DCP Midstream (DCP-PC) 10-Q 8 Aug 18 2018 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2018	Aug. 03, 2018
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q2
Trading Symbol	DCP
Entity Registrant Name	DCP MIDSTREAM, LP
Entity Central Index Key	1,338,065
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		143,309,828

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 4	$ 156
Accounts receivable:
Trade, net of allowance for doubtful accounts of $6 and $8 million, respectively	824	773
Affiliates	189	191
Other	16	17
Inventories	47	68
Unrealized gains on derivative instruments	45	30
Collateral cash deposits	138	75
Other	19	12
Total current assets	1,282	1,322
Property, plant and equipment, net	9,080	8,983
Goodwill	231	231
Intangible assets, net	101	106
Investments in unconsolidated affiliates	3,165	3,050
Unrealized gains on derivative instruments	8	3
Other long-term assets	174	183
Total assets	14,041	13,878
Accounts payable:
Trade	968	989
Affiliates	112	68
Other	27	19
Current maturities of long-term debt	325	0
Unrealized losses on derivative instruments	141	76
Accrued interest	71	71
Accrued taxes	60	58
Accrued wages and benefits	42	65
Capital spending accrual	33	39
Other	108	103
Total current liabilities	1,887	1,488
Long-term debt	4,510	4,707
Unrealized losses on derivative instruments	29	15
Deferred income taxes	29	29
Other long-term liabilities	233	201
Total liabilities	6,688	6,440
Commitments and contingent liabilities (see note 14)
Equity:
Limited partners (143,309,828 and 143,309,828 common units authorized, issued and outstanding, respectively)	6,577	6,772
General partner	109	154
Accumulated other comprehensive loss	(8)	(9)
Total partners’ equity	7,323	7,408
Noncontrolling interests	30	30
Total equity	7,353	7,438
Total liabilities and equity	14,041	13,878
Series A Preferred Limited Partners [Member]
Equity:
Preferred Units, Preferred Partners' Capital Accounts	488	491
Total equity	488	491
Series B Preferred Limited Partners [Member]
Equity:
Preferred Units, Preferred Partners' Capital Accounts	157	0
Total equity	$ 157	$ 0

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Condensed Balance Sheet Statements, Captions [Line Items]
Goodwill	$ 231	$ 231
Allowance for Doubtful Accounts Receivable, Current	$ 6	$ 8
Common unitholders, units issued (in shares)	143,309,828	143,309,828
Common unitholders, units outstanding (in shares)	143,309,828	143,309,828
Series A Preferred Limited Partners [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Preferred Units, Issued	500,000	500,000
Preferred Units, Outstanding	500,000	500,000
Series B Preferred Limited Partners [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Preferred Units, Issued	6,450,000	0
Preferred Units, Outstanding	6,450,000	0

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Operating revenues:
Sales of natural gas, NGLs and condensate	$ 2,257	$ 1,772	$ 4,326	$ 3,705
Transportation, processing and other	127	155	238	312
Trading and marketing (losses) gains, net	(67)	22	(108)	53
Total operating revenues	2,317	1,949	4,456	4,070
Operating costs and expenses:
Purchases and related costs	1,928	1,557	3,697	3,244
Operating and maintenance expense	185	178	347	345
Depreciation and amortization expense	97	94	191	188
General and administrative expense	70	71	129	133
Other expense, net	3	5	5	15
Total operating costs and expenses	2,283	1,871	4,369	3,891
Operating income	34	78	87	179
Earnings from unconsolidated affiliates	96	86	174	160
Interest expense, net	(67)	(73)	(134)	(146)
Income before income taxes	63	91	127	193
Income tax expense	(1)	(2)	(2)	(3)
Net income	62	89	125	190
Net income attributable to noncontrolling interests	(1)	(1)	(2)	(1)
Net income attributable to partners	61	88	123	189
General partner’s interest in net income	(40)	(41)	(81)	(83)
Series A preferred limited partners' interest in net income	(9)	0	(18)	0
Net Income (Loss) Allocated to Preferred Series B Limited Partners	(2)	0	(2)	0
Net (loss) income allocable to limited partners	$ 10	$ 47	$ 22	$ 106
Net (loss) income per limited partner unit — basic and diluted	$ 0.07	$ 0.33	$ 0.15	$ 0.74
Weighted Average Limited Partnership Units Outstanding, Basic	143.3	143.3	143.3	143.3
Weighted Average Limited Partnership Units Outstanding, Diluted	143.3	143.3	143.3	143.3
Affiliated Entity
Operating revenues:
Sales of natural gas, NGLs and condensate	$ 408	$ 278	$ 733	$ 567
Operating costs and expenses:
Purchases and related costs	225	138	390	266
Third Party
Operating revenues:
Sales of natural gas, NGLs and condensate	1,849	1,494	3,593	3,138
Operating costs and expenses:
Purchases and related costs	$ 1,703	$ 1,419	$ 3,307	$ 2,978

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 62	$ 89	$ 125	$ 190
Other comprehensive income:
Reclassification of cash flow hedge losses into earnings	1	0	1	1
Total other comprehensive income	1	0	1	1
Total comprehensive income	63	89	126	191
Total comprehensive income attributable to noncontrolling interests	(1)	(1)	(2)	(1)
Total comprehensive income attributable to partners	$ 62	$ 88	$ 124	$ 190

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
OPERATING ACTIVITIES:
Net income	$ 125	$ 190
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization expense	191	188
Earnings from unconsolidated affiliates	(174)	(160)
Distributions from unconsolidated affiliates	193	177
Net unrealized losses (gains) on derivative instruments	66	(60)
Other, net	9	21
Change in operating assets and liabilities, which provided (used) cash, net of effects of acquisitions:
Accounts receivable	(50)	98
Inventories	21	21
Accounts payable	42	(137)
Increase (Decrease) in Other Operating Assets and Liabilities, Net	(92)	56
Net cash provided by operating activities	331	360
INVESTING ACTIVITIES:
Capital expenditures	(268)	(159)
Investments in unconsolidated affiliates, net	(126)	(41)
Proceeds from sale of assets	3	129
Net cash used in investing activities	(391)	(71)
FINANCING ACTIVITIES:
Proceeds from long-term debt	1,803	0
Payments of long-term debt	(1,678)	(195)
Proceeds from Issuance of Preferred Limited Partners Units	155	0
Net change in advances to predecessor from DCP Midstream, LLC	0	418
Distributions to preferred limited partners	21	0
Distributions to limited partners and general partner	(349)	(256)
Distributions to noncontrolling interests	(2)	(4)
Other	0	(2)
Net cash used in financing activities	(92)	(39)
Net change in cash and cash equivalents	(152)	250
Cash and cash equivalents, beginning of period	156	1
Cash and cash equivalents, end of period	$ 4	$ 251

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]	General Partner	Limited Partners	Accumulated Other Comprehensive (Loss) Income	Noncontrolling Interests
Beginning balance (Predecessor) at Dec. 31, 2016	$ 4,220
Beginning balance at Dec. 31, 2016	6,853			$ 18	$ 2,591	$ (8)	$ 32
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income | Predecessor	0
Net income	190			83	106		1
Other comprehensive income	1					1
Net change in parent advances	(418)				(418)
Acquisition of the DCP Midstream Business | Predecessor	(4,220)
Acquisition of the DCP Midstream Business	(4,220)
Deficit purchase price under carrying value of the Transaction	3,092				3,094	(2)
Proceeds from Issuance of Preferred Limited Partners Units	0
Proceeds from issuance of common units, net of offering costs	1,125			92	1,033
Distributions to unitholders	(256)			(54)	(202)
Distributions to noncontrolling interests	(4)						(4)
Ending balance (Predecessor) at Jun. 30, 2017	0
Ending balance at Jun. 30, 2017	7,199			139	7,040	(9)	29
Beginning balance at Dec. 31, 2017	7,438	$ 491	$ 0	154	6,772	(9)	30
Increase (Decrease) in Partners' Capital [Roll Forward]
Cumulative effect adjustment for Adoption of ASC 606	6	0	0	0	6	0	0
Net income	125	18	2	81	22		2
Other comprehensive income	1					(1)
Proceeds from Issuance of Preferred Limited Partners Units	155	0	155		0
Distributions to unitholders	(370)	21	0	(126)	(223)
Distributions to noncontrolling interests	(2)	0	0	0	0	0	(2)
Ending balance at Jun. 30, 2018	$ 7,353	$ 488	$ 157	$ 109	$ 6,577	$ (8)	$ 30

Consolidated Statements of Cha8

Consolidated Statements of Changes in Equity (Parenthetical)	3 Months Ended	6 Months Ended
	Jun. 30, 2017shares	Jun. 30, 2018shares
Issuance of 6,450,000 Series B Preferred Units [Member] | Series B Preferred Limited Partners [Member]
Sale of Preferred Limited Partnership Units		6,450,000
Issuance of 28,552,480 common units and 2,550,644 general partner units to DCP Midstream, LLC and affiliates [Member] | Limited Partners
Issuance of common units (in shares)	28,552,480
Issuance of 28,552,480 common units and 2,550,644 general partner units to DCP Midstream, LLC and affiliates [Member] | General Partner
Issuance of common units (in shares)	2,550,644

Description of Business and Bas

Description of Business and Basis of Presentation	6 Months Ended
	Jun. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business and Basis of Presentation	1. Description of Business and Basis of Presentation DCP Midstream, LP, with its consolidated subsidiaries, or "us", "we", "our" or the "Partnership" is a Delaware limited partnership formed in 2005 by DCP Midstream, LLC to own, operate, acquire and develop a diversified portfolio of complementary midstream energy assets. Our Partnership includes our Gathering and Processing and Logistics and Marketing segments. For additional information regarding these segments, see Note 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 June 30, 2018 , DCP Midstream, LLC owned approximately 38.1% of us, including limited partner and general partner interests. The condensed consolidated financial statements include the accounts of the Partnership and all majority-owned subsidiaries where we have the ability to exercise control. Investments in greater than 20% owned affiliates that are not variable interest entities and where we do not have the ability to exercise control, and investments in less than 20% owned affiliates where we have the ability to exercise significant influence, are accounted for using the equity method. The condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America, or GAAP. All intercompany balances and transactions have been eliminated in consolidation. The accompanying unaudited condensed consolidated financial statements in this Quarterly Report on Form 10-Q have been prepared pursuant to the rules and regulations of the U.S. Securities and Exchange Commission ("SEC"). Accordingly, these condensed consolidated financial statements reflect all adjustments, consisting of normal recurring adjustments, that are, in the opinion of management, necessary to present fairly the financial position and results of operations for the respective interim periods. Certain information and note disclosures normally included in our annual financial statements prepared in accordance with GAAP have been condensed or omitted from these interim financial statements pursuant to such rules and regulations, although we believe that the disclosures made are adequate to make the information presented not misleading. Results of operations for the three and six months ended June 30, 2018 are not necessarily indicative of the results that may be expected for the year ending December 31, 2018 . These unaudited condensed consolidated financial statements and other information included in this Quarterly Report on Form 10-Q should be read in conjunction with the 2017 audited consolidated financial statements and notes thereto included in our Annual Report on Form 10-K for the year ended December 31, 2017..

New Accounting Pronouncements

New Accounting Pronouncements	6 Months Ended
	Jun. 30, 2018
New Accounting Pronouncements, Policy [Abstract]
New Accounting Pronouncements	New Accounting Pronouncements Financial Accounting Standards Board, or FASB, Accounting Standards Update, or ASU, 2016-15 “Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments,” or ASU 2016-15 - In August 2016, the FASB issued ASU 2016-15, which amends certain cash flow statement classification guidance. We adopted the ASU on January 1, 2018 and it has not had any impact on our condensed consolidated results of operations, cash flows and financial position. FASB ASU, 2016-02 “Leases (Topic 842),” or ASU 2016-02 - In February 2016, the FASB issued ASU 2016-02, which requires lessees to recognize a lease liability on a discounted basis and the right of use of a specified asset at the commencement date for all leases. This ASU is effective for interim and annual reporting periods beginning after December 15, 2018, with the option to early adopt for financial statements that have not been issued. We are currently evaluating the potential impact this standard will have on our condensed consolidated financial statements and related disclosures. FASB ASU 2014-09 “Revenue from Contracts with Customers (Topic 606),” or ASU 2014-09 and related interpretations and amendments - In May 2014, the FASB issued ASU 2014-09, which supersedes the revenue recognition requirements of Accounting Standards Codification Topic 605 “Revenue Recognition.” We adopted this ASU on January 1, 2018 using the modified retrospective method for contracts that were not completed as of the date of adoption. Under this method, the comparative information has not been restated and continues to be reported under the accounting standards in effect for those prior periods. Under the new standard, revenue is recognized when a customer obtains control of promised goods or services in an amount that reflects the consideration the entity expects to receive in exchange for those goods or services. We recognized the initial cumulative effect of applying this ASU as an adjustment to the opening balance of total partners’ equity. In accordance with the new revenue standard requirements, the impact of adoption on our consolidated statement of operations was as follows: Three Months Ended June 30, 2018 Six Months Ended June 30, 2018 As Reported Effect of Change Presentation Without Adoption of ASC 606 As Reported Effect of Change Presentation Without Adoption of ASC 606 (millions) Statement of Operations Operating revenues Sales of natural gas, NGLs and condensate $ 1,849 $ 44 $ 1,893 $ 3,593 $ 75 $ 3,668 Transportation, processing and other $ 127 $ 39 $ 166 $ 238 $ 79 $ 317 Costs and expenses Purchases and related costs $ 1,703 $ 83 $ 1,786 $ 3,307 $ 154 $ 3,461 Net income $ 62 $ — $ 62 $ 125 $ — $ 125

Revenue Recognition

Revenue Recognition	6 Months Ended
	Jun. 30, 2018
Revenue Recognition [Abstract]
Revenue from External Customers by Products and Services [Table Text Block]	Revenue Recognition Our operating revenues are primarily derived from the following activities: • sales of natural gas, NGLs, and condensate; • services related to gathering, compressing, treating and processing NGLs and natural gas; and • services related to transportation and storage of natural gas and NGLs. Sales of natural gas, NGLs and condensate - We sell our commodities to a variety of customers ranging from large, multi-national petrochemical and refining companies to regional retail propane distributors. We recognize revenue from commodity sales at the point in time when the product is delivered to the customer. Generally, the transaction price is determined at the time of each delivery as the uncertainty of commodity pricing is resolved. Customers usually pay monthly based on the products purchased that month. Sales of natural gas, NGLs and condensate include physical sales contracts which qualify as financial derivative instruments, and buy-sell and exchange transactions which involve purchases and sales of inventory with the same counterparty that are legally contingent or in contemplation of one another as a single transaction on a combined net basis. Neither of these types of arrangements are contracts with customers within the scope of Topic 606. Gathering, compressing, treating and processing natural gas - For natural gas gathering and processing activities, we receive either fees and/or a percentage of proceeds from commodity sales as payment for these services, depending on the type of contract. For gathering and processing agreements within the scope of Topic 606, we recognize the revenue associated with our services when the gas is gathered, treated or processed at our facilities. Under fee-based contracts, we receive a fee for our services based on throughput volumes. Under percent-of-proceeds contracts, we receive either an agreed upon percentage of the actual proceeds received from our sale of the residue natural gas and NGLs or an agreed upon percentage based on index related prices for the natural gas and NGLs. Our percent-of-proceeds contracts may also include a fee-based component. Transportation and storage - Revenue from transportation and storage agreements is recognized based on contracted volumes transported and stored in the period the services are provided. Our service contracts generally have terms that extend beyond one year, and are recognized over time. The performance obligation for most of our service contracts encompasses a series of distinct services performed on discrete daily quantities of natural gas or NGLs for purposes of allocating variable consideration and recognizing revenue while the customer simultaneously receives and consumes the benefits of the services provided. Revenue is recognized over time consistent with the transfer of good or service over time to the customer based on daily volumes delivered. Consideration is generally variable, and the transaction price cannot be determined at the inception of the contract, because the volume of natural gas or NGLs for which the service is provided is only specified on a daily or monthly basis. The transaction price is determined at the time the service is provided and the uncertainty is resolved. Customers usually pay monthly based on the services performed that month. Purchase arrangements - Under purchase arrangements, we purchase natural gas at either the wellhead or the tailgate of a plant. These purchase arrangements represent an arrangement with a supplier and are recorded in “Purchases and related costs”. Often, we earn fees for services performed prior to taking control of the product in these arrangements and service revenue is recorded for these fees. Revenue generated from the sale of product obtained in these purchase arrangements are reported as “Sales of natural gas, NGLs and condensate” on the consolidated statements of operations and are recognized on a gross basis as we purchase and take control of the product prior to sale and are the principal in the transaction. Practical expedients - We apply the practical expedients in Topic 606 and do not disclose information about transaction prices allocated to remaining performance obligations that have original expected durations of one year or less, nor do we disclose information about transaction prices allocated to remaining performance obligations if the variable consideration is allocated entirely to a wholly unsatisfied performance obligation. We disaggregate our revenue from contracts with customers by type for each of our reportable segments, as we believe it best depicts the nature, timing and uncertainty of our revenue and cash flows. The following tables set forth our revenue by those categories: Revenue by type was as follows: Three Months Ended June 30, 2018 Gathering and Processing Logistics and Marketing Eliminations Total (millions) Sales of natural gas $ 398 $ 463 $ (353 ) $ 508 Sales of NGLs and condensate (a) 870 1,714 (835 ) 1,749 Transportation, processing and other 112 16 (1 ) 127 Trading and marketing losses, net (c) (66 ) (1 ) — (67 ) Total operating revenues $ 1,314 $ 2,192 $ (1,189 ) $ 2,317 Six Months Ended June 30, 2018 Gathering and Processing Logistics and Marketing Eliminations Total (millions) Sales of natural gas $ 844 $ 1,016 $ (772 ) $ 1,088 Sales of NGLs and condensate (b) 1,610 3,170 (1,542 ) 3,238 Transportation, processing and other 209 30 (1 ) 238 Trading and marketing losses, net (c) (63 ) (45 ) — (108 ) Total operating revenues $ 2,600 $ 4,171 $ (2,315 ) $ 4,456 (a) Includes $1,108 million of revenues from physical sales contracts and buy-sell exchange transactions in our logistics and marketing segment, which are not within the scope of Topic 606. (b) Includes $ 1,901 million of revenues from physical sales contracts and buy-sell exchange transactions in our logistics and marketing segment, which are not within the scope of Topic 606. (c) Not within the scope of Topic 606.

Contract Assets and Liabilities

Contract Assets and Liabilities	6 Months Ended
	Jun. 30, 2018
Contract Assets and Liabilities [Abstract]
Revenue from External Customers by Products and Services [Table Text Block]	Revenue Recognition Our operating revenues are primarily derived from the following activities: • sales of natural gas, NGLs, and condensate; • services related to gathering, compressing, treating and processing NGLs and natural gas; and • services related to transportation and storage of natural gas and NGLs. Sales of natural gas, NGLs and condensate - We sell our commodities to a variety of customers ranging from large, multi-national petrochemical and refining companies to regional retail propane distributors. We recognize revenue from commodity sales at the point in time when the product is delivered to the customer. Generally, the transaction price is determined at the time of each delivery as the uncertainty of commodity pricing is resolved. Customers usually pay monthly based on the products purchased that month. Sales of natural gas, NGLs and condensate include physical sales contracts which qualify as financial derivative instruments, and buy-sell and exchange transactions which involve purchases and sales of inventory with the same counterparty that are legally contingent or in contemplation of one another as a single transaction on a combined net basis. Neither of these types of arrangements are contracts with customers within the scope of Topic 606. Gathering, compressing, treating and processing natural gas - For natural gas gathering and processing activities, we receive either fees and/or a percentage of proceeds from commodity sales as payment for these services, depending on the type of contract. For gathering and processing agreements within the scope of Topic 606, we recognize the revenue associated with our services when the gas is gathered, treated or processed at our facilities. Under fee-based contracts, we receive a fee for our services based on throughput volumes. Under percent-of-proceeds contracts, we receive either an agreed upon percentage of the actual proceeds received from our sale of the residue natural gas and NGLs or an agreed upon percentage based on index related prices for the natural gas and NGLs. Our percent-of-proceeds contracts may also include a fee-based component. Transportation and storage - Revenue from transportation and storage agreements is recognized based on contracted volumes transported and stored in the period the services are provided. Our service contracts generally have terms that extend beyond one year, and are recognized over time. The performance obligation for most of our service contracts encompasses a series of distinct services performed on discrete daily quantities of natural gas or NGLs for purposes of allocating variable consideration and recognizing revenue while the customer simultaneously receives and consumes the benefits of the services provided. Revenue is recognized over time consistent with the transfer of good or service over time to the customer based on daily volumes delivered. Consideration is generally variable, and the transaction price cannot be determined at the inception of the contract, because the volume of natural gas or NGLs for which the service is provided is only specified on a daily or monthly basis. The transaction price is determined at the time the service is provided and the uncertainty is resolved. Customers usually pay monthly based on the services performed that month. Purchase arrangements - Under purchase arrangements, we purchase natural gas at either the wellhead or the tailgate of a plant. These purchase arrangements represent an arrangement with a supplier and are recorded in “Purchases and related costs”. Often, we earn fees for services performed prior to taking control of the product in these arrangements and service revenue is recorded for these fees. Revenue generated from the sale of product obtained in these purchase arrangements are reported as “Sales of natural gas, NGLs and condensate” on the consolidated statements of operations and are recognized on a gross basis as we purchase and take control of the product prior to sale and are the principal in the transaction. Practical expedients - We apply the practical expedients in Topic 606 and do not disclose information about transaction prices allocated to remaining performance obligations that have original expected durations of one year or less, nor do we disclose information about transaction prices allocated to remaining performance obligations if the variable consideration is allocated entirely to a wholly unsatisfied performance obligation. We disaggregate our revenue from contracts with customers by type for each of our reportable segments, as we believe it best depicts the nature, timing and uncertainty of our revenue and cash flows. The following tables set forth our revenue by those categories: Revenue by type was as follows: Three Months Ended June 30, 2018 Gathering and Processing Logistics and Marketing Eliminations Total (millions) Sales of natural gas $ 398 $ 463 $ (353 ) $ 508 Sales of NGLs and condensate (a) 870 1,714 (835 ) 1,749 Transportation, processing and other 112 16 (1 ) 127 Trading and marketing losses, net (c) (66 ) (1 ) — (67 ) Total operating revenues $ 1,314 $ 2,192 $ (1,189 ) $ 2,317 Six Months Ended June 30, 2018 Gathering and Processing Logistics and Marketing Eliminations Total (millions) Sales of natural gas $ 844 $ 1,016 $ (772 ) $ 1,088 Sales of NGLs and condensate (b) 1,610 3,170 (1,542 ) 3,238 Transportation, processing and other 209 30 (1 ) 238 Trading and marketing losses, net (c) (63 ) (45 ) — (108 ) Total operating revenues $ 2,600 $ 4,171 $ (2,315 ) $ 4,456 (a) Includes $1,108 million of revenues from physical sales contracts and buy-sell exchange transactions in our logistics and marketing segment, which are not within the scope of Topic 606. (b) Includes $ 1,901 million of revenues from physical sales contracts and buy-sell exchange transactions in our logistics and marketing segment, which are not within the scope of Topic 606. (c) Not within the scope of Topic 606.
Contract Assets and Liabilities [Text Block]	. Contract Liabilities We have contracts with customers whereby the customer reimburses us for costs to construct certain connections to our operating assets. These agreements are typically entered into in contemplation with gathering and processing agreements and transportation agreements with customers, and are part of the consideration of the contract. Prior to the adoption of Topic 606, we accounted for these arrangements as a reduction to the cost basis of our long-lived assets which were amortized as a reduction to depreciation expense over the estimated useful life of the related assets. Under Topic 606, we record these payments as deferred revenue which will be amortized into revenue over the expected contract term. The noncurrent portion of deferred revenue is included in other long-term liabilities on our condensed consolidated balance sheet. The following table summarizes changes in contract liabilities included in our balance sheet: June 30, 2018 (millions) Balance, beginning of period $ — Cumulative effect of implementation of Topic 606 36 Revenue recognized (a) (1 ) Balance, end of period $ 35 Current contract liabilities — Long-term contract liabilities $ 35 (a) Deferred revenue recognized is included in transportation, processing and other on the condensed consolidated statement of operations. The contract liabilities disclosed in the table above will be recognized as revenue as the obligations are satisfied over the next 35 years as of June 30, 2018 .

Agreements and Transactions wit

Agreements and Transactions with Affiliates	6 Months Ended
	Jun. 30, 2018
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 June 30, Six Months Ended June 30, 2018 2017 2018 2017 (millions) Employee related costs charged by DCP Midstream, LLC Operating and maintenance expense $ 53 $ 49 $ 102 $ 99 General and administrative expense $ 47 $ 39 $ 85 $ 70 Phillips 66 and its Affiliates We sell a portion of our residue gas and NGLs to Phillips 66 and Chevron Phillips Chemical LLC, or CPChem. CPChem is owned 50% by Phillips 66, and is considered a related party . Approximately 18% of our NGL production was committed to Phillips 66 and CPChem as of June 30, 2018 . The primary production commitment on certain contracts began a ratable wind down period in December 2014 which expires in January 2019. We ant icipate continuing to purchase and sell commodities with Phillips 66 and CPChem in the ordinary course of business. Enbridge and its Affiliates We sell NGLs to and purchase NGLs from Enbridge and its affiliates. We anticipate continuing to sell commodities to and purchase commodities from Enbridge and its affiliates in the ordinary course of business. Unconsolidated Affiliates We sell a portion of our residue gas and NGLs to, purchase natural gas and other NGL products from, and provide gathering and transportation services to other unconsolidated affiliates. We anticipate continuing to purchase and sell commodities and provide services to unconsolidated affiliates in the ordinary course of business. Summary of Transactions with Affiliates The following table summarizes our transactions with affiliates: Three Months Ended June 30, Six Months Ended June 30, 2018 2017 2018 2017 (millions) Phillips 66 (including its affiliates): Sales of natural gas, NGLs and condensate to affiliates $ 381 $ 251 $ 683 $ 525 Purchases and related costs from affiliates $ 28 $ 8 $ 38 $ 15 Operating and maintenance and general administrative expenses $ 3 $ — $ 6 $ 1 Enbridge (including its affiliates): Sales of natural gas, NGLs and condensate to affiliates $ 13 $ 15 $ 25 $ 20 Purchases and related costs from affiliates $ 18 $ 11 $ 28 $ 19 Operating and maintenance and general administrative expenses $ — $ — $ — $ 1 Unconsolidated affiliates: Sales of natural gas, NGLs and condensate to affiliates $ 14 $ 12 $ 25 $ 22 Transportation, processing, and other to affiliates $ 2 $ 2 $ 3 $ 3 Purchases and related costs from affiliates $ 179 $ 119 $ 324 $ 232 We had balances with affiliates as follows: June 30, December 31, (millions) Phillips 66 (including its affiliates): Accounts receivable $ 153 $ 156 Accounts payable $ 24 $ 6 Other assets $ 1 $ — Enbridge (including its affiliates): Accounts receivable $ 14 $ 11 Accounts payable $ 21 $ 9 Unconsolidated affiliates: Accounts receivable $ 22 $ 24 Accounts payable $ 67 $ 53 Other assets $ 3 $ 4

Inventories

Inventories	6 Months Ended
	Jun. 30, 2018
Inventory Disclosure [Abstract]
Inventories	Inventories Inventories were as follows: June 30, December 31, (millions) Natural gas $ 18 $ 30 NGLs 29 38 Total inventories $ 47 $ 68 We recognize lower of cost or market adjustments when the carrying value of our inventories exceeds their estimated market value. These non-cash charges are a component of purchases and related costs in the condensed consolidated statements of operations. We recognized no lower of cost or net realizable value adjustments during the three and six months ended June 30, 2018 and June 30, 2017 , respectively.

Property, Plant and Equipment

Property, Plant and Equipment	6 Months Ended
	Jun. 30, 2018
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 June 30, December 31, (millions) Gathering and transmission systems 20 — 50 Years $ 8,599 $ 8,473 Processing, storage and terminal facilities 35 — 60 Years 5,141 5,128 Other 3 — 30 Years 563 557 Construction work in progress 520 374 Property, plant and equipment 14,823 14,532 Accumulated depreciation (5,743 ) (5,549 ) Property, plant and equipment, net $ 9,080 $ 8,983 Interest capitalized on construction projects was $6 million and $1 million for the three months ended June 30, 2018 and 2017 , respectively, and $11 million and $2 million for the six months ended June 30, 2018 and 2017 , respectively. Depreciation expense was $94 million and $90 million for the three months ended June 30, 2018 and 2017 , respectively, and $186 million and $182 million for the six months ended June 30, 2018 and 2017 , respectively.

Investments in Unconsolidated A

Investments in Unconsolidated Affiliates	6 Months Ended
	Jun. 30, 2018
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 June 30, December 31, (millions) DCP Sand Hills Pipeline, LLC 66.67% $ 1,730 $ 1,633 DCP Southern Hills Pipeline, LLC 66.67% 735 739 Discovery Producer Services LLC 40.00% 354 362 Front Range Pipeline LLC 33.33% 163 165 Texas Express Pipeline LLC 10.00% 91 90 Gulf Coast Express Pipeline LLC 25.00% 28 — Mont Belvieu Enterprise Fractionator 12.50% 25 23 Panola Pipeline Company, LLC 15.00% 23 24 Mont Belvieu 1 Fractionator 20.00% 12 10 Other Various 4 4 Total investments in unconsolidated affiliates $ 3,165 $ 3,050 Earnings from investments in unconsolidated affiliates were as follows: Three Months Ended June 30, Six Months Ended June 30, 2018 2017 2018 2017 (millions) DCP Sand Hills Pipeline, LLC $ 58 $ 37 $ 106 $ 68 DCP Southern Hills Pipeline, LLC 16 13 29 24 Discovery Producer Services LLC 2 25 3 45 Front Range Pipeline LLC 5 3 10 7 Texas Express Pipeline LLC 8 1 10 3 Mont Belvieu Enterprise Fractionator 3 4 7 7 Mont Belvieu 1 Fractionator 4 3 8 4 Other — — 1 2 Total earnings from unconsolidated affiliates $ 96 $ 86 $ 174 $ 160 The following tables summarize the combined financial information of our investments in unconsolidated affiliates: Three Months Ended June 30, Six Months Ended June 30, 2018 2017 2018 2017 (millions) Statements of operations: (a) Operating revenue $ 408 $ 368 $ 742 $ 705 Operating expenses $ 147 $ 152 $ 286 $ 300 Net income $ 260 $ 216 $ 454 $ 404 June 30, December 31, (millions) Balance sheets: (a) Current assets $ 379 $ 244 Long-term assets 5,596 5,319 Current liabilities (256 ) (196 ) Long-term liabilities (227 ) (200 ) Net assets $ 5,492 $ 5,167 (a) In accordance with the Gulf Coast Express Pipeline LLC ("GCX") joint venture agreement, earnings do not accrue to our interest until the construction of the pipeline is complete. Accordingly, we will not include activity related to GCX in the above tables until the period in which the construction is complete and earnings accrue to our interest.

Fair Value Measurement

Fair Value Measurement	6 Months Ended
	Jun. 30, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurement	Fair Value Measurement Determination of Fair Value Below is a general description of our valuation methodologies for derivative financial assets and liabilities which are measured at fair value. Fair values are generally based upon quoted market prices or prices obtained through external sources, where available. If listed market prices or quotes are not available, we determine fair value based upon a market quote, adjusted by other market-based or independently sourced market data such as historical commodity volatilities, crude oil future yield curves, and/or counterparty specific considerations. These adjustments result in a fair value for each asset or liability under an “exit price” methodology, in line with how we believe a marketplace participant would value that asset or liability. Fair values are adjusted to reflect the credit risk inherent in the transaction as well as the potential impact of liquidating open positions in an orderly manner over a reasonable time period under current conditions. These adjustments may include amounts to reflect counterparty credit quality, the effect of our own creditworthiness, and/or the liquidity of the market. • Counterparty credit valuation adjustments are necessary when the market price of an instrument is not indicative of the fair value as a result of the credit quality of the counterparty. Generally, market quotes assume that all counterparties have near zero, or low, default rates and have equal credit quality. Therefore, an adjustment may be necessary to reflect the credit quality of a specific counterparty to determine the fair value of the instrument. We record counterparty credit valuation adjustments on all derivatives that are in a net asset position as of the measurement date in accordance with our established counterparty credit policy, which takes into account any collateral margin that a counterparty may have posted with us as well as any letters of credit that they have provided. • Entity valuation adjustments are necessary to reflect the effect of our own credit quality on the fair value of our net liability positions with each counterparty. This adjustment takes into account any credit enhancements, such as collateral margin we may have posted with a counterparty, as well as any letters of credit that we have provided. The methodology to determine this adjustment is consistent with how we evaluate counterparty credit risk, taking into account our own credit rating, current credit spreads, as well as any change in such spreads since the last measurement date. • Liquidity valuation adjustments are necessary when we are not able to observe a recent market price for financial instruments that trade in less active markets for the fair value to reflect the cost of exiting the position. Exchange traded contracts are valued at market value without making any additional valuation adjustments and, therefore, no liquidity reserve is applied. For contracts other than exchange traded instruments, we mark our positions to the midpoint of the bid/ask spread, and record a liquidity reserve based upon our total net position. We believe that such practice results in the most reliable fair value measurement as viewed by a market participant. We manage our derivative instruments on a portfolio basis and the valuation adjustments described above are calculated on this basis. We believe that the portfolio level approach represents the highest and best use for these assets as there are benefits inherent in naturally offsetting positions within the portfolio at any given time, and this approach is consistent with how a market participant would view and value the assets and liabilities. Although we take a portfolio approach to managing these assets/liabilities, in order to reflect the fair value of any one individual contract within the portfolio, we allocate all valuation adjustments down to the contract level, to the extent deemed necessary, based upon either the notional contract volume, or the contract value, whichever is more applicable. The methods described above may produce a fair value calculation that may not be indicative of net realizable value or reflective of future fair values. While we believe that our valuation methods are appropriate and consistent with other market participants, we recognize that the use of different methodologies or assumptions to determine the fair value of certain financial instruments could result in a different estimate of fair value at the reporting date. We review our fair value policies on a regular basis taking into consideration changes in the marketplace and, if necessary, will adjust our policies accordingly. See Note 11 - Risk Management and Hedging Activities. Valuation Hierarchy Our fair value measurements are grouped into a three-level valuation hierarchy and are categorized in their entirety in the same level of the fair value hierarchy as the lowest level input that is significant to the entire measurement. The valuation hierarchy is based upon the transparency of inputs to the valuation of an asset or liability as of the measurement date. The three levels are defined as follows. • Level 1 — inputs are unadjusted quoted prices for identical assets or liabilities in active markets. • Level 2 — inputs include quoted prices for similar assets and liabilities in active markets, and inputs that are observable for the asset or liability, either directly or indirectly, for substantially the full term of the financial instrument. • Level 3 — inputs are unobservable and considered significant to the fair value measurement. A financial instrument’s categorization within the hierarchy is based upon the level of judgment involved in the most significant input in the determination of the instrument’s fair value. Following is a description of the valuation methodologies used as well as the general classification of such instruments pursuant to the hierarchy. Commodity Derivative Assets and Liabilities We enter into a variety of derivative financial instruments, which may include exchange traded instruments (such as New York Mercantile Exchange, or NYMEX, crude oil or natural gas futures) or over-the-counter, or OTC, instruments (such as natural gas contracts, crude oil or NGL swaps). The exchange traded instruments are generally executed with a highly rated broker dealer serving as the clearinghouse for individual transactions. Our activities expose us to varying degrees of commodity price risk. To mitigate a portion of this risk and to manage commodity price risk related primarily to owned natural gas storage and pipeline assets, we engage in natural gas asset based trading and marketing, and we may enter into natural gas and crude oil derivatives to lock in a specific margin when market conditions are favorable. A portion of this may be accomplished through the use of exchange traded derivative contracts. Such instruments are generally classified as Level 1 since the value is equal to the quoted market price of the exchange traded instrument as of our balance sheet date, and no adjustments are required. Depending upon market conditions and our strategy we may enter into exchange traded derivative positions with a significant time horizon to maturity. Although such instruments are exchange traded, market prices may only be readily observable for a portion of the duration of the instrument. In order to calculate the fair value of these instruments, readily observable market information is utilized to the extent it is available; however, in the event that readily observable market data is not available, we may interpolate or extrapolate based upon observable data. In instances where we utilize an interpolated or extrapolated value, and it is considered significant to the valuation of the contract as a whole, we would classify the instrument within Level 3. We also engage in the business of trading energy related products and services, which exposes us to market variables and commodity price risk. We may enter into physical contracts or financial instruments with the objective of realizing a positive margin from the purchase and sale of these commodity-based instruments. We may enter into derivative instruments for NGLs or other energy related products, primarily using the OTC derivative instrument markets, which are not as active and liquid as exchange traded instruments. Market quotes for such contracts may only be available for short dated positions (up to six months), and an active market itself may not exist beyond such time horizon. Contracts entered into with a relatively short time horizon for which prices are readily observable in the OTC market are generally classified within Level 2. Contracts with a longer time horizon, for which we internally generate a forward curve to value such instruments, are generally classified within Level 3. The internally generated curve may utilize a variety of assumptions including, but not limited to, data obtained from third-party pricing services, historical and future expected relationship of NGL prices to crude oil prices, the knowledge of expected supply sources coming online, expected weather trends within certain regions of the United States, and the future expected demand for NGLs. Each instrument is assigned to a level within the hierarchy at the end of each financial quarter depending upon the extent to which the valuation inputs are observable. Generally, an instrument will move toward a level within the hierarchy that requires a lower degree of judgment as the time to maturity approaches, and as the markets in which the asset trades will likely become more liquid and prices more readily available in the market, thus reducing the need to rely upon our internally developed assumptions. However, the level of a given instrument may change, in either direction, depending upon market conditions and the availability of market observable data. Nonfinancial Assets and Liabilities We utilize fair value to perform impairment tests as required on our property, plant and equipment, goodwill, equity investments, and other long-lived intangible assets. Assets and liabilities acquired in third party business combinations are recorded at their fair value as of the date of acquisition. The inputs used to determine such fair value are primarily based upon internally developed cash flow models and would generally be classified within Level 3 in the event that we were required to measure and record such assets at fair value within our condensed consolidated financial statements. Additionally, we use fair value to determine the inception value of our asset retirement obligations. The inputs used to determine such fair value are primarily based upon costs incurred historically for similar work, as well as estimates from independent third parties for costs that would be incurred to restore leased property to the contractually stipulated condition, and would generally be classified within Level 3. The following table presents the financial instruments carried at fair value as of June 30, 2018 and December 31, 2017 , by condensed consolidated balance sheet caption and by valuation hierarchy, as described above: June 30, 2018 December 31, 2017 Level 1 Level 2 Level 3 Total Carrying Value Level 1 Level 2 Level 3 Total Carrying Value (millions) Current assets: Commodity derivatives (a) $ 36 $ 8 $ 1 $ 45 $ 10 $ 17 $ 3 $ 30 Short-term investments (b) $ 3 $ — $ — $ 3 $ 156 $ — $ — $ 156 Long-term assets: Commodity derivatives (c) $ 6 $ 1 $ 1 $ 8 $ 1 $ 1 $ 1 $ 3 Current liabilities: Commodity derivatives (d) $ (77 ) $ (54 ) $ (10 ) $ (141 ) $ (29 ) $ (34 ) $ (13 ) $ (76 ) Long-term liabilities: Commodity derivatives (e) $ (12 ) $ (10 ) $ (7 ) $ (29 ) $ (3 ) $ (11 ) $ (1 ) $ (15 ) (a) Included in current unrealized gains on derivative instruments in our condensed consolidated balance sheets. (b) Includes short-term money market securities included in cash and cash equivalents in our condensed consolidated balance sheets. (c) Included in long-term unrealized gains on derivative instruments in our condensed consolidated balance sheets. (d) Included in current unrealized losses on derivative instruments in our condensed consolidated balance sheets. (e) Included in long-term unrealized losses on derivative instruments in our condensed consolidated balance sheets. Changes in Levels 1 and 2 Fair Value Measurements The determination to classify a financial instrument within Level 1 or Level 2 is based upon the availability of quoted prices for identical or similar assets and liabilities in active markets. Depending upon the information readily observable in the market, and/or the use of identical or similar quoted prices, which are significant to the overall valuation, the classification of any individual financial instrument may differ from one measurement date to the next. To qualify as a transfer, the asset or liability must have existed in the previous reporting period and moved into a different level during the current period. In the event that there is a movement between the classification of an instrument as Level 1 or 2, the transfer would be reflected in a table as “Transfers into or out of Level 1 and Level 2”. During the six months ended June 30, 2018 and 2017 , there were no transfers between Level 1 and Level 2 of the fair value hierarchy. Changes in Level 3 Fair Value Measurements The tables below illustrate a rollforward of the amounts included in our condensed consolidated balance sheets for derivative financial instruments that we have classified within Level 3. Since financial instruments classified as Level 3 typically include a combination of observable components (that is, components that are actively quoted and can be validated to external sources) and unobservable components, the gains and losses in the table below may include changes in fair value due in part to observable market factors, or changes to our assumptions on the unobservable components. Depending upon the information readily observable in the market, and/or the use of unobservable inputs, which are significant to the overall valuation, the classification of any individual financial instrument may differ from one measurement date to the next. The significant unobservable inputs used in determining fair value include adjustments by other market-based or independently sourced market data such as historical commodity volatilities, crude oil future yield curves, and/or counterparty specific considerations. In the event that there is a movement to/from the classification of an instrument as Level 3, we would reflect such items in the table below within the “Transfers into/out of Level 3” captions. We manage our overall risk at the portfolio level and in the execution of our strategy, we may use a combination of financial instruments, which may be classified within any level. Since Level 1 and Level 2 risk management instruments are not included in the rollforward below, the gains or losses in the table do not reflect the effect of our total risk management activities. Commodity Derivative Instruments Current Long-Term Current Long-Term (millions) Three months ended June 30, 2018 (a): Beginning balance $ 2 $ — $ (6 ) $ (3 ) Net unrealized gains (losses) included in earnings (b) 1 1 (14 ) (4 ) Transfers out of Level 3 (c) (2 ) — 8 — Settlements — — 2 — Ending balance $ 1 $ 1 $ (10 ) $ (7 ) Net unrealized gains (losses) on derivatives still held included in earnings (b) $ 1 $ 1 $ (8 ) $ (4 ) Three months ended June 30, 2017 (a): Beginning balance $ 8 $ 2 $ (8 ) $ (3 ) Net unrealized gains included in earnings (b) 3 — 1 — Transfers out of Level 3 (c) (3 ) — 3 — Settlements (1 ) — 2 — Ending balance $ 7 $ 2 $ (2 ) $ (3 ) Net unrealized gains on derivatives still held included in earnings (b) $ 4 $ — $ — $ — Commodity Derivative Instruments Current Long-Term Current Long-Term (millions) Six months ended June 30, 2018 (a): Beginning balance $ 3 $ 1 $ (13 ) $ (1 ) Net unrealized losses included in earnings (b) — — (12 ) (6 ) Transfers out of Level 3 (c) (2 ) — 12 — Settlements — — 3 — Ending balance $ 1 $ 1 $ (10 ) $ (7 ) Net unrealized gains (losses) on derivatives still held included in earnings (b) $ 1 $ — $ (7 ) $ (6 ) Six months ended June 30, 2017 (a): Beginning balance $ 9 $ 5 $ (23 ) $ — Net unrealized gains (losses) included in earnings (b) 1 (3 ) 13 (3 ) Transfers out of Level 3 (c) (2 ) — 3 — Settlements (1 ) — 5 — Ending balance $ 7 $ 2 $ (2 ) $ (3 ) Net unrealized gains (losses) on derivatives still held included in earnings (b) $ 6 $ (2 ) $ 3 $ (3 ) (a) There were no purchases, issuances or sales of derivatives or transfers into Level 3 for the three and six months ended June 30, 2018 and 2017 . (b) Represents the amount of unrealized gains or losses for the period, included in trading and marketing gains (losses), net. (c) Amounts transferred out of Level 3 are reflected at fair value at the end of the period. Quantitative Information and Fair Value Sensitivities Related to Level 3 Unobservable Inputs We utilize the market approach to measure the fair value of our commodity contracts. The significant unobservable inputs used in this approach to fair value are longer dated price quotes. Our sensitivity to these longer dated forward curve prices are presented in the table below. Significant changes in any of those inputs in isolation would result in significantly different fair value measurements, depending on our short or long position in contracts. June 30, 2018 Product Group Fair Value Forward Curve Range (millions) Assets NGLs $ 2 $0.29-$1.08 Per gallon Liabilities NGLs $ (12 ) $0.14-$1.49 Per gallon Natural gas $ (5 ) $1.57-$2.66 Per MMBtu Estimated Fair Value of Financial Instruments Valuation of a contract’s fair value is validated by an internal group independent of the marketing group. While common industry practices are used to develop valuation techniques, changes in pricing methodologies or the underlying assumptions could result in significantly different fair values and income recognition. When available, quoted market prices or prices obtained through external sources are used to determine a contract’s fair value. For contracts with a delivery location or duration for which quoted market prices are not available, fair value is determined based on pricing models developed primarily from historical and expected relationships with quoted market prices. Values are adjusted to reflect the credit risk inherent in the transaction as well as the potential impact of liquidating open positions in an orderly manner over a reasonable time period under current conditions. Changes in market prices and management estimates directly affect the estimated fair value of these contracts. Accordingly, it is reasonably possible that such estimates may change in the near term. The fair value of our interest rate swaps, if any, and commodity non-trading derivatives is based on prices supported by quoted market prices and other external sources and prices based on models and other valuation methods. The “prices supported by quoted market prices and other external sources” category includes our interest rate swaps, if any, our NGL and crude oil swaps and our NYMEX positions in natural gas. In addition, this category includes our forward positions in natural gas for which our forward price curves are obtained from a third party pricing service and then validated through an internal process which includes the use of independent broker quotes. This category also includes our forward positions in NGLs at points for which OTC broker quotes for similar assets or liabilities are available for the full term of the instrument. This category also includes “strip” transactions whose pricing inputs are directly or indirectly observable from external sources and then modeled to daily or monthly prices as appropriate. The “prices based on models and other valuation methods” category includes the value of transactions for which inputs to the fair value of the instrument are unobservable in the marketplace and are considered significant to the overall fair value of the instrument. The fair value of these instruments may be based upon an internally developed price curve, which was constructed as a result of the long dated nature of the transaction or the illiquidity of the specific market point. We have determined fair value amounts using available market information and appropriate valuation methodologies. However, considerable judgment is required in interpreting market data to develop the estimates of fair value. Accordingly, the estimates presented herein are not necessarily indicative of the amounts that we could realize in a current market exchange. The use of different market assumptions and/or estimation methods may have a material effect on the estimated fair value amounts. The fair value of accounts receivable, accounts payable and short-term borrowings 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. We determine the fair value of borrowings under our Credit Agreement based upon the discounted present value of expected future cash flows, taking into account the difference between the contractual borrowing spread and the spread for similar credit facilities available in the marketplace. We classify the fair values of our outstanding debt balances within Level 2 of the valuation hierarchy. As of June 30, 2018 and December 31, 2017 , the carrying value and fair value of our total debt, including current maturities, were as follows: June 30, 2018 December 31, 2017 Carrying Value (a) Fair Value Carrying Value (a) Fair Value (millions) Total debt $ 4,861 $ 4,896 $ 4,736 $ 4,885 (a) Excludes unamortized issuance costs.

Debt

Debt	6 Months Ended
	Jun. 30, 2018
Debt Disclosure [Abstract]
Debt	Debt June 30, December 31, (millions) Senior notes: Issued February 2009, interest at 9.750% payable semiannually, due March 2019 (a) $ 450 $ 450 Issued March 2014, interest at 2.700% payable semi-annually, due April 2019 325 325 Issued March 2010, interest at 5.350% payable semiannually, due March 2020 (a) 600 600 Issued September 2011, interest at 4.750% payable semiannually, due September 2021 500 500 Issued March 2012, interest at 4.950% payable semi-annually, due April 2022 350 350 Issued March 2013, interest at 3.875% payable semi-annually, due March 2023 500 500 Issued August 2000, interest at 8.125% payable semi-annually, due August 2030 (a) 300 300 Issued October 2006, interest at 6.450% payable semi-annually, due November 2036 300 300 Issued September 2007, interest at 6.750% payable semi-annually, due September 2037 450 450 Issued March 2014, interest at 5.600% payable semi-annually, due April 2044 400 400 Junior subordinated notes: Issued May 2013, interest at 5.850% payable semi-annually, due May 2043 550 550 Credit agreement: Revolving credit facility, weighted-average variable interest rate of 3.452%, as of June 30, 2018, due December 2022 125 — Fair value adjustments related to interest rate swap fair value hedges (a) 22 23 Unamortized issuance costs (26 ) (29 ) Unamortized discount (11 ) (12 ) Total debt 4,835 4,707 Current maturities of long-term debt 325 — Total long-term debt $ 4,510 $ 4,707 (a) The swaps associated with this debt were previously terminated. The remaining long-term fair value of approximately $22 million related to the swaps is being amortized as a reduction to interest expense through 2019, 2020 and 2030, the original maturity dates of the debt. Credit Agreement We are a party to a $ 1.4 billion unsecured revolving Credit Agreement which matures on December 6, 2022 . The Credit Agreement also grants us the option to increase the revolving loan commitment by an aggregate principal amount of up to $500 million , subject to requisite lender approval. The Credit Agreement may be extended for up to two additional one-year periods subject to requisite lender approval. Loans under the Credit Agreement may be used for working capital and other general partnership purposes including acquisitions. The Credit Agreement allows for unrestricted cash and cash equivalents to be netted against consolidated indebtedness for purposes of calculating the Partnership’s Consolidated Leverage Ratio (as defined in the Credit Agreement). Additionally, under the Credit Agreement, the Consolidated Leverage Ratio of the Partnership as of the end of any fiscal quarter shall not exceed: (a) 5.25 to 1.0 for the fiscal quarter ending June 30, 2018, and (b) 5.00 to 1.0 for each fiscal quarter ending thereafter; provided that, if there is a Qualified Acquisition (as defined in the Credit Agreement) during any fiscal quarter ending June 30, 2018 or thereafter, the maximum Consolidated Leverage Ratio shall not exceed 5.50 to 1.0 at the end of the three consecutive fiscal quarters, including the fiscal quarter in which the Qualified Acquisition occurs. Our cost of borrowing under the Credit Agreement is determined by a ratings-based pricing grid. Indebtedness under the Credit Agreement bears interest at either: (1) LIBOR, plus an applicable margin of 1.45% based on our current credit rating; or (2) (a) the base rate which shall be the higher of the prime rate, the Federal Funds rate plus 0.50% or the LIBOR Market Index rate plus 1% , plus (b) an applicable margin of 0.45% based on our current credit rating. The Credit Agreement incurs an annual facility fee of 0.30% based on our current credit rating. This fee is paid on drawn and undrawn portions of the $1.4 billion revolving credit facility. As of June 30, 2018 , we had unused borrowing capacity of $1,250 million , net of $25 million of letters of credit, under the Credit Agreement. Our borrowing capacity may be limited by financial covenants set forth in the Credit Agreement. The financial covenants set forth in the Credit Agreement limit the Partnership's ability to incur incremental debt by the unused borrowing capacity of $1,250 million as of June 30, 2018 . Except in the case of a default, amounts borrowed under our Credit Agreement will not become due prior to the December 6, 2022 maturity date. Senior Notes and Junior Subordinated Notes Our senior notes and junior subordinated notes, collectively referred to as our debt securities, mature and become payable on their respective due dates, and are not subject to any sinking fund or mandatory redemption provisions. The senior notes are senior unsecured obligations that are guaranteed by the Partnership and rank equally in a right of payment with our other senior unsecured indebtedness, including indebtedness under our Credit Agreement, and the junior subordinated notes are unsecured and rank subordinate in right of payment to all of our existing and future senior indebtedness. The debt securities include an optional redemption whereby we may elect to redeem the notes, in whole or in part from time-to-time for a premium. Additionally, we may defer the payment of all or part of the interest on the junior subordinated notes for one or more periods up to five consecutive years. The underwriters’ fees and related expenses are recorded in our condensed consolidated balance sheets within the carrying amount of long-term debt and will be amortized over the term of the notes. The maturities of our long-term debt as of June 30, 2018 are as follows: Debt Maturities (millions) 2018 $ — 2019 775 2020 600 2021 500 2022 475 Thereafter 2,500 Total long-term debt $ 4,850

Risk Management and Hedging Act

Risk Management and Hedging Activities	6 Months Ended
	Jun. 30, 2018
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, or the Risk Management Committee, to monitor and manage market risks associated with commodity prices and counterparty credit. The Risk Management Committee is composed of senior executives who receive regular briefings on positions and exposures, credit exposures and overall risk management in the context of market activities. The Risk Management Committee is responsible for the overall management of credit risk and commodity price risk, including monitoring exposure limits. The following describes each of the risks that we manage. Commodity Price Risk Our portfolio of commodity derivative activity is primarily accounted for using the mark-to-market method of accounting; however, depending upon our risk profile and objectives, in certain limited cases, we may execute transactions that qualify for the hedge method of accounting. The risks, strategies and instruments used to mitigate such risks, as well as the method of accounting are discussed and summarized below. Natural Gas Asset Based Trading and Marketing Our natural gas storage and pipeline assets are exposed to certain risks including changes in commodity prices. We manage commodity price risk related to our natural gas storage and pipeline assets through our commodity derivative program. The commercial activities related to our natural gas storage and pipeline assets primarily consist of the purchase and sale of gas and associated time spreads and basis spreads. A time spread transaction is executed by establishing a long gas position at one point in time and establishing an equal short gas position at a different point in time. Time spread transactions allow us to lock in a margin supported by the injection, withdrawal, and storage capacity of our natural gas storage assets. We may execute basis spread transactions to mitigate the risk of sale and purchase price differentials across our system. A basis spread transaction allows us to lock in a margin on our physical purchases and sales of gas, including injections and withdrawals from storage. We typically use swaps to execute these transactions, which are not designated as hedging instruments and are recorded at fair value with changes in fair value recorded in the current period condensed consolidated statements of operations. While gas held in our storage locations is recorded at the lower of average cost or market, the derivative instruments that are used to manage our storage facilities are recorded at fair value and any changes in fair value are currently recorded in our condensed consolidated statements of operations. Even though we may have economically hedged our exposure and locked in a future margin, the use of lower-of-cost-or-market accounting for our physical inventory and the use of mark-to-market accounting for our derivative instruments may subject our earnings to market volatility. Commodity Cash Flow Hedges In order for our natural gas storage facility to remain operational, a minimum level of base gas must be maintained in each storage cavern, which is capitalized on our condensed consolidated balance sheets as a component of property, plant and equipment, net. During construction or expansion of our storage caverns, we may execute a series of derivative financial instruments to mitigate a portion of the risk associated with the forecasted purchase of natural gas when we bring the storage caverns into operation. These derivative financial instruments may be designated as cash flow hedges. While the cash paid upon settlement of these hedges economically fixes the cash required to purchase base gas, the deferred losses or gains would remain in accumulated other comprehensive income, or AOCI, until the cavern is emptied and the base gas is sold. The balance in AOCI of our previously settled base gas cash flow hedges was in a loss position of $6 million as of June 30, 2018 . Commodity Cash Flow Protection Activities We are exposed to the impact of market fluctuations in the prices of natural gas, NGLs and condensate as a result of our gathering, processing, sales and storage activities. For gathering, processing and storage services, we may receive cash or commodities as payment for these services, depending on the contract type. We may enter into derivative financial instruments to mitigate a portion of the risk of weakening natural gas, NGL and condensate prices associated with our gathering, processing and sales activities, thereby stabilizing our cash flows. Our derivative financial instruments used to mitigate a portion of the risk of weakening natural gas, NGL and condensate prices extend through the first quarter of 2020. The commodity derivative instruments used for our hedging programs are a combination of direct NGL product, crude oil and natural gas hedges. Crude oil and NGL transactions are primarily accomplished through the use of forward contracts that effectively exchange floating price risk for a fixed price. The type of instrument used to mitigate a portion of the risk may vary depending on our risk management objectives. These transactions are not designated as hedging instruments for accounting purposes and the change in fair value is reflected in the current period within our condensed consolidated statements of operations as trading and marketing gains and (losses), net. NGL Proprietary Trading Our NGL proprietary trading activity includes trading energy related products and services. We undertake these activities through the use of fixed forward sales and purchases, basis and spread trades, storage opportunities, put/call options, term contracts and spot market trading. These energy trading operations are exposed to market variables and commodity price risk with respect to these products and services, and these operations may enter into physical contracts and financial instruments with the objective of realizing a positive margin from the purchase and sale of commodity-based instruments. These physical and financial instruments are not designated as hedging instruments and are recorded at fair value with changes in fair value recorded in the current period condensed consolidated statements of operations. We employ established risk limits, policies and procedures to manage risks associated with our natural gas asset based trading and marketing and NGL proprietary trading. Credit Risk Our principal customers range from large, natural gas marketers to industrial end-users for our natural gas products and services, as well as large multi-national petrochemical and refining companies, to small regional propane distributors for our NGL products and services. Substantially all of our natural gas and NGL sales are made at market-based prices. Approximately 18% of our NGL production was committed to Phillips 66 and CPChem as of June 30, 2018 . This concentration of credit risk may affect our overall credit risk, in that these customers may be similarly affected by changes in economic, regulatory or other factors. Where exposed to credit risk, we analyze the counterparties’ financial condition prior to entering into an agreement, establish credit limits and monitor the appropriateness of these limits on an ongoing basis. We may use various master agreements that include language giving us the right to request collateral to mitigate credit exposure. The collateral language provides for a counterparty to po st cash or letters of credit for exposure in excess of the established threshold. The threshold amount represents an open credit limit, determined in accordance with o ur credit policy. The collateral language also provides that the inability to post collateral is sufficient cause to terminate a contract and liquidate all positions. In addition, our master agreements and our standard gas and NGL sales contracts contain adequate assurance provisions, which allow us to suspend deliveries and cancel agreements, or continue deliveries to the buyer after the buyer provides acceptable security for payment . Contingent Credit Features Each of the above risks is managed through the execution of individual contracts with a variety of counterparties. Certain of our derivative contracts may contain credit-risk related contingent provisions that may require us to take certain actions in certain circumstances. We have International Swaps and Derivatives Association, or ISDA, contracts which are standardized master legal arrangements that establish key terms and conditions which govern certain derivative transactions. These ISDA contracts contain standard credit-risk related contingent provisions. Some of the provisions we are subject to are outlined below. • If we were to have an effective event of default under our Credit Agreement that occurs and is continuing, our ISDA counterparties may have the right to request early termination and net settlement of any outstanding derivative liability positions. • Our ISDA counterparties generally have collateral thresholds of zero, requiring us to fully collateralize any commodity contracts in a net liability position, when our credit rating is below investment grade. • Additionally, in some cases, our ISDA contracts contain cross-default provisions that could constitute a credit-risk related contingent feature. These provisions apply if we default in making timely payments under other credit arrangements and the amount of the default is above certain predefined thresholds, which are significantly high and are generally consistent with the terms of our Credit Agreement. As of June 30, 2018 , we were not a party to any agreements that would trigger the cross-default provisions. Our commodity derivative contracts that are not governed by ISDA contracts do not have any credit-risk related contingent features. Depending upon the movement of commodity prices and interest rates, each of our individual contracts with counterparties to our commodity derivative instruments or interest rate swap instruments are in either a net asset or net liability position. As of June 30, 2018, we had less than $1 million of individual commodity derivative contracts that contain credit-risk related contingent features that were in a net liability position. If we were required to net settle our position with an individual counterparty, due to a credit-risk related event, our ISDA contracts may permit us to net all outstanding contracts with that counterparty, whether in a net asset or net liability position, as well as any cash collateral already posted. As of June 30, 2018, we have not been required to post additional collateral. Collateral As of June 30, 2018 , we had cash deposits of $138 million , included in collateral cash deposits in our condensed consolidated balance sheets, and letters of credit of $13 million with counterparties to secure our obligations to provide future services or to perform under financial contracts. Additionally, as of June 30, 2018 , we held cash of $6 million , included in other current liabilities in our condensed consolidated balance sheet, related to cash postings by third parties and letters of credit of $43 million from counterparties to secure their future performance under financial or physical contracts. Collateral amounts held or posted may be fixed or may vary, depending on the value of the underlying contracts, and could cover normal purchases and sales, services, trading and hedging contracts. In many cases, we and our counterparties have publicly disclosed credit ratings, which may impact the amounts of collateral requirements. Physical forward contracts and financial derivatives are generally cash settled at the expiration of the contract term. These transactions are generally subject to specific credit provisions within the contracts that would allow the seller, at its discretion, to suspend deliveries, cancel agreements or continue deliveries to the buyer after the buyer provides security for payment satisfactory to the seller . Offsetting Certain of our derivative instruments are subject to a master netting or similar arrangement, whereby we may elect to settle multiple positions with an individual counterparty through a single net payment. Each of our individual derivative instruments are presented on a gross basis on the condensed consolidated balance sheets, regardless of our ability to net settle our positions. Instruments that are governed by agreements that include net settle provisions allow final settlement, when presented with a termination event, of outstanding amounts by extinguishing the mutual debts owed between the parties in exchange for a net amount due. We have trade receivables and payables associated with derivative instruments, subject to master netting or similar agreements, which are not included in the table below. The following summarizes the gross and net amounts of our derivative instruments: June 30, 2018 December 31, 2017 Gross Amounts Amounts Not Net Gross Amounts Amounts Not Net (millions) Assets: Commodity derivatives $ 53 $ — $ 53 $ 33 $ — $ 33 Liabilities: Commodity derivatives $ (170 ) $ — $ (170 ) $ (91 ) $ — $ (91 ) Summarized Derivative Information The fair value of our derivative instruments that are marked-to-market each period, as well as the location of each within our condensed consolidated balance sheets, by major category, is summarized below. We have no derivative instruments that are designated as hedging instruments for accounting purposes as of June 30, 2018 and December 31, 2017 . Balance Sheet Line Item June 30, December 31, Balance Sheet Line Item June 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 $ 45 $ 30 Unrealized losses on derivative instruments — current $ (141 ) $ (76 ) Unrealized gains on derivative instruments — long-term 8 3 Unrealized losses on derivative instruments — long-term (29 ) (15 ) Total $ 53 $ 33 Total $ (170 ) $ (91 ) The following summarizes the balance and activity within AOCI relative to our interest rate, commodity and foreign currency cash flow hedges as of and for the three months ended June 30, 2018 : Interest Commodity Foreign Total (millions) Net deferred (losses) gains in AOCI (beginning balance) $ (4 ) $ (6 ) $ 1 $ (9 ) Losses reclassified from AOCI to earnings — effective portion 1 — — 1 Net deferred (losses) gains in AOCI (ending balance) $ (3 ) $ (6 ) $ 1 $ (8 ) Deferred losses in AOCI expected to be reclassified into earnings over the next 12 months $ (1 ) $ — $ — $ (1 ) The following summarizes the balance and activity within AOCI relative to our interest rate, commodity and foreign currency cash flow hedges as of and for the six months ended June 30, 2018 : Interest Commodity Foreign Total (millions) Net deferred (losses) gains in AOCI (beginning balance) $ (4 ) $ (6 ) $ 1 $ (9 ) Losses reclassified from AOCI to earnings — effective portion 1 — — 1 Net deferred (losses) gains in AOCI (ending balance) $ (3 ) $ (6 ) $ 1 $ (8 ) Deferred losses in AOCI expected to be reclassified into earnings over the next 12 months $ (1 ) $ — $ — $ (1 ) (a) Relates to Discovery Producer Services LLC ("Discovery"), an unconsolidated affiliate. The following summarizes the balance and activity within AOCI relative to our interest rate, commodity and foreign currency cash flow hedges as of and for the three months ended June 30, 2017 : Interest Commodity Foreign Total (millions) Net deferred (losses) gains in AOCI (beginning balance) $ (4 ) $ (6 ) $ 1 $ (9 ) Net deferred (losses) gains in AOCI (ending balance) $ (4 ) $ (6 ) $ 1 $ (9 ) The following summarizes the balance and activity within AOCI relative to our interest rate, commodity and foreign currency cash flow hedges as of and for the six months ended June 30, 2017 : Interest Commodity Foreign Total (millions) Net deferred (losses) gains in AOCI (beginning balance) $ (3 ) $ (6 ) $ 1 $ (8 ) Losses reclassified from AOCI to earnings — effective portion 1 — — 1 Deficit purchase price under carrying value (2 ) — — (2 ) Net deferred (losses) gains in AOCI (ending balance) $ (4 ) $ (6 ) $ 1 $ (9 ) (a) Relates to Discovery, an unconsolidated affiliate. For the three and six months ended June 30, 2018 and 2017 , no derivative losses attributable to the ineffective portion or to amounts excluded from effectiveness testing were recognized in trading and marketing gains or losses, net or interest expense in our condensed consolidated statements of operations. For the three and six months ended June 30, 2018 and 2017 , no derivative losses were reclassified from AOCI to trading and marketing gains or losses, net or interest expense as a result of the discontinuance of cash flow hedges related to certain forecasted transactions that are not probable of occurring. Changes in the value of derivative instruments, for which the hedge method of accounting has not been elected from one period to the next, are recorded in the condensed consolidated statements of operations. The following summarizes these amounts and the location within the condensed consolidated statements of operations that such amounts are reflected: Commodity Derivatives: Statements of Operations Line Item Three Months Ended June 30, Six Months Ended June 30, 2018 2017 2018 2017 (millions) Realized losses $ (30 ) $ (2 ) $ (42 ) $ (7 ) Unrealized (losses) gains (37 ) 24 (66 ) 60 Trading and marketing (losses) gains, net $ (67 ) $ 22 $ (108 ) $ 53 We do not have any derivative financial instruments that qualify as a hedge of a net investment. The following tables represent, by commodity type, our net long or short positions that are expected to partially or entirely settle in each respective year. To the extent that we have long dated derivative positions that span multiple calendar years, the contract will appear in more than one line item in the tables below. June 30, 2018 Crude Oil Natural Gas Natural Gas Liquids Natural Gas Basis Swaps Year of Expiration Net Short Position (Bbls) Net Short Position (MMBtu) Net Short Position (Bbls) Net Long Position (MMBtu) 2018 (1,646,000 ) (21,623,200 ) (25,737,691 ) 2,257,500 2019 (1,900,000 ) — (19,314,335 ) 1,512,500 2020 (128,000 ) — (13,568,452 ) 3,660,000 2021 — — (5,750,000 ) — June 30, 2017 Crude Oil Natural Gas Natural Gas Liquids Natural Gas Basis Swaps Year of Expiration Net Short Position (Bbls) Net Short Position (MMBtu) Net (Short) Long Position (Bbls) Net Long Position (MMBtu) 2017 (282,000 ) (29,043,200 ) (15,547,868 ) 2,075,000 2018 (772,000 ) (17,855,000 ) (2,262,338 ) 2,350,000 2019 (150,000 ) — 292,700 2,025,000 2020 (50,000 ) — 238,548 —

Partnership Equity and Distribu

Partnership Equity and Distributions	6 Months Ended
	Jun. 30, 2018
Equity [Abstract]
Partnership Equity and Distributions	Partnership Equity and Distributions Preferred Units — On May 11, 2018 , we issued 6,000,000 of our Series B Preferred Units representing limited partnership interests at a price of $25 per unit. On June 4, 2018 , we issued an additional 450,000 Series B Preferred Units which represented the partial exercise of the underwriters’ option to purchase additional Series B Preferred Units. We used the net proceeds of $ 155 million from the issuance of the Series B Preferred Units for general partnership purposes including funding capital expenditures and the repayment of outstanding indebtedness under our revolving credit facility. Distributions of the Series B Preferred Units are payable out of available cash, accrue and are cumulative from the date of original issuance of the Series B Preferred Units and are payable quarterly in arrears on March 15th, June 15th, September 15th and December 15th of each year to holders of record as of the close of business on the first business day of the month in which the distribution will be made. The initial distribution rate will be 7.875% per year of the $25 liquidation preference per unit (equal to $1.9688 per unit). On and after June 15, 2023, distributions will accumulate at a percentage of the $25 liquidation preference equal to an annual floating rate of the three-month LIBOR plus a spread of 4.919% . The Series B Preferred Units rank senior to our common units with respect to distribution rights and rights upon liquidation. At any time prior to June 15, 2023, within 120 days of a ratings event, we may, at our option, redeem the Series B Preferred Units in whole, but not in part, at a redemption price per unit equal to $ 25.50 ( 102% of the liquidation preference), plus an amount equal to all accumulated and unpaid distributions. At any time on or after June 15, 2023, we may redeem, in whole or in part, the units at a redemption price of $ 25 per unit, plus an amount equal to all accumulated and unpaid distributions. Upon occurrence of a change in control triggering event, we may, at our option, (i) redeem the Series B Preferred Units, in whole or in part, within 120 days, by paying $ 25 per unit, plus all accumulated and unpaid distributions, and (ii) each holder of Series B Preferred Units will have the right (unless the Partnership provided notice of its election to redeem such holder’s Series B Preferred Units) to convert some or all of the Series B Preferred Units held by such holder on the change of control conversion date into a number of the Partnership’s common units per Series B Preferred Unit as defined in our Partnership Agreement. Holders of the Series B Preferred Units have no voting rights except for certain limited protective voting rights set forth in our Partnership Agreement. Common Units — During the six months ended June 30, 2018 and 2017 , we issued no common units pursuant to our 2014 equity distribution agreement. As of June 30, 2018, approximately $ 750 million of common units remained available for sale pursuant to our at-the-market program. The following table presents our cash distributions paid in 2018 and 2017 : Payment Date Per Unit Distribution Total Cash Distribution (millions) Distributions to common unitholders May 15, 2018 $ 0.7800 $ 155 February 14, 2018 $ 0.7800 $ 194 November 14, 2017 $ 0.7800 $ 155 August 14, 2017 $ 0.7800 $ 134 May 15, 2017 $ 0.7800 $ 135 Distributions to Series A Preferred unitholders June 15, 2018 $ 41.9965 $ 21

Net Income or Loss per Limited

Net Income or Loss per Limited Partner Unit	6 Months Ended
	Jun. 30, 2018
Earnings Per Share [Abstract]
Net Income or Loss per Limited Partner Unit	Net Income or Loss per Limited Partner Unit Basic and diluted net income or loss per Limited Partner Unit ("LPU") is calculated by dividing net income or loss allocable to limited partners, by the weighted-average number of LPUs outstanding during the period. Diluted net income or loss per LPU is computed based on the weighted average number of units plus the effect of potential dilutive units outstanding during the period using the two-class method. Potential dilutive units include outstanding awards under the Partnership's Long Term Incentive Plans.

Commitments and Contingent Liab

Commitments and Contingent Liabilities	6 Months Ended
	Jun. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingent Liabilities	Commitments and Contingent Liabilities Litigation — We are not a party to any significant legal proceedings, but are a party to various administrative and regulatory proceedings and commercial disputes that have arisen in the ordinary course of our business. Management currently believes that the ultimate resolution of the foregoing matters, taken as a whole, and after consideration of amounts accrued, insurance coverage or other indemnification arrangements, will not have a material adverse effect on our results of operations, financial position, or cash flow. Insurance — Our insurance coverage is carried with third-party insurers and with an affiliate of Phillips 66. Our insurance coverage includes: (i) general liability insurance covering third-party exposures; (ii) statutory workers’ compensation insurance; (iii) automobile liability insurance for all owned, non-owned and hired vehicles; (iv) excess liability insurance above the established primary limits for general liability and automobile liability insurance; (v) property insurance, which covers the replacement value of real and personal property and includes business interruption; and (vi) insurance covering our directors and officers for acts related to our business activities. All coverage is subject to certain limits and deductibles, the terms and conditions of which are common for companies with similar types of operations. Environmental — The operation of pipelines, plants and other facilities for gathering, transporting, processing, treating, fractionating, or storing natural gas, NGLs and other products is subject to stringent and complex laws and regulations pertaining to health, safety and the environment. As an owner or operator of these facilities, we must comply with laws and regulations at the federal, state and, in some cases, local levels that relate to worker safety, air and water quality, solid and hazardous waste management and disposal, and other environmental matters. The cost of planning, designing, constructing and operating pipelines, plants, and other facilities incorporates compliance with environmental laws and regulations, worker safety standards, and safety standards applicable to our various facilities. In addition, there is increasing focus from (i) city, state and federal regulatory officials and through litigation, on hydraulic fracturing and the real or perceived environmental impacts of this technique, which indirectly presents some risk to our available supply of natural gas and the resulting supply of NGLs, (ii) federal regulatory agencies regarding pipeline system safety which could impose additional regulatory burdens and increase the cost of our operations, (iii) state and federal regulatory officials regarding the emission of greenhouse gases, which could impose regulatory burdens and increase the cost of our operations, and (iv) regulatory bodies and communities that could prevent or delay the development of fossil fuel energy infrastructure such as pipelines, plants, and other facilities used in our business. Failure to comply with these various health, safety and environmental laws and regulations may trigger a variety of administrative, civil and potentially criminal enforcement measures, including citizen suits, which can include the assessment of monetary penalties, the imposition of remedial requirements, and the issuance of injunctions or restrictions on operation. Management believes that, based on currently known information, compliance with these existing laws and regulations will not have a material adverse effect on our results of operations, financial position or cash flows. On May 24, 2018, we agreed to an administrative civil penalty of approximately $ 100,700 with the New Mexico Environment Department to resolve claims in a notice of violation issued on July 14, 2017 in connection with malfunction-related excess emissions at one our gas processing plants occurring between January and April 2017 that we recorded and reported to the agency.

Business Segments

Business Segments	6 Months Ended
	Jun. 30, 2018
Segment Reporting [Abstract]
Business Segments	Business Segments Our operations are organized into two reportable segments: (i) Gathering and Processing and (ii) Logistics and Marketing. These segments are monitored separately by management for performance against our internal forecast and are consistent with internal financial reporting. These segments have been identified based on the differing products and services, regulatory environment and the expertise required for these operations. Our Gathering and Processing reportable segment includes operating segments that have been aggregated based on the nature of the products and services provided. Gross margin is a performance measure utilized by management to monitor the operations of each segment. The accounting policies of the reportable segments are the same as those described in the summary of significant accounting policies included in Note 2 of the Notes to Consolidated Financial Statements in “Financial Statements and Supplementary Data” included as Item 8 in our Annual Report on Form 10-K for the year ended December 31, 2017. Our Gathering and Processing segment consists of gathering, compressing, treating, processing natural gas, producing and fractionating NGLs, and recovering condensate. Our Logistics and Marketing segment includes transporting, trading, marketing, and storing natural gas and NGLs, fractionating NGLs, and wholesale propane logistics. The remainder of our business operations is presented as “Other,” and consists of unallocated corporate costs. Elimination of inter-segment transactions are reflected in the eliminations column. The following tables set forth our segment information: Three Months Ended June 30, 2018 Gathering and Processing Logistics and Marketing Other Eliminations Total (millions) Total operating revenue $ 1,314 $ 2,192 $ — $ (1,189 ) $ 2,317 Gross margin (a) $ 333 $ 56 $ — $ — $ 389 Operating and maintenance expense (169 ) (11 ) (5 ) — (185 ) Depreciation and amortization expense (87 ) (3 ) (7 ) — (97 ) General and administrative expense (2 ) (3 ) (65 ) — (70 ) Other expense — (3 ) — — (3 ) Earnings from unconsolidated affiliates 2 94 — — 96 Interest expense — — (67 ) — (67 ) Income tax expense — — (1 ) — (1 ) Net income (loss) $ 77 $ 130 $ (145 ) $ — $ 62 Net income attributable to noncontrolling interests (1 ) — — — (1 ) Net income (loss) attributable to partners $ 76 $ 130 $ (145 ) $ — $ 61 Non-cash derivative mark-to-market (b) $ (42 ) $ 5 $ — $ — $ (37 ) Capital expenditures $ 140 $ — $ 4 $ — $ 144 Investments in unconsolidated affiliates, net $ — $ 66 $ — $ — $ 66 Three Months Ended June 30, 2017 : Gathering and Processing Logistics and Marketing Other Eliminations Total (millions) Total operating revenue $ 1,269 $ 1,756 $ — $ (1,076 ) $ 1,949 Gross margin (a) $ 342 $ 50 $ — $ — $ 392 Operating and maintenance expense (162 ) (13 ) (3 ) — (178 ) Depreciation and amortization expense (86 ) (3 ) (5 ) — (94 ) General and administrative expense (7 ) (2 ) (62 ) — (71 ) Other expense (3 ) (2 ) — — (5 ) Gain on sale of assets, net 34 — — — 34 Earnings from unconsolidated affiliates 24 62 — — 86 Interest expense — — (73 ) — (73 ) Income tax expense — — (2 ) — (2 ) Net income (loss) $ 142 $ 92 $ (145 ) $ — $ 89 Net income attributable to noncontrolling interests (1 ) — — — (1 ) Net income (loss) attributable to partners $ 141 $ 92 $ (145 ) $ — $ 88 Non-cash derivative mark-to-market (b) $ 16 $ 8 $ — $ — $ 24 Capital expenditures $ 103 $ — $ 8 $ — $ 111 Investments in unconsolidated affiliates, net $ — $ 21 $ — $ — $ 21 Six Months Ended June 30, 2018 : Gathering and Processing Logistics and Marketing Other Eliminations Total (millions) Total operating revenue $ 2,600 $ 4,171 $ — $ (2,315 ) $ 4,456 Gross margin (a) $ 685 $ 74 $ — $ — $ 759 Operating and maintenance expense (317 ) (22 ) (8 ) — (347 ) Depreciation and amortization expense (171 ) (6 ) (14 ) — (191 ) General and administrative expense (6 ) (6 ) (117 ) — (129 ) Other expense, net (3 ) (2 ) — — (5 ) Earnings from unconsolidated affiliates 3 171 — — 174 Interest expense — — (134 ) — (134 ) Income tax expense — — (2 ) — (2 ) Net income (loss) $ 191 $ 209 $ (275 ) $ — $ 125 Net income attributable to noncontrolling interests (2 ) — — — (2 ) Net income (loss) attributable to partners $ 189 $ 209 $ (275 ) $ — $ 123 Non-cash derivative mark-to-market (b) $ (28 ) $ (38 ) $ — $ — $ (66 ) Capital expenditures $ 260 $ 1 $ 7 $ — $ 268 Investments in unconsolidated affiliates, net $ 1 $ 125 $ — $ — $ 126 Six Months Ended June 30, 2017 : Gathering and Processing Logistics and Marketing Other Eliminations Total (millions) Total operating revenue $ 2,628 $ 3,683 $ — $ (2,241 ) $ 4,070 Gross margin (a) $ 718 $ 108 $ — $ — $ 826 Operating and maintenance expense (315 ) (22 ) (8 ) — (345 ) Depreciation and amortization expense (171 ) (7 ) (10 ) — (188 ) General and administrative expense (13 ) (5 ) (115 ) — (133 ) Other expense (3 ) (11 ) (1 ) — (15 ) Gain on sale of assets, net 34 — — — 34 Earnings from unconsolidated affiliates 44 116 — — 160 Interest expense — — (146 ) — (146 ) Income tax expense — — (3 ) — (3 ) Net income (loss) $ 294 $ 179 $ (283 ) $ — $ 190 Net income attributable to noncontrolling interests (1 ) — — — (1 ) Net income (loss) attributable to partners $ 293 $ 179 $ (283 ) $ — $ 189 Non-cash derivative mark-to-market (b) $ 47 $ 13 $ — $ — $ 60 Capital expenditures $ 146 $ 1 $ 12 $ — $ 159 Investments in unconsolidated affiliates, net $ — $ 41 $ — $ — $ 41 June 30, December 31, 2018 2017 (millions) Segment long-term assets: Gathering and Processing $ 9,048 $ 8,943 Logistics and Marketing 3,462 3,348 Other (c) 249 265 Total long-term assets 12,759 12,556 Current assets 1,282 1,322 Total assets $ 14,041 $ 13,878 (a) Gross margin consists of total operating revenues, including commodity derivative activity, less purchases and related costs. Gross margin is viewed as a non-GAAP financial measure under the rules of the SEC, but is included as a supplemental disclosure because it is a primary performance measure used by management as it represents the results of product sales versus product purchases. As an indicator of our operating performance, gross margin should not be considered an alternative to, or more meaningful than, net income or net cash provided by operating activities as determined in accordance with GAAP. Our gross margin may not be comparable to a similarly titled measure of another company because other entities may not calculate gross margin in the same manner. (b) Non-cash commodity derivative mark-to-market is included in gross margin, along with cash settlements for our commodity derivative contracts. (c) Other long-term assets not allocable to segments consist of corporate leasehold improvements and other long-term assets.

Supplemental Cash Flow Informat

Supplemental Cash Flow Information	6 Months Ended
	Jun. 30, 2018
Additional Cash Flow Elements and Supplemental Cash Flow Information [Abstract]
Supplemental Cash Flow Information	Supplemental Cash Flow Information Six Months Ended June 30, 2018 2017 (millions) Cash paid for interest: Cash paid for interest, net of amounts capitalized $ 129 $ 143 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 $ 42 $ 33 Other non-cash changes in property, plant and equipment $ — $ (2 ) Issuance of common and general partner units $ — $ 1,125 Deficit purchase price $ — $ 3,094

Condensed Consolidating Financi

Condensed Consolidating Financial Information	6 Months Ended
	Jun. 30, 2018
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Condensed Consolidating Financial Information	Condensed Consolidating Financial Information The following condensed consolidating financial information presents the results of operations, financial position and cash flows of DCP Midstream, LP, or parent guarantor, DCP Midstream Operating LP, or subsidiary issuer, which is a 100% owned subsidiary, and non-guarantor subsidiaries, as well as the consolidating adjustments necessary to present DCP Midstream, LP’s results on a consolidated basis. The parent guarantor has agreed to fully and unconditionally guarantee debt securities of the subsidiary issuer. For the purpose of the following financial information, investments in subsidiaries are reflected in accordance with the equity method of accounting. The financial information may not necessarily be indicative of results of operations, cash flows, or financial position had the subsidiaries operated as independent entities. Condensed Consolidating Balance Sheet June 30, 2018 Parent Guarantor Subsidiary Issuer Non-Guarantor Subsidiaries Consolidating Adjustments Consolidated (millions) ASSETS Current assets: Cash and cash equivalents $ — $ — $ 4 $ — $ 4 Accounts receivable, net — — 1,029 — 1,029 Inventories — — 47 — 47 Other — — 202 — 202 Total current assets — — 1,282 — 1,282 Property, plant and equipment, net — — 9,080 — 9,080 Goodwill and intangible assets, net — — 332 — 332 Advances receivable — consolidated subsidiaries 2,680 1,763 — (4,443 ) — Investments in consolidated subsidiaries 4,643 7,785 — (12,428 ) — Investments in unconsolidated affiliates — — 3,165 — 3,165 Other long-term assets — — 182 — 182 Total assets $ 7,323 $ 9,548 $ 14,041 $ (16,871 ) $ 14,041 LIABILITIES AND EQUITY Accounts payable and other current liabilities $ — $ 70 $ 1,492 $ — $ 1,562 Current maturities of long-term debt — 325 — — 325 Advances payable — consolidated subsidiaries — — 4,443 (4,443 ) — Long-term debt — 4,510 — — 4,510 Other long-term liabilities — — 291 — 291 Total liabilities — 4,905 6,226 (4,443 ) 6,688 Commitments and contingent liabilities Equity: Partners’ equity: Net equity 7,323 4,646 7,790 (12,428 ) 7,331 Accumulated other comprehensive loss — (3 ) (5 ) — (8 ) Total partners’ equity 7,323 4,643 7,785 (12,428 ) 7,323 Noncontrolling interests — — 30 — 30 Total equity 7,323 4,643 7,815 (12,428 ) 7,353 Total liabilities and equity $ 7,323 $ 9,548 $ 14,041 $ (16,871 ) $ 14,041 Condensed Consolidating Balance Sheet December 31, 2017 Parent Guarantor Subsidiary Issuer Non-Guarantor Subsidiaries Consolidating Adjustments Consolidated (millions) ASSETS Current assets: Cash and cash equivalents $ — $ 155 $ 1 $ — $ 156 Accounts receivable, net — — 981 — 981 Inventories — — 68 — 68 Other — — 117 — 117 Total current assets — 155 1,167 — 1,322 Property, plant and equipment, net — — 8,983 — 8,983 Goodwill and intangible assets, net — — 337 — 337 Advances receivable — consolidated subsidiaries 2,895 1,614 — (4,509 ) — Investments in consolidated subsidiaries 4,513 7,522 — (12,035 ) — Investments in unconsolidated affiliates — — 3,050 — 3,050 Other long-term assets — — 186 — 186 Total assets $ 7,408 $ 9,291 $ 13,723 $ (16,544 ) $ 13,878 LIABILITIES AND EQUITY Accounts payable and other current liabilities $ — $ 71 $ 1,417 $ — $ 1,488 Advances payable — consolidated subsidiaries — — 4,509 (4,509 ) — Long-term debt — 4,707 — — 4,707 Other long-term liabilities — — 245 — 245 Total liabilities — 4,778 6,171 (4,509 ) 6,440 Commitments and contingent liabilities Equity: Partners’ equity: Net equity 7,408 4,517 7,527 (12,035 ) 7,417 Accumulated other comprehensive loss — (4 ) (5 ) — (9 ) Total partners’ equity 7,408 4,513 7,522 (12,035 ) 7,408 Noncontrolling interests — — 30 — 30 Total equity 7,408 4,513 7,552 (12,035 ) 7,438 Total liabilities and equity $ 7,408 $ 9,291 $ 13,723 $ (16,544 ) $ 13,878 Condensed Consolidating Statement of Operations Three Months Ended June 30, 2018 Parent Guarantor Subsidiary Issuer Non- Guarantor Subsidiaries Consolidating Adjustments Consolidated (millions) Operating revenues: Sales of natural gas, NGLs and condensate $ — $ — $ 2,257 $ — $ 2,257 Transportation, processing and other — — 127 — 127 Trading and marketing losses, net — — (67 ) — (67 ) Total operating revenues — — 2,317 — 2,317 Operating costs and expenses: Purchases and related costs — — 1,928 — 1,928 Operating and maintenance expense — — 185 — 185 Depreciation and amortization expense — — 97 — 97 General and administrative expense — — 70 — 70 Other expense, net — — 3 — 3 Total operating costs and expenses — — 2,283 — 2,283 Operating income — — 34 — 34 Interest expense, net — (67 ) — — (67 ) Income from consolidated subsidiaries 61 128 — (189 ) — Earnings from unconsolidated affiliates — — 96 — 96 Income before income taxes 61 61 130 (189 ) 63 Income tax expense — — (1 ) — (1 ) Net income 61 61 129 (189 ) 62 Net income attributable to noncontrolling interests — — (1 ) — (1 ) Net income attributable to partners $ 61 $ 61 $ 128 $ (189 ) $ 61 Condensed Consolidating Statement of Comprehensive Income Three Months Ended June 30, 2018 Parent Guarantor Subsidiary Issuer Non-Guarantor Subsidiaries Consolidating Adjustments Consolidated (millions) Net income $ 61 $ 61 $ 129 $ (189 ) $ 62 Other comprehensive income: Reclassification of cash flow hedge losses into earnings — 1 — — 1 Other comprehensive income from consolidated subsidiaries 1 — — (1 ) — Total other comprehensive income 1 1 — (1 ) 1 Total comprehensive income 62 62 129 (190 ) 63 Total comprehensive income attributable to noncontrolling interests — — (1 ) — (1 ) Total comprehensive income attributable to partners $ 62 $ 62 $ 128 $ (190 ) $ 62 Condensed Consolidating Statement of Operations Three Months Ended June 30, 2017 Parent Guarantor Subsidiary Issuer Non-Guarantor Subsidiaries Consolidating Adjustments Consolidated (millions) Operating revenues: Sales of natural gas, NGLs and condensate $ — $ — $ 1,772 $ — $ 1,772 Transportation, processing and other — — 155 — 155 Trading and marketing gains, net — — 22 — 22 Total operating revenues — — 1,949 — 1,949 Operating costs and expenses: Purchases of natural gas and NGLs — — 1,557 — 1,557 Operating and maintenance expense — — 178 — 178 Depreciation and amortization expense — — 94 — 94 General and administrative expense — — 71 — 71 Gain on sale of assets, net — — (34 ) — (34 ) Other expense, net — — 5 — 5 Total operating costs and expenses — — 1,871 — 1,871 Operating income — — 78 — 78 Interest expense, net — (73 ) — — (73 ) Income from consolidated subsidiaries 88 161 — (249 ) — Earnings from unconsolidated affiliates — — 86 — 86 Income before income taxes 88 88 164 (249 ) 91 Income tax expense — — (2 ) — (2 ) Net income 88 88 162 (249 ) 89 Net income attributable to noncontrolling interests — — (1 ) — (1 ) Net income attributable to partners $ 88 $ 88 $ 161 $ (249 ) $ 88 Condensed Consolidating Statement of Comprehensive Income Three Months Ended June 30, 2017 Parent Guarantor Subsidiary Issuer Non-Guarantor Subsidiaries Consolidating Adjustments Consolidated (millions) Net income $ 88 $ 88 $ 162 $ (249 ) $ 89 Total other comprehensive income — — — — — Total comprehensive income 88 88 162 (249 ) 89 Total comprehensive income attributable to noncontrolling interests — — (1 ) — (1 ) Total comprehensive income attributable to partners $ 88 $ 88 $ 161 $ (249 ) $ 88 Condensed Consolidating Statement of Operations Six Months Ended June 30, 2018 Parent Guarantor Subsidiary Issuer Non- Guarantor Subsidiaries Consolidating Adjustments Consolidated (millions) Operating revenues: Sales of natural gas, NGLs and condensate $ — $ — $ 4,326 $ — $ 4,326 Transportation, processing and other — — 238 — 238 Trading and marketing losses, net — — (108 ) — (108 ) Total operating revenues — — 4,456 — 4,456 Operating costs and expenses: Purchases and related costs — — 3,697 — 3,697 Operating and maintenance expense — — 347 — 347 Depreciation and amortization expense — — 191 — 191 General and administrative expense — — 129 — 129 Other expense, net — — 5 — 5 Total operating costs and expenses — — 4,369 — 4,369 Operating income — — 87 — 87 Interest expense, net — (134 ) — — (134 ) Income from consolidated subsidiaries 123 257 — (380 ) — Earnings from unconsolidated affiliates — — 174 — 174 Income before income taxes 123 123 261 (380 ) 127 Income tax expense — — (2 ) — (2 ) Net income 123 123 259 (380 ) 125 Net income attributable to noncontrolling interests — — (2 ) — (2 ) Net income attributable to partners $ 123 $ 123 $ 257 $ (380 ) $ 123 Condensed Consolidating Statement of Comprehensive Income Six Months Ended June 30, 2018 Parent Guarantor Subsidiary Issuer Non-Guarantor Subsidiaries Consolidating Adjustments Consolidated (millions) Net income $ 123 $ 123 $ 259 $ (380 ) $ 125 Other comprehensive income: Reclassification of cash flow hedge losses into earnings — 1 — — 1 Other comprehensive income from consolidated subsidiaries 1 — — (1 ) — Total other comprehensive income 1 1 — (1 ) 1 Total comprehensive income 124 124 259 (381 ) 126 Total comprehensive income attributable to noncontrolling interests — — (2 ) — (2 ) Total comprehensive income attributable to partners $ 124 $ 124 $ 257 $ (381 ) $ 124 Condensed Consolidating Statement of Operations Six Months Ended June 30, 2017 Parent Guarantor Subsidiary Issuer Non- Guarantor Subsidiaries Consolidating Adjustments Consolidated (millions) Operating revenues: Sales of natural gas, NGLs and condensate $ — $ — $ 3,705 $ — $ 3,705 Transportation, processing and other — — 312 — 312 Trading and marketing losses, net — — 53 — 53 Total operating revenues — — 4,070 — 4,070 Operating costs and expenses: Purchases and related costs — — 3,244 — 3,244 Operating and maintenance expense — — 345 — 345 Depreciation and amortization expense — — 188 — 188 General and administrative expense — — 133 — 133 Gain on sale of assets, net — — (34 ) — (34 ) Other expense, net — — 15 — 15 Total operating costs and expenses — — 3,891 — 3,891 Operating income — — 179 — 179 Interest expense, net — (146 ) — — (146 ) Income from consolidated subsidiaries 189 335 — (524 ) — Earnings from unconsolidated affiliates — — 160 — 160 Income before income taxes 189 189 339 (524 ) 193 Income tax expense — — (3 ) — (3 ) Net income 189 189 336 (524 ) 190 Net income attributable to noncontrolling interests — — (1 ) — (1 ) Net income attributable to partners $ 189 $ 189 $ 335 $ (524 ) $ 189 Condensed Consolidating Statement of Comprehensive Income Six Months Ended June 30, 2017 Parent Guarantor Subsidiary Issuer Non-Guarantor Subsidiaries Consolidating Adjustments Consolidated (millions) Net income $ 189 $ 189 $ 336 $ (524 ) $ 190 Other comprehensive income: Reclassification of cash flow hedge losses into earnings — 1 — — 1 Other comprehensive income from consolidated subsidiaries 1 — — (1 ) — Total other comprehensive income 1 1 — (1 ) 1 Total comprehensive income 190 190 336 (525 ) 191 Total comprehensive income attributable to noncontrolling interests — — (1 ) — (1 ) Total comprehensive income attributable to partners $ 190 $ 190 $ 335 $ (525 ) $ 190 Condensed Consolidating Statement of Cash Flows Six Months Ended June 30, 2018 Parent Guarantor Subsidiary Issuer Non-Guarantor Subsidiaries Consolidating Adjustments Consolidated (millions) OPERATING ACTIVITIES Net cash (used in) provided by operating activities $ — $ (131 ) $ 462 $ — $ 331 INVESTING ACTIVITIES: Intercompany transfers 215 (149 ) — (66 ) — Capital expenditures — — (268 ) — (268 ) Investments in unconsolidated affiliates, net — — (126 ) — (126 ) Proceeds from sale of assets — — 3 — 3 Net cash provided by (used in) investing activities 215 (149 ) (391 ) (66 ) (391 ) FINANCING ACTIVITIES: Intercompany transfers — — (66 ) 66 — Proceeds from long-term debt — 1,803 — — 1,803 Payments of long-term debt — (1,678 ) — — (1,678 ) Proceeds from issuance of preferred limited partner units, net of offering costs 155 — — — 155 Distributions to preferred limited partners (21 ) — — — (21 ) Distributions to limited partners and general partner (349 ) — — — (349 ) Distributions to noncontrolling interests — — (2 ) — (2 ) Net cash (used in) provided by financing activities (215 ) 125 (68 ) 66 (92 ) Net change in cash and cash equivalents — (155 ) 3 — (152 ) Cash and cash equivalents, beginning of period — 155 1 — 156 Cash and cash equivalents, end of period $ — $ — $ 4 $ — $ 4 Condensed Consolidating Statements of Cash Flows Six Months Ended June 30, 2017 Parent Guarantor Subsidiary Issuer Non-Guarantor Subsidiaries Consolidating Adjustments Consolidated (millions) OPERATING ACTIVITIES Net cash (used in) provided by operating activities $ — $ (143 ) $ 503 $ — $ 360 INVESTING ACTIVITIES: Intercompany transfers 256 590 — (846 ) — Capital expenditures — — (159 ) — (159 ) Investments in unconsolidated affiliates, net — — (41 ) — (41 ) Proceeds from sale of assets — — 129 — 129 Net cash provided by (used in) investing activities 256 590 (71 ) (846 ) (71 ) FINANCING ACTIVITIES: Intercompany transfers — — (846 ) 846 — Payments of long-term debt — (195 ) — — (195 ) Net change in advances to predecessor from DCP Midstream, LLC — — 418 — 418 Distributions to limited partners and general partner (256 ) — — — (256 ) Distributions to noncontrolling interests — — (4 ) — (4 ) Other — (2 ) — — (2 ) Net cash (used in) provided by financing activities (256 ) (197 ) (432 ) 846 (39 ) Net change in cash and cash equivalents — 250 — — 250 Cash and cash equivalents, beginning of period — — 1 — 1 Cash and cash equivalents, end of period $ — $ 250 $ 1 $ — $ 251

Subsequent Events

Subsequent Events	6 Months Ended
	Jun. 30, 2018
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events On July 24, 2018 , we announced that the board of directors of the General Partner declared a quarterly distribution on our common units of $0.78 per common unit. The distribution will be paid on August 14, 2018 to unitholders of record on August 3, 2018 . On the same date, we announced that the board of directors of the General Partner declared a quarterly distribution on our Series B Preferred Units of $0.6781 per Series B Preferred Unit, which includes the distribution attributable to the partial-period from and including the original issue date of May 11, 2018 . The distribution will be paid on September 17, 2018 to unitholders of record on September 4, 2018 . On July 17, 2018 , we issued $500 million of 5.375% Senior Notes due July 2025 , unless redeemed prior to maturity. We received proceeds of $495 million , net of underwriters’ fees, related expenses and unamortized discounts which we expect to use to redeem our $450 million 9.750% Senior Notes due March, 2019. Interest on the notes will be paid semi-annually in arrears on January 15 and July 15 of each year, commencing January 15, 2019 . The notes are senior unsecured obligations, ranking equally in right of payment with other unsecured indebtedness, including indebtedness under our Credit Agreement. We are not required to make mandatory redemption or sinking fund payments with respect to any of these notes, and they are redeemable at a premium at our option. The underwriters’ fees and related expenses are deferred in other long-term assets in our condensed consolidated balance sheets and will be amortized over the term of the notes.

Description of Business and B27

Description of Business and Basis of Presentation (Policies)	6 Months Ended
	Jun. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation and Significant Accounting Policies [Text Block]	The condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America, or GAAP.
Equity Method Investments	Investments in greater than 20% owned affiliates that are not variable interest entities and where we do not have the ability to exercise control, and investments in less than 20% owned affiliates where we have the ability to exercise significant influence, are accounted for using the equity method.

New Accounting Pronouncements N

New Accounting Pronouncements New Accounting Pronouncements (Tables)	6 Months Ended
	Jun. 30, 2018
Item Effected [Line Items]
Schedule of Cumulative Impact of Prospective Adoption of Accounting Policy [Table Text Block]	Three Months Ended June 30, 2018 Six Months Ended June 30, 2018 As Reported Effect of Change Presentation Without Adoption of ASC 606 As Reported Effect of Change Presentation Without Adoption of ASC 606 (millions) Statement of Operations Operating revenues Sales of natural gas, NGLs and condensate $ 1,849 $ 44 $ 1,893 $ 3,593 $ 75 $ 3,668 Transportation, processing and other $ 127 $ 39 $ 166 $ 238 $ 79 $ 317 Costs and expenses Purchases and related costs $ 1,703 $ 83 $ 1,786 $ 3,307 $ 154 $ 3,461 Net income $ 62 $ — $ 62 $ 125 $ — $ 125

Revenue Recognition (Tables)

Revenue Recognition (Tables)	6 Months Ended
	Jun. 30, 2018
Disaggregation of Revenue [Line Items]
Disaggregation of Revenue [Table Text Block]	Three Months Ended June 30, 2018 Gathering and Processing Logistics and Marketing Eliminations Total (millions) Sales of natural gas $ 398 $ 463 $ (353 ) $ 508 Sales of NGLs and condensate (a) 870 1,714 (835 ) 1,749 Transportation, processing and other 112 16 (1 ) 127 Trading and marketing losses, net (c) (66 ) (1 ) — (67 ) Total operating revenues $ 1,314 $ 2,192 $ (1,189 ) $ 2,317 Six Months Ended June 30, 2018 Gathering and Processing Logistics and Marketing Eliminations Total (millions) Sales of natural gas $ 844 $ 1,016 $ (772 ) $ 1,088 Sales of NGLs and condensate (b) 1,610 3,170 (1,542 ) 3,238 Transportation, processing and other 209 30 (1 ) 238 Trading and marketing losses, net (c) (63 ) (45 ) — (108 ) Total operating revenues $ 2,600 $ 4,171 $ (2,315 ) $ 4,456

Contract Assets and Liabiliti30

Contract Assets and Liabilities (Tables)	6 Months Ended
	Jun. 30, 2018
Contract Assets and Liabilities [Abstract]
Contract with Customer, Asset and Liability [Table Text Block]	June 30, 2018 (millions) Balance, beginning of period $ — Cumulative effect of implementation of Topic 606 36 Revenue recognized (a) (1 ) Balance, end of period $ 35 Current contract liabilities — Long-term contract liabilities $ 35

Agreements and Transactions w31

Agreements and Transactions with Affiliates (Tables)	6 Months Ended
	Jun. 30, 2018
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 June 30, Six Months Ended June 30, 2018 2017 2018 2017 (millions) Employee related costs charged by DCP Midstream, LLC Operating and maintenance expense $ 53 $ 49 $ 102 $ 99 General and administrative expense $ 47 $ 39 $ 85 $ 70
Summary of Transactions with Affiliates	The following table summarizes our transactions with affiliates: Three Months Ended June 30, Six Months Ended June 30, 2018 2017 2018 2017 (millions) Phillips 66 (including its affiliates): Sales of natural gas, NGLs and condensate to affiliates $ 381 $ 251 $ 683 $ 525 Purchases and related costs from affiliates $ 28 $ 8 $ 38 $ 15 Operating and maintenance and general administrative expenses $ 3 $ — $ 6 $ 1 Enbridge (including its affiliates): Sales of natural gas, NGLs and condensate to affiliates $ 13 $ 15 $ 25 $ 20 Purchases and related costs from affiliates $ 18 $ 11 $ 28 $ 19 Operating and maintenance and general administrative expenses $ — $ — $ — $ 1 Unconsolidated affiliates: Sales of natural gas, NGLs and condensate to affiliates $ 14 $ 12 $ 25 $ 22 Transportation, processing, and other to affiliates $ 2 $ 2 $ 3 $ 3 Purchases and related costs from affiliates $ 179 $ 119 $ 324 $ 232 We had balances with affiliates as follows: June 30, December 31, (millions) Phillips 66 (including its affiliates): Accounts receivable $ 153 $ 156 Accounts payable $ 24 $ 6 Other assets $ 1 $ — Enbridge (including its affiliates): Accounts receivable $ 14 $ 11 Accounts payable $ 21 $ 9 Unconsolidated affiliates: Accounts receivable $ 22 $ 24 Accounts payable $ 67 $ 53 Other assets $ 3 $ 4

Inventories (Tables)

Inventories (Tables)	6 Months Ended
	Jun. 30, 2018
Inventory Disclosure [Abstract]
Schedule of Inventories	Inventories were as follows: June 30, December 31, (millions) Natural gas $ 18 $ 30 NGLs 29 38 Total inventories $ 47 $ 68

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	6 Months Ended
	Jun. 30, 2018
Property, Plant and Equipment [Abstract]
Classification of Property, Plant and Equipment	A summary of property, plant and equipment by classification is as follows: Depreciable June 30, December 31, (millions) Gathering and transmission systems 20 — 50 Years $ 8,599 $ 8,473 Processing, storage and terminal facilities 35 — 60 Years 5,141 5,128 Other 3 — 30 Years 563 557 Construction work in progress 520 374 Property, plant and equipment 14,823 14,532 Accumulated depreciation (5,743 ) (5,549 ) Property, plant and equipment, net $ 9,080 $ 8,983

Investments in Unconsolidated34

Investments in Unconsolidated Affiliates (Tables)	6 Months Ended
	Jun. 30, 2018
Equity Method Investments and Joint Ventures [Abstract]
Investments in Unconsolidated Affiliates	The following table summarizes our investments in unconsolidated affiliates: Carrying Value as of Percentage June 30, December 31, (millions) DCP Sand Hills Pipeline, LLC 66.67% $ 1,730 $ 1,633 DCP Southern Hills Pipeline, LLC 66.67% 735 739 Discovery Producer Services LLC 40.00% 354 362 Front Range Pipeline LLC 33.33% 163 165 Texas Express Pipeline LLC 10.00% 91 90 Gulf Coast Express Pipeline LLC 25.00% 28 — Mont Belvieu Enterprise Fractionator 12.50% 25 23 Panola Pipeline Company, LLC 15.00% 23 24 Mont Belvieu 1 Fractionator 20.00% 12 10 Other Various 4 4 Total investments in unconsolidated affiliates $ 3,165 $ 3,050
Schedule Of Earnings From Investment In Unconsolidated Affiliates [Table Text Block]	Earnings from investments in unconsolidated affiliates were as follows: Three Months Ended June 30, Six Months Ended June 30, 2018 2017 2018 2017 (millions) DCP Sand Hills Pipeline, LLC $ 58 $ 37 $ 106 $ 68 DCP Southern Hills Pipeline, LLC 16 13 29 24 Discovery Producer Services LLC 2 25 3 45 Front Range Pipeline LLC 5 3 10 7 Texas Express Pipeline LLC 8 1 10 3 Mont Belvieu Enterprise Fractionator 3 4 7 7 Mont Belvieu 1 Fractionator 4 3 8 4 Other — — 1 2 Total earnings from unconsolidated affiliates $ 96 $ 86 $ 174 $ 160
Equity Method Investment Summarized Financial Information, Statement of Operations [Table Text Block]	The following tables summarize the combined financial information of our investments in unconsolidated affiliates: Three Months Ended June 30, Six Months Ended June 30, 2018 2017 2018 2017 (millions) Statements of operations: (a) Operating revenue $ 408 $ 368 $ 742 $ 705 Operating expenses $ 147 $ 152 $ 286 $ 300 Net income $ 260 $ 216 $ 454 $ 404
Equity Method Investment Summarized Financial Information Balance Sheet Table [Table Text Block]	June 30, December 31, (millions) Balance sheets: (a) Current assets $ 379 $ 244 Long-term assets 5,596 5,319 Current liabilities (256 ) (196 ) Long-term liabilities (227 ) (200 ) Net assets $ 5,492 $ 5,167

Fair Value Measurement (Tables)

Fair Value Measurement (Tables)	6 Months Ended
	Jun. 30, 2018
Fair Value Disclosures [Abstract]
Schedule of Impaired Assets	The following table presents the financial instruments carried at fair value as of
Financial Instruments Carried at Fair Value	June 30, 2018 December 31, 2017 Level 1 Level 2 Level 3 Total Carrying Value Level 1 Level 2 Level 3 Total Carrying Value (millions) Current assets: Commodity derivatives (a) $ 36 $ 8 $ 1 $ 45 $ 10 $ 17 $ 3 $ 30 Short-term investments (b) $ 3 $ — $ — $ 3 $ 156 $ — $ — $ 156 Long-term assets: Commodity derivatives (c) $ 6 $ 1 $ 1 $ 8 $ 1 $ 1 $ 1 $ 3 Current liabilities: Commodity derivatives (d) $ (77 ) $ (54 ) $ (10 ) $ (141 ) $ (29 ) $ (34 ) $ (13 ) $ (76 ) Long-term liabilities: Commodity derivatives (e) $ (12 ) $ (10 ) $ (7 ) $ (29 ) $ (3 ) $ (11 ) $ (1 ) $ (15 ) (a) Included in current unrealized gains on derivative instruments in our condensed consolidated balance sheets. (b) Includes short-term money market securities included in cash and cash equivalents in our condensed consolidated balance sheets. (c) Included in long-term unrealized gains on derivative instruments in our condensed consolidated balance sheets. (d) Included in current unrealized losses on derivative instruments in our condensed consolidated balance sheets. (e) Included in long-term unrealized losses on derivative instruments in our condensed consolidated balance sheets.
Fair Value Assets and Liabilities Measured On Recurring Basis Unobservable Input Reconciliation	Commodity Derivative Instruments Current Long-Term Current Long-Term (millions) Three months ended June 30, 2018 (a): Beginning balance $ 2 $ — $ (6 ) $ (3 ) Net unrealized gains (losses) included in earnings (b) 1 1 (14 ) (4 ) Transfers out of Level 3 (c) (2 ) — 8 — Settlements — — 2 — Ending balance $ 1 $ 1 $ (10 ) $ (7 ) Net unrealized gains (losses) on derivatives still held included in earnings (b) $ 1 $ 1 $ (8 ) $ (4 ) Three months ended June 30, 2017 (a): Beginning balance $ 8 $ 2 $ (8 ) $ (3 ) Net unrealized gains included in earnings (b) 3 — 1 — Transfers out of Level 3 (c) (3 ) — 3 — Settlements (1 ) — 2 — Ending balance $ 7 $ 2 $ (2 ) $ (3 ) Net unrealized gains on derivatives still held included in earnings (b) $ 4 $ — $ — $ — Commodity Derivative Instruments Current Long-Term Current Long-Term (millions) Six months ended June 30, 2018 (a): Beginning balance $ 3 $ 1 $ (13 ) $ (1 ) Net unrealized losses included in earnings (b) — — (12 ) (6 ) Transfers out of Level 3 (c) (2 ) — 12 — Settlements — — 3 — Ending balance $ 1 $ 1 $ (10 ) $ (7 ) Net unrealized gains (losses) on derivatives still held included in earnings (b) $ 1 $ — $ (7 ) $ (6 ) Six months ended June 30, 2017 (a): Beginning balance $ 9 $ 5 $ (23 ) $ — Net unrealized gains (losses) included in earnings (b) 1 (3 ) 13 (3 ) Transfers out of Level 3 (c) (2 ) — 3 — Settlements (1 ) — 5 — Ending balance $ 7 $ 2 $ (2 ) $ (3 ) Net unrealized gains (losses) on derivatives still held included in earnings (b) $ 6 $ (2 ) $ 3 $ (3 ) (a) There were no purchases, issuances or sales of derivatives or transfers into Level 3 for the three and six months ended June 30, 2018 and 2017 . (b) Represents the amount of unrealized gains or losses for the period, included in trading and marketing gains (losses), net. (c) Amounts transferred out of Level 3 are reflected at fair value at the end of the period.
Schedule of Valuation Processes	June 30, 2018 Product Group Fair Value Forward Curve Range (millions) Assets NGLs $ 2 $0.29-$1.08 Per gallon Liabilities NGLs $ (12 ) $0.14-$1.49 Per gallon Natural gas $ (5 ) $1.57-$2.66 Per MMBtu
Schedule of Carrying Values and Estimated Fair Values of Debt Instruments [Table Text Block]	We determine the fair value of our fixed-rate senior notes and junior subordinated notes based on quotes obtained from bond dealers. We determine the fair value of borrowings under our Credit Agreement based upon the discounted present value of expected future cash flows, taking into account the difference between the contractual borrowing spread and the spread for similar credit facilities available in the marketplace. We classify the fair values of our outstanding debt balances within Level 2 of the valuation hierarchy. As of June 30, 2018 and December 31, 2017 , the carrying value and fair value of our total debt, including current maturities, were as follows: June 30, 2018 December 31, 2017 Carrying Value (a) Fair Value Carrying Value (a) Fair Value (millions) Total debt $ 4,861 $ 4,896 $ 4,736 $ 4,885 (a) Excludes unamortized issuance costs.

Debt (Tables)

Debt (Tables)	6 Months Ended
	Jun. 30, 2018
Debt Disclosure [Abstract]
Schedule of Debt	June 30, December 31, (millions) Senior notes: Issued February 2009, interest at 9.750% payable semiannually, due March 2019 (a) $ 450 $ 450 Issued March 2014, interest at 2.700% payable semi-annually, due April 2019 325 325 Issued March 2010, interest at 5.350% payable semiannually, due March 2020 (a) 600 600 Issued September 2011, interest at 4.750% payable semiannually, due September 2021 500 500 Issued March 2012, interest at 4.950% payable semi-annually, due April 2022 350 350 Issued March 2013, interest at 3.875% payable semi-annually, due March 2023 500 500 Issued August 2000, interest at 8.125% payable semi-annually, due August 2030 (a) 300 300 Issued October 2006, interest at 6.450% payable semi-annually, due November 2036 300 300 Issued September 2007, interest at 6.750% payable semi-annually, due September 2037 450 450 Issued March 2014, interest at 5.600% payable semi-annually, due April 2044 400 400 Junior subordinated notes: Issued May 2013, interest at 5.850% payable semi-annually, due May 2043 550 550 Credit agreement: Revolving credit facility, weighted-average variable interest rate of 3.452%, as of June 30, 2018, due December 2022 125 — Fair value adjustments related to interest rate swap fair value hedges (a) 22 23 Unamortized issuance costs (26 ) (29 ) Unamortized discount (11 ) (12 ) Total debt 4,835 4,707 Current maturities of long-term debt 325 — Total long-term debt $ 4,510 $ 4,707 (a) The swaps associated with this debt were previously terminated. The remaining long-term fair value of approximately $22 million related to the swaps is being amortized as a reduction to interest expense through 2019, 2020 and 2030, the original maturity dates of the debt.
Future Maturities of Long-Term Debt	The maturities of our long-term debt as of June 30, 2018 are as follows: Debt Maturities (millions) 2018 $ — 2019 775 2020 600 2021 500 2022 475 Thereafter 2,500 Total long-term debt $ 4,850

Risk Management and Hedging A37

Risk Management and Hedging Activities (Tables)	6 Months Ended
	Jun. 30, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Summary of Gross and Net Amounts of Derivative Instruments	June 30, 2018 December 31, 2017 Gross Amounts Amounts Not Net Gross Amounts Amounts Not Net (millions) Assets: Commodity derivatives $ 53 $ — $ 53 $ 33 $ — $ 33 Liabilities: Commodity derivatives $ (170 ) $ — $ (170 ) $ (91 ) $ — $ (91 )
Schedule of Designated and Non-Designated Derivative Instruments in Statement of Financial Position, Fair Value	June 30, 2018 and December 31, 2017 . Balance Sheet Line Item June 30, December 31, Balance Sheet Line Item June 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 $ 45 $ 30 Unrealized losses on derivative instruments — current $ (141 ) $ (76 ) Unrealized gains on derivative instruments — long-term 8 3 Unrealized losses on derivative instruments — long-term (29 ) (15 ) Total $ 53 $ 33 Total $ (170 ) $ (91 )
Schedule of Cash Flow Hedges Included in Accumulated Other Comprehensive Income (Loss) [Table Text Block]	The following summarizes the balance and activity within AOCI relative to our interest rate, commodity and foreign currency cash flow hedges as of and for the three months ended June 30, 2018 : Interest Commodity Foreign Total (millions) Net deferred (losses) gains in AOCI (beginning balance) $ (4 ) $ (6 ) $ 1 $ (9 ) Losses reclassified from AOCI to earnings — effective portion 1 — — 1 Net deferred (losses) gains in AOCI (ending balance) $ (3 ) $ (6 ) $ 1 $ (8 ) Deferred losses in AOCI expected to be reclassified into earnings over the next 12 months $ (1 ) $ — $ — $ (1 ) The following summarizes the balance and activity within AOCI relative to our interest rate, commodity and foreign currency cash flow hedges as of and for the six months ended June 30, 2018 : Interest Commodity Foreign Total (millions) Net deferred (losses) gains in AOCI (beginning balance) $ (4 ) $ (6 ) $ 1 $ (9 ) Losses reclassified from AOCI to earnings — effective portion 1 — — 1 Net deferred (losses) gains in AOCI (ending balance) $ (3 ) $ (6 ) $ 1 $ (8 ) Deferred losses in AOCI expected to be reclassified into earnings over the next 12 months $ (1 ) $ — $ — $ (1 ) (a) Relates to Discovery Producer Services LLC ("Discovery"), an unconsolidated affiliate. The following summarizes the balance and activity within AOCI relative to our interest rate, commodity and foreign currency cash flow hedges as of and for the three months ended June 30, 2017 : Interest Commodity Foreign Total (millions) Net deferred (losses) gains in AOCI (beginning balance) $ (4 ) $ (6 ) $ 1 $ (9 ) Net deferred (losses) gains in AOCI (ending balance) $ (4 ) $ (6 ) $ 1 $ (9 ) The following summarizes the balance and activity within AOCI relative to our interest rate, commodity and foreign currency cash flow hedges as of and for the six months ended June 30, 2017 : Interest Commodity Foreign Total (millions) Net deferred (losses) gains in AOCI (beginning balance) $ (3 ) $ (6 ) $ 1 $ (8 ) Losses reclassified from AOCI to earnings — effective portion 1 — — 1 Deficit purchase price under carrying value (2 ) — — (2 ) Net deferred (losses) gains in AOCI (ending balance) $ (4 ) $ (6 ) $ 1 $ (9 ) (a) Relates to Discovery, an unconsolidated affiliate.
Schedule of Changes in Derivative Instruments Not Designated as Hedging Instruments	Commodity Derivatives: Statements of Operations Line Item Three Months Ended June 30, Six Months Ended June 30, 2018 2017 2018 2017 (millions) Realized losses $ (30 ) $ (2 ) $ (42 ) $ (7 ) Unrealized (losses) gains (37 ) 24 (66 ) 60 Trading and marketing (losses) gains, net $ (67 ) $ 22 $ (108 ) $ 53
Schedule of Net Long or Short Positions Expected to be Realized	June 30, 2018 Crude Oil Natural Gas Natural Gas Liquids Natural Gas Basis Swaps Year of Expiration Net Short Position (Bbls) Net Short Position (MMBtu) Net Short Position (Bbls) Net Long Position (MMBtu) 2018 (1,646,000 ) (21,623,200 ) (25,737,691 ) 2,257,500 2019 (1,900,000 ) — (19,314,335 ) 1,512,500 2020 (128,000 ) — (13,568,452 ) 3,660,000 2021 — — (5,750,000 ) — June 30, 2017 Crude Oil Natural Gas Natural Gas Liquids Natural Gas Basis Swaps Year of Expiration Net Short Position (Bbls) Net Short Position (MMBtu) Net (Short) Long Position (Bbls) Net Long Position (MMBtu) 2017 (282,000 ) (29,043,200 ) (15,547,868 ) 2,075,000 2018 (772,000 ) (17,855,000 ) (2,262,338 ) 2,350,000 2019 (150,000 ) — 292,700 2,025,000 2020 (50,000 ) — 238,548 —

Partnership Equity and Distri38

Partnership Equity and Distributions (Tables)	6 Months Ended
	Jun. 30, 2018
Equity [Abstract]
Cash Distribution	The following table presents our cash distributions paid in 2018 and 2017 : Payment Date Per Unit Distribution Total Cash Distribution (millions) Distributions to common unitholders May 15, 2018 $ 0.7800 $ 155 February 14, 2018 $ 0.7800 $ 194 November 14, 2017 $ 0.7800 $ 155 August 14, 2017 $ 0.7800 $ 134 May 15, 2017 $ 0.7800 $ 135 Distributions to Series A Preferred unitholders June 15, 2018 $ 41.9965 $ 21

Business Segments (Tables)

Business Segments (Tables)	6 Months Ended
	Jun. 30, 2018
Segment Reporting [Abstract]
Segment Information	Three Months Ended June 30, 2018 Gathering and Processing Logistics and Marketing Other Eliminations Total (millions) Total operating revenue $ 1,314 $ 2,192 $ — $ (1,189 ) $ 2,317 Gross margin (a) $ 333 $ 56 $ — $ — $ 389 Operating and maintenance expense (169 ) (11 ) (5 ) — (185 ) Depreciation and amortization expense (87 ) (3 ) (7 ) — (97 ) General and administrative expense (2 ) (3 ) (65 ) — (70 ) Other expense — (3 ) — — (3 ) Earnings from unconsolidated affiliates 2 94 — — 96 Interest expense — — (67 ) — (67 ) Income tax expense — — (1 ) — (1 ) Net income (loss) $ 77 $ 130 $ (145 ) $ — $ 62 Net income attributable to noncontrolling interests (1 ) — — — (1 ) Net income (loss) attributable to partners $ 76 $ 130 $ (145 ) $ — $ 61 Non-cash derivative mark-to-market (b) $ (42 ) $ 5 $ — $ — $ (37 ) Capital expenditures $ 140 $ — $ 4 $ — $ 144 Investments in unconsolidated affiliates, net $ — $ 66 $ — $ — $ 66 Three Months Ended June 30, 2017 : Gathering and Processing Logistics and Marketing Other Eliminations Total (millions) Total operating revenue $ 1,269 $ 1,756 $ — $ (1,076 ) $ 1,949 Gross margin (a) $ 342 $ 50 $ — $ — $ 392 Operating and maintenance expense (162 ) (13 ) (3 ) — (178 ) Depreciation and amortization expense (86 ) (3 ) (5 ) — (94 ) General and administrative expense (7 ) (2 ) (62 ) — (71 ) Other expense (3 ) (2 ) — — (5 ) Gain on sale of assets, net 34 — — — 34 Earnings from unconsolidated affiliates 24 62 — — 86 Interest expense — — (73 ) — (73 ) Income tax expense — — (2 ) — (2 ) Net income (loss) $ 142 $ 92 $ (145 ) $ — $ 89 Net income attributable to noncontrolling interests (1 ) — — — (1 ) Net income (loss) attributable to partners $ 141 $ 92 $ (145 ) $ — $ 88 Non-cash derivative mark-to-market (b) $ 16 $ 8 $ — $ — $ 24 Capital expenditures $ 103 $ — $ 8 $ — $ 111 Investments in unconsolidated affiliates, net $ — $ 21 $ — $ — $ 21 Six Months Ended June 30, 2018 : Gathering and Processing Logistics and Marketing Other Eliminations Total (millions) Total operating revenue $ 2,600 $ 4,171 $ — $ (2,315 ) $ 4,456 Gross margin (a) $ 685 $ 74 $ — $ — $ 759 Operating and maintenance expense (317 ) (22 ) (8 ) — (347 ) Depreciation and amortization expense (171 ) (6 ) (14 ) — (191 ) General and administrative expense (6 ) (6 ) (117 ) — (129 ) Other expense, net (3 ) (2 ) — — (5 ) Earnings from unconsolidated affiliates 3 171 — — 174 Interest expense — — (134 ) — (134 ) Income tax expense — — (2 ) — (2 ) Net income (loss) $ 191 $ 209 $ (275 ) $ — $ 125 Net income attributable to noncontrolling interests (2 ) — — — (2 ) Net income (loss) attributable to partners $ 189 $ 209 $ (275 ) $ — $ 123 Non-cash derivative mark-to-market (b) $ (28 ) $ (38 ) $ — $ — $ (66 ) Capital expenditures $ 260 $ 1 $ 7 $ — $ 268 Investments in unconsolidated affiliates, net $ 1 $ 125 $ — $ — $ 126 Six Months Ended June 30, 2017 : Gathering and Processing Logistics and Marketing Other Eliminations Total (millions) Total operating revenue $ 2,628 $ 3,683 $ — $ (2,241 ) $ 4,070 Gross margin (a) $ 718 $ 108 $ — $ — $ 826 Operating and maintenance expense (315 ) (22 ) (8 ) — (345 ) Depreciation and amortization expense (171 ) (7 ) (10 ) — (188 ) General and administrative expense (13 ) (5 ) (115 ) — (133 ) Other expense (3 ) (11 ) (1 ) — (15 ) Gain on sale of assets, net 34 — — — 34 Earnings from unconsolidated affiliates 44 116 — — 160 Interest expense — — (146 ) — (146 ) Income tax expense — — (3 ) — (3 ) Net income (loss) $ 294 $ 179 $ (283 ) $ — $ 190 Net income attributable to noncontrolling interests (1 ) — — — (1 ) Net income (loss) attributable to partners $ 293 $ 179 $ (283 ) $ — $ 189 Non-cash derivative mark-to-market (b) $ 47 $ 13 $ — $ — $ 60 Capital expenditures $ 146 $ 1 $ 12 $ — $ 159 Investments in unconsolidated affiliates, net $ — $ 41 $ — $ — $ 41 June 30, December 31, 2018 2017 (millions) Segment long-term assets: Gathering and Processing $ 9,048 $ 8,943 Logistics and Marketing 3,462 3,348 Other (c) 249 265 Total long-term assets 12,759 12,556 Current assets 1,282 1,322 Total assets $ 14,041 $ 13,878 (a) Gross margin consists of total operating revenues, including commodity derivative activity, less purchases and related costs. Gross margin is viewed as a non-GAAP financial measure under the rules of the SEC, but is included as a supplemental disclosure because it is a primary performance measure used by management as it represents the results of product sales versus product purchases. As an indicator of our operating performance, gross margin should not be considered an alternative to, or more meaningful than, net income or net cash provided by operating activities as determined in accordance with GAAP. Our gross margin may not be comparable to a similarly titled measure of another company because other entities may not calculate gross margin in the same manner. (b) Non-cash commodity derivative mark-to-market is included in gross margin, along with cash settlements for our commodity derivative contracts. (c) Other long-term assets not allocable to segments consist of corporate leasehold improvements and other long-term assets.

Supplemental Cash Flow Inform40

Supplemental Cash Flow Information (Tables)	6 Months Ended
	Jun. 30, 2018
Additional Cash Flow Elements and Supplemental Cash Flow Information [Abstract]
Summary of Supplemental Cash Flow Information	Six Months Ended June 30, 2018 2017 (millions) Cash paid for interest: Cash paid for interest, net of amounts capitalized $ 129 $ 143 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 $ 42 $ 33 Other non-cash changes in property, plant and equipment $ — $ (2 ) Issuance of common and general partner units $ — $ 1,125 Deficit purchase price $ — $ 3,094

Condensed Consolidating Finan41

Condensed Consolidating Financial Information (Tables)	6 Months Ended
	Jun. 30, 2018
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Condensed Consolidating Balance Sheets	Condensed Consolidating Balance Sheet June 30, 2018 Parent Guarantor Subsidiary Issuer Non-Guarantor Subsidiaries Consolidating Adjustments Consolidated (millions) ASSETS Current assets: Cash and cash equivalents $ — $ — $ 4 $ — $ 4 Accounts receivable, net — — 1,029 — 1,029 Inventories — — 47 — 47 Other — — 202 — 202 Total current assets — — 1,282 — 1,282 Property, plant and equipment, net — — 9,080 — 9,080 Goodwill and intangible assets, net — — 332 — 332 Advances receivable — consolidated subsidiaries 2,680 1,763 — (4,443 ) — Investments in consolidated subsidiaries 4,643 7,785 — (12,428 ) — Investments in unconsolidated affiliates — — 3,165 — 3,165 Other long-term assets — — 182 — 182 Total assets $ 7,323 $ 9,548 $ 14,041 $ (16,871 ) $ 14,041 LIABILITIES AND EQUITY Accounts payable and other current liabilities $ — $ 70 $ 1,492 $ — $ 1,562 Current maturities of long-term debt — 325 — — 325 Advances payable — consolidated subsidiaries — — 4,443 (4,443 ) — Long-term debt — 4,510 — — 4,510 Other long-term liabilities — — 291 — 291 Total liabilities — 4,905 6,226 (4,443 ) 6,688 Commitments and contingent liabilities Equity: Partners’ equity: Net equity 7,323 4,646 7,790 (12,428 ) 7,331 Accumulated other comprehensive loss — (3 ) (5 ) — (8 ) Total partners’ equity 7,323 4,643 7,785 (12,428 ) 7,323 Noncontrolling interests — — 30 — 30 Total equity 7,323 4,643 7,815 (12,428 ) 7,353 Total liabilities and equity $ 7,323 $ 9,548 $ 14,041 $ (16,871 ) $ 14,041 Condensed Consolidating Balance Sheet December 31, 2017 Parent Guarantor Subsidiary Issuer Non-Guarantor Subsidiaries Consolidating Adjustments Consolidated (millions) ASSETS Current assets: Cash and cash equivalents $ — $ 155 $ 1 $ — $ 156 Accounts receivable, net — — 981 — 981 Inventories — — 68 — 68 Other — — 117 — 117 Total current assets — 155 1,167 — 1,322 Property, plant and equipment, net — — 8,983 — 8,983 Goodwill and intangible assets, net — — 337 — 337 Advances receivable — consolidated subsidiaries 2,895 1,614 — (4,509 ) — Investments in consolidated subsidiaries 4,513 7,522 — (12,035 ) — Investments in unconsolidated affiliates — — 3,050 — 3,050 Other long-term assets — — 186 — 186 Total assets $ 7,408 $ 9,291 $ 13,723 $ (16,544 ) $ 13,878 LIABILITIES AND EQUITY Accounts payable and other current liabilities $ — $ 71 $ 1,417 $ — $ 1,488 Advances payable — consolidated subsidiaries — — 4,509 (4,509 ) — Long-term debt — 4,707 — — 4,707 Other long-term liabilities — — 245 — 245 Total liabilities — 4,778 6,171 (4,509 ) 6,440 Commitments and contingent liabilities Equity: Partners’ equity: Net equity 7,408 4,517 7,527 (12,035 ) 7,417 Accumulated other comprehensive loss — (4 ) (5 ) — (9 ) Total partners’ equity 7,408 4,513 7,522 (12,035 ) 7,408 Noncontrolling interests — — 30 — 30 Total equity 7,408 4,513 7,552 (12,035 ) 7,438 Total liabilities and equity $ 7,408 $ 9,291 $ 13,723 $ (16,544 ) $ 13,878
Condensed Income Statement	Condensed Consolidating Statement of Operations Six Months Ended June 30, 2018 Parent Guarantor Subsidiary Issuer Non- Guarantor Subsidiaries Consolidating Adjustments Consolidated (millions) Operating revenues: Sales of natural gas, NGLs and condensate $ — $ — $ 4,326 $ — $ 4,326 Transportation, processing and other — — 238 — 238 Trading and marketing losses, net — — (108 ) — (108 ) Total operating revenues — — 4,456 — 4,456 Operating costs and expenses: Purchases and related costs — — 3,697 — 3,697 Operating and maintenance expense — — 347 — 347 Depreciation and amortization expense — — 191 — 191 General and administrative expense — — 129 — 129 Other expense, net — — 5 — 5 Total operating costs and expenses — — 4,369 — 4,369 Operating income — — 87 — 87 Interest expense, net — (134 ) — — (134 ) Income from consolidated subsidiaries 123 257 — (380 ) — Earnings from unconsolidated affiliates — — 174 — 174 Income before income taxes 123 123 261 (380 ) 127 Income tax expense — — (2 ) — (2 ) Net income 123 123 259 (380 ) 125 Net income attributable to noncontrolling interests — — (2 ) — (2 ) Net income attributable to partners $ 123 $ 123 $ 257 $ (380 ) $ 123 Condensed Consolidating Statement of Operations Six Months Ended June 30, 2017 Parent Guarantor Subsidiary Issuer Non- Guarantor Subsidiaries Consolidating Adjustments Consolidated (millions) Operating revenues: Sales of natural gas, NGLs and condensate $ — $ — $ 3,705 $ — $ 3,705 Transportation, processing and other — — 312 — 312 Trading and marketing losses, net — — 53 — 53 Total operating revenues — — 4,070 — 4,070 Operating costs and expenses: Purchases and related costs — — 3,244 — 3,244 Operating and maintenance expense — — 345 — 345 Depreciation and amortization expense — — 188 — 188 General and administrative expense — — 133 — 133 Gain on sale of assets, net — — (34 ) — (34 ) Other expense, net — — 15 — 15 Total operating costs and expenses — — 3,891 — 3,891 Operating income — — 179 — 179 Interest expense, net — (146 ) — — (146 ) Income from consolidated subsidiaries 189 335 — (524 ) — Earnings from unconsolidated affiliates — — 160 — 160 Income before income taxes 189 189 339 (524 ) 193 Income tax expense — — (3 ) — (3 ) Net income 189 189 336 (524 ) 190 Net income attributable to noncontrolling interests — — (1 ) — (1 ) Net income attributable to partners $ 189 $ 189 $ 335 $ (524 ) $ 189
Condensed Statement of Comprehensive Income	Condensed Consolidating Statement of Comprehensive Income Six Months Ended June 30, 2018 Parent Guarantor Subsidiary Issuer Non-Guarantor Subsidiaries Consolidating Adjustments Consolidated (millions) Net income $ 123 $ 123 $ 259 $ (380 ) $ 125 Other comprehensive income: Reclassification of cash flow hedge losses into earnings — 1 — — 1 Other comprehensive income from consolidated subsidiaries 1 — — (1 ) — Total other comprehensive income 1 1 — (1 ) 1 Total comprehensive income 124 124 259 (381 ) 126 Total comprehensive income attributable to noncontrolling interests — — (2 ) — (2 ) Total comprehensive income attributable to partners $ 124 $ 124 $ 257 $ (381 ) $ 124 Condensed Consolidating Statement of Comprehensive Income Six Months Ended June 30, 2017 Parent Guarantor Subsidiary Issuer Non-Guarantor Subsidiaries Consolidating Adjustments Consolidated (millions) Net income $ 189 $ 189 $ 336 $ (524 ) $ 190 Other comprehensive income: Reclassification of cash flow hedge losses into earnings — 1 — — 1 Other comprehensive income from consolidated subsidiaries 1 — — (1 ) — Total other comprehensive income 1 1 — (1 ) 1 Total comprehensive income 190 190 336 (525 ) 191 Total comprehensive income attributable to noncontrolling interests — — (1 ) — (1 ) Total comprehensive income attributable to partners $ 190 $ 190 $ 335 $ (525 ) $ 190
Condensed Consolidating Statements of Cash Flows	Condensed Consolidating Statement of Cash Flows Six Months Ended June 30, 2018 Parent Guarantor Subsidiary Issuer Non-Guarantor Subsidiaries Consolidating Adjustments Consolidated (millions) OPERATING ACTIVITIES Net cash (used in) provided by operating activities $ — $ (131 ) $ 462 $ — $ 331 INVESTING ACTIVITIES: Intercompany transfers 215 (149 ) — (66 ) — Capital expenditures — — (268 ) — (268 ) Investments in unconsolidated affiliates, net — — (126 ) — (126 ) Proceeds from sale of assets — — 3 — 3 Net cash provided by (used in) investing activities 215 (149 ) (391 ) (66 ) (391 ) FINANCING ACTIVITIES: Intercompany transfers — — (66 ) 66 — Proceeds from long-term debt — 1,803 — — 1,803 Payments of long-term debt — (1,678 ) — — (1,678 ) Proceeds from issuance of preferred limited partner units, net of offering costs 155 — — — 155 Distributions to preferred limited partners (21 ) — — — (21 ) Distributions to limited partners and general partner (349 ) — — — (349 ) Distributions to noncontrolling interests — — (2 ) — (2 ) Net cash (used in) provided by financing activities (215 ) 125 (68 ) 66 (92 ) Net change in cash and cash equivalents — (155 ) 3 — (152 ) Cash and cash equivalents, beginning of period — 155 1 — 156 Cash and cash equivalents, end of period $ — $ — $ 4 $ — $ 4 Condensed Consolidating Statements of Cash Flows Six Months Ended June 30, 2017 Parent Guarantor Subsidiary Issuer Non-Guarantor Subsidiaries Consolidating Adjustments Consolidated (millions) OPERATING ACTIVITIES Net cash (used in) provided by operating activities $ — $ (143 ) $ 503 $ — $ 360 INVESTING ACTIVITIES: Intercompany transfers 256 590 — (846 ) — Capital expenditures — — (159 ) — (159 ) Investments in unconsolidated affiliates, net — — (41 ) — (41 ) Proceeds from sale of assets — — 129 — 129 Net cash provided by (used in) investing activities 256 590 (71 ) (846 ) (71 ) FINANCING ACTIVITIES: Intercompany transfers — — (846 ) 846 — Payments of long-term debt — (195 ) — — (195 ) Net change in advances to predecessor from DCP Midstream, LLC — — 418 — 418 Distributions to limited partners and general partner (256 ) — — — (256 ) Distributions to noncontrolling interests — — (4 ) — (4 ) Other — (2 ) — — (2 ) Net cash (used in) provided by financing activities (256 ) (197 ) (432 ) 846 (39 ) Net change in cash and cash equivalents — 250 — — 250 Cash and cash equivalents, beginning of period — — 1 — 1 Cash and cash equivalents, end of period $ — $ 250 $ 1 $ — $ 251

Description of Business and B42

Description of Business and Basis of Presentation - Additional Information (Detail)	6 Months Ended
	Jun. 30, 2018
Investments in Greater Than 20%
Business Acquisition [Line Items]
Equity method ownership investment (as percent)	20.00%
Investments in Less Than 20%
Business Acquisition [Line Items]
Equity method ownership investment (as percent)	20.00%
DCP Midstream, LLC | DCP Midstream GP, LLC
Business Acquisition [Line Items]
Ownership interest percentage by parent	100.00%
DCP Midstream, LLC | DCP Midstream LP
Business Acquisition [Line Items]
Ownership interest percentage by parent	38.10%
Phillips 66 | DCP Midstream, LLC
Business Acquisition [Line Items]
Ownership interest percentage by parent	50.00%
Enbridge | DCP Midstream, LLC
Business Acquisition [Line Items]
Ownership interest percentage by parent	50.00%

Revenue Impact of Adoption (Det

Revenue Impact of Adoption (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Item Effected [Line Items]
Sales Revenue, Goods, Net	$ 2,257	$ 1,772	$ 4,326	$ 3,705
Transportation, processing and other	127	155	238	312
Purchases and related costs	1,928	1,557	3,697	3,244
Net income	62	89	125	190
Third Party
Item Effected [Line Items]
Sales Revenue, Goods, Net	1,849	1,494	3,593	3,138
Purchases and related costs	1,703	$ 1,419	3,307	$ 2,978
Calculated under Revenue Guidance in Effect before Topic 606 [Member]
Item Effected [Line Items]
Transportation, processing and other	39		79
Net income	0		0
Calculated under Revenue Guidance in Effect before Topic 606 [Member] | Third Party
Item Effected [Line Items]
Sales Revenue, Goods, Net			75
Purchases and related costs	83		154
Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
Item Effected [Line Items]
Transportation, processing and other	166		317
Net income	62		125
Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Third Party
Item Effected [Line Items]
Sales Revenue, Goods, Net	1,893		3,668
Purchases and related costs	$ 1,786		$ 3,461

Revenue Recognition (Details)

Revenue Recognition (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Disaggregation of Revenue [Line Items]
Sales of natural gas, NGLs and condensate	$ 2,257	$ 1,772	$ 4,326	$ 3,705
Transportation, processing and other	127	155	238	312
Trading and marketing (losses) gains, net	(67)	22	(108)	53
Total operating revenues	2,317	$ 1,949	4,456	$ 4,070
Revenue from contract with customer not within the scope of Topic 606	1,108		1,901
Natural Gas
Disaggregation of Revenue [Line Items]
Sales of natural gas, NGLs and condensate	508		1,088
NGLs and Condensate [Member]
Disaggregation of Revenue [Line Items]
Sales of natural gas, NGLs and condensate	1,749		3,238
Logistics and Marketing
Disaggregation of Revenue [Line Items]
Transportation, processing and other	16		30
Trading and marketing (losses) gains, net	(1)		(45)
Total operating revenues	2,192		4,171
Logistics and Marketing | Natural Gas
Disaggregation of Revenue [Line Items]
Sales of natural gas, NGLs and condensate	463		1,016
Logistics and Marketing | NGLs and Condensate [Member]
Disaggregation of Revenue [Line Items]
Sales of natural gas, NGLs and condensate	1,714		3,170
Eliminations
Disaggregation of Revenue [Line Items]
Transportation, processing and other	(1)		(1)
Trading and marketing (losses) gains, net	0		0
Total operating revenues	(1,189)		(2,315)
Eliminations | Natural Gas
Disaggregation of Revenue [Line Items]
Sales of natural gas, NGLs and condensate	(353)		(772)
Eliminations | NGLs and Condensate [Member]
Disaggregation of Revenue [Line Items]
Sales of natural gas, NGLs and condensate	(835)		(1,542)
Gathering and Processing
Disaggregation of Revenue [Line Items]
Transportation, processing and other	112		209
Trading and marketing (losses) gains, net	(66)		(63)
Total operating revenues	1,314		2,600
Gathering and Processing | Natural Gas
Disaggregation of Revenue [Line Items]
Sales of natural gas, NGLs and condensate	398		844
Gathering and Processing | NGLs and Condensate [Member]
Disaggregation of Revenue [Line Items]
Sales of natural gas, NGLs and condensate	$ 870		$ 1,610

Contract Assets and Liabiliti45

Contract Assets and Liabilities (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2018	Jan. 01, 2018	Dec. 31, 2017
Contract Assets and Liabilities [Abstract]
Contract with Customer, Liability	$ 35		$ 0
Cumulative effect of implementation of Topic 606		$ 36
Contract with Customer, Liability, Revenue Recognized	(1)
Contract with Customer, Liability, Increase (Decrease) for Contract Acquired in Business Combination	0
Contract with Customer, Liability, Current	0
Contract with Customer, Liability, Noncurrent	$ 35
Revenue, Performance Obligation, Recognition Period in Years	35 years

Agreements and Transactions w46

Agreements and Transactions with Affiliates - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Affiliated Entity | Natural Gas Liquids
Related Party Transaction [Line Items]
Production Committed To Related Parties, Percent	18.00%		18.00%
Affiliated Entity | Phillips 66 | Chevron Phillips Chemical LLC
Related Party Transaction [Line Items]
Equity method ownership investment (as percent)	50.00%		50.00%
Operating Expense
Related Party Transaction [Line Items]
Labor and related expense	$ 53	$ 49	$ 102	$ 99
General and Administrative Expense
Related Party Transaction [Line Items]
Labor and related expense	$ 47	$ 39	$ 85	$ 70

Agreements and Transactions w47

Agreements and Transactions with Affiliates - Transactions with Affiliates (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Related Party Transaction [Line Items]
Sales of natural gas, NGLs and condensate	$ 2,257	$ 1,772	$ 4,326	$ 3,705
Transportation, processing and other	127	155	238	312
Purchases and related costs	1,928	1,557	3,697	3,244
Operating and maintenance expense	185	178	347	345
Affiliated Entity | Unconsolidated Affiliates
Related Party Transaction [Line Items]
Sales of natural gas, NGLs and condensate	14	12	25	22
Transportation, processing and other	2	2	3	3
Purchases and related costs	179	119	324	232
Affiliated Entity | Phillips 66
Related Party Transaction [Line Items]
Sales of natural gas, NGLs and condensate	381	251	683	525
Purchases and related costs	28	8	38	15
Operating and maintenance expense	3	0	6	1
Affiliated Entity | Enbridge
Related Party Transaction [Line Items]
Sales of natural gas, NGLs and condensate	13	15	25	20
Purchases and related costs	18	11	28	19
Operating and maintenance expense	$ 0	$ 0	$ 0	$ 1
Natural Gas Liquids | Affiliated Entity
Related Party Transaction [Line Items]
Production Committed To Related Parties, Percent	18.00%		18.00%

Agreements and Transactions w48

Agreements and Transactions with Affiliates - Balances with Affiliates (Detail) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Related Party Transaction [Line Items]
Accounts receivable	$ 189	$ 191
Accounts payable	112	68
Unconsolidated Affiliates
Related Party Transaction [Line Items]
Accounts receivable	22	24
Accounts payable	67	53
Other assets	3	4
Phillips 66
Related Party Transaction [Line Items]
Accounts receivable	153	156
Accounts payable	24	6
Other assets	1	0
Enbridge
Related Party Transaction [Line Items]
Accounts receivable	14	11
Accounts payable	$ 21	$ 9

Inventories - Schedule of Inven

Inventories - Schedule of Inventories (Detail) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Components Of Inventory [Line Items]
Total inventories	$ 47	$ 68
Natural Gas
Components Of Inventory [Line Items]
Total inventories	18	30
Natural Gas Liquids
Components Of Inventory [Line Items]
Total inventories	$ 29	$ 38

Inventories - Additional Inform

Inventories - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Inventory Disclosure [Abstract]
Lower of cost or market adjustment	$ 0	$ 0	$ 0	$ 0

Property, Plant and Equipment -

Property, Plant and Equipment - Classification of Property, Plant and Equipment (Detail) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 14,823	$ 14,532
Accumulated depreciation	(5,743)	(5,549)
Property, plant and equipment, net	9,080	8,983
Gathering and transmission systems
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 8,599	8,473
Gathering and transmission systems | Minimum
Property, Plant and Equipment [Line Items]
Depreciable life of property, plant and equipment	20 years
Gathering and transmission systems | Maximum
Property, Plant and Equipment [Line Items]
Depreciable life of property, plant and equipment	50 years
Processing, storage and terminal facilities
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 5,141	5,128
Processing, storage and terminal facilities | Minimum
Property, Plant and Equipment [Line Items]
Depreciable life of property, plant and equipment	35 years
Processing, storage and terminal facilities | Maximum
Property, Plant and Equipment [Line Items]
Depreciable life of property, plant and equipment	60 years
Other
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 563	557
Other | Minimum
Property, Plant and Equipment [Line Items]
Depreciable life of property, plant and equipment	3 years
Other | Maximum
Property, Plant and Equipment [Line Items]
Depreciable life of property, plant and equipment	30 years
Construction work in progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 520	$ 374

Property, Plant and Equipment52

Property, Plant and Equipment - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Property, Plant and Equipment [Abstract]
Interest capitalized on construction projects	$ 6	$ 1	$ 11	$ 2
Depreciation expense	$ 94	$ 90	$ 186	$ 182

Investments In Unconsolidated53

Investments In Unconsolidated Affiliates - Investments In Unconsolidated Affiliates (Detail) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Schedule of Equity Method Investments [Line Items]
Investments in unconsolidated affiliates	$ 3,165	$ 3,050
DCP Sand Hills Pipeline, LLC
Schedule of Equity Method Investments [Line Items]
Equity method ownership investment (as percent)	66.67%
Investments in unconsolidated affiliates	$ 1,730	1,633
DCP Southern Hills Pipeline, LLC
Schedule of Equity Method Investments [Line Items]
Equity method ownership investment (as percent)	66.67%
Investments in unconsolidated affiliates	$ 735	739
Discovery Producer Services LLC
Schedule of Equity Method Investments [Line Items]
Equity method ownership investment (as percent)	40.00%
Investments in unconsolidated affiliates	$ 354	362
Front Range Pipeline LLC
Schedule of Equity Method Investments [Line Items]
Equity method ownership investment (as percent)	33.33%
Investments in unconsolidated affiliates	$ 163	165
Texas Express Pipeline LLC
Schedule of Equity Method Investments [Line Items]
Equity method ownership investment (as percent)	10.00%
Investments in unconsolidated affiliates	$ 91	90
Panola Pipeline Company, LLC
Schedule of Equity Method Investments [Line Items]
Equity method ownership investment (as percent)	15.00%
Investments in unconsolidated affiliates	$ 23	24
Mont Belvieu Enterprise Fractionator
Schedule of Equity Method Investments [Line Items]
Equity method ownership investment (as percent)	12.50%
Investments in unconsolidated affiliates	$ 25	23
Gulf Coast Express [Member]
Schedule of Equity Method Investments [Line Items]
Equity method ownership investment (as percent)	25.00%
Investments in unconsolidated affiliates	$ 28	0
Mont Belvieu 1 Fractionator
Schedule of Equity Method Investments [Line Items]
Equity method ownership investment (as percent)	20.00%
Investments in unconsolidated affiliates	$ 12	10
Other
Schedule of Equity Method Investments [Line Items]
Investments in unconsolidated affiliates	$ 4	$ 4

Investments in Unconsolidated54

Investments in Unconsolidated Affiliates - Earnings from Investments in Unconsolidated Affiliates (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Schedule of Equity Method Investments [Line Items]
Earnings from unconsolidated affiliates	$ 96	$ 86	$ 174	$ 160
DCP Sand Hills Pipeline, LLC
Schedule of Equity Method Investments [Line Items]
Earnings from unconsolidated affiliates	58	37	106	68
DCP Southern Hills Pipeline, LLC
Schedule of Equity Method Investments [Line Items]
Earnings from unconsolidated affiliates	16	13	29	24
Discovery Producer Services LLC
Schedule of Equity Method Investments [Line Items]
Earnings from unconsolidated affiliates	2	25	3	45
Front Range Pipeline LLC
Schedule of Equity Method Investments [Line Items]
Earnings from unconsolidated affiliates	5	3	10	7
Texas Express Pipeline LLC
Schedule of Equity Method Investments [Line Items]
Earnings from unconsolidated affiliates	8	1	10	3
Mont Belvieu Enterprise Fractionator
Schedule of Equity Method Investments [Line Items]
Earnings from unconsolidated affiliates	3	4	7	7
Mont Belvieu 1 Fractionator
Schedule of Equity Method Investments [Line Items]
Earnings from unconsolidated affiliates	4	3	8	4
Other
Schedule of Equity Method Investments [Line Items]
Earnings from unconsolidated affiliates	$ 0	$ 0	$ 1	$ 2

Investments in Unconsolidated55

Investments in Unconsolidated Affiliates - Equity Method Investment Summarized Financial Information, Statement of Operations (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Equity Method Investments and Joint Ventures [Abstract]
Operating revenue	$ 408	$ 368	$ 742	$ 705
Operating expenses	147	152	286	300
Net income	$ 260	$ 216	$ 454	$ 404

Investments in Unconsolidated56

Investments in Unconsolidated Affiliates - Equity Method Investment Summarized Financial Information, Balance Sheet (Detail) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Equity Method Investments and Joint Ventures [Abstract]
Current assets	$ 379	$ 244
Long-term assets	5,596	5,319
Current liabilities	(256)	(196)
Long-term liabilities	(227)	(200)
Net assets	$ 5,492	$ 5,167

Fair Value Measurement - Financ

Fair Value Measurement - Financial Instruments Carried at Fair Value (Detail) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Current Assets
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term investments	$ 3	$ 156
Current Assets | Commodity derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives	45	30
Long- Term Assets | Commodity derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives	8	3
Current Liabilities | Commodity derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives	(141)	(76)
Long- Term Liabilities | Commodity derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives	(29)	(15)
Level 1 | Current Assets
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term investments	3	156
Level 1 | Current Assets | Commodity derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives	36	10
Level 1 | Long- Term Assets | Commodity derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives	6	1
Level 1 | Current Liabilities | Commodity derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives	(77)	(29)
Level 1 | Long- Term Liabilities | Commodity derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives	(12)	(3)
Level 2 | Current Assets
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term investments	0	0
Level 2 | Current Assets | Commodity derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives	8	17
Level 2 | Long- Term Assets | Commodity derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives	1	1
Level 2 | Current Liabilities | Commodity derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives	(54)	(34)
Level 2 | Long- Term Liabilities | Commodity derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives	(10)	(11)
Level 3 | Current Assets
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short-term investments	0	0
Level 3 | Current Assets | Commodity derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives	1	3
Level 3 | Long- Term Assets | Commodity derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives	1	1
Level 3 | Current Liabilities | Commodity derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives	(10)	(13)
Level 3 | Long- Term Liabilities | Commodity derivatives
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Commodity derivatives	$ (7)	$ 1

Fair Value Measurement - Conden

Fair Value Measurement - Condensed Consolidated Balance Sheets for Derivative Financial Instruments (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Current Assets
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 2	$ 8	$ 3	$ 9
Net realized and unrealized gains (losses) included in earnings	1	3	0	1
Transfers out of Level 3	(2)	(3)	(2)	(2)
Settlements	0	(1)	0	(1)
Ending balance	1	7	1	7
Net unrealized gains (losses) on derivatives still held included in earnings	1	4	1	6
Long- Term Assets
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	0	2	1	5
Net realized and unrealized gains (losses) included in earnings	1	0	0	(3)
Transfers out of Level 3	0	0	0	0
Settlements	0	0	0	0
Ending balance	1	2	1	2
Net unrealized gains (losses) on derivatives still held included in earnings	1	0	0	(2)
Current Liabilities
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	(6)	(8)	(13)	(23)
Net realized and unrealized (losses) gains included in earnings	(14)	1	(12)	13
Transfers out of Level 3	8	3	12	3
Settlements	2	2	3	5
Ending balance	(10)	(2)	(10)	(2)
Net unrealized gains (losses) on derivatives still held included in earnings	(8)	0	(7)	3
Long- Term Liabilities
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	(3)	(3)	(1)	0
Net realized and unrealized (losses) gains included in earnings	(4)	0	(6)	(3)
Transfers out of Level 3	0	0	0	0
Settlements	0	0	0	0
Ending balance	(7)	(3)	(7)	(3)
Net unrealized gains (losses) on derivatives still held included in earnings	$ (4)	$ 0	$ (6)	$ (3)

Fair Value Measurement - Schedu

Fair Value Measurement - Schedule of Valuation Processes (Detail) $ in Millions	Jun. 30, 2018USD ($)$ / gal
Level 3 | Market Approach Valuation Technique | Derivative Liabilities | Natural Gas Liquids
Fair Value Inputs Assets And Liabilities Quantitative Information [Line Items]
Liabilities, fair value | $	$ (12)
Level 3 | Market Approach Valuation Technique | Derivative Liabilities | Natural Gas Liquids | Minimum
Fair Value Inputs Assets And Liabilities Quantitative Information [Line Items]
Forward Curve Range	0.14
Level 3 | Market Approach Valuation Technique | Derivative Liabilities | Natural Gas Liquids | Maximum
Fair Value Inputs Assets And Liabilities Quantitative Information [Line Items]
Forward Curve Range	1.49
Level 3 | Market Approach Valuation Technique | Derivative Liabilities | Natural Gas
Fair Value Inputs Assets And Liabilities Quantitative Information [Line Items]
Liabilities, fair value | $	$ (5)
Level 3 | Market Approach Valuation Technique | Derivative Liabilities | Natural Gas | Minimum
Fair Value Inputs Assets And Liabilities Quantitative Information [Line Items]
Forward Curve Range	1.57
Level 3 | Market Approach Valuation Technique | Derivative Liabilities | Natural Gas | Maximum
Fair Value Inputs Assets And Liabilities Quantitative Information [Line Items]
Forward Curve Range	2.66
Level 3 | Market Approach Valuation Technique | Derivative Assets | Natural Gas Liquids
Fair Value Inputs Assets And Liabilities Quantitative Information [Line Items]
Assets, fair value | $	$ 2
Level 3 | Market Approach Valuation Technique | Derivative Assets | Natural Gas Liquids | Minimum
Fair Value Inputs Assets And Liabilities Quantitative Information [Line Items]
Forward Curve Range	0.29
Level 3 | Market Approach Valuation Technique | Derivative Assets | Natural Gas Liquids | Maximum
Fair Value Inputs Assets And Liabilities Quantitative Information [Line Items]
Forward Curve Range	1.08
Affiliated Entity | Natural Gas Liquids
Fair Value Inputs Assets And Liabilities Quantitative Information [Line Items]
Production Committed To Related Parties, Percent	18.00%

Fair Value Measurement - Carryi

Fair Value Measurement - Carrying Value and Fair Value of Debt (Detail) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Total Debt, Carrying Value	$ 4,861	$ 4,736
Total Debt, Fair Value	$ 4,896	$ 4,885

Debt - Schedule of Long-Term De

Debt - Schedule of Long-Term Debt (Detail) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Facility [Line Items]
Fair value adjustments related to interest rate swap fair value hedges	$ 22	$ 23
Unamortized issuance costs	(26)	(29)
Unamortized discount	(11)	(12)
Total debt	4,835	4,707
Current maturities of long-term debt	325	0
Long-term debt	4,510	4,707
Credit Agreement
Facility [Line Items]
Credit Facility	$ 125	0
Weighted-average variable interest rate	3.452%
Line of Credit Facility, Maximum Borrowing Capacity	$ 1,400
Senior Notes | Issued November 2012, interest at 2.500% payable semi-annually, due December 2017
Facility [Line Items]
Debt interest rate percentage	2.50%
Senior Notes | Issued February 2009, interest at 9.750% payable semiannually, due March 2019
Facility [Line Items]
Senior Notes	$ 450	450
Debt interest rate percentage	9.75%
Senior Notes | Issued March 2014, interest at 2.700% payable semi-annually, due April 2019
Facility [Line Items]
Senior Notes	$ 325	325
Debt interest rate percentage	2.70%
Senior Notes | Issued March 2010, interest at 5.350% payable semiannually, due March 2020
Facility [Line Items]
Senior Notes	$ 600	600
Debt interest rate percentage	5.35%
Senior Notes | Issued September 2011, interest at 4.750% payable semiannually, due September 2021
Facility [Line Items]
Senior Notes	$ 500	500
Debt interest rate percentage	4.75%
Senior Notes | Issued March 2012, interest at 4.950% payable semi-annually, due April 2022
Facility [Line Items]
Senior Notes	$ 350	350
Debt interest rate percentage	4.95%
Senior Notes | Issued March 2013, interest at 3.875% payable semi-annually, due March 2023
Facility [Line Items]
Senior Notes	$ 500	500
Debt interest rate percentage	3.875%
Senior Notes | Issued August 2000, interest at 8.125% payable semi-annually, due August 2030
Facility [Line Items]
Senior Notes	$ 300	300
Debt interest rate percentage	8.125%
Senior Notes | Issued October 2006, interest at 6.450% payable semi-annually, due November 2036
Facility [Line Items]
Senior Notes	$ 300	300
Debt interest rate percentage	6.45%
Senior Notes | Issued September 2007, interest at 6.750% payable semi-annually, due September 2037
Facility [Line Items]
Senior Notes	$ 450	450
Debt interest rate percentage	6.75%
Senior Notes | Issued March 2014, interest at 5.600% payable semi-annually, due April 2044
Facility [Line Items]
Senior Notes	$ 400	400
Debt interest rate percentage	5.60%
Junior subordinated notes | Issued May 2013, interest at 5.850% payable semi-annually, due May 2043
Facility [Line Items]
Senior Notes	$ 550	$ 550
Debt interest rate percentage	5.85%

Debt - Additional Information (

Debt - Additional Information (Detail) $ in Millions	6 Months Ended
	Jun. 30, 2018USD ($)	Dec. 31, 2017
Debt Instrument [Line Items]
Letter of credit amount outstanding	$ 13
Line of Credit Facility, Borrowing Capacity, Description	$ 500
Interest deferment period	5 years
Credit Agreement
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 1,400
Basis spread determined by credit rating	0.45%
Commitment fee percentage	0.30%
Unused capacity under the credit agreement	$ 1,250
Letter of credit amount outstanding	25
Debt covenants, maximum borrowing amount	$ 1,250
Credit Agreement | LIBOR
Debt Instrument [Line Items]
Variable rate basis spread	1.45%
Credit Agreement | Federal Funds Rate
Debt Instrument [Line Items]
Variable rate basis spread	0.50%
Credit Agreement | LIBOR Market Index
Debt Instrument [Line Items]
Variable rate basis spread	1.00%
Credit Agreement | Maximum
Debt Instrument [Line Items]
Maximum leverage ratio in event of acquisition		5.50
Credit Agreement | Quarter Ending June 30, 2018 | Maximum
Debt Instrument [Line Items]
Maximum leverage ratio		5.25
Credit Agreement | Quarters After June 30, 2018 | Maximum
Debt Instrument [Line Items]
Maximum leverage ratio		5

Debt - Future Maturities of Lon

Debt - Future Maturities of Long-Term Debt (Detail) $ in Millions	Jun. 30, 2018USD ($)
Maturities of Long-term Debt [Abstract]
2,018	$ 0
2,019	775
2,020	600
2,021	500
2,022	475
Thereafter	2,500
Total long-term debt	$ 4,850

Risk Management and Hedging A64

Risk Management and Hedging Activities - Additional Information (Detail) - USD ($) $ in Millions	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016
Derivative [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	$ (8)		$ (9)
Collateral, cash deposits	138
Letter of credit amount outstanding	13
Collateral, cash held	6
Letters of credit received	43
Commodity derivatives
Derivative [Line Items]
Derivative contracts that contain credit-risk related contingent features that were in a net liability position (less than)	$ 1
Affiliated Entity | Natural Gas Liquids
Derivative [Line Items]
Percent of NGL production committed	18.00%
Accumulated Net Gain (Loss) from Cash Flow Hedges
Derivative [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	$ (8)	$ (9)	(9)	$ (9)	$ (9)	$ (8)
Accumulated Net Gain (Loss) from Cash Flow Hedges | Commodity derivatives
Derivative [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	$ (6)	$ (6)	$ (6)	$ (6)	$ (6)	$ (6)

Risk Management and Hedging A65

Risk Management and Hedging Activities - Summary of Gross and Net Amounts of Derivative Instruments (Detail) - Commodity derivatives - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Offsetting Assets [Line Items]
Gross Amounts of Assets Presented in the Balance Sheet	$ 53	$ 33
Amounts Not Offset in the Balance Sheet - Financial Instruments	0	0
Net Amount	53	33
Offsetting Liabilities [Line Items]
Gross Amounts of Liabilities Presented in the Balance Sheet	(170)	(91)
Amounts Not Offset in the Balance Sheet - Financial Instruments	0	0
Net Amount	$ (170)	$ (91)

Risk Management and Hedging A66

Risk Management and Hedging Activities - Schedule of Designated and Non-Designated Derivative Instruments in Statement of Financial Position, Fair Value (Detail) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Derivative Asset [Abstract]
Derivative Instruments and Hedges, Current Assets	$ 45	$ 30
Derivative Instruments and Hedges, Assets, Noncurrent	8	3
Derivative Liability [Abstract]
Derivative Instruments and Hedges, Current Liabilities	141	76
Derivative Instruments and Hedges, Liabilities, Noncurrent	29	15
Commodity derivatives | Derivative Asset Not Designated As Hedging Instruments [Member]
Derivative Asset [Abstract]
Derivative Instruments and Hedges, Current Assets	45	30
Derivative Instruments and Hedges, Assets, Noncurrent	8	3
Derivative Instruments Not Designated as Hedging Instruments, Total Assets, at Fair Value	53	33
Commodity derivatives | Derivative Liabilities Not Designated As Hedging Instruments [Member]
Derivative Liability [Abstract]
Derivative Instruments and Hedges, Current Liabilities	141	76
Derivative Instruments and Hedges, Liabilities, Noncurrent	29	15
Derivative Instruments Not Designated as Hedging Instruments, Total Liabilities, at Fair Value	$ 170	$ 91

Risk Management and Hedging A67

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

Risk Management and Hedging A68

Risk Management and Hedging Activities - Schedule of Changes in Derivative Instruments not Designated as Hedging Instruments (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Derivative [Line Items]
Trading and marketing gains, net	$ (67)	$ 22	$ (108)	$ 53
Derivative Assets Not Designated As Hedging Instruments | Third Party | Commodity derivatives
Derivative [Line Items]
Realized losses	(30)	(2)	(42)	(7)
Unrealized (losses) gains	(37)	24	(66)	60
Trading and marketing gains, net	$ (67)	$ 22	$ (108)	$ 53

Risk Management and Hedging A69

Risk Management and Hedging Activities - Schedule of Net Long or Short Positions Expected to be Realized (Detail)	6 Months Ended
	Jun. 30, 2018MMBTUbbl	Jun. 30, 2017MMBTUbbl
Crude Oil
Net (Short) Position, Volume [Abstract]
Net (Short) Position (Bbls), Year One | bbl	(1,646,000)	(282,000)
Net (Short) Position (Bbls), Year Two | bbl	(1,900,000)	(772,000)
Net (Short) Position (Bbls), Year Three | bbl	(128,000)	(150,000)
Net (Short) Position (Bbls), Year Four | bbl	0	(50,000)
Natural Gas
Net Long (Short) Position, MMBtu [Abstract]
Net Long (Short) Position (MMBtu), Year One | MMBTU	(21,623,200)	(29,043,200)
Net Long (Short) Position (MMBtu), Year Two | MMBTU	0	(17,855,000)
Net Long (Short) Position (MMBtu), Year Three | MMBTU	0	0
Net Long (Short) Position (MMBtu), Year Four | MMBTU	0	0
Natural Gas Liquids
Net (Short) Position, Volume [Abstract]
Net (Short) Position (Bbls), Year One | bbl	(25,737,691)	(15,547,868)
Net (Short) Position (Bbls), Year Two | bbl	(19,314,335)	(2,262,338)
Net (Short) Position (Bbls), Year Three | bbl	(13,568,452)	292,700
Net (Short) Position (Bbls), Year Four | bbl	(5,750,000)	238,548
Natural Gas Basis Swaps
Net Long (Short) Position, MMBtu [Abstract]
Net Long (Short) Position (MMBtu), Year One | MMBTU	2,257,500	2,075,000
Net Long (Short) Position (MMBtu), Year Two | MMBTU	1,512,500	2,350,000
Net Long (Short) Position (MMBtu), Year Three | MMBTU	3,660,000	2,025,000
Net Long (Short) Position (MMBtu), Year Four | MMBTU	0	0

Partnership Equity and Distri70

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

Partnership Equity and Distri71

Partnership Equity and Distributions - Cash Distribution (Detail) - USD ($)	Jun. 15, 2018	May 15, 2018	Feb. 14, 2018	Nov. 14, 2017	Aug. 14, 2017	May 15, 2017	Jun. 30, 2018	Jun. 30, 2017
Distribution Made to Limited Partner [Line Items]
Total Cash Distribution							$ 370,000,000	$ 256,000,000
Limited Partners
Distribution Made to Limited Partner [Line Items]
Per Unit Distribution (in dollars per share)		$ 0.78	$ 0.78	$ 0.78	$ 0.78	$ 0.78
Total Cash Distribution		$ 155,000,000	$ 194,000,000	$ 155,000,000	$ 134,000,000	$ 135,000,000	223,000,000	$ 202,000,000
Series A Preferred Limited Partners [Member]
Distribution Made to Limited Partner [Line Items]
Total Cash Distribution						$ 21,000,000	$ (21,000,000)
Preferred Limited Partnership Distribution; Distribution Amount Paid	$ 41.9965

Partnership Equity and Distri72

Partnership Equity and Distributions Partnership Equity and Distributions Preferred Series B Distributions (Details) - USD ($) $ / shares in Units, $ in Millions	Jun. 30, 2018	May 11, 2018	Jun. 30, 2018	Jun. 30, 2017	Jun. 04, 2018	Dec. 31, 2017
Preferred Units [Line Items]
Proceeds from Issuance of Preferred Limited Partners Units			$ 155	$ 0
Series B Preferred Limited Partners [Member]
Preferred Units [Line Items]
Preferred Units, Issued	6,450,000	6,000,000	6,450,000		450,000	0
Units Sold Under Private Placement Price Per Unit		$ 25
Preferred Limited Partner Unit Distribution, Annual Per Unit	$ 1.9688
Proceeds from Issuance of Preferred Limited Partners Units			$ 155
Prior to June 15, 2023 [Member] [Member] | Series B Preferred Limited Partners [Member]
Preferred Units [Line Items]
Preferred Limited Partnership Unit Distribution; Distribution Rate		7.875%
On and after June 15, 2023 [Member] | Series B Preferred Limited Partners [Member]
Preferred Units [Line Items]
Preferred Limited Partnership Unit Distribution; Distribution Rate		4.919%

Partnership Equity and Distri73

Partnership Equity and Distributions Partnership Equity and Distributions Preferred Series B Redemption Options (Details) - Series B Preferred Limited Partners [Member]	May 11, 2018$ / shares
Prior to June 15, 2023 [Member] [Member]
Preferred Units [Line Items]
Preferred Limited Partnership Units. Redemption as a Percentage of Liquidation Preference	102.00%
Preferred Stock, Redemption Price Per Share	$ 25.50
On and after June 15, 2023 [Member]
Preferred Units [Line Items]
Preferred Stock, Redemption Price Per Share	25
Redemption upon change in control triggering event [Member]
Preferred Units [Line Items]
Preferred Stock, Redemption Price Per Share	$ 25

Commitments and Contingent Li74

Commitments and Contingent Liabilities Commitments and Contingent Liabilities (Details)	May 24, 2018USD ($)
Commitments and Contingencies Disclosure [Abstract]
Payments for Legal Settlements	$ 100,700

Business Segments - Segment Inf

Business Segments - Segment Information (Detail) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018USD ($)	Jun. 30, 2017USD ($)	Jun. 30, 2018USD ($)Segment	Jun. 30, 2017USD ($)
Segment Reporting [Abstract]
Number of reportable segments | Segment			2
Segment Reporting Information [Line Items]
Total operating revenues	$ 2,317	$ 1,949	$ 4,456	$ 4,070
Gross margin	389	392	759	826
Operating and maintenance expense	(185)	(178)	(347)	(345)
Depreciation and amortization expense	(97)	(94)	(191)	(188)
General and administrative expense	(70)	(71)	(129)	(133)
Other income (expense)	(3)	(5)	(5)	(15)
Gain (loss) on sale of assets, net	0	34	0	34
Earnings from unconsolidated affiliates	96	86	174	160
Interest expense, net	(67)	(73)	(134)	(146)
Income tax expense	(1)	(2)	(2)	(3)
Net income	62	89	125	190
Net income attributable to noncontrolling interests	(1)	(1)	(2)	(1)
Net income attributable to partners	61	88	123	189
Non-cash derivative mark-to-market	(37)	24	(66)	60
Non-cash lower of cost or market adjustment	0	0	0	0
Capital expenditures	144	111	268	159
Investments in unconsolidated affiliates, net	66	21	126	41
Gathering and Processing
Segment Reporting Information [Line Items]
Total operating revenues	1,314		2,600
Logistics and Marketing
Segment Reporting Information [Line Items]
Total operating revenues	2,192		4,171
Operating Segments | Gathering and Processing
Segment Reporting Information [Line Items]
Total operating revenues	1,314	1,269	2,600	2,628
Gross margin	333	342	685	718
Operating and maintenance expense	(169)	(162)	(317)	(315)
Depreciation and amortization expense	(87)	(86)	(171)	(171)
General and administrative expense	(2)	(7)	(6)	(13)
Other income (expense)	0	(3)	(3)	(3)
Gain (loss) on sale of assets, net		34		34
Earnings from unconsolidated affiliates	2	24	3	44
Interest expense, net	0	0	0	0
Income tax expense	0	0	0	0
Net income	77	142	191	294
Net income attributable to noncontrolling interests	(1)	(1)	(2)	(1)
Net income attributable to partners	76	141	189	293
Non-cash derivative mark-to-market	(42)	16	(28)	47
Capital expenditures	140	103	260	146
Investments in unconsolidated affiliates, net	0	0	1	0
Operating Segments | Logistics and Marketing
Segment Reporting Information [Line Items]
Total operating revenues	2,192	1,756	4,171	3,683
Gross margin	56	50	74	108
Operating and maintenance expense	(11)	(13)	(22)	(22)
Depreciation and amortization expense	(3)	(3)	(6)	(7)
General and administrative expense	(3)	(2)	(6)	(5)
Other income (expense)	(3)	(2)	(2)	(11)
Gain (loss) on sale of assets, net		0		0
Earnings from unconsolidated affiliates	94	62	171	116
Interest expense, net	0	0	0	0
Income tax expense	0	0	0	0
Net income	130	92	209	179
Net income attributable to noncontrolling interests	0	0	0	0
Net income attributable to partners	130	92	209	179
Non-cash derivative mark-to-market	5	8	(38)	13
Capital expenditures	0	0	1	1
Investments in unconsolidated affiliates, net	66	21	125	41
Other
Segment Reporting Information [Line Items]
Total operating revenues	0	0	0	0
Gross margin	0	0	0	0
Operating and maintenance expense	(5)	(3)	(8)	(8)
Depreciation and amortization expense	(7)	(5)	(14)	(10)
General and administrative expense	(65)	(62)	(117)	(115)
Other income (expense)	0	0	0	(1)
Gain (loss) on sale of assets, net		0		0
Earnings from unconsolidated affiliates	0	0	0	0
Interest expense, net	(67)	(73)	(134)	(146)
Income tax expense	(1)	(2)	(2)	(3)
Net income	(145)	(145)	(275)	(283)
Net income attributable to noncontrolling interests	0	0	0	0
Net income attributable to partners	(145)	(145)	(275)	(283)
Non-cash derivative mark-to-market	0	0	0	0
Capital expenditures	4	8	7	12
Investments in unconsolidated affiliates, net	0	0	0	0
Eliminations
Segment Reporting Information [Line Items]
Total operating revenues	(1,189)	(1,076)	(2,315)	(2,241)
Gross margin	0	0	0	0
Operating and maintenance expense	0	0		0
Depreciation and amortization expense	0	0	0	0
General and administrative expense	0	0	0	0
Other income (expense)	0	0		0
Gain (loss) on sale of assets, net		0	0	0
Earnings from unconsolidated affiliates	0	0	0	0
Interest expense, net	0	0	0	0
Income tax expense	0	0	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		0
Non-cash lower of cost or market adjustment			0
Capital expenditures	0	0	0	0
Investments in unconsolidated affiliates, net	$ 0	$ 0	$ 0	$ 0

Business Segments - Segment Ass

Business Segments - Segment Assets (Detail) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Segment Reporting, Asset Reconciling Item [Line Items]
Segment long-term assets	$ 12,759	$ 12,556
Current assets	1,282	1,322
Total assets	14,041	13,878
Operating Segments | Gathering and Processing
Segment Reporting, Asset Reconciling Item [Line Items]
Segment long-term assets	9,048	8,943
Operating Segments | Logistics and Marketing
Segment Reporting, Asset Reconciling Item [Line Items]
Segment long-term assets	3,462	3,348
Other
Segment Reporting, Asset Reconciling Item [Line Items]
Segment long-term assets	$ 249	$ 265

Supplemental Cash Flow Inform77

Supplemental Cash Flow Information - Summary of Supplemental Cash Flow Information (Detail) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Supplemental Cash Flow Information [Abstract]
Cash paid for interest, net of amounts capitalized	$ 129	$ 143
Income Taxes Paid, Net	3	2
Noncash Investing and Financing Items [Abstract]
Property, plant and equipment acquired with accounts payable and accrued liabilities	42	33
Property, Plant and Equipment, Other Increase (Decrease)	0	(2)
Stock Issued	0	1,125
Non Cash Excess Purchase Price	$ 0	$ 3,094

Condensed Consolidating Finan78

Condensed Consolidating Financial Information - Additional Information (Detail)	6 Months Ended
	Jun. 30, 2018
Parent Guarantor
Condensed Financial Statements, Captions [Line Items]
Ownership interest percentage in subsidiary	100.00%

Condensed Consolidating Finan79

Condensed Consolidating Financial Information - Condensed Consolidating Balance Sheets (Detail) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017	Dec. 31, 2016
ASSETS
Cash and cash equivalents	$ 4	$ 156	$ 251	$ 1
Accounts receivable, net	1,029	981
Inventories	47	68
Other	202	117
Total current assets	1,282	1,322
Property, plant and equipment, net	9,080	8,983
Goodwill and intangible assets, net	332	337
Advances receivable — consolidated subsidiaries	0	0
Investments in unconsolidated affiliates	0	0
Investments in unconsolidated affiliates	3,165	3,050
Other long-term assets	182	186
Total assets	14,041	13,878
LIABILITIES AND EQUITY
Accounts payable and other current liabilities	1,562	1,488
Current maturities of long-term debt	325	0
Advances payable — consolidated subsidiaries	0	0
Long-term debt	4,510	4,707
Other long-term liabilities	291	245
Total liabilities	6,688	6,440
Commitments and contingent liabilities (see note 14)
Equity:
Net equity	7,331	7,417
Accumulated other comprehensive loss	(8)	(9)
Total partners’ equity	7,323	7,408
Noncontrolling interests	30	30
Total equity	7,353	7,438	7,199	6,853
Total liabilities and equity	14,041	13,878
Reportable Legal Entities | Parent Guarantor
ASSETS
Cash and cash equivalents	0	0	0	0
Accounts receivable, net	0	0
Inventories	0	0
Other	0	0
Total current assets	0	0
Property, plant and equipment, net	0	0
Goodwill and intangible assets, net	0	0
Advances receivable — consolidated subsidiaries	2,680	2,895
Investments in unconsolidated affiliates	4,643	4,513
Investments in unconsolidated affiliates	0	0
Other long-term assets	0	0
Total assets	7,323	7,408
LIABILITIES AND EQUITY
Accounts payable and other current liabilities	0	0
Current maturities of long-term debt	0
Advances payable — consolidated subsidiaries	0	0
Long-term debt	0	0
Other long-term liabilities	0	0
Total liabilities	0	0
Commitments and contingent liabilities (see note 14)
Equity:
Net equity	7,323	7,408
Accumulated other comprehensive loss	0	0
Total partners’ equity	7,323	7,408
Noncontrolling interests	0	0
Total equity	7,323	7,408
Total liabilities and equity	7,323	7,408
Reportable Legal Entities | Subsidiary Issuer
ASSETS
Cash and cash equivalents	0	155	250	0
Accounts receivable, net	0	0
Inventories	0	0
Other	0	0
Total current assets	0	155
Property, plant and equipment, net	0	0
Goodwill and intangible assets, net	0	0
Advances receivable — consolidated subsidiaries	1,763	1,614
Investments in unconsolidated affiliates	7,785	7,522
Investments in unconsolidated affiliates	0	0
Other long-term assets	0	0
Total assets	9,548	9,291
LIABILITIES AND EQUITY
Accounts payable and other current liabilities	70	71
Current maturities of long-term debt	325
Advances payable — consolidated subsidiaries	0	0
Long-term debt	4,510	4,707
Other long-term liabilities	0	0
Total liabilities	4,905	4,778
Commitments and contingent liabilities (see note 14)
Equity:
Net equity	4,646	4,517
Accumulated other comprehensive loss	(3)	(4)
Total partners’ equity	4,643	4,513
Noncontrolling interests	0	0
Total equity	4,643	4,513
Total liabilities and equity	9,548	9,291
Reportable Legal Entities | Non-Guarantor Subsidiaries
ASSETS
Cash and cash equivalents	4	1	1	1
Accounts receivable, net	1,029	981
Inventories	47	68
Other	202	117
Total current assets	1,282	1,167
Property, plant and equipment, net	9,080	8,983
Goodwill and intangible assets, net	332	337
Advances receivable — consolidated subsidiaries	0	0
Investments in unconsolidated affiliates	0	0
Investments in unconsolidated affiliates	3,165	3,050
Other long-term assets	182	186
Total assets	14,041	13,723
LIABILITIES AND EQUITY
Accounts payable and other current liabilities	1,492	1,417
Current maturities of long-term debt	0
Advances payable — consolidated subsidiaries	4,443	4,509
Long-term debt	0	0
Other long-term liabilities	291	245
Total liabilities	6,226	6,171
Commitments and contingent liabilities (see note 14)
Equity:
Net equity	7,790	7,527
Accumulated other comprehensive loss	(5)	(5)
Total partners’ equity	7,785	7,522
Noncontrolling interests	30	30
Total equity	7,815	7,552
Total liabilities and equity	14,041	13,723
Consolidating Adjustments
ASSETS
Cash and cash equivalents	0	0	$ 0	$ 0
Accounts receivable, net	0	0
Inventories	0	0
Other	0	0
Total current assets	0	0
Property, plant and equipment, net	0	0
Goodwill and intangible assets, net	0	0
Advances receivable — consolidated subsidiaries	(4,443)	(4,509)
Investments in unconsolidated affiliates	(12,428)	(12,035)
Investments in unconsolidated affiliates	0	0
Other long-term assets	0	0
Total assets	(16,871)	(16,544)
LIABILITIES AND EQUITY
Accounts payable and other current liabilities	0	0
Current maturities of long-term debt	0
Advances payable — consolidated subsidiaries	(4,443)	(4,509)
Long-term debt	0	0
Other long-term liabilities	0	0
Total liabilities	(4,443)	(4,509)
Commitments and contingent liabilities (see note 14)
Equity:
Net equity	(12,428)	(12,035)
Accumulated other comprehensive loss	0	0
Total partners’ equity	(12,428)	(12,035)
Noncontrolling interests	0	0
Total equity	(12,428)	(12,035)
Total liabilities and equity	$ (16,871)	$ (16,544)

Condensed Consolidating Finan80

Condensed Consolidating Financial Information - Condensed Consolidating Statements of Operations (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Operating revenues:
Sales of natural gas, NGLs and condensate	$ 2,257	$ 1,772	$ 4,326	$ 3,705
Transportation, processing and other	127	155	238	312
Trading and marketing (losses) gains, net	(67)	22	(108)	53
Total operating revenues	2,317	1,949	4,456	4,070
Purchases and related costs	1,928	1,557	3,697	3,244
Operating and maintenance expense	185	178	347	345
Depreciation and amortization expense	97	94	191	188
General and administrative expense	70	71	129	133
Gain on sale of assets, net	0	(34)	0	(34)
Other expense, net	3	5	5	15
Total operating costs and expenses	2,283	1,871	4,369	3,891
Operating income	34	78	87	179
Interest expense, net	(67)	(73)	(134)	(146)
Income from consolidated subsidiaries	0	0	0	0
Earnings from unconsolidated affiliates	96	86	174	160
Income before income taxes	63	91	127	193
Income tax expense	(1)	(2)	(2)	(3)
Net income	62	89	125	190
Net income attributable to noncontrolling interests	(1)	(1)	(2)	(1)
Net income attributable to partners	61	88	123	189
Reportable Legal Entities | Parent Guarantor
Operating revenues:
Sales of natural gas, NGLs and condensate	0	0	0	0
Transportation, processing and other	0	0	0	0
Trading and marketing (losses) gains, net	0	0	0	0
Total operating revenues	0	0	0	0
Purchases and related costs	0	0	0	0
Operating and maintenance expense	0	0	0	0
Depreciation and amortization expense	0	0	0	0
General and administrative expense	0	0	0	0
Gain on sale of assets, net		0		0
Other expense, net	0	0	0	0
Total operating costs and expenses	0	0	0	0
Operating income	0	0	0	0
Interest expense, net	0	0	0	0
Income from consolidated subsidiaries	61	88	123	189
Earnings from unconsolidated affiliates	0	0	0	0
Income before income taxes	61	88	123	189
Income tax expense	0	0	0	0
Net income	61	88	123	189
Net income attributable to noncontrolling interests	0	0	0	0
Net income attributable to partners	61	88	123	189
Reportable Legal Entities | Subsidiary Issuer
Operating revenues:
Sales of natural gas, NGLs and condensate	0	0	0	0
Transportation, processing and other	0	0	0	0
Trading and marketing (losses) gains, net	0	0	0	0
Total operating revenues	0	0	0	0
Purchases and related costs	0	0	0	0
Operating and maintenance expense	0	0	0	0
Depreciation and amortization expense	0	0	0	0
General and administrative expense	0	0	0	0
Gain on sale of assets, net		0		0
Other expense, net	0	0	0	0
Total operating costs and expenses	0	0	0	0
Operating income	0	0	0	0
Interest expense, net	(67)	(73)	(134)	(146)
Income from consolidated subsidiaries	128	161	257	335
Earnings from unconsolidated affiliates	0	0	0	0
Income before income taxes	61	88	123	189
Income tax expense	0	0	0	0
Net income	61	88	123	189
Net income attributable to noncontrolling interests	0	0	0	0
Net income attributable to partners	61	88	123	189
Reportable Legal Entities | Non-Guarantor Subsidiaries
Operating revenues:
Sales of natural gas, NGLs and condensate	2,257	1,772	4,326	3,705
Transportation, processing and other	127	155	238	312
Trading and marketing (losses) gains, net	(67)	22	(108)	53
Total operating revenues	2,317	1,949	4,456	4,070
Purchases and related costs	1,928	1,557	3,697	3,244
Operating and maintenance expense	185	178	347	345
Depreciation and amortization expense	97	94	191	188
General and administrative expense	70	71	129	133
Gain on sale of assets, net		(34)		(34)
Other expense, net	3	5	5	15
Total operating costs and expenses	2,283	1,871	4,369	3,891
Operating income	34	78	87	179
Interest expense, net	0	0	0	0
Income from consolidated subsidiaries	0	0	0	0
Earnings from unconsolidated affiliates	96	86	174	160
Income before income taxes	130	164	261	339
Income tax expense	(1)	(2)	(2)	(3)
Net income	129	162	259	336
Net income attributable to noncontrolling interests	(1)	(1)	(2)	(1)
Net income attributable to partners	128	161	257	335
Consolidating Adjustments
Operating revenues:
Sales of natural gas, NGLs and condensate	0	0	0	0
Transportation, processing and other	0	0	0	0
Trading and marketing (losses) gains, net	0	0	0	0
Total operating revenues	0	0	0	0
Purchases and related costs	0	0	0	0
Operating and maintenance expense	0	0	0	0
Depreciation and amortization expense	0	0	0	0
General and administrative expense	0	0	0	0
Gain on sale of assets, net		0		0
Other expense, net	0	0	0	0
Total operating costs and expenses	0	0	0	0
Operating income	0	0	0	0
Interest expense, net	0	0	0	0
Income from consolidated subsidiaries	(189)	(249)	(380)	(524)
Earnings from unconsolidated affiliates	0	0	0	0
Income before income taxes	(189)	(249)	(380)	(524)
Income tax expense	0	0	0	0
Net income	(189)	(249)	(380)	(524)
Net income attributable to noncontrolling interests	0	0	0	0
Net income attributable to partners	(189)	(249)	(380)	(524)
Eliminations
Operating revenues:
Total operating revenues	(1,189)	(1,076)	(2,315)	(2,241)
Operating and maintenance expense	0	0		0
Depreciation and amortization expense	0	0	0	0
General and administrative expense	0	0	0	0
Gain on sale of assets, net		0	0	0
Other expense, net	0	0		0
Interest expense, net	0	0	0	0
Earnings from unconsolidated affiliates	0	0	0	0
Income tax expense	0	0	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

Condensed Consolidating Finan81

Condensed Consolidating Financial Information - Condensed Consolidating Statement of Comprehensive Income (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Condensed Financial Statements, Captions [Line Items]
Net income	$ 62	$ 89	$ 125	$ 190
Other comprehensive income (loss):
Reclassification of cash flow hedge losses into earnings	1	0	1	1
Other comprehensive income from consolidated subsidiaries	0		0	0
Total other comprehensive income	1	0	1	1
Total comprehensive income	63	89	126	191
Total comprehensive income attributable to noncontrolling interests	(1)	(1)	(2)	(1)
Total comprehensive income attributable to partners	62	88	124	190
Reportable Legal Entities | Parent Guarantor
Condensed Financial Statements, Captions [Line Items]
Net income	61	88	123	189
Other comprehensive income (loss):
Reclassification of cash flow hedge losses into earnings	0		0	0
Other comprehensive income from consolidated subsidiaries	1		1	1
Total other comprehensive income	1	0	1	1
Total comprehensive income	62	88	124	190
Total comprehensive income attributable to noncontrolling interests	0	0	0	0
Total comprehensive income attributable to partners	62	88	124	190
Reportable Legal Entities | Subsidiary Issuer
Condensed Financial Statements, Captions [Line Items]
Net income	61	88	123	189
Other comprehensive income (loss):
Reclassification of cash flow hedge losses into earnings	1		1	1
Other comprehensive income from consolidated subsidiaries	0		0	0
Total other comprehensive income	1	0	1	1
Total comprehensive income	62	88	124	190
Total comprehensive income attributable to noncontrolling interests	0	0	0	0
Total comprehensive income attributable to partners	62	88	124	190
Reportable Legal Entities | Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Net income	129	162	259	336
Other comprehensive income (loss):
Reclassification of cash flow hedge losses into earnings	0		0	0
Other comprehensive income from consolidated subsidiaries	0		0	0
Total other comprehensive income	0	0	0	0
Total comprehensive income	129	162	259	336
Total comprehensive income attributable to noncontrolling interests	(1)	(1)	(2)	(1)
Total comprehensive income attributable to partners	128	161	257	335
Consolidating Adjustments
Condensed Financial Statements, Captions [Line Items]
Net income	(189)	(249)	(380)	(524)
Other comprehensive income (loss):
Reclassification of cash flow hedge losses into earnings	0		0	0
Other comprehensive income from consolidated subsidiaries	(1)		(1)	(1)
Total other comprehensive income	(1)	0	(1)	(1)
Total comprehensive income	(190)	(249)	(381)	(525)
Total comprehensive income attributable to noncontrolling interests	0	0	0	0
Total comprehensive income attributable to partners	$ (190)	$ (249)	$ (381)	$ (525)

Condensed Consolidating Finan82

Condensed Consolidating Financial Information - Condensed Consolidating Statements of Cash Flows (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
OPERATING ACTIVITIES
Net cash (used in) provided by operating activities			$ 331	$ 360
INVESTING ACTIVITIES:
Intercompany transfers			0	0
Capital expenditures	$ (144)	$ (111)	(268)	(159)
Investments in unconsolidated affiliates, net	(66)	(21)	(126)	(41)
Proceeds from sale of assets			3	129
Net cash used in investing activities			(391)	(71)
FINANCING ACTIVITIES:
Intercompany transfers			0	0
Proceeds from long-term debt			1,803	0
Payments of long-term debt			(1,678)	(195)
Proceeds from Issuance of Preferred Limited Partners Units			155	0
Distribution Made to Limited Partner, Cash Distributions Paid			(21)	0
Net change in advances to predecessor from DCP Midstream, LLC			0	418
Distributions to limited partners and general partner			(349)	(256)
Distributions to noncontrolling interests			(2)	(4)
Proceeds from (Payments for) Other Financing Activities			0	(2)
Net cash used in financing activities			(92)	(39)
Net change in cash and cash equivalents			(152)	250
Cash and cash equivalents, beginning of period			156	1
Cash and cash equivalents, end of period	4	251	4	251
Reportable Legal Entities | Parent Guarantor
OPERATING ACTIVITIES
Net cash (used in) provided by operating activities			0	0
INVESTING ACTIVITIES:
Intercompany transfers			215	256
Capital expenditures			0	0
Investments in unconsolidated affiliates, net			0	0
Proceeds from sale of assets			0	0
Net cash used in investing activities			215	256
FINANCING ACTIVITIES:
Intercompany transfers			0	0
Proceeds from long-term debt			0
Payments of long-term debt			0	0
Proceeds from Issuance of Preferred Limited Partners Units			155
Distribution Made to Limited Partner, Cash Distributions Paid			(21)
Net change in advances to predecessor from DCP Midstream, LLC				0
Distributions to limited partners and general partner			(349)	(256)
Distributions to noncontrolling interests			0	0
Proceeds from (Payments for) Other Financing Activities				0
Net cash used in financing activities			(215)	(256)
Net change in cash and cash equivalents			0	0
Cash and cash equivalents, beginning of period			0	0
Cash and cash equivalents, end of period	0	0	0	0
Reportable Legal Entities | Subsidiary Issuer
OPERATING ACTIVITIES
Net cash (used in) provided by operating activities			(131)	(143)
INVESTING ACTIVITIES:
Intercompany transfers			(149)	590
Capital expenditures			0	0
Investments in unconsolidated affiliates, net			0	0
Proceeds from sale of assets			0	0
Net cash used in investing activities			(149)	590
FINANCING ACTIVITIES:
Intercompany transfers			0	0
Proceeds from long-term debt			1,803
Payments of long-term debt			(1,678)	(195)
Proceeds from Issuance of Preferred Limited Partners Units			0
Distribution Made to Limited Partner, Cash Distributions Paid			0
Net change in advances to predecessor from DCP Midstream, LLC				0
Distributions to limited partners and general partner			0	0
Distributions to noncontrolling interests			0	0
Proceeds from (Payments for) Other Financing Activities				(2)
Net cash used in financing activities			125	(197)
Net change in cash and cash equivalents			(155)	250
Cash and cash equivalents, beginning of period			155	0
Cash and cash equivalents, end of period	0	250	0	250
Reportable Legal Entities | Non-Guarantor Subsidiaries
OPERATING ACTIVITIES
Net cash (used in) provided by operating activities			462	503
INVESTING ACTIVITIES:
Intercompany transfers			0	0
Capital expenditures			(268)	(159)
Investments in unconsolidated affiliates, net			(126)	(41)
Proceeds from sale of assets			3	129
Net cash used in investing activities			(391)	(71)
FINANCING ACTIVITIES:
Intercompany transfers			(66)	(846)
Proceeds from long-term debt			0
Payments of long-term debt			0	0
Proceeds from Issuance of Preferred Limited Partners Units			0
Distribution Made to Limited Partner, Cash Distributions Paid			0
Net change in advances to predecessor from DCP Midstream, LLC				418
Distributions to limited partners and general partner			0	0
Distributions to noncontrolling interests			(2)	(4)
Proceeds from (Payments for) Other Financing Activities				0
Net cash used in financing activities			(68)	(432)
Net change in cash and cash equivalents			3	0
Cash and cash equivalents, beginning of period			1	1
Cash and cash equivalents, end of period	4	1	4	1
Consolidating Adjustments
OPERATING ACTIVITIES
Net cash (used in) provided by operating activities			0	0
INVESTING ACTIVITIES:
Intercompany transfers			(66)	(846)
Capital expenditures			0	0
Investments in unconsolidated affiliates, net			0	0
Proceeds from sale of assets			0	0
Net cash used in investing activities			(66)	(846)
FINANCING ACTIVITIES:
Intercompany transfers			66	846
Proceeds from long-term debt			0
Payments of long-term debt			0	0
Proceeds from Issuance of Preferred Limited Partners Units			0
Distribution Made to Limited Partner, Cash Distributions Paid			0
Net change in advances to predecessor from DCP Midstream, LLC				0
Distributions to limited partners and general partner			0	0
Distributions to noncontrolling interests			0	0
Proceeds from (Payments for) Other Financing Activities				0
Net cash used in financing activities			66	846
Net change in cash and cash equivalents			0	0
Cash and cash equivalents, beginning of period			0	0
Cash and cash equivalents, end of period	$ 0	$ 0	$ 0	$ 0

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail) - USD ($)	Sep. 17, 2018	Sep. 04, 2018	Aug. 14, 2018	Aug. 07, 2018	Jul. 24, 2018	Jul. 17, 2018	Jun. 30, 2018	Dec. 31, 2017
Subsequent Event
Subsequent Event [Line Items]
Distribution declaration date					Jul. 24, 2018
Quarterly distribution (in dollars per share)					$ 0.78
Distribution payable date			Aug. 14, 2018
Distribution record date				Aug. 3, 2018
Preferred Limited Partnership Distribution; Distribution Amount Declared	$ 0.6781
Preferred Limited Partnership Distribution; Distribution Date	Sep. 17, 2018
Preferred Limited Partner Distribution: Record Date		Sep. 4, 2018
Issued February 2009, interest at 9.750% payable semiannually, due March 2019 | Senior Notes
Subsequent Event [Line Items]
Debt Instrument, Face Amount							$ 450,000,000	$ 450,000,000
Debt Instrument, Interest Rate, Stated Percentage							9.75%
Senior Notes Five Point Three Seven Five Percent Due July Twenty Twenty Five [Member] [Member] | Senior Notes | Subsequent Event
Subsequent Event [Line Items]
Debt Instrument, Face Amount						$ 500,000,000
Proceeds from Issuance of Senior Long-term Debt						$ 495,000,000
Debt Instrument, Interest Rate, Stated Percentage						5.375%