our current credit rating. This fee is paid on drawn and undrawn portions of the $1.4 billion revolving credit facility. As of September 30, 2021, we had unused borrowing capacity of $846 million, net of $552 million of outstanding borrowings and $2 million of letters of credit, under the Credit Agreement, of which $846 million would have been available to borrow for working capital and other general partnership purposes based on the financial covenants set forth in the Credit Agreement. Except in the case of a default, amounts borrowed under our Credit Agreement will not become due prior to the December 9, 2024 maturity date. Accounts Receivable Securitization Facility On August 2, 2021 we entered into an amendment to our Securitization Facility to extend the term of the facility until August 12, 2024. The amendment also includes Environmental, Social, and Governance linked Key Performance Indicators that increase or decrease certain fees based on our safety performance relative to our peers, and year-over-year change in our greenhouse gas emissions intensity rate. The Securitization Facility provides up to $350 million of borrowing capacity through August 2024 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 may be limited by the availability of eligible receivables and other customary factors and conditions, as well as the covenants set forth in the Securitization Facility. As of September 30, 2021, DCP Receivables had approximately $963 million of our accounts receivable securing borrowings of $350 million under the Securitization Facility. The maturities of our debt as of September 30, 2021 are as follows: Debt (millions) 2021 $ — 2022 350 2023 500 2024 902 2025 825 Thereafter 3,100 Total debt $ 5,677

Risk Management and Hedging Act

Risk Management and Hedging Activities (Notes)	9 Months Ended
	Sep. 30, 2021
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Risk Management and Hedging Activities	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 September 30, 2021, we had cash deposits of $231 million, included in collateral cash deposits in our condensed consolidated balance sheets. Additionally, as of September 30, 2021, we held letters of credit of $103 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 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 financial derivative instruments are subject to a master netting or similar arrangement, whereby we may elect to settle multiple positions with an individual counterparty through a single net payment. Each of our individual derivative instruments are presented on a gross basis on the condensed consolidated balance sheets, regardless of our ability to net settle our positions. Instruments that are governed by agreements that include net settle provisions allow final settlement, when presented with a termination event, of outstanding amounts by extinguishing the mutual debts owed between the parties in exchange for a net amount due. We have trade receivables and payables associated with derivative instruments, subject to master netting or similar agreements, which are not included in the table below. The following summarizes the gross and net amounts of our derivative instruments: September 30, 2021 December 31, 2020 Gross Amounts Amounts Not Net Gross Amounts Amounts Not Net (millions) Assets: Commodity derivatives $ 154 $ — $ 154 $ 79 $ — $ 79 Liabilities: Commodity derivatives $ (369) $ — $ (369) $ (63) $ — $ (63) Summarized Derivative Information The fair value of our derivative instruments that are marked-to-market each period, as well as the location of each within our condensed consolidated balance sheets, by major category, is summarized below. We have no derivative instruments that are designated as hedging instruments for accounting purposes as of September 30, 2021 and December 31, 2020. Balance Sheet Line Item September 30, December 31, Balance Sheet Line Item September 30, December 31, (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 $ 141 $ 63 Unrealized losses on derivative instruments — current $ (321) $ (56) Unrealized gains on derivative instruments — long-term 13 16 Unrealized losses on derivative instruments — long-term (48) (7) Total $ 154 $ 79 Total $ (369) $ (63) The following summarizes the balance and activity within AOCI relative to our interest rate, commodity and foreign currency cash flow hedges as of and for the three months ended September 30, 2021: Interest Commodity Foreign Total (millions) Net deferred (losses) gains in AOCI (beginning balance) $ (2) $ (6) $ 1 $ (7) Losses reclassified from AOCI to earnings — effective portion 1 — — 1 Net deferred (losses) gains in AOCI (ending balance) $ (1) $ (6) $ 1 $ (6) Deferred losses in AOCI expected to be reclassified into earnings over the next 12 months $ — $ — $ — $ — (a) Relates to 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 nine months ended September 30, 2021: Interest Commodity Foreign Total (millions) Net deferred (losses) gains in AOCI (beginning balance) $ (2) $ (6) $ 1 $ (7) Losses reclassified from AOCI to earnings — effective portion 1 — — 1 Net deferred (losses) gains in AOCI (ending balance) $ (1) $ (6) $ 1 $ (6) Deferred losses in AOCI expected to be reclassified into earnings over the next 12 months $ — $ — $ — $ — (a) Relates to Discovery, an unconsolidated affiliate. The following summarizes the balance and activity within AOCI relative to our interest rate, commodity and foreign currency cash flow hedges as of and for the three months ended September 30, 2020: Interest Commodity Foreign Total (millions) Net deferred (losses) gains in AOCI (beginning balance) $ (2) $ (6) $ 1 $ (7) Net deferred (losses) gains in AOCI (ending balance) $ (2) $ (6) $ 1 $ (7) 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 nine months ended September 30, 2020: Interest Commodity Foreign Total (millions) Net deferred (losses) gains in AOCI (beginning balance) $ (2) $ (6) $ 1 $ (7) Net deferred (losses) gains in AOCI (ending balance) $ (2) $ (6) $ 1 $ (7) Deferred losses in AOCI expected to be reclassified into earnings over the next 12 months $ (1) $ — $ — $ (1) (a) Relates to Discovery, an unconsolidated affiliate. For the nine months ended September 30, 2021 and 2020, 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 nine months ended September 30, 2021 and 2020, no derivative losses were reclassified from AOCI to trading and marketing gains or losses, net or interest expense as a result of the discontinuance of cash flow hedges related to certain forecasted transactions that are not probable of occurring. Changes in the value of derivative instruments, for which the hedge method of accounting has not been elected from one period to the next, are recorded in the condensed consolidated statements of operations. The following summarizes these amounts and the location within the condensed consolidated statements of operations that such amounts are reflected: Commodity Derivatives: Statements of Operations Line Item Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (millions) (millions) Realized (losses) gains $ (66) $ 22 $ (399) $ 90 Unrealized (losses) gains (107) (11) (296) 66 Trading and marketing (losses) gains, net $ (173) $ 11 $ (695) $ 156 We do not have any derivative financial instruments that are designated as a hedge of a net investment. The following tables represent, by commodity type, our net long or short positions that are expected to partially or entirely settle in each respective year. To the extent that we have long dated derivative positions that span multiple calendar years, the contract will appear in more than one line item in the tables below. September 30, 2021 Crude Oil Natural Gas Natural Gas Natural Gas Year of Expiration Net Short Net (Short) Long Position Net Long (Short) Net (Short) Long 2021 (405,000) (31,457,300) 168,546 (2,245,000) 2022 (1,286,000) (59,980,200) (8,817,555) (2,362,500) 2023 (446,000) 912,500 (1,296,000) (13,605,000) 2024 — — (1,446,000) 1,380,000 2025 — — (1,440,000) 21,020,000 2026 — — (1,080,000) 457,500 September 30, 2020 Crude Oil Natural Gas Natural Gas Natural Gas Year of Expiration Net Short Net Short Position Net Short Net Long (Short) 2020 (253,000) (14,287,500) (932,160) 5,600,000 2021 (791,000) (65,332,500) (8,471,590) (735,000) 2022 (43,000) (21,900,000) (1,486,842) 12,775,000 2023 — — (1,440,000) 7,300,000 2024 — — (1,440,000) 7,630,000 2025 — — (960,000) 1,365,000

Partnership Equity and Distribu

Partnership Equity and Distributions (Notes)	9 Months Ended
	Sep. 30, 2021
Equity [Abstract]
Partnership Equity and Distributions	Partnership Equity and Distributions Common Units — During the nine months ended September 30, 2021 and 2020, we issued no common units pursuant to our at-the-market program. As of September 30, 2021, $750 million of common units remained available for sale pursuant to our at-the-market program. Our general partner is entitled to a percentage of all quarterly distributions equal to its limited partner interest, together with DCP Midstream, LLC, of approximately 57% as of September 30, 2021. Distributions — The following table presents our cash distributions paid in 2021 and 2020: Payment Date Per Unit Total Cash (millions) Distributions to common unitholders August 13, 2021 $ 0.39 $ 81 May 14, 2021 $ 0.39 $ 82 February 12, 2021 $ 0.39 $ 81 November 13, 2020 $ 0.39 $ 81 August 14, 2020 $ 0.39 $ 82 May 15, 2020 $ 0.39 $ 81 February 14, 2020 $ 0.78 $ 162 Distributions to Series A Preferred unitholders June 15, 2021 $ 36.8750 $ 18 December 15, 2020 $ 36.8750 $ 19 June 15, 2020 $ 36.8750 $ 18 Distributions to Series B Preferred unitholders September 15, 2021 $ 0.4922 $ 4 June 15, 2021 $ 0.4922 $ 3 March 15, 2021 $ 0.4922 $ 3 December 15, 2020 $ 0.4922 $ 4 September 15, 2020 $ 0.4922 $ 3 June 15, 2020 $ 0.4922 $ 3 March 16, 2020 $ 0.4922 $ 3 Distributions to Series C Preferred unitholders July 15, 2021 $ 0.4969 $ 2 April 15, 2021 $ 0.4969 $ 2 January 15, 2021 $ 0.4969 $ 2 October 15, 2020 $ 0.4969 $ 2 July 15, 2020 $ 0.4969 $ 3 April 15, 2020 $ 0.4969 $ 2 January 15, 2020 $ 0.4969 $ 2

Net Income or Loss per Limited

Net Income or Loss per Limited Partner Unit (Notes)	9 Months Ended
	Sep. 30, 2021
Earnings Per Share [Abstract]
Net Income or Loss per Limited Partner Unit	13. Net Income or Loss per Limited Partner Unit We have the ability to elect to settle restricted phantom units at our discretion in either cash or common units. For restricted phantom units granted during 2021 and 2020, we have the ability and intent to settle vested units through the issuance of common units. There were 319,350 restricted phantom units outstanding as of September 30, 2020 that were not included in the calculation of diluted net loss per unit for the nine months ended September 30, 2020 because including them would have been anti-dilutive. Basic and diluted net income per limited partner unit was calculated as follows for the three and nine months ended September 30, 2021 and 2020, respectively. Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (millions, except per unit amounts) Net income (loss) attributable to limited partners $ 38 $ 96 $ 31 $ (436) Weighted average limited partner units outstanding, basic 208,368,605 208,342,746 208,363,754 208,334,185 Dilutive effects of nonvested restricted phantom units 291,364 319,350 188,470 — Weighted average limited partner units outstanding, diluted 208,659,969 208,662,096 208,552,224 208,334,185 Net income (loss) per limited partner unit, basic and diluted $ 0.18 $ 0.46 $ 0.15 $ (2.09)

Commitments and Contingent Liab

Commitments and Contingent Liabilities (Notes)	9 Months Ended
	Sep. 30, 2021
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingent Liabilities	Commitments and Contingent Liabilities Litigation — We are not a party to any material 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. Environment, Health and Safety — 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 the environment, health and safety. 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 health and safety, public health and 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, health and safety standards applicable to workers and the public, 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 and other air emissions, 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 as a party under federal, state, and local laws regulating the discharge of materials into the environment. We have elected to disclose matters where we reasonably believe such proceeding would result in monetary sanctions, exclusive of interest and costs, of $1.0 million or more. 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 on our results of operations, financial position, or cash flows: • In June 2020, the New Mexico Environment Department (the "NMED") issued an Administrative Compliance Order (the "June ACO") alleging that emissions at several of our field compression sites exceeded respective air permit limits or requirements during various instances of what we reported were facility upsets, malfunctions, startups or shutdowns from 2018 through the first half of 2019. The June ACO asserts an administrative civil penalty of approximately $5.3 million. Separately, in August 2020, the NMED issued an Administrative Compliance Order (the "August ACO" and, together with the June ACO, the "ACOs") alleging that emissions at four of our natural gas processing plants exceeded respective air permit limits or requirements during various instances also what were instances of facility upsets, malfunctions, startups or shutdowns from May of 2017 through August 2018, and asserting an administrative civil penalty of approximately $3.3 million for those emissions events during the stated period of time. We formally challenged the allegations and asserted penalties of the ACOs based on legal limitations, including that emissions that exceed permit limits or requirements due to facility upset, malfunction, startup, and shutdown events are not subject to civil penalties under New Mexico law. We formally responded to the ACOs and engaged in information exchanges and discussions with NMED about the propriety of the allegations and asserted penalties. In September 2021, we resolved the ACOs in a Settlement Agreement with the NMED for an administrative civil penalty of $950,000, certain reporting and flare operation requirements at our New Mexico gas plants, and an agreement to retire the gas processing elements and equipment at our Eunice Gas Plant in Lea County, New Mexico. • In March 2019, Region 8 of the U.S. Environmental Protection Agency (“EPA”) issued a Notice of Violation alleging various non-compliance with federal Leak Detection and Repair regulations, known as Subparts KKK and OOOO that exist to mitigate emissions of volatile organic compounds from certain equipment at natural gas plants, at various times over the course of late 2011 through 2017 at five of our Colorado natural gas processing plants. DCP does not agree with many of the allegations of non-compliance. DCP has been and is engaging in information exchanges and discussions with EPA about the propriety of the allegations, including the facts and regulatory underpinnings of the various allegations. DCP’s recent discussions with EPA include the possibility of resolving the allegations, including potential civil penalties and other elements, although this matter may end up in formal proceedings. EPA may require a civil penalty or equivalent that is larger than the disclosure threshold amount described above, although we do not believe that the result of this matter would have a material adverse effect on our results of operations, financial position, or cash flows. • In 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, which we had self-disclosed to CDPHE in December 2017. Following information exchanges and discussions with CDPHE, 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; while the revised air permit was issued in May 2019, this matter remains unresolved. Subsequently, in July 2020 CDPHE issued a Notice of Violation in relation to amine treater emissions at this gas processing plant, which we had self-disclosed to CDPHE in April 2020. We are still exchanging information and holding discussions with CDPHE as to this and the foregoing flare-related enforcement matter, including possible settlement terms, although these matters, which have since been combined, may end up in formal legal proceedings. It is possible that resolution of this matter may include an administrative penalty and economic benefit payment, further revising the facility air permit, or installation of emissions management equipment, or a combination of these, that could, in the aggregate, exceed the disclosure threshold amount described above, although we do not believe that resolution of this matter would have a material adverse effect on our results of operations, financial position, or cash flows.

Business Segments (Notes)

Business Segments (Notes)	9 Months Ended
	Sep. 30, 2021
Segment Reporting [Abstract]
Business Segments	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. Adjusted 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 the 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, 2020. Our Logistics and Marketing segment includes transporting, trading, marketing, storing natural gas and NGLs, and fractionating NGLs. 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 September 30, 2021 Logistics and Marketing Gathering and Processing Other Eliminations Total (millions) Total operating revenue $ 2,668 $ 1,821 $ — $ (1,662) $ 2,827 Adjusted gross margin (a) $ 35 $ 281 $ — $ — $ 316 Operating and maintenance expense (11) (157) — — (168) General and administrative expense (1) (4) (58) — (63) Depreciation and amortization expense (3) (80) (6) — (89) Other expense, net — (2) — — (2) Earnings from unconsolidated affiliates 133 1 — — 134 Interest expense — — (73) — (73) Net income (loss) $ 153 $ 39 $ (137) $ — $ 55 Net income attributable to noncontrolling interests — (1) — — (1) Net income (loss) attributable to partners $ 153 $ 38 $ (137) $ — $ 54 Non-cash derivative mark-to-market $ (7) $ (100) $ — $ — $ (107) Capital expenditures $ 2 $ 25 $ 1 $ — $ 28 Investments in unconsolidated affiliates, net $ 4 $ — $ — $ — $ 4 Nine Months Ended September 30, 2021 Logistics and Marketing Gathering and Processing Other Eliminations Total (millions) Total operating revenue $ 6,683 $ 4,449 $ — $ (3,902) $ 7,230 Adjusted gross margin (a) $ 78 $ 765 $ — $ — $ 843 Operating and maintenance expense (29) (443) (10) — (482) General and administrative expense (4) (12) (142) — (158) Depreciation and amortization expense (9) (243) (21) — (273) Asset impairments (13) (7) — — (20) Other income (expense), net 5 (1) — — 4 Loss on sale of assets, net — (1) — — (1) Earnings from unconsolidated affiliates 380 13 — — 393 Interest expense — — (227) — (227) Net income (loss) $ 408 $ 71 $ (400) $ — $ 79 Net income attributable to noncontrolling interests — (3) — — (3) Net income (loss) attributable to partners $ 408 $ 68 $ (400) $ — $ 76 Non-cash derivative mark-to-market $ (47) $ (249) $ — $ — $ (296) Capital expenditures $ 2 $ 62 $ 5 $ — $ 69 Investments in unconsolidated affiliates, net $ 4 $ — $ — $ — $ 4 Three Months Ended September 30, 2020 Logistics and Marketing Gathering and Processing Other Eliminations Total (millions) Total operating revenue $ 1,438 $ 857 $ — $ (709) $ 1,586 Adjusted gross margin (a) $ 88 $ 280 $ — $ — $ 368 Operating and maintenance expense (8) (135) (3) — (146) General and administrative expense (1) (8) (57) — (66) Depreciation and amortization expense (3) (82) (7) — (92) Other expense, net (2) (2) — — (4) Earnings (loss) from unconsolidated affiliates 132 (2) — — 130 Interest expense — — (77) — (77) Income tax expense — — (1) — (1) Net income (loss) $ 206 $ 51 $ (145) $ — $ 112 Net income attributable to noncontrolling interests — (1) — — (1) Net income (loss) attributable to partners $ 206 $ 50 $ (145) $ — $ 111 Non-cash derivative mark-to-market $ 28 $ (39) $ — $ — $ (11) Capital expenditures $ 1 $ 13 $ 9 $ — $ 23 Investments in unconsolidated affiliates, net $ 12 $ — $ — $ — $ 12 Nine Months Ended September 30, 2020: Logistics and Marketing Gathering and Processing Other Eliminations Total (millions) Total operating revenue $ 3,946 $ 2,388 $ — $ (1,817) $ 4,517 Adjusted gross margin (a) $ 268 $ 911 $ — $ — $ 1,179 Operating and maintenance expense (24) (411) (12) — (447) General and administrative expense (4) (15) (154) — (173) Depreciation and amortization expense (9) (253) (22) — (284) Asset impairments — (746) — — (746) Other expense, net (6) (4) (2) — (12) Restructuring costs — — (9) — (9) Earnings (loss) from unconsolidated affiliates 394 (63) — — 331 Interest expense — — (226) — (226) Income tax expense — — (2) — (2) Net income (loss) $ 619 $ (581) $ (427) $ — $ (389) Net income attributable to noncontrolling interests — (3) — — (3) Net income (loss) attributable to partners $ 619 $ (584) $ (427) $ — $ (392) Non-cash derivative mark-to-market $ 75 $ (9) $ — $ — $ 66 Non-cash lower of cost or net realizable value adjustments $ 6 $ — $ — $ — $ 6 Capital expenditures $ 2 $ 112 $ 11 $ — $ 125 Investments in unconsolidated affiliates, net $ 102 $ — $ — $ — $ 102 September 30, December 31, 2021 2020 (millions) Segment long-term assets: Gathering and Processing $ 7,603 $ 7,788 Logistics and Marketing 3,871 3,929 Other (b) 221 232 Total long-term assets 11,695 11,949 Current assets 2,001 1,008 Total assets $ 13,696 $ 12,957 (a) Adjusted gross margin consists of total operating revenues, including commodity derivative activity, less purchases and related costs. Adjusted 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, adjusted gross margin should not be considered an alternative to, or more meaningful than, net income, net cash provided by operating activities or gross margin as determined in accordance with GAAP. Our adjusted gross margin may not be comparable to a similarly titled measure of another company because other entities may not calculate adjusted gross margin in the same manner.

Supplemental Cash Flow Informat

Supplemental Cash Flow Information (Notes)	9 Months Ended
	Sep. 30, 2021
Supplemental Cash Flow Elements [Abstract]
Supplemental Cash Flow Information	Supplemental Cash Flow Information Nine Months Ended September 30, 2021 2020 (millions) Cash paid for interest: Cash paid for interest, net of amounts capitalized $ 234 $ 222 Cash paid for income taxes, net of income tax refunds $ 3 $ 2 Non-cash investing and financing activities: Property, plant and equipment acquired with accounts payable and accrued liabilities $ 8 $ 5 Other non-cash changes in property, plant and equipment $ (2) $ — Other non-cash activities: Right-of-use assets obtained in exchange for operating and finance lease liabilities $ 29 $ 11

Subsequent Events (Notes)

Subsequent Events (Notes)	9 Months Ended
	Sep. 30, 2021
Subsequent Events [Abstract]
Subsequent Events	On October 12, 2021, we announced that the board of directors of the General Partner declared a quarterly distribution on our common units of $0.39 per common unit. The distribution will be paid on November 12, 2021 to unitholders of record on October 29, 2021. On the same date, the board of directors of the General Partner declared a semi-annual distribution on our Series A Preferred Units of $36.875 per unit. The distribution will be paid on December 15, 2021 to unitholders of record on December 1, 2021. 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 December 15, 2021 to unitholders of record on December 1, 2021. The Series C distribution will be paid on January 18, 2022 to unitholders of record on January 3, 2022.

Description of Business and B_2

Description of Business and Basis of Presentation (Policies)	9 Months Ended
	Sep. 30, 2021
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 GAAP. Conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the condensed consolidated financial statements and notes. Although these estimates are based on management's best available knowledge of current and expected future events, actual results could differ from these estimates, which may be significantly impacted by various factors, including those outside of our control, such as the impact of a sustained deterioration in commodity prices and volumes, which would negatively impact our results of operations, financial condition and cash flows. All intercompany balances and transactions have been eliminated in consolidation. These unaudited condensed consolidated financial statements in this Quarterly Report on Form 10-Q have been prepared pursuant to the rules and regulations of 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 nine months ended September 30, 2021 are not necessarily indicative of the results that may be expected for the year ending December 31, 2021. 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 2020 audited consolidated financial statements and notes thereto included in our Annual Report on Form 10-K for the year ended December 31, 2020.
Business Description and Basis of Presentation [Text Block]	The condensed consolidated financial statements have been prepared in accordance with GAAP. Conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the condensed consolidated financial statements and notes. Although these estimates are based on management's best available knowledge of current and expected future events, actual results could differ from these estimates, which may be significantly impacted by various factors, including those outside of our control, such as the impact of a sustained deterioration in commodity prices and volumes, which would negatively impact our results of operations, financial condition and cash flows. All intercompany balances and transactions have been eliminated in consolidation. These unaudited condensed consolidated financial statements in this Quarterly Report on Form 10-Q have been prepared pursuant to the rules and regulations of 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 nine months ended September 30, 2021 are not necessarily indicative of the results that may be expected for the year ending December 31, 2021. 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 2020 audited consolidated financial statements and notes thereto included in our Annual Report on Form 10-K for the year ended December 31, 2020.

Accounting Policies (Policies)

Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2021
Accounting Policies [Abstract]
Basis of Presentation and Significant Accounting Policies [Text Block]	The condensed consolidated financial statements have been prepared in accordance with GAAP. Conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the condensed consolidated financial statements and notes. Although these estimates are based on management's best available knowledge of current and expected future events, actual results could differ from these estimates, which may be significantly impacted by various factors, including those outside of our control, such as the impact of a sustained deterioration in commodity prices and volumes, which would negatively impact our results of operations, financial condition and cash flows. All intercompany balances and transactions have been eliminated in consolidation. These unaudited condensed consolidated financial statements in this Quarterly Report on Form 10-Q have been prepared pursuant to the rules and regulations of 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 nine months ended September 30, 2021 are not necessarily indicative of the results that may be expected for the year ending December 31, 2021. 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 2020 audited consolidated financial statements and notes thereto included in our Annual Report on Form 10-K for the year ended December 31, 2020.

Revenue Recognition (Tables)

Revenue Recognition (Tables)	9 Months Ended
	Sep. 30, 2021
Disaggregation of Revenue [Line Items]
Disaggregation of Revenue [Table Text Block]	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 September 30, 2021 Logistics and Marketing Gathering and Processing Eliminations Total (millions) Sales of natural gas $ 895 $ 715 $ (695) $ 915 Sales of NGLs and condensate (a) 1,768 1,139 (966) 1,941 Transportation, processing and other 19 126 (1) 144 Trading and marketing losses, net (b) (14) (159) — (173) Total operating revenues $ 2,668 $ 1,821 $ (1,662) $ 2,827 Nine Months Ended September 30, 2021 Logistics and Marketing Gathering and Processing Eliminations Total (millions) Sales of natural gas $ 2,625 $ 1,832 $ (1,673) $ 2,784 Sales of NGLs and condensate (a) 4,296 2,686 (2,228) 4,754 Transportation, processing and other 46 342 (1) 387 Trading and marketing losses, net (b) (284) (411) — (695) Total operating revenues $ 6,683 $ 4,449 $ (3,902) $ 7,230 (a) Includes $589 million and $1,473 million for the three and nine months ended September 30, 2021, respectively, of revenues from physical sales contracts and buy-sell exchange transactions in our Logistics and Marketing segment. For the three and nine months ended September 30, 2021, these revenues are net of $741 million and $1,692 million, respectively, of buy-sell purchases related to buy-sell revenues of $786 million and $1,867 million, respectively, which are not within the scope of FASB ASU 2014-09 "Revenue from Contractors with Customer" ("Topic 606"). (b) Not within the scope of Topic 606. Three Months Ended September 30, 2020 Logistics and Marketing Gathering and Processing Eliminations Total (millions) Sales of natural gas $ 437 $ 330 $ (308) $ 459 Sales of NGLs and condensate (a) 951 456 (400) 1,007 Transportation, processing and other 13 97 (1) 109 Trading and marketing gains (losses), net (b) 37 (26) — 11 Total operating revenues $ 1,438 $ 857 $ (709) $ 1,586 Nine Months Ended September 30, 2020 Logistics and Marketing Gathering and Processing Eliminations Total (millions) Sales of natural gas $ 1,203 $ 927 $ (842) $ 1,288 Sales of NGLs and condensate (a) 2,592 1,125 (974) 2,743 Transportation, processing and other 37 294 (1) 330 Trading and marketing gains, net (b) 114 42 — 156 Total operating revenues $ 3,946 $ 2,388 $ (1,817) $ 4,517 (a) Includes $303 million and $2,006 million for the three and nine months ended September 30, 2020, 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.
Revenue from External Customers by Products and Services [Table Text Block]	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 September 30, 2021 Logistics and Marketing Gathering and Processing Eliminations Total (millions) Sales of natural gas $ 895 $ 715 $ (695) $ 915 Sales of NGLs and condensate (a) 1,768 1,139 (966) 1,941 Transportation, processing and other 19 126 (1) 144 Trading and marketing losses, net (b) (14) (159) — (173) Total operating revenues $ 2,668 $ 1,821 $ (1,662) $ 2,827 Nine Months Ended September 30, 2021 Logistics and Marketing Gathering and Processing Eliminations Total (millions) Sales of natural gas $ 2,625 $ 1,832 $ (1,673) $ 2,784 Sales of NGLs and condensate (a) 4,296 2,686 (2,228) 4,754 Transportation, processing and other 46 342 (1) 387 Trading and marketing losses, net (b) (284) (411) — (695) Total operating revenues $ 6,683 $ 4,449 $ (3,902) $ 7,230 (a) Includes $589 million and $1,473 million for the three and nine months ended September 30, 2021, respectively, of revenues from physical sales contracts and buy-sell exchange transactions in our Logistics and Marketing segment. For the three and nine months ended September 30, 2021, these revenues are net of $741 million and $1,692 million, respectively, of buy-sell purchases related to buy-sell revenues of $786 million and $1,867 million, respectively, which are not within the scope of FASB ASU 2014-09 "Revenue from Contractors with Customer" ("Topic 606"). (b) Not within the scope of Topic 606. Three Months Ended September 30, 2020 Logistics and Marketing Gathering and Processing Eliminations Total (millions) Sales of natural gas $ 437 $ 330 $ (308) $ 459 Sales of NGLs and condensate (a) 951 456 (400) 1,007 Transportation, processing and other 13 97 (1) 109 Trading and marketing gains (losses), net (b) 37 (26) — 11 Total operating revenues $ 1,438 $ 857 $ (709) $ 1,586 Nine Months Ended September 30, 2020 Logistics and Marketing Gathering and Processing Eliminations Total (millions) Sales of natural gas $ 1,203 $ 927 $ (842) $ 1,288 Sales of NGLs and condensate (a) 2,592 1,125 (974) 2,743 Transportation, processing and other 37 294 (1) 330 Trading and marketing gains, net (b) 114 42 — 156 Total operating revenues $ 3,946 $ 2,388 $ (1,817) $ 4,517 (a) Includes $303 million and $2,006 million for the three and nine months ended September 30, 2020, 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 $467 million as of September 30, 2021. Our remaining performance obligations primarily consist of minimum volume commitment fee arrangements and are expected to be recognized through 2031 with a weighted average remaining life of four years as of September 30, 2021. 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.

Contract Liabilities (Tables)

Contract Liabilities (Tables)	9 Months Ended
	Sep. 30, 2021
Contract Assets and Liabilities [Abstract]
Contract with Customer, Asset and Liability [Table Text Block]	September 30, 2021 (millions) Balance, beginning of period $ 35 Revenue recognized (a) (2) Balance, end of period $ 33

Agreements and Transactions w_2

Agreements and Transactions with Affiliates (Tables)	9 Months Ended
	Sep. 30, 2021
Related Party Transaction [Line Items]
Schedule of Fees Incurred and Other Fees Paid	The following table summarizes employee related costs that were charged by DCP Midstream, LLC to the Partnership that are included in the condensed consolidated statements of operations: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (millions) Employee related costs charged by DCP Midstream, LLC Operating and maintenance expense $ 39 $ 39 $ 116 $ 121 General and administrative expense $ 44 $ 43 $ 109 $ 113 Restructuring costs $ — $ — $ — $ 9
Summary of Transactions with Affiliates	The following table summarizes our transactions with affiliates: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (millions) Phillips 66 (including its affiliates): Sales of natural gas, NGLs and condensate to affiliates $ 893 $ 247 $ 2,066 $ 616 Purchases and related costs from affiliates $ 45 $ 15 $ 94 $ 52 Transportation and related costs from affiliates $ 39 $ 26 $ 113 $ 70 Operating and maintenance and general administrative expenses $ 3 $ 4 $ 9 $ 10 Enbridge (including its affiliates): Sales of natural gas, NGLs and condensate to affiliates $ — $ 1 $ 4 $ 2 Purchases and related costs from affiliates $ 12 $ 2 $ 27 $ 2 Transportation and related costs from affiliates $ 1 $ 1 $ 1 $ 1 Operating and maintenance and general administrative expenses $ 1 $ — $ 1 $ 1 Unconsolidated affiliates: Sales of natural gas, NGLs and condensate to affiliates $ 28 $ 14 $ 73 $ 35 Transportation, processing, and other to affiliates $ 3 $ 3 $ 13 $ 9 Purchases and related costs from affiliates $ 24 $ 15 $ 62 $ 35 Transportation and related costs from affiliates $ 209 $ 215 $ 606 $ 639 We had balances with affiliates as follows: September 30, 2021 December 31, 2020 (millions) Phillips 66 (including its affiliates): Accounts receivable $ 457 $ 217 Accounts payable $ 158 $ 89 Other assets $ 1 $ 1 Enbridge (including its affiliates): Accounts payable $ 4 $ 2 Unconsolidated affiliates: Accounts receivable $ 27 $ 21 Accounts payable $ 84 $ 70

Inventories (Tables)

Inventories (Tables)	9 Months Ended
	Sep. 30, 2021
Inventory Disclosure [Abstract]
Schedule of Inventories	Inventories were as follows: September 30, 2021 December 31, 2020 (millions) Natural gas $ 29 $ 18 NGLs 29 20 Total inventories $ 58 $ 38

Property, Plant and Equipment_2

Property, Plant and Equipment (Tables)	9 Months Ended
	Sep. 30, 2021
Property, Plant and Equipment [Abstract]
Classification of Property, Plant and Equipment	A summary of property, plant and equipment by classification is as follows: Depreciable September 30, 2021 December 31, 2020 (millions) Gathering and transmission systems 20 — 50 Years $ 7,660 $ 7,680 Processing, storage and terminal facilities 35 — 60 Years 5,059 4,986 Other 3 — 30 Years 585 585 Finance lease assets 2 — 5 Years 28 25 Construction work in progress 87 144 Property, plant and equipment 13,419 13,420 Accumulated depreciation (5,644) (5,427) Property, plant and equipment, net $ 7,775 $ 7,993

Investments in Unconsolidated_2

Investments in Unconsolidated Affiliates (Tables)	9 Months Ended
	Sep. 30, 2021
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 September 30, December 31, 2020 (millions) DCP Sand Hills Pipeline, LLC 66.67% $ 1,707 $ 1,723 DCP Southern Hills Pipeline, LLC 66.67% 721 734 Gulf Coast Express LLC 25.00% 425 436 Front Range Pipeline LLC 33.33% 193 198 Texas Express Pipeline LLC 10.00% 94 97 Discovery Producer Services LLC 40.00% 231 244 Mont Belvieu 1 Fractionator 20.00% 7 7 Mont Belvieu Enterprise Fractionator 12.50% 27 26 Cheyenne Connector, LLC 50.00% 149 152 Panola Pipeline Company, LLC 15.00% 20 21 Other Various 3 3 Total investments in unconsolidated affiliates $ 3,577 $ 3,641
Schedule Of Earnings From Investment In Unconsolidated Affiliates [Table Text Block]	: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (millions) DCP Sand Hills Pipeline, LLC $ 68 $ 73 $ 202 $ 221 DCP Southern Hills Pipeline, LLC 21 19 67 59 Gulf Coast Express LLC 16 17 46 49 Front Range Pipeline LLC 10 9 28 29 Texas Express Pipeline LLC 5 4 14 13 Discovery Producer Services LLC (a) 2 (3) 13 (63) Mont Belvieu 1 Fractionator 6 3 12 9 Mont Belvieu Enterprise Fractionator 2 4 1 10 Cheyenne Connector, LLC 4 3 8 3 Other — 1 2 1 Total earnings from unconsolidated affiliates $ 134 $ 130 $ 393 $ 331
Equity Method Investment Summarized Financial Information, Statement of Operations [Table Text Block]	The following tables summarize the combined financial information of our investments in unconsolidated affiliates: Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (millions) Statements of operations: Operating revenue $ 535 $ 523 $ 1,552 $ 1,560 Operating expenses $ 231 $ 196 $ 631 $ 572 Net income $ 303 $ 326 $ 917 $ 985
Equity Method Investment Summarized Financial Information Balance Sheet Table [Table Text Block]	September 30, December 31, (millions) Balance sheets: Current assets $ 384 $ 355 Long-term assets 7,331 7,510 Current liabilities (208) (177) Long-term liabilities (253) (258) Net assets $ 7,254 $ 7,430

Fair Value Measurement (Tables)

Fair Value Measurement (Tables)	9 Months Ended
	Sep. 30, 2021
Fair Value Disclosures [Abstract]
Financial Instruments Carried at Fair Value	September 30, 2021 December 31, 2020 Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total (millions) Current assets: Commodity derivatives $ 58 $ 83 $ — $ 141 $ 21 $ 42 $ — $ 63 Short-term investments (a) $ 2 $ 1 $ — $ 3 $ — $ — $ — $ — Long-term assets: Commodity derivatives $ 3 $ 7 $ 3 $ 13 $ 1 $ 13 $ 2 $ 16 Investments in marketable securities (a) $ 31 $ — $ — $ 31 $ 22 $ 1 $ — $ 23 Current liabilities: Commodity derivatives $ (90) $ (226) $ (5) $ (321) $ (19) $ (34) $ (3) $ (56) Long-term liabilities: Commodity derivatives $ (7) $ (38) $ (3) $ (48) $ — $ (6) $ (1) $ (7)
Fair Value Assets and Liabilities Measured On Recurring Basis Unobservable Input Reconciliation	Commodity Derivative Instruments Current Long-Term Current Long-Term (millions) Nine months ended September 30, 2021 (a): Beginning balance $ — $ 2 $ (3) $ (1) Net unrealized gains (losses) included in earnings — 1 (16) (3) Transfers out of Level 3 — — 9 1 Settlements — — 5 — Ending balance $ — $ 3 $ (5) $ (3) Net unrealized gains (losses) on derivatives still held included in earnings $ — $ 1 $ (5) $ (3) Nine months ended September 30, 2020 (a): Beginning balance $ 4 $ — $ (1) $ (3) Net unrealized (losses) gains included in earnings (1) 8 8 2 Transfers out of Level 3 — (4) — — Settlements (3) — (8) — Ending balance $ — $ 4 $ (1) $ (1) Net unrealized (losses) gains on derivatives still held included in earnings $ (2) $ 4 $ (1) $ 1 (a) There were no purchases, issuances or sales of derivatives or transfers into Level 3 for the three and nine months ended September 30, 2021 and 2020.
Schedule of Valuation Processes	September 30, 2021 Product Group Fair Value Valuation Techniques Unobservable Input Forward Weighted Average (a) (millions) Assets Natural gas $ 3 Market approach Longer dated forward curve prices $2.24-$3.40 $2.71 Per MMBtu Liabilities NGLs $ (6) Market approach Longer dated forward curve prices $0.33-$1.75 $0.92 Per gallon Natural gas $ (2) Market approach Longer dated forward curve prices $2.24-$3.30 $2.50 Per MMBtu
Schedule of Carrying Values and Estimated Fair Values of Debt Instruments [Table Text Block]	September 30, 2021 and December 31, 2020, the carrying value and fair value of our total debt, including current maturities, were as follows: September 30, 2021 December 31, 2020 Carrying Value (a) Fair Value Carrying Value (a) Fair Value (millions) Total debt $ 5,687 $ 6,274 $ 5,635 $ 5,938

Leases (Tables)

Leases (Tables)	9 Months Ended
	Sep. 30, 2021
Leases [Abstract]
Schedule of Leasing Assets and Liabilities [Table Text Block]	Location in Condensed Consolidated Balance Sheet As of September 30, 2021 December 31, 2020 (millions) Assets Operating lease assets Operating lease assets $ 93 $ 85 Finance lease assets Property, plant and equipment 28 25 Total right of use assets $ 121 $ 110 Liabilities Current liabilities Operating lease liabilities Other current liabilities $ 26 $ 24 Finance lease liabilities Current debt 5 5 Noncurrent liabilities Operating lease liabilities Operating lease liabilities $ 81 $ 76 Finance lease liabilities Long-term debt 21 22 Total lease liabilities $ 133 $ 127
Lease, Cost [Table Text Block]	Location in Condensed Consolidated Statement of Operations Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (millions) Operating lease cost Operating and maintenance expense $ 7 $ 7 $ 21 $ 21 Finance lease cost Amortization of right of use assets Depreciation and amortization expense 1 1 2 2 Interest on lease liabilities Interest expense 1 1 1 1 Variable lease cost Operating and maintenance expense 1 2 3 5 Short term lease cost Operating and maintenance expense 1 1 2 3 Total lease cost $ 11 $ 12 $ 29 $ 32
Lessee, Operating Lease, Liability, Maturity [Table Text Block]	Future Minimum Lease Payments as of September 30, 2021 Operating Leases Finance Leases (millions) 2021 - remainder $ 7 $ 2 2022 29 6 2023 26 6 2024 17 7 2025 13 3 Thereafter 26 9 Total lease payments $ 118 $ 33 Less imputed interest (11) (7) Total lease liabilities $ 107 $ 26
Leases - Other Information	Nine Months Ended September 30, 2021 2020 (millions) Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 23 $ 20 Operating cash flows from finance leases 3 3 Financing cash flows from finance leases 1 1 Right-of-use assets obtained in exchange for operating lease obligations: $ 26 $ 6 Right-of-use assets obtained in exchange for finance lease obligations: $ 3 $ 5 Other information related to operating leases as follows: Weighted average remaining lease term 5 years 6 years Weighted average discount rate 4.00 % 4.00 % Other information related to finance leases as follows: Weighted average remaining lease term 4 years 5 years Weighted average discount rate 3.00 % 3.00 %

Debt (Tables)

Debt (Tables)	9 Months Ended
	Sep. 30, 2021
Debt Disclosure [Abstract]
Schedule of Debt	September 30, 2021 December 31, 2020 (millions) Senior notes: Issued September 2011, interest at 4.750% payable semi-annually, due September 2021 $ — $ 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 825 825 Issued June 2020, interest at 5.625% payable semi-annually, due July 2027 500 500 Issued May 2019, interest at 5.125% payable semi-annually, due May 2029 600 600 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, variable interest rate of 1.440% as of September 30, 2021, due December 2024 552 — Accounts receivable securitization facility: Accounts receivable securitization facility, interest at 0.980% as of September 30, 2021, due August 2024 350 350 Fair value adjustments related to interest rate swap fair value hedges (a) 16 17 Unamortized issuance costs (33) (38) Unamortized discount, net (6) (7) Finance lease liabilities 26 27 Total debt 5,680 5,624 Current finance lease liabilities 5 5 Current debt 350 500 Total long-term debt $ 5,325 $ 5,119
Future Maturities of Long-Term Debt	The maturities of our debt as of September 30, 2021 are as follows: Debt (millions) 2021 $ — 2022 350 2023 500 2024 902 2025 825 Thereafter 3,100 Total debt $ 5,677

Risk Management and Hedging A_2

Risk Management and Hedging Activities (Tables)	9 Months Ended
	Sep. 30, 2021
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Summary of Gross and Net Amounts of Derivative Instruments	September 30, 2021 December 31, 2020 Gross Amounts Amounts Not Net Gross Amounts Amounts Not Net (millions) Assets: Commodity derivatives $ 154 $ — $ 154 $ 79 $ — $ 79 Liabilities: Commodity derivatives $ (369) $ — $ (369) $ (63) $ — $ (63)
Schedule of Designated and Non-Designated Derivative Instruments in Statement of Financial Position, Fair Value	The fair value of our derivative instruments that are marked-to-market each period, as well as the location of each within our condensed consolidated balance sheets, by major category, is summarized below. We have no derivative instruments that are designated as hedging instruments for accounting purposes as of September 30, 2021 and December 31, 2020. Balance Sheet Line Item September 30, December 31, Balance Sheet Line Item September 30, December 31, (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 $ 141 $ 63 Unrealized losses on derivative instruments — current $ (321) $ (56) Unrealized gains on derivative instruments — long-term 13 16 Unrealized losses on derivative instruments — long-term (48) (7) Total $ 154 $ 79 Total $ (369) $ (63)
Schedule of Cash Flow Hedges Included in Accumulated Other Comprehensive Income (Loss) [Table Text Block]	The following summarizes the balance and activity within AOCI relative to our interest rate, commodity and foreign currency cash flow hedges as of and for the three months ended September 30, 2021: Interest Commodity Foreign Total (millions) Net deferred (losses) gains in AOCI (beginning balance) $ (2) $ (6) $ 1 $ (7) Losses reclassified from AOCI to earnings — effective portion 1 — — 1 Net deferred (losses) gains in AOCI (ending balance) $ (1) $ (6) $ 1 $ (6) Deferred losses in AOCI expected to be reclassified into earnings over the next 12 months $ — $ — $ — $ — (a) Relates to 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 nine months ended September 30, 2021: Interest Commodity Foreign Total (millions) Net deferred (losses) gains in AOCI (beginning balance) $ (2) $ (6) $ 1 $ (7) Losses reclassified from AOCI to earnings — effective portion 1 — — 1 Net deferred (losses) gains in AOCI (ending balance) $ (1) $ (6) $ 1 $ (6) Deferred losses in AOCI expected to be reclassified into earnings over the next 12 months $ — $ — $ — $ — (a) Relates to Discovery, an unconsolidated affiliate. The following summarizes the balance and activity within AOCI relative to our interest rate, commodity and foreign currency cash flow hedges as of and for the three months ended September 30, 2020: Interest Commodity Foreign Total (millions) Net deferred (losses) gains in AOCI (beginning balance) $ (2) $ (6) $ 1 $ (7) Net deferred (losses) gains in AOCI (ending balance) $ (2) $ (6) $ 1 $ (7) 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 nine months ended September 30, 2020: Interest Commodity Foreign Total (millions) Net deferred (losses) gains in AOCI (beginning balance) $ (2) $ (6) $ 1 $ (7) Net deferred (losses) gains in AOCI (ending balance) $ (2) $ (6) $ 1 $ (7) Deferred losses in AOCI expected to be reclassified into earnings over the next 12 months $ (1) $ — $ — $ (1) (a) Relates to Discovery, an unconsolidated affiliate.
Schedule of Changes in Derivative Instruments Not Designated as Hedging Instruments	Commodity Derivatives: Statements of Operations Line Item Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (millions) (millions) Realized (losses) gains $ (66) $ 22 $ (399) $ 90 Unrealized (losses) gains (107) (11) (296) 66 Trading and marketing (losses) gains, net $ (173) $ 11 $ (695) $ 156
Schedule of Net Long or Short Positions Expected to be Realized	September 30, 2021 Crude Oil Natural Gas Natural Gas Natural Gas Year of Expiration Net Short Net (Short) Long Position Net Long (Short) Net (Short) Long 2021 (405,000) (31,457,300) 168,546 (2,245,000) 2022 (1,286,000) (59,980,200) (8,817,555) (2,362,500) 2023 (446,000) 912,500 (1,296,000) (13,605,000) 2024 — — (1,446,000) 1,380,000 2025 — — (1,440,000) 21,020,000 2026 — — (1,080,000) 457,500 September 30, 2020 Crude Oil Natural Gas Natural Gas Natural Gas Year of Expiration Net Short Net Short Position Net Short Net Long (Short) 2020 (253,000) (14,287,500) (932,160) 5,600,000 2021 (791,000) (65,332,500) (8,471,590) (735,000) 2022 (43,000) (21,900,000) (1,486,842) 12,775,000 2023 — — (1,440,000) 7,300,000 2024 — — (1,440,000) 7,630,000 2025 — — (960,000) 1,365,000

Partnership Equity and Distri_2

Partnership Equity and Distributions (Tables)	9 Months Ended
	Sep. 30, 2021
Equity [Abstract]
Cash Distribution	Payment Date Per Unit Total Cash (millions) Distributions to common unitholders August 13, 2021 $ 0.39 $ 81 May 14, 2021 $ 0.39 $ 82 February 12, 2021 $ 0.39 $ 81 November 13, 2020 $ 0.39 $ 81 August 14, 2020 $ 0.39 $ 82 May 15, 2020 $ 0.39 $ 81 February 14, 2020 $ 0.78 $ 162 Distributions to Series A Preferred unitholders June 15, 2021 $ 36.8750 $ 18 December 15, 2020 $ 36.8750 $ 19 June 15, 2020 $ 36.8750 $ 18 Distributions to Series B Preferred unitholders September 15, 2021 $ 0.4922 $ 4 June 15, 2021 $ 0.4922 $ 3 March 15, 2021 $ 0.4922 $ 3 December 15, 2020 $ 0.4922 $ 4 September 15, 2020 $ 0.4922 $ 3 June 15, 2020 $ 0.4922 $ 3 March 16, 2020 $ 0.4922 $ 3 Distributions to Series C Preferred unitholders July 15, 2021 $ 0.4969 $ 2 April 15, 2021 $ 0.4969 $ 2 January 15, 2021 $ 0.4969 $ 2 October 15, 2020 $ 0.4969 $ 2 July 15, 2020 $ 0.4969 $ 3 April 15, 2020 $ 0.4969 $ 2 January 15, 2020 $ 0.4969 $ 2

Earnings Per Share (Tables)

Earnings Per Share (Tables)	9 Months Ended
	Sep. 30, 2021
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	. Three Months Ended September 30, Nine Months Ended September 30, 2021 2020 2021 2020 (millions, except per unit amounts) Net income (loss) attributable to limited partners $ 38 $ 96 $ 31 $ (436) Weighted average limited partner units outstanding, basic 208,368,605 208,342,746 208,363,754 208,334,185 Dilutive effects of nonvested restricted phantom units 291,364 319,350 188,470 — Weighted average limited partner units outstanding, diluted 208,659,969 208,662,096 208,552,224 208,334,185 Net income (loss) per limited partner unit, basic and diluted $ 0.18 $ 0.46 $ 0.15 $ (2.09)

Business Segments (Tables)

Business Segments (Tables)	9 Months Ended
	Sep. 30, 2021
Segment Reporting [Abstract]
Segment Information	Logistics and Marketing Gathering and Processing Other Eliminations Total (millions) Total operating revenue $ 6,683 $ 4,449 $ — $ (3,902) $ 7,230 Adjusted gross margin (a) $ 78 $ 765 $ — $ — $ 843 Operating and maintenance expense (29) (443) (10) — (482) General and administrative expense (4) (12) (142) — (158) Depreciation and amortization expense (9) (243) (21) — (273) Asset impairments (13) (7) — — (20) Other income (expense), net 5 (1) — — 4 Loss on sale of assets, net — (1) — — (1) Earnings from unconsolidated affiliates 380 13 — — 393 Interest expense — — (227) — (227) Net income (loss) $ 408 $ 71 $ (400) $ — $ 79 Net income attributable to noncontrolling interests — (3) — — (3) Net income (loss) attributable to partners $ 408 $ 68 $ (400) $ — $ 76 Non-cash derivative mark-to-market $ (47) $ (249) $ — $ — $ (296) Capital expenditures $ 2 $ 62 $ 5 $ — $ 69 Investments in unconsolidated affiliates, net $ 4 $ — $ — $ — $ 4 Three Months Ended September 30, 2020 Logistics and Marketing Gathering and Processing Other Eliminations Total (millions) Total operating revenue $ 1,438 $ 857 $ — $ (709) $ 1,586 Adjusted gross margin (a) $ 88 $ 280 $ — $ — $ 368 Operating and maintenance expense (8) (135) (3) — (146) General and administrative expense (1) (8) (57) — (66) Depreciation and amortization expense (3) (82) (7) — (92) Other expense, net (2) (2) — — (4) Earnings (loss) from unconsolidated affiliates 132 (2) — — 130 Interest expense — — (77) — (77) Income tax expense — — (1) — (1) Net income (loss) $ 206 $ 51 $ (145) $ — $ 112 Net income attributable to noncontrolling interests — (1) — — (1) Net income (loss) attributable to partners $ 206 $ 50 $ (145) $ — $ 111 Non-cash derivative mark-to-market $ 28 $ (39) $ — $ — $ (11) Capital expenditures $ 1 $ 13 $ 9 $ — $ 23 Investments in unconsolidated affiliates, net $ 12 $ — $ — $ — $ 12 Nine Months Ended September 30, 2020: Logistics and Marketing Gathering and Processing Other Eliminations Total (millions) Total operating revenue $ 3,946 $ 2,388 $ — $ (1,817) $ 4,517 Adjusted gross margin (a) $ 268 $ 911 $ — $ — $ 1,179 Operating and maintenance expense (24) (411) (12) — (447) General and administrative expense (4) (15) (154) — (173) Depreciation and amortization expense (9) (253) (22) — (284) Asset impairments — (746) — — (746) Other expense, net (6) (4) (2) — (12) Restructuring costs — — (9) — (9) Earnings (loss) from unconsolidated affiliates 394 (63) — — 331 Interest expense — — (226) — (226) Income tax expense — — (2) — (2) Net income (loss) $ 619 $ (581) $ (427) $ — $ (389) Net income attributable to noncontrolling interests — (3) — — (3) Net income (loss) attributable to partners $ 619 $ (584) $ (427) $ — $ (392) Non-cash derivative mark-to-market $ 75 $ (9) $ — $ — $ 66 Non-cash lower of cost or net realizable value adjustments $ 6 $ — $ — $ — $ 6 Capital expenditures $ 2 $ 112 $ 11 $ — $ 125 Investments in unconsolidated affiliates, net $ 102 $ — $ — $ — $ 102 September 30, December 31, 2021 2020 (millions) Segment long-term assets: Gathering and Processing $ 7,603 $ 7,788 Logistics and Marketing 3,871 3,929 Other (b) 221 232 Total long-term assets 11,695 11,949 Current assets 2,001 1,008 Total assets $ 13,696 $ 12,957 (a) Adjusted gross margin consists of total operating revenues, including commodity derivative activity, less purchases and related costs. Adjusted 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, adjusted gross margin should not be considered an alternative to, or more meaningful than, net income, net cash provided by operating activities or gross margin as determined in accordance with GAAP. Our adjusted gross margin may not be comparable to a similarly titled measure of another company because other entities may not calculate adjusted gross margin in the same manner.

Statement of Cash Flows, Supple

Statement of Cash Flows, Supplemental Disclosures (Tables)	9 Months Ended
	Sep. 30, 2021
Additional Cash Flow Elements and Supplemental Cash Flow Information [Abstract]
Summary of Supplemental Cash Flow Information	Nine Months Ended September 30, 2021 2020 (millions) Cash paid for interest: Cash paid for interest, net of amounts capitalized $ 234 $ 222 Cash paid for income taxes, net of income tax refunds $ 3 $ 2 Non-cash investing and financing activities: Property, plant and equipment acquired with accounts payable and accrued liabilities $ 8 $ 5 Other non-cash changes in property, plant and equipment $ (2) $ — Other non-cash activities: Right-of-use assets obtained in exchange for operating and finance lease liabilities $ 29 $ 11

Description of Business and B_3

Description of Business and Basis of Presentation - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2021
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	57.00%
Phillips 66 | DCP Midstream, LLC
Business Acquisition [Line Items]
Ownership interest percentage by parent	50.00%
Enbridge | DCP Midstream, LLC
Business Acquisition [Line Items]
Ownership interest percentage by parent	50.00%

Revenue Recognition (Details)

Revenue Recognition (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Disaggregation of Revenue [Line Items]
Trading and marketing gains (losses), net	$ (173)	$ 11	$ (695)	$ 156
Total operating revenues	2,827	1,586	7,230	4,517
Revenue, Remaining Performance Obligation, Amount	467		$ 467
Revenue, Performance Obligation, Description of Timing			four years
Revenue from contract with customer not within the scope of Topic 606	589	303	$ 1,473	2,006
Buy-Sell Purchases	741		1,692
Buy-Sell Revenues	786		1,867
Natural Gas [Member]
Disaggregation of Revenue [Line Items]
Sales of natural gas, NGLs and condensate	915	459	2,784	1,288
NGLs and Condensate [Member]
Disaggregation of Revenue [Line Items]
Sales of natural gas, NGLs and condensate	1,941	1,007	4,754	2,743
Transportation, Processing and Other [Member]
Disaggregation of Revenue [Line Items]
Sales of natural gas, NGLs and condensate	144	109	387	330
Gathering and Processing
Disaggregation of Revenue [Line Items]
Sales of natural gas, NGLs and condensate	126	97
Trading and marketing gains (losses), net	(159)	(26)	(411)	42
Total operating revenues	1,821	857	4,449	2,388
Gathering and Processing | Natural Gas [Member]
Disaggregation of Revenue [Line Items]
Sales of natural gas, NGLs and condensate	715	330	1,832	927
Gathering and Processing | NGLs and Condensate [Member]
Disaggregation of Revenue [Line Items]
Sales of natural gas, NGLs and condensate	1,139	456	2,686	1,125
Gathering and Processing | Transportation, Processing and Other [Member]
Disaggregation of Revenue [Line Items]
Sales of natural gas, NGLs and condensate			342	294
Logistics and Marketing
Disaggregation of Revenue [Line Items]
Sales of natural gas, NGLs and condensate	19	13	46	37
Trading and marketing gains (losses), net	(14)	37	(284)	114
Total operating revenues	2,668	1,438	6,683	3,946
Logistics and Marketing | Natural Gas [Member]
Disaggregation of Revenue [Line Items]
Sales of natural gas, NGLs and condensate	895	437	2,625	1,203
Logistics and Marketing | NGLs and Condensate [Member]
Disaggregation of Revenue [Line Items]
Sales of natural gas, NGLs and condensate	1,768	951	4,296	2,592
Logistics and Marketing | Transportation, Processing and Other [Member]
Disaggregation of Revenue [Line Items]
Sales of natural gas, NGLs and condensate			46	37
Eliminations
Disaggregation of Revenue [Line Items]
Sales of natural gas, NGLs and condensate	(1)	(1)
Trading and marketing gains (losses), net	0	0	0	0
Total operating revenues	(1,662)	(709)	(3,902)	(1,817)
Eliminations | Natural Gas [Member]
Disaggregation of Revenue [Line Items]
Sales of natural gas, NGLs and condensate	(695)	(308)	(1,673)	(842)
Eliminations | NGLs and Condensate [Member]
Disaggregation of Revenue [Line Items]
Sales of natural gas, NGLs and condensate	$ (966)	$ (400)	(2,228)	(974)
Eliminations | Transportation, Processing and Other [Member]
Disaggregation of Revenue [Line Items]
Sales of natural gas, NGLs and condensate			$ (1)	$ (1)

Contract Liabilities (Details)

Contract Liabilities (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Contract Assets and Liabilities [Abstract]
Contract with Customer, Liability	$ 33	$ 35
Contract with Customer, Liability, Revenue Recognized	$ (2)
Contract with Customer, Timing of Satisfaction of Performance Obligation and Payment	35 years

Agreements and Transactions w_3

Agreements and Transactions with Affiliates - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Operating Expense
Related Party Transaction [Line Items]
Employee related costs	$ 39	$ 39	$ 116	$ 121
General and Administrative Expense
Related Party Transaction [Line Items]
Employee related costs	44	43	109	113
Restructuring costs
Related Party Transaction [Line Items]
Employee related costs	$ 0	$ 0	$ 0	$ 9

Agreements and Transactions w_4

Agreements and Transactions with Affiliates - Transactions with Affiliates (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Related Party Transaction [Line Items]
Operating and maintenance expense	$ 168	$ 146	$ 482	$ 447
Affiliated Entity | Phillips 66
Related Party Transaction [Line Items]
Operating and maintenance expense	3	4	9	10
Natural Gas, NGLs and Condensate [Member] | Affiliated Entity | Unconsolidated Affiliates
Related Party Transaction [Line Items]
Sales of natural gas, NGLs and condensate	28	14	73	35
Purchases and related costs	24	15	62	35
Natural Gas, NGLs and Condensate [Member] | Affiliated Entity | Phillips 66
Related Party Transaction [Line Items]
Sales of natural gas, NGLs and condensate	893	247	2,066	616
Purchases and related costs	45	15	94	52
Natural Gas, NGLs and Condensate [Member] | Affiliated Entity | Enbridge
Related Party Transaction [Line Items]
Sales of natural gas, NGLs and condensate	0	1	4	2
Purchases and related costs	12	2	27	2
Operating and maintenance expense	1	0	1	1
Transportation, Processing and Other [Member]
Related Party Transaction [Line Items]
Sales of natural gas, NGLs and condensate	144	109	387	330
Transportation, Processing and Other [Member] | Affiliated Entity | Unconsolidated Affiliates
Related Party Transaction [Line Items]
Sales of natural gas, NGLs and condensate	3	3	13	9
Purchases and related costs	209	215	606	639
Transportation, Processing and Other [Member] | Affiliated Entity | Phillips 66
Related Party Transaction [Line Items]
Purchases and related costs	39	26	113	70
Transportation, Processing and Other [Member] | Affiliated Entity | Enbridge
Related Party Transaction [Line Items]
Purchases and related costs	$ 1	$ 1	$ 1	$ 1

Agreements and Transactions w_5

Agreements and Transactions with Affiliates - Balances with Affiliates (Detail) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Related Party Transaction [Line Items]
Accounts receivable	$ 484	$ 238
Accounts payable	246	161
Unconsolidated Affiliates
Related Party Transaction [Line Items]
Accounts receivable	27	21
Accounts payable	84	70
Phillips 66
Related Party Transaction [Line Items]
Accounts receivable	457	217
Accounts payable	158	89
Related Party Transaction, Due from (to) Related Party, Noncurrent	1	1
Enbridge
Related Party Transaction [Line Items]
Accounts payable	$ 4	$ 2

Inventories - Schedule of Inven

Inventories - Schedule of Inventories (Detail) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Components Of Inventory [Line Items]
Total inventories	$ 58	$ 38
Natural Gas [Member]
Components Of Inventory [Line Items]
Total inventories	29	18
Natural Gas Liquids
Components Of Inventory [Line Items]
Total inventories	$ 29	$ 20

Inventories - Additional Inform

Inventories - Additional Information (Detail) $ in Millions	9 Months Ended
	Sep. 30, 2020USD ($)
Inventory Disclosure [Abstract]
Lower of cost or net realizable value adjustment	$ 6

Property, Plant and Equipment -

Property, Plant and Equipment - Classification of Property, Plant and Equipment (Detail) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 13,419	$ 13,420
Accumulated depreciation	(5,644)	(5,427)
Property, plant and equipment, net	7,775	7,993
Gathering and transmission systems
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 7,660	7,680
Gathering and transmission systems | Minimum
Property, Plant and Equipment [Line Items]
Depreciable life of property, plant and equipment	20 years
Gathering and transmission systems | Maximum
Property, Plant and Equipment [Line Items]
Depreciable life of property, plant and equipment	50 years
Processing, storage and terminal facilities
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 5,059	4,986
Processing, storage and terminal facilities | Minimum
Property, Plant and Equipment [Line Items]
Depreciable life of property, plant and equipment	35 years
Processing, storage and terminal facilities | Maximum
Property, Plant and Equipment [Line Items]
Depreciable life of property, plant and equipment	60 years
Other
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 585	585
Other | Minimum
Property, Plant and Equipment [Line Items]
Depreciable life of property, plant and equipment	3 years
Other | Maximum
Property, Plant and Equipment [Line Items]
Depreciable life of property, plant and equipment	30 years
Finance lease assets [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 28	25
Finance lease assets [Member] | Minimum
Property, Plant and Equipment [Line Items]
Depreciable life of property, plant and equipment	2 years
Finance lease assets [Member] | Maximum
Property, Plant and Equipment [Line Items]
Depreciable life of property, plant and equipment	5 years
Construction work in progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 87	$ 144

Property, Plant and Equipment_3

Property, Plant and Equipment - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Property, Plant and Equipment [Abstract]
Interest capitalized on construction projects		$ 1	$ 1	$ 3
Depreciation expense	$ 88	$ 90	$ 269	$ 279

Intangible Assets (Details)

Intangible Assets (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Finite-Lived Intangible Assets [Line Items]
Intangible assets, net	$ 41	$ 44

Investments In Unconsolidated_3

Investments In Unconsolidated Affiliates - Investments In Unconsolidated Affiliates (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Schedule of Equity Method Investments [Line Items]
Investments in unconsolidated affiliates	$ 3,577		$ 3,577		$ 3,641
Earnings from unconsolidated affiliates	$ 134	$ 130	$ 393	$ 331
DCP Sand Hills Pipeline, LLC
Schedule of Equity Method Investments [Line Items]
Equity method ownership investment (as percent)	66.67%		66.67%
Investments in unconsolidated affiliates	$ 1,707		$ 1,707		1,723
Earnings from unconsolidated affiliates	$ 68	73	$ 202	221
DCP Southern Hills Pipeline, LLC
Schedule of Equity Method Investments [Line Items]
Equity method ownership investment (as percent)	66.67%		66.67%
Investments in unconsolidated affiliates	$ 721		$ 721		734
Earnings from unconsolidated affiliates	$ 21	19	$ 67	59
Front Range Pipeline LLC
Schedule of Equity Method Investments [Line Items]
Equity method ownership investment (as percent)	33.33%		33.33%
Investments in unconsolidated affiliates	$ 193		$ 193		198
Earnings from unconsolidated affiliates	$ 10	9	$ 28	29
Gulf Coast Express [Member]
Schedule of Equity Method Investments [Line Items]
Equity method ownership investment (as percent)	25.00%		25.00%
Investments in unconsolidated affiliates	$ 425		$ 425		436
Earnings from unconsolidated affiliates	$ 16	17	$ 46	49
Texas Express Pipeline LLC
Schedule of Equity Method Investments [Line Items]
Equity method ownership investment (as percent)	10.00%		10.00%
Investments in unconsolidated affiliates	$ 94		$ 94		97
Earnings from unconsolidated affiliates	$ 5	4	$ 14	13
Cheyenne Connector
Schedule of Equity Method Investments [Line Items]
Equity method ownership investment (as percent)	50.00%		50.00%
Investments in unconsolidated affiliates	$ 149		$ 149		152
Earnings from unconsolidated affiliates	$ 4	3	$ 8	3
Mont Belvieu Enterprise Fractionator
Schedule of Equity Method Investments [Line Items]
Equity method ownership investment (as percent)	12.50%		12.50%
Investments in unconsolidated affiliates	$ 27		$ 27		26
Earnings from unconsolidated affiliates	$ 2	4	$ 1	10
Mont Belvieu 1 Fractionator
Schedule of Equity Method Investments [Line Items]
Equity method ownership investment (as percent)	20.00%		20.00%
Investments in unconsolidated affiliates	$ 7		$ 7		7
Earnings from unconsolidated affiliates	$ 6	3	$ 12	9
Discovery Producer Services LLC
Schedule of Equity Method Investments [Line Items]
Equity method ownership investment (as percent)	40.00%		40.00%
Investments in unconsolidated affiliates	$ 231		$ 231		244
Earnings from unconsolidated affiliates	$ 2	(3)	$ 13	(63)
Panola Pipeline Company, LLC
Schedule of Equity Method Investments [Line Items]
Equity method ownership investment (as percent)	15.00%		15.00%
Investments in unconsolidated affiliates	$ 20		$ 20		21
Other
Schedule of Equity Method Investments [Line Items]
Investments in unconsolidated affiliates	3		3		$ 3
Earnings from unconsolidated affiliates	$ 0	$ 1	$ 2	$ 1

Investments in Unconsolidated_4

Investments in Unconsolidated Affiliates - Earnings from Investments in Unconsolidated Affiliates (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Schedule of Equity Method Investments [Line Items]
Earnings from unconsolidated affiliates	$ 134	$ 130	$ 393	$ 331
DCP Sand Hills Pipeline, LLC
Schedule of Equity Method Investments [Line Items]
Earnings from unconsolidated affiliates	68	73	202	221
DCP Southern Hills Pipeline, LLC
Schedule of Equity Method Investments [Line Items]
Earnings from unconsolidated affiliates	21	19	67	59
Front Range Pipeline LLC
Schedule of Equity Method Investments [Line Items]
Earnings from unconsolidated affiliates	10	9	28	29
Gulf Coast Express [Member]
Schedule of Equity Method Investments [Line Items]
Earnings from unconsolidated affiliates	16	17	46	49
Texas Express Pipeline LLC
Schedule of Equity Method Investments [Line Items]
Earnings from unconsolidated affiliates	5	4	14	13
Cheyenne Connector
Schedule of Equity Method Investments [Line Items]
Earnings from unconsolidated affiliates	4	3	8	3
Mont Belvieu Enterprise Fractionator
Schedule of Equity Method Investments [Line Items]
Earnings from unconsolidated affiliates	2	4	1	10
Mont Belvieu 1 Fractionator
Schedule of Equity Method Investments [Line Items]
Earnings from unconsolidated affiliates	6	3	12	9
Discovery Producer Services LLC
Schedule of Equity Method Investments [Line Items]
Earnings from unconsolidated affiliates	2	(3)	13	(63)
Other
Schedule of Equity Method Investments [Line Items]
Earnings from unconsolidated affiliates	$ 0	$ 1	$ 2	$ 1

Investments in Unconsolidated_5

Investments in Unconsolidated Affiliates - Equity Method Investment Summarized Financial Information, Statement of Operations (Detail) - USD ($) $ in Millions	3 Months Ended						9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
Schedule of Equity Method Statement of Operations [Line Items]
Total operating revenues	$ 2,827			$ 1,586			$ 7,230	$ 4,517
Operating expenses	231			196
Net (loss) income	55	$ (30)	$ 54	112	$ 48	$ (549)	79	(389)
Unconsolidated Affiliates
Schedule of Equity Method Statement of Operations [Line Items]
Total operating revenues	535			523			1,552	1,560
Operating Expenses							631	572
Net (loss) income	$ 303			$ 326			$ 917	$ 985

Investments in Unconsolidated_6

Investments in Unconsolidated Affiliates - Equity Method Investment Summarized Financial Information, Balance Sheet (Detail) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Schedule of Equity Method Balance Sheet [Line Items]
Current assets	$ 2,001	$ 1,008
Long-term assets	11,695	11,949
Total current liabilities	2,286	1,621
Total assets	13,696	12,957
Unconsolidated Affiliates
Schedule of Equity Method Balance Sheet [Line Items]
Current assets	384	355
Long-term assets	7,331	7,510
Total current liabilities	208	177
Liabilities, Noncurrent	253	258
Total assets	$ 7,254	$ 7,430

Fair Value Measurement - Impair

Fair Value Measurement - Impairment (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Impaired Long-Lived Assets Held and Used [Line Items]
Property, plant, and equipment impairment				$ (587)
Asset Impairment	$ 0	$ 0	$ 20	746
Equity Method Investment, Other than Temporary Impairment				$ 61
Logistics and Marketing
Impaired Long-Lived Assets Held and Used [Line Items]
Property, plant, and equipment impairment			(13)
Gathering and Processing
Impaired Long-Lived Assets Held and Used [Line Items]
Property, plant, and equipment impairment			$ (7)

Fair Value Measurement - Financ

Fair Value Measurement - Financial Instruments Carried at Fair Value (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020	Dec. 31, 2019
Current Assets
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	$ 0	$ 0	$ 0	$ 0	$ 1	$ 0	$ 1	$ 4
Net realized and unrealized gains (losses) included in earnings	1	(1)	0	(1)
Transfers out of Level 3	2	0	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	0	0	0	(3)
Net unrealized gains (losses) on derivatives still held included in earnings	0	0	0	(2)
Current Assets | Commodity derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives - assets	141		141			63
Current Assets | Equity Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Restricted Investments, at Fair Value	3		3			0
Long- Term Assets
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	3	4	3	4	1	2	0	0
Net realized and unrealized gains (losses) included in earnings	2	4	1	8
Transfers out of Level 3	0	0	0	(4)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	0	0	0	0
Net unrealized gains (losses) on derivatives still held included in earnings	2	4	1	4
Long- Term Assets | Commodity derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives - assets	13		13			16
Long- Term Assets | Equity Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Restricted Investments, at Fair Value	31		31			23
Current Liabilities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability Value	(5)	1	(5)	1	(9)	(3)	(3)	(1)
Net realized and unrealized (losses) gains included in earnings	(10)	(1)	(16)	8
Transfers out of Level 3	12	(2)	(9)	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	(2)	1
Settlements			5	(8)
Net unrealized gains (losses) on derivatives still held included in earnings	(3)	1	(5)	(1)
Current Liabilities | Commodity derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives - liabilities	321		321			56
Long- Term Liabilities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability Value	(3)	1	(3)	1	$ 5	(1)	$ (4)	$ (3)
Net realized and unrealized (losses) gains included in earnings	2	3	(3)	2
Transfers out of Level 3	0	0	(1)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	0	0
Settlements			0	0
Net unrealized gains (losses) on derivatives still held included in earnings	2	$ 3	(3)	$ 1
Long- Term Liabilities | Commodity derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives - liabilities	48		48			7
Level 1 | Current Assets | Commodity derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives - assets	58		58			21
Level 1 | Current Assets | Equity Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Restricted Investments, at Fair Value	2		2			0
Level 1 | Long- Term Assets | Commodity derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives - assets	3		3			1
Level 1 | Long- Term Assets | Equity Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Restricted Investments, at Fair Value	31		31			22
Level 1 | Current Liabilities | Commodity derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives - liabilities	90		90			19
Level 1 | Long- Term Liabilities | Commodity derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives - liabilities	7		7			0
Level 2 | Current Assets | Commodity derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives - assets	83		83			42
Level 2 | Current Assets | Equity Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Restricted Investments, at Fair Value	1		1			0
Level 2 | Long- Term Assets | Commodity derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives - assets	7		7			13
Level 2 | Long- Term Assets | Equity Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Restricted Investments, at Fair Value	0		0			1
Level 2 | Current Liabilities | Commodity derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives - liabilities	226		226			34
Level 2 | Long- Term Liabilities | Commodity derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives - liabilities	38		38			6
Level 3 | Current Assets | Commodity derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives - assets	0		0			0
Level 3 | Current Assets | Equity Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Restricted Investments, at Fair Value	0		0			0
Level 3 | Long- Term Assets | Commodity derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives - assets	3		3			2
Level 3 | Long- Term Assets | Equity Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Restricted Investments, at Fair Value	0		0			0
Level 3 | Current Liabilities | Commodity derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives - liabilities	5		5			3
Level 3 | Long- Term Liabilities | Commodity derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives - liabilities	$ 3		$ 3			$ (1)

Fair Value Measurement - Conden

Fair Value Measurement - Condensed Consolidated Balance Sheets for Derivative Financial Instruments (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Current Assets
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Ending balance	$ 1	$ 1	$ 0	$ 4
Net realized and unrealized gains (losses) included in earnings	1	(1)	0	(1)
Transfers out of Level 3	2	0	0	0
Settlements	0	0	0	(3)
Ending balance	0	0	0	0
Net unrealized gains (losses) on derivatives still held included in earnings	0	0	0	(2)
Long- Term Assets
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Ending balance	1	0	2	0
Net realized and unrealized gains (losses) included in earnings	2	4	1	8
Transfers out of Level 3	0	0	0	(4)
Settlements	0	0	0	0
Ending balance	3	4	3	4
Net unrealized gains (losses) on derivatives still held included in earnings	2	4	1	4
Current Liabilities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Transfers out of Level 3	12	(2)	(9)	0
Settlements	(2)	1
Net unrealized gains (losses) on derivatives still held included in earnings	(3)	1	(5)	(1)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	(9)	(3)	(3)	(1)
Net realized and unrealized (losses) gains included in earnings	(10)	(1)	(16)	8
Settlements			5	(8)
Ending balance	(5)	1	(5)	1
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
Net unrealized gains (losses) on derivatives still held included in earnings	2	3	(3)	1
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	5	(4)	(1)	(3)
Net realized and unrealized (losses) gains included in earnings	2	3	(3)	2
Transfers out of Level 3				0
Settlements			0	0
Ending balance	$ (3)	$ 1	$ (3)	$ 1

Schedule of Valuation Processes

Schedule of Valuation Processes (Detail) - Level 3 - Market Approach Valuation Technique $ in Millions	Sep. 30, 2021USD ($)$ / gal
Derivative Liabilities | Natural Gas Liquids
Fair Value Inputs Assets And Liabilities Quantitative Information [Line Items]
Liabilities, fair value | $	$ (6)
Derivative Liabilities | Natural Gas Liquids | Minimum
Fair Value Inputs Assets And Liabilities Quantitative Information [Line Items]
Forward curve prices	0.33
Derivative Liabilities | Natural Gas Liquids | Maximum
Fair Value Inputs Assets And Liabilities Quantitative Information [Line Items]
Forward curve prices	1.75
Derivative Liabilities | Natural Gas Liquids | Weighted Average [Member]
Fair Value Inputs Assets And Liabilities Quantitative Information [Line Items]
Forward curve prices	0.92
Derivative Liabilities | Natural Gas [Member]
Fair Value Inputs Assets And Liabilities Quantitative Information [Line Items]
Liabilities, fair value | $	$ (2)
Derivative Liabilities | Natural Gas [Member] | Minimum
Fair Value Inputs Assets And Liabilities Quantitative Information [Line Items]
Forward curve prices	2.24
Derivative Liabilities | Natural Gas [Member] | Maximum
Fair Value Inputs Assets And Liabilities Quantitative Information [Line Items]
Forward curve prices	3.30
Derivative Liabilities | Natural Gas [Member] | Weighted Average [Member]
Fair Value Inputs Assets And Liabilities Quantitative Information [Line Items]
Forward curve prices	2.50
Derivative Assets | Natural Gas [Member]
Fair Value Inputs Assets And Liabilities Quantitative Information [Line Items]
Assets | $	$ 3
Derivative Assets | Natural Gas [Member] | Minimum
Fair Value Inputs Assets And Liabilities Quantitative Information [Line Items]
Forward curve prices	2.24
Derivative Assets | Natural Gas [Member] | Maximum
Fair Value Inputs Assets And Liabilities Quantitative Information [Line Items]
Forward curve prices	3.40
Derivative Assets | Natural Gas [Member] | Weighted Average [Member]
Fair Value Inputs Assets And Liabilities Quantitative Information [Line Items]
Forward curve prices	2.71

Carrying Value and Fair Value o

Carrying Value and Fair Value of Debt (Detail) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Total Debt, Carrying Value	$ 5,687	$ 5,635
Total Debt, Fair Value	$ 6,274	$ 5,938

Leases, Additional Information

Leases, Additional Information (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Lessee, Lease, Description [Line Items]
Operating Lease, Payments	$ 23	$ 20
Finance Lease, Interest Payment on Liability	3	3
Finance Lease, Principal Payments	1	1
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	$ 26	$ 6
Finance Lease, Weighted Average Remaining Lease Term	4 years	5 years
Finance Lease, Weighted Average Discount Rate, Percent	3.00%	3.00%
Right-of-Use Asset Obtained in Exchange for Finance Lease Liability	$ 3	$ 5
Operating Lease, Weighted Average Remaining Lease Term	5 years	6 years
Operating Lease, Weighted Average Discount Rate, Percent	4.00%	4.00%
Minimum
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Renewal Term	1 year
Lessee, Finance Lease, Renewal Term	1 year
Maximum
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Renewal Term	20 years
Lessee, Finance Lease, Renewal Term	20 years

Schedule of Leased Assets and L

Schedule of Leased Assets and Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Leases [Abstract]
Operating lease assets	$ 93	$ 85
Finance lease assets	28	25
Total right of use assets	121	110
Operating Lease, Liability, Current	26	24
Finance Lease, Liability, Current	5	5
Operating lease liabilities	81	76
Finance Lease, Liability, Noncurrent	21	22
Total lease liabilities	$ 133	$ 127

Leases, Lease Cost (Details)

Leases, Lease Cost (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Income and Expenses, Lessee [Abstract]
Operating Lease, Cost	$ 7	$ 7	$ 21	$ 21
Finance Lease, Right-of-Use Asset, Amortization	1	1	2	2
Finance Lease, Interest Expense	1	1	1	1
Variable Lease, Cost	1	2	3	5
Short-term Lease, Cost	1	1	2	3
Lease, Cost	$ 11	$ 12	$ 29	$ 32

Leases, Schedule of Minimum Ope

Leases, Schedule of Minimum Operating and Finance Lease Payments (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Leases [Abstract]
Lessee, Operating Lease, Liability, Payments, Year One	$ 7
Lessee, Operating Lease, Liability, Payments, Due Year Two	29
Lessee, Operating Lease, Liability, Payments, Due Year Three	26
Lessee, Operating Lease, Liability, Payments, Due Year Four	17
Lessee, Operating Lease, Liability, Payments, Due Year Five	13
Lessee, Operating Lease, Liability, Payments, Due after Year Five	26
Lessee, Operating Lease, Liability, Payments, Due	118
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	11
Operating Lease, Liability	107
Finance Lease, Liability, Payments, Year One	2
Finance Lease, Liability, Payments, Due Year Two	6
Finance Lease, Liability, Payments, Due Year Three	6
Finance Lease, Liability, Payments, Due Year Four	7
Finance Lease, Liability, Payments, Due Year Five	3
Finance Lease, Liability, Payments, Due after Year Five	9
Finance Lease, Liability, Payments, Due	33
Finance Lease, Liability, Undiscounted Excess Amount	7
Finance Lease, Liability	$ 26	$ 27

Leases, Supplemental Cash Flow

Leases, Supplemental Cash Flow and Other Information (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Lessee Disclosure [Abstract]
Operating Lease, Payments	$ 23	$ 20
Finance Lease, Interest Payment on Liability	3	3
Finance Lease, Principal Payments	1	1
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	26	6
Right-of-Use Asset Obtained in Exchange for Finance Lease Liability	$ 3	$ 5
Operating Lease, Weighted Average Remaining Lease Term	5 years	6 years
Finance Lease, Weighted Average Remaining Lease Term	4 years	5 years
Operating Lease, Weighted Average Discount Rate, Percent	4.00%	4.00%
Finance Lease, Weighted Average Discount Rate, Percent	3.00%	3.00%

Debt - Schedule of Debt (Detail

Debt - Schedule of Debt (Detail) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Facility [Line Items]
Fair value adjustments related to interest rate swap fair value hedges	$ 16	$ 17
Unamortized issuance costs	(33)	(38)
Unamortized discount	(6)	(7)
Finance Lease, Liability	26	27
Total debt	5,680	5,624
Finance Lease, Liability, Current	5	5
Current debt	350	500
Long-term debt	5,325	5,119
Credit Agreement
Facility [Line Items]
Credit Facility	$ (552)	0
Weighted-average variable interest rate	1.44%
Accounts Receivable Securitization Facility
Facility [Line Items]
Accounts Receivable Securitization Agreement	$ 350	350
Weighted-average variable interest rate	0.98%
Accounts Recievable included in the Securitization Transaction	$ 963
Senior Notes | Issued September 2011, interest at 4.750% payable semiannually, due September 2021
Facility [Line Items]
Senior Notes	$ 0	500
Debt interest rate percentage	4.75%
Debt Instrument, Interest Rate, Stated Percentage [Abstract]
Debt Instrument, Face Amount	$ 0	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 and January 2019, interest at 5.375% payable semi-annually, due July 2025
Facility [Line Items]
Senior Notes	$ 825	825
Debt interest rate percentage	5.375%
Debt Instrument, Interest Rate, Stated Percentage [Abstract]
Debt Instrument, Face Amount	$ 825	825
Senior Notes | Issued June 2020, interest at 5.625% payable semi-annually, due July 2027
Facility [Line Items]
Senior Notes	$ 500	500
Debt interest rate percentage	5.625%
Debt Instrument, Interest Rate, Stated Percentage [Abstract]
Debt Instrument, Face Amount	$ 500	500
Senior Notes | Issued May 2019, interest at 5.125% payable semiannually, due May 2029
Facility [Line Items]
Senior Notes	$ 600	600
Debt interest rate percentage	5.125%
Debt Instrument, Interest Rate, Stated Percentage [Abstract]
Debt Instrument, Face Amount	$ 600	600
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 (

Debt - Additional Information (Detail) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Line of Credit Facility, Borrowing Capacity, Description	$ 500
Accounts Receivable Securitization Facility
Debt Instrument [Line Items]
Accounts Recievable included in the Securitization Transaction	963
Credit Agreement
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 1,400
Basis spread determined by credit rating	0.35%
Commitment fee percentage	0.275%
Letter of credit amount outstanding	$ (2)
Debt covenants, maximum borrowing amount	$ 846
Credit Agreement | LIBOR
Debt Instrument [Line Items]
Variable rate basis spread	1.35%
Credit Agreement | Federal Funds Rate
Debt Instrument [Line Items]
Variable rate basis spread	0.50%
Credit Agreement | LIBOR Market Index
Debt Instrument [Line Items]
Variable rate basis spread	1.00%
Credit Agreement | Maximum
Debt Instrument [Line Items]
Maximum leverage ratio in event of acquisition	5.5
Credit Agreement | Quarters After June 30, 2018 | Maximum
Debt Instrument [Line Items]
Maximum leverage ratio	5
Credit Agreement | Quarters After June 30, 2018 | Minimum
Debt Instrument [Line Items]
Maximum leverage ratio	1
Issued July 2018 and January 2019, interest at 5.375% payable semi-annually, due July 2025 | Senior Notes
Debt Instrument [Line Items]
Debt Instrument, Face Amount	$ 825	$ 825
Debt Instrument, Interest Rate, Stated Percentage	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
Debt Instrument, Interest Rate, Stated Percentage	5.125%

Debt - Future Maturities of Lon

Debt - Future Maturities of Long-Term Debt (Detail) $ in Millions	Sep. 30, 2021USD ($)
Maturities of Long-term Debt [Abstract]
2021	$ 0
2022	350
2023	500
2024	902
2025	825
Thereafter	3,100
Long Term Debt Maturities Repayments Of Principal Total	$ 5,677

Risk Management and Hedging A_3

Risk Management and Hedging Activities - Additional Information (Detail) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Derivative [Line Items]
Collateral, cash deposits	$ 231
Letters of credit received	103
Unrealized gains on derivative instruments	141	$ 63
Unrealized gains on derivative instruments	13	16
Derivative Instruments and Hedges, Liabilities	(321)	(56)
Derivative Instruments and Hedges, Liabilities, Noncurrent	$ (48)	$ (7)

Risk Management and Hedging A_4

Risk Management and Hedging Activities - Summary of Gross and Net Amounts of Derivative Instruments (Detail) - Commodity derivatives - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Offsetting Assets [Line Items]
Gross Amounts of Assets Presented in the Balance Sheet	$ 154	$ 79
Derivative Asset, Not Offset in Balance Sheet	0	0
Net Amount	154	79
Offsetting Liabilities [Line Items]
Gross Amounts of Liabilities Presented in the Balance Sheet	369	63
Derivative Liability, Not Offset in Balance Sheet	0	0
Net Amount	$ 369	$ 63

Risk Management and Hedging A_5

Risk Management and Hedging Activities - Schedule of Designated and Non-Designated Derivative Instruments in Statement of Financial Position, Fair Value (Detail) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Derivative Asset [Abstract]
Derivative Instruments and Hedges, Current Assets	$ 141	$ 63
Derivative Instruments and Hedges, Assets, Noncurrent	13	16
Derivative Liability [Abstract]
Derivative Instruments and Hedges, Current Liabilities	321	56
Derivative Instruments and Hedges, Liabilities, Noncurrent	48	7
Commodity derivatives | Derivative Asset Not Designated As Hedging Instruments [Member]
Derivative Asset [Abstract]
Derivative Instruments and Hedges, Current Assets	141	63
Derivative Instruments and Hedges, Assets, Noncurrent	13	16
Derivative Instruments Not Designated as Hedging Instruments, Total Assets, at Fair Value	154	79
Commodity derivatives | Derivative Liabilities Not Designated As Hedging Instruments [Member]
Derivative Liability [Abstract]
Derivative Instruments and Hedges, Current Liabilities	321	56
Derivative Instruments and Hedges, Liabilities, Noncurrent	48	7
Derivative Instruments Not Designated as Hedging Instruments, Total Liabilities, at Fair Value	$ 369	$ 63

Risk Management and Hedging A_6

Risk Management and Hedging Activities - Schedule of Cash Flow Hedges Included in Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020	Dec. 31, 2019
Derivative [Line Items]
Accumulated Other Comprehensive (Loss) Income	$ (6)		$ (6)			$ (7)
Trading and marketing gains (losses), net	(173)	$ 11	(695)	$ 156
Commodity derivatives | Derivative Assets Not Designated As Hedging Instruments
Derivative [Line Items]
Realized gains	(66)	22	(399)	90
Unrealized gains (losses)	(107)	(11)	(296)	66
Trading and marketing gains (losses), net	(173)	11	(695)	156
Accumulated Net Gain (Loss) from Cash Flow Hedges
Derivative [Line Items]
Accumulated Other Comprehensive (Loss) Income	(6)	(7)	(6)	(7)	$ (7)	(7)	$ (7)	$ (7)
Accumulated Net Gain (Loss) from Cash Flow Hedges | Interest Rate Derivatives
Derivative [Line Items]
Accumulated Other Comprehensive (Loss) Income	(1)	(2)	(1)	(2)	(2)	(2)	(2)	(2)
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)
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 out of Accumulated Other Comprehensive Income
Derivative [Line Items]
Accumulated Other Comprehensive (Loss) Income	1		1
Reclassification out of Accumulated Other Comprehensive Income | Interest Rate Derivatives
Derivative [Line Items]
Accumulated Other Comprehensive (Loss) Income	1		1
Reclassification out of Accumulated Other Comprehensive Income | Commodity derivatives
Derivative [Line Items]
Accumulated Other Comprehensive (Loss) Income	0		0
Reclassification out of Accumulated Other Comprehensive Income | Foreign Currency Derivatives
Derivative [Line Items]
Accumulated Other Comprehensive (Loss) Income	0		0
Cash Flow Hedging [Member]
Derivative [Line Items]
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months	0	(1)	0	(1)
Cash Flow Hedging [Member] | Interest Rate Derivatives
Derivative [Line Items]
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months	0	(1)	0	(1)
Cash Flow Hedging [Member] | Commodity derivatives
Derivative [Line Items]
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months	0	0	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	$ 0	$ 0

Risk Management and Hedging A_7

Risk Management and Hedging Activities - Schedule of Changes in Derivative Instruments not Designated as Hedging Instruments (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Derivative [Line Items]
Trading and marketing (losses) gains, net	$ (173)	$ 11	$ (695)	$ 156
Derivative Assets Not Designated As Hedging Instruments | Commodity derivatives
Derivative [Line Items]
Realized gains	(66)	22	(399)	90
Unrealized gains (losses)	(107)	(11)	(296)	66
Trading and marketing (losses) gains, net	$ (173)	$ 11	$ (695)	$ 156

Risk Management and Hedging A_8

Risk Management and Hedging Activities - Schedule of Net Long or Short Positions Expected to be Realized (Detail)	9 Months Ended
	Sep. 30, 2021MMBTUbbl	Sep. 30, 2020MMBTUbbl
Crude Oil
Net (Short) Position, Volume [Abstract]
Net (Short) Position (Bbls), Year One | bbl	(405,000)	(253,000)
Net (Short) Position (Bbls), Year Two | bbl	(1,286,000)	(791,000)
Net (Short) Position (Bbls), Year Three | bbl	(446,000)	(43,000)
Net (Short) Position (Bbls), Year Four | bbl	0	0
Net Long (Short) Position (Bbls), Year Five | bbl	0	0
Net (Short) Positions (Bbls), Year Six | bbl	0	0
Natural Gas [Member]
Net Long (Short) Position, MMBtu [Abstract]
Net (Short) Long Position (MMBtu), Year One | MMBTU	(31,457,300)	(14,287,500)
Net (Short) Long Position (MMBtu), Year Two | MMBTU	(59,980,200)	(65,332,500)
Net Long Position (MMBtu), Year Three | MMBTU	912,500	(21,900,000)
Net Long Position (MMBtu), Year Four | MMBTU	0	0
Net Long Position (MMBtu), Year Five | MMBTU	0	0
Net Long (Short) Positions (MMBtu), year Six | MMBTU	0	0
Natural Gas Liquids
Net (Short) Position, Volume [Abstract]
Net (Short) Position (Bbls), Year One | bbl	168,546	(932,160)
Net (Short) Position (Bbls), Year Two | bbl	(8,817,555)	(8,471,590)
Net (Short) Position (Bbls), Year Three | bbl	(1,296,000)	(1,486,842)
Net (Short) Position (Bbls), Year Four | bbl	(1,446,000)	(1,440,000)
Net Long (Short) Position (Bbls), Year Five | bbl	(1,440,000)	(1,440,000)
Net (Short) Positions (Bbls), Year Six | bbl	(1,080,000)	(960,000)
Natural Gas Basis Swaps
Net Long (Short) Position, MMBtu [Abstract]
Net (Short) Long Position (MMBtu), Year One | MMBTU	(2,245,000)	5,600,000
Net (Short) Long Position (MMBtu), Year Two | MMBTU	(2,362,500)	(735,000)
Net Long Position (MMBtu), Year Three | MMBTU	(13,605,000)	12,775,000
Net Long Position (MMBtu), Year Four | MMBTU	1,380,000	7,300,000
Net Long Position (MMBtu), Year Five | MMBTU	21,020,000	7,630,000
Net Long (Short) Positions (MMBtu), year Six | MMBTU	457,500	1,365,000

Partnership Equity and Distri_3

Partnership Equity and Distributions - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended						9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Dec. 31, 2020
Partnership Equity And Distribution [Line Items]
Common unitholders, units issued (in shares)	208,373,672						208,373,672	208,351,528
Total Cash Distribution	$ 88	$ 105	$ 86	$ 88	$ 104	$ 167
DCP Midstream LP | DCP Midstream, LLC
Partnership Equity And Distribution [Line Items]
Ownership interest percentage by parent							57.00%
Equity Distribution Agreement [Member]
Partnership Equity And Distribution [Line Items]
Offer Value Of Common Stock Unit Remaining Available For Sale	$ 750						$ 750

Partnership Equity and Distri_4

Partnership Equity and Distributions - Cash Distribution (Detail) - USD ($) $ / shares in Units, $ in Millions	Sep. 15, 2021	Aug. 13, 2021	Jul. 15, 2021	Jun. 15, 2021	May 14, 2021	Apr. 15, 2021	Mar. 15, 2021	Feb. 12, 2021	Jan. 15, 2021	Dec. 15, 2020	Nov. 13, 2020	Oct. 15, 2020	Sep. 15, 2020	Aug. 14, 2020	Jul. 15, 2020	Jun. 15, 2020	May 15, 2020	Apr. 15, 2020	Mar. 16, 2020	Feb. 14, 2020	Jan. 15, 2020	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020
Distribution Made to Limited Partner [Line Items]
Total Cash Distribution																						$ 88	$ 105	$ 86	$ 88	$ 104	$ 167
Series A Preferred Limited Partners [Member]
Distribution Made to Limited Partner [Line Items]
Preferred Limited Partnership Distribution; Distribution Amount Paid				$ 36.8750						$ 36.8750						$ 36.8750
Total Cash Distribution				$ 18						$ 19						$ 18						0	18	0	0	18	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			$ 0.4922			$ 0.4922			$ 0.4922			$ 0.4922
Total Cash Distribution	$ 4			$ 3			$ 3			$ 4			$ 3			$ 3			$ 3			4	3	3	3	3	3
Series C Preferred Limited Partners [Member]
Distribution Made to Limited Partner [Line Items]
Preferred Limited Partnership Distribution; Distribution Amount Paid			$ 0.4969			$ 0.4969			$ 0.4969			$ 0.4969			$ 0.4969			$ 0.4969			$ 0.4969
Total Cash Distribution			$ 2			$ 2			$ 2			$ 2			$ 3			$ 2			$ 2	3	2	2	3	2	2
Limited Partners
Distribution Made to Limited Partner [Line Items]
Per Unit Distribution (in dollars per share)		$ 0.39			$ 0.39			$ 0.39			$ 0.39			$ 0.39			$ 0.39			$ 0.78
Total Cash Distribution		$ 81			$ 82			$ 81			$ 81			$ 82			$ 81			$ 162		$ 81	$ 82	$ 81	$ 82	$ 81	$ 162

Net Income or Loss per Limite_2

Net Income or Loss per Limited Partner Unit Additional Detail (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Earnings Per Share [Abstract]
Weighted Average Number Diluted Shares Outstanding Adjustment	208,659,969	208,662,096	208,552,224	208,334,185
Net Income (Loss), Per Outstanding Limited Partnership Unit, Basic, Net of Tax	$ 0.18	$ 0.46	$ 0.15	$ (2.09)
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements	291,364	319,350	188,470	0
Weighted Average Number of Shares Outstanding, Basic	208,368,605	208,342,746	208,363,754	208,334,185
Net Income (Loss) Allocated to Limited Partners	$ 38	$ 96	$ 31	$ (436)
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount				319,350

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Income tax expense	$ 0	$ 1	$ 0	$ 2
Deferred income taxes	$ 30		$ 30		$ 30

Restructuring (Details)

Restructuring (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Restructuring Cost and Reserve [Line Items]
Restructuring costs	$ 0	$ 0	$ 0	$ 9

Business Segments - Segment Inf

Business Segments - Segment Information (Detail) - USD ($) $ in Millions	3 Months Ended						9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
Segment Reporting Information [Line Items]
Total operating revenues	$ 2,827			$ 1,586			$ 7,230	$ 4,517
Gross margin	316			368			843	1,179
Operating and maintenance expense	(168)			(146)			(482)	(447)
Depreciation and amortization expense	(89)			(92)			(273)	(284)
General and administrative expense	(63)			(66)			(158)	(173)
Asset Impairments	0			0			(20)	(746)
Other expense, net	(2)			(4)			4	(12)
Loss on sale of assets, net	0			0			(1)	0
Restructuring Costs	0			0			0	(9)
Earnings from unconsolidated affiliates	134			130			393	331
Interest expense, net	(73)			(77)			(227)	(226)
Income tax expense	0			1			0	2
Net income	55	$ (30)	$ 54	112	$ 48	$ (549)	79	(389)
Net income attributable to noncontrolling interests	(1)			(1)			(3)	(3)
Net income attributable to partners	54			111			76	(392)
Non-cash derivative mark-to-market	(107)			(11)			(296)	66
Non-cash lower of cost or net realizable value adjustment								6
Capital expenditures	28			23			69	125
Investments in unconsolidated affiliates, net	4			12			4	102
Other Income	(2)						4
Logistics and Marketing
Segment Reporting Information [Line Items]
Total operating revenues	2,668			1,438			6,683	3,946
Gathering and Processing
Segment Reporting Information [Line Items]
Total operating revenues	1,821			857			4,449	2,388
Operating Segments | Logistics and Marketing
Segment Reporting Information [Line Items]
Total operating revenues	2,668			1,438			6,683	3,946
Gross margin	35			88			78	268
Operating and maintenance expense	(11)			(8)			(29)	(24)
Depreciation and amortization expense	(3)			(3)			(9)	(9)
General and administrative expense	(1)			(1)			(4)	(4)
Asset Impairments								0
Other expense, net	0			(2)			5	(6)
Loss on sale of assets, net							0
Restructuring Costs								0
Earnings from unconsolidated affiliates	133			132			380	394
Interest expense, net	0			0			0	0
Income tax expense				0				0
Net income	153			206			408	619
Net income attributable to noncontrolling interests	0			0			0	0
Net income attributable to partners	153			206			408	619
Non-cash derivative mark-to-market	(7)			28			(47)	75
Capital expenditures	2			1			2	2
Investments in unconsolidated affiliates, net	4			12			4	102
Operating Segments | Gathering and Processing
Segment Reporting Information [Line Items]
Total operating revenues	1,821			857			4,449	2,388
Gross margin	281			280			765	911
Operating and maintenance expense	(157)			(135)			(443)	(411)
Depreciation and amortization expense	(80)			(82)			(243)	(253)
General and administrative expense	(4)			(8)			(12)	(15)
Asset Impairments								(746)
Other expense, net	(2)			(2)			(1)	(4)
Loss on sale of assets, net							(1)
Restructuring Costs								0
Earnings from unconsolidated affiliates	1			(2)			13	(63)
Interest expense, net	0			0			0	0
Income tax expense				0				0
Net income	39			51			71	(581)
Net income attributable to noncontrolling interests	(1)			(1)			(3)	(3)
Net income attributable to partners	38			50			68	(584)
Non-cash derivative mark-to-market	(100)			(39)			(249)	(9)
Non-cash lower of cost or net realizable value adjustment								0
Capital expenditures	25			13			62	112
Investments in unconsolidated affiliates, net	0			0			0	0
Other
Segment Reporting Information [Line Items]
Total operating revenues	0			0			0	0
Gross margin	0			0			0	0
Operating and maintenance expense	0			(3)			(10)	(12)
Depreciation and amortization expense	(6)			(7)			(21)	(22)
General and administrative expense	(58)			(57)			(142)	(154)
Asset Impairments							0	0
Other expense, net	0			0			0	(2)
Loss on sale of assets, net							0
Restructuring Costs								(9)
Earnings from unconsolidated affiliates	0			0			0	0
Interest expense, net	(73)			(77)			(227)	(226)
Income tax expense				1				2
Net income	(137)			(145)			(400)	(427)
Net income attributable to noncontrolling interests	0			0			0	0
Net income attributable to partners	(137)			(145)			(400)	(427)
Non-cash derivative mark-to-market	0			0			0	0
Non-cash lower of cost or net realizable value adjustment								0
Capital expenditures	1			9			5	11
Investments in unconsolidated affiliates, net	0			0			0	0
Eliminations
Segment Reporting Information [Line Items]
Total operating revenues	(1,662)			(709)			(3,902)	(1,817)
Gross margin	0			0			0	0
Operating and maintenance expense				0				0
Depreciation and amortization expense	0			0			0	0
General and administrative expense	0			0			0	0
Asset Impairments								0
Other expense, net				0				0
Restructuring Costs								0
Earnings from unconsolidated affiliates	0			0			0	0
Interest expense, net	0			0			0	0
Income tax expense				0				0
Net income	0			0			0	0
Net income attributable to noncontrolling interests	0			0			0	0
Net income attributable to partners	0			0			0	0
Non-cash derivative mark-to-market				0				0
Non-cash lower of cost or net realizable value adjustment	0						0	0
Capital expenditures	0			0			0	0
Investments in unconsolidated affiliates, net	$ 0			$ 0			$ 0	$ 0

Business Segments - Segment Ass

Business Segments - Segment Assets (Detail) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Segment Reporting, Asset Reconciling Item [Line Items]
Segment long-term assets	$ 11,695	$ 11,949
Current assets	2,001	1,008
Total assets	13,696	12,957
Operating Segments | Logistics and Marketing
Segment Reporting, Asset Reconciling Item [Line Items]
Segment long-term assets	3,871	3,929
Operating Segments | Gathering and Processing
Segment Reporting, Asset Reconciling Item [Line Items]
Segment long-term assets	7,603	7,788
Other
Segment Reporting, Asset Reconciling Item [Line Items]
Segment long-term assets	$ 221	$ 232

Statement of Cash Flows, Supp_2

Statement of Cash Flows, Supplemental Disclosures (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Item Effected [Line Items]
Cash paid for interest, net of amounts capitalized	$ 234	$ 222
Income Taxes Paid, Net	3	2
Property, plant and equipment acquired with accounts payable and accrued liabilities	8	5
Property, Plant and Equipment, Other Increase (Decrease)	(2)	0
Right-of-Use Assets Obtained in Exchange for Operating and Finance Lease Liabilities	$ 29	$ 11

Other Income and Expenses (Deta

Other Income and Expenses (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended						9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
Other Income and Expenses [Abstract]
Operating Income (Loss)	$ (6)			$ 60			$ (87)	$ (492)
Net Income (Loss) Attributable to Parent	54			111			76	(392)
Net income attributable to noncontrolling interests	(1)			(1)			(3)	(3)
Net (loss) income	55	$ (30)	$ 54	112	$ 48	$ (549)	79	(389)
Net Income (Loss) Allocated to Limited Partners	$ 38			$ 96			$ 31	$ (436)
Net income per limited partner unit — basic and diluted	$ 0.18			$ 0.46			$ 0.15	$ (2.09)
Total operating revenues	$ 2,827			$ 1,586			$ 7,230	$ 4,517

Condensed Consolidating Financi

Condensed Consolidating Financial Information - Condensed Consolidating Balance Sheets (Detail) - USD ($) $ in Millions	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019
ASSETS
Cash and cash equivalents	$ 3			$ 52	$ 14
Inventories	58			38
Total current assets	2,001			1,008
Property, plant and equipment, net	7,775			7,993
Investments in unconsolidated affiliates	3,577			3,641
Total assets	13,696			12,957
LIABILITIES AND EQUITY
Current debt	355			505
Long-term debt	5,325			5,119
Total liabilities	8,030			7,096
Equity:
Accumulated other comprehensive loss	(6)			(7)
Total partners’ equity	5,640			5,834
Noncontrolling interests	26			27
Total equity	5,666	$ 5,697	$ 5,832	5,861	$ 5,882	$ 5,859	$ 5,916	$ 6,633
Total liabilities and equity	$ 13,696			$ 12,957

Condensed Consolidating Finan_2

Condensed Consolidating Financial Information - Condensed Consolidating Statements of Operations (Detail) - USD ($) $ in Millions	3 Months Ended						9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
Operating revenues:
Trading and marketing gains (losses), net	$ (173)			$ 11			$ (695)	$ 156
Total operating revenues	2,827			1,586			7,230	4,517
Operating and maintenance expense	168			146			482	447
Depreciation and amortization expense	89			92			273	284
General and administrative expense	63			66			158	173
Asset Impairment	0			0			20	746
Loss on sale of assets, net	0			0			1	0
Restructuring costs	0			0			0	9
Other income (expense)	2			4			(4)	12
Costs and Expenses	2,833			1,526			7,317	5,009
Operating (loss) income	(6)			60			(87)	(492)
Interest Expense	(73)			(77)			(227)	(226)
Earnings from unconsolidated affiliates	134			130			393	331
(Loss) income before income taxes	55			113			79	(387)
Income tax expense	0			1			0	2
Net income	55	$ (30)	$ 54	112	$ 48	$ (549)	79	(389)
Net income attributable to noncontrolling interests	(1)			(1)			(3)	(3)
Net income attributable to partners	54			111			76	(392)
Other comprehensive income	1			0			1	0
Total comprehensive income	56			112			80	(389)
Total comprehensive income attributable to noncontrolling interests	(1)			(1)			(3)	(3)
Total comprehensive income attributable to partners	55			111			77	(392)
Consolidating Adjustments
Operating revenues:
Total operating revenues	(1,662)			(709)			(3,902)	(1,817)
Operating and maintenance expense				0				0
Depreciation and amortization expense	0			0			0	0
General and administrative expense	0			0			0	0
Asset Impairment								0
Restructuring costs								0
Other income (expense)				0				0
Interest Expense	0			0			0	0
Earnings from unconsolidated affiliates	0			0			0	0
Income tax expense				0				0
Net income	0			0			0	0
Net income attributable to noncontrolling interests	0			0			0	0
Net income attributable to partners	0			0			0	0
Transportation, Processing and Other [Member]
Operating revenues:
Sales of natural gas, NGLs and condensate	$ 144			$ 109			$ 387	$ 330

Condensed Consolidating Finan_3

Condensed Consolidating Financial Information - Condensed Consolidating Statement of Comprehensive Income (Detail) - USD ($) $ in Millions	3 Months Ended						9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
Condensed Financial Statements, Captions [Line Items]
Net (loss) income	$ 55	$ (30)	$ 54	$ 112	$ 48	$ (549)	$ 79	$ (389)
Other comprehensive income (loss):
Other comprehensive income	1			0			1	0
Total comprehensive income	56			112			80	(389)
Total comprehensive income attributable to noncontrolling interests	(1)			(1)			(3)	(3)
Total comprehensive income attributable to partners	$ 55			$ 111			$ 77	$ (392)

Condensed Consolidating Finan_4

Condensed Consolidating Financial Information - Condensed Consolidating Statements of Cash Flows (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
OPERATING ACTIVITIES
Net cash (used in) provided by operating activities			$ 255	$ 791
INVESTING ACTIVITIES:
Capital expenditures	$ (28)	$ (23)	(69)	(125)
Investments in unconsolidated affiliates	(4)	(12)	(4)	(102)
Proceeds from sale of assets			0	2
Net cash used in investing activities			(73)	(225)
FINANCING ACTIVITIES:
Proceeds from debt			3,380	3,958
Payments of debt			(3,332)	(4,137)
Distribution Made to Limited Partner, Cash Distributions Paid			(35)	(34)
Distributions to limited partners and general partner			(244)	(325)
Proceeds from (Payments for) Other Financing Activities			0	(1)
Net cash provided by (used in) financing activities			(235)	(550)
Cash and cash equivalents, beginning of period			52
Cash and cash equivalents, end of period	$ 3	$ 14	$ 3	$ 14

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail) - $ / shares

Jan. 18, 2022

Jan. 03, 2022

Dec. 15, 2021

Dec. 01, 2021

Nov. 12, 2021

Oct. 29, 2021

Oct. 12, 2021

Oct. 01, 2021

Sep. 15, 2021

Jul. 15, 2021

Jun. 15, 2021

Apr. 15, 2021

Mar. 15, 2021

Jan. 15, 2021

Dec. 15, 2020

Oct. 15, 2020

Sep. 15, 2020

Jul. 15, 2020

Jun. 15, 2020

Apr. 15, 2020

Mar. 16, 2020

Jan. 15, 2020

Series A Preferred Limited Partners [Member]

Subsequent Event [Line Items]

Preferred Limited Partnership Unit; Distribution Amount Declared

$ 36.8750

$ 36.8750

$ 36.8750

Series B Preferred Limited Partners [Member]

Subsequent Event [Line Items]

Preferred Limited Partnership Unit; Distribution Amount Declared

$ 0.4922

$ 0.4922

$ 0.4922

$ 0.4922

$ 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

$ 0.4969

$ 0.4969

$ 0.4969

$ 0.4969

$ 0.4969

Subsequent Event [Member]

Subsequent Event [Line Items]

Distribution Made to Limited Partner, Distributions Declared, Per Unit

$ 0.39

Distribution Made to Limited Partner, Date of Record

Oct. 29, 2021

Distribution Made to Limited Partner, Distribution Date

Nov. 12, 2021

Subsequent Event [Member] | Series A Preferred Limited Partners [Member]

Subsequent Event [Line Items]

Preferred Limited Partner Distribution: Record Date

Dec. 1, 2021

Preferred Limited Partnership Distribution; Distribution Date

Dec. 15, 2021

Preferred Limited Partnership Unit; Distribution Amount Declared

$ 36.875

Subsequent Event [Member] | Series B Preferred Limited Partners [Member]

Subsequent Event [Line Items]

Distribution Made to Common Unitholders, Declaration Date

Oct. 12, 2021

Preferred Limited Partner Distribution: Record Date

Dec. 1, 2021

Preferred Limited Partnership Distribution; Distribution Date

Dec. 15, 2021

Preferred Limited Partnership Unit; Distribution Amount Declared

$ 0.4922

Subsequent Event [Member] | Series C Preferred Limited Partners [Member]

Subsequent Event [Line Items]

Preferred Limited Partner Distribution: Record Date

Jan. 3, 2022

Preferred Limited Partnership Distribution; Distribution Date

Jan. 18, 2022

Preferred Limited Partnership Unit; Distribution Amount Declared

$ 0.4969