Spectra Energy Partners 10-Q 3 Aug 18 2018 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information	6 Months Ended
	Jun. 30, 2018shares
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	SEP
Entity Registrant Name	SPECTRA ENERGY PARTNERS, LP
Entity Central Index Key	1,394,074
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding	484,890,253

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations (Unaudited) - 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
Transportation of natural gas	$ 575	$ 538	$ 1,189	$ 1,076
Transportation of crude oil	97	100	195	201
Storage of natural gas and other	54	57	121	118
Total operating revenues	726	695	1,505	1,395
Operating expenses
Operating, maintenance and other	191	209	379	436
Depreciation, Amortization and Accretion, Net			184	175
Depreciation and amortization	90	87	179	172
Property and other taxes	59	56	119	112
Total operating expenses	340	352	677	720
Operating income	386	343	828	675
Other income and expenses
Earnings from equity investments	71	40	129	78
Other income and expenses, net	26	49	34	94
Total other income and expenses	97	89	163	172
Interest expense	85	60	170	116
Earnings before income taxes	398	372	821	731
Income tax expense	7	5	12	10
Net income	391	367	809	721
Net income attributable to controlling interests	381	328	788	645
Calculation of Limited Partners’ Interest in Net Income:
Net income attributable to controlling interests	381	328	788	645
Net income attributable to general partner	0	94	0	183
Net income attributable to limited partners	$ 381	$ 234	$ 788	$ 462
Weighted average limited partner units outstanding—basic and diluted	485	310	465	310
Net income per limited partner unit—basic and diluted	$ 0.78	$ 0.75	$ 1.69	$ 1.49
Distributions paid per limited partner unit	$ 0.75125	$ 0.70125	$ 1.49	$ 1.39
Net Income (Loss) Attributable to Noncontrolling Interest	$ 10	$ 39		$ 76
Noncontrolling Interests
Other income and expenses
Net income				$ 76
Calculation of Limited Partners’ Interest in Net Income:
Net Income (Loss) Attributable to Noncontrolling Interest			$ 21

Condensed Consolidated Stateme3

Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Net income	$ 391	$ 367	$ 809	$ 721
Foreign currency translation adjustments	(7)	6	(14)	7
Restructure Costs			(3)
Restructuring Costs	0
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax	9	0	35	0
Other Comprehensive Income (Loss), Net of Tax	2	6	18	7
Comprehensive income	393	373	827	728
Net Income (Loss) Attributable to Noncontrolling Interest	10	39		76
Comprehensive income attributable to controlling interests	$ 383	$ 334	806	652
Noncontrolling Interests
Net income				$ 76
Net Income (Loss) Attributable to Noncontrolling Interest			$ 21

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Current assets
Cash and cash equivalents	$ 96	$ 107
Receivables (net of allowance for doubtful accounts of $13 million and $10 million at June 30, 2018 and December 31, 2017, respectively)	326	372
Inventory	62	40
Fuel tracker	101	19
Other assets, net	36	23
Total current assets	621	561
Investments and Other Assets
Investments in and loans to unconsolidated affiliates	2,789	3,302
Goodwill	2,953	2,957
Property, Plant and Equipment
Property, plant and equipment, net	15,128	14,899
Regulatory and other assets	352	337
Total assets	21,843	22,056
Current Liabilities
Accounts payable	286	259
Taxes payable	112	84
Interest payable	85	68
Current portion of long-term debt	500	500
Other	144	194
Total current liabilities	1,127	1,105
Long-term Debt	7,651	7,963
Deferred Credits and Other Liabilities
Deferred income taxes	46	46
Regulatory and other liabilities	1,018	1,041
Partners’ Capital
Common units (311.0 and 308.4 units issued and outstanding at September 30, 2017 and December 31, 2016, respectively)	11,655	11,183
General partner units (6.3 units issued and outstanding at September 30, 2017 and December 31, 2016)	0	386
Accumulated other comprehensive loss	(15)	(33)
Total partners’ capital	11,640	11,536
Noncontrolling interests	361	365
Total equity	12,001	11,901
Total Liabilities and Equity	21,843	22,056
Liabilities	$ 9,842	$ 10,155

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
OPERATING ACTIVITIES
Net income	$ 809	$ 721
Depreciation, Amortization and Accretion, Net	184	175
Adjustments to reconcile net income to net cash provided by operating activities:
Deferred income tax expense	0	2
Earnings from equity investments	(129)	(78)
Distributions from equity investments	99	57
Increase (Decrease) in Regulatory Liabilities	(25)	0
Change in operating assets and liabilities	(55)	(69)
Net cash provided by operating activities	883	808
INVESTING ACTIVITIES
Capital expenditures	(385)	(1,361)
Investments in and loans to unconsolidated affiliates	(232)	(158)
Distributions from equity investments	36	21
Other	0	2
Net cash provided by (used in) investing activities	163	(1,496)
FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	794	400
Payments for the redemption of long-term debt	0	(416)
Net change in credit facility draws and commercial paper borrowings	(1,093)	750
Distributions to noncontrolling interests	(28)	(25)
Contributions from noncontrolling interests	1	416
Proceeds from the issuances of units	0	87
Distributions to partners	(722)	(597)
Other	(11)	(1)
Net cash provided by (used in) financing activities	(1,059)	614
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect	(13)	(74)
Supplemental Information
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	114	233
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	101	159
Sabal Trail Transmission, LLC [Member]
INVESTING ACTIVITIES
Distributions from equity investments	$ 744	$ 0

Condensed Consolidated Stateme6

Condensed Consolidated Statements of Equity (Unaudited) - USD ($) $ in Millions	Total	Limited Partners Common	General Partner	Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interests
Net income attributable to controlling interests	$ 645
Beginning balance at Dec. 31, 2016	13,404	$ 11,650	$ 452	$ (45)	$ 1,347
Increase (Decrease) in Equity
Net income	721	462	183		76
Net Income (Loss) Attributable to Noncontrolling Interest	76
Other Comprehensive Income (Loss), Net of Tax	7			7
Attributed deferred tax benefit	65		42		23
Issuance of units	87	85	2
Distributions to partners	(597)	(430)	(167)
Contributions from noncontrolling interests	416				416
Distributions to noncontrolling interests	(25)				(25)
Ending balance at Jun. 30, 2017	14,078	11,767	512	(38)	1,837
Net income attributable to controlling interests	788
Beginning balance at Dec. 31, 2017	11,901	11,183	386	(33)	365
Increase (Decrease) in Equity
Net income	809		0
Net Income (Loss) Attributable to Noncontrolling Interest					21
Equity Restructuring - Common Units	389
Equity Restructuring - General Partner Units	(386)
Equity Restructuring - AOCI	(3)
Other Comprehensive Income, Excluding Restructuring	21
Other Comprehensive Income (Loss), Net of Tax	18
Attributed deferred tax benefit	23	21	0		2
Incentive Distribution Rights - Restructuring Fees	(4)
Distributions to partners	(722)	(722)	0
Distributions to noncontrolling interests	(28)				(28)
Ending balance at Jun. 30, 2018	$ 12,001	$ 11,655	$ 0	$ (15)	$ 361

General

General	6 Months Ended
	Jun. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
General	General The terms “we,” “our,” “us” and “Spectra Energy Partners” as used in this report refer collectively to Spectra Energy Partners, LP (SEP) and its subsidiaries unless the context suggests otherwise. These terms are used for convenience only and are not intended as a precise description of any separate legal entity within Spectra Energy Partners. Nature of Operations. Spectra Energy Partners, through its subsidiaries and equity investments, is engaged in the transmission, storage and gathering of natural gas and the transportation and storage of crude oil through interstate pipeline systems. We are a Delaware master limited partnership (MLP). As of June 30, 2018 , Enbridge Inc. (Enbridge) and its subsidiaries collectively owned 83% of us and the remaining 17% was publicly owned. Enbridge owns and controls our general partner, Spectra Energy Partners (DE) GP, LP (SEP GP), which owns a non-economic general partner interest in us. See Note 13 for additional information on our general partner interest. We manage our business in two reportable segments: U.S. Transmission and Liquids. The U.S. Transmission segment provides interstate transmission, storage and gathering of natural gas. The Liquids segment provides transportation of crude oil and storage of natural gas. Basis of Presentation. The accompanying Condensed Consolidated Financial Statements have been prepared in accordance with generally accepted accounting principles in the United States of America (U.S. GAAP) for interim consolidated financial information and with the instructions to Form 10-Q and Rule 10-01 of Regulation S-X. They do not include all of the information and notes required by U.S. GAAP for annual consolidated financial statements and should therefore be read in conjunction with our annual consolidated financial statements and notes presented in our Annual Report on Form 10-K for the year ended December 31, 2017 . In the opinion of management, the Condensed Consolidated Financial Statements contain all adjustments, consisting only of normal recurring adjustments, necessary to present fairly our financial position, results of operations and cash flows for the interim periods reported. These Condensed Consolidated Financial Statements follow the same significant accounting policies as those included in our annual consolidated financial statements for the year ended December 31, 2017 , except for the adoption of new standards. See Note 2 for additional information on the adoption of new standards.

Business Segments

Business Segments	6 Months Ended
	Jun. 30, 2018
Segment Reporting [Abstract]
Business Segments	We manage our business in two reportable segments: U.S. Transmission and Liquids. The remainder of our business operations is presented as “Other”, and consists of certain corporate costs. Segment results are presented as earnings before interest, taxes, depreciation and amortization (EBITDA). Condensed Consolidated Statements of Income Total Operating Revenues Depreciation and Amortization Segment EBITDA/ Consolidated Earnings Before Income Taxes (in millions) Three Months Ended June 30, 2018 U.S. Transmission $ 624 $ 82 $ 505 Liquids 102 8 67 Total reportable segments 726 90 572 Other — — (2 ) Depreciation and amortization — — 90 Interest expense — — 85 Interest income and other — — 3 Total consolidated $ 726 $ 90 $ 398 Three Months Ended June 30, 2017 U.S. Transmission $ 592 $ 79 $ 480 Liquids 103 8 64 Total reportable segments 695 87 544 Other — — (25 ) Depreciation and amortization — — 87 Interest expense — — 60 Interest income and other — — — Total consolidated $ 695 $ 87 $ 372 Six Months Ended June 30, 2018 U.S. Transmission $ 1,295 $ 163 $ 1,027 Liquids 210 16 142 Total reportable segments 1,505 179 1,169 Other — — (3 ) Depreciation and amortization — — 179 Interest expense — — 170 Interest income and other — — 4 Total consolidated $ 1,505 $ 179 $ 821 Six Months Ended June 30, 2017 U.S. Transmission $ 1,188 $ 156 $ 959 Liquids 207 16 130 Total reportable segments 1,395 172 1,089 Other — — (71 ) Depreciation and amortization — — 172 Interest expense — — 116 Interest income and other — — 1 Total consolidated $ 1,395 $ 172 $ 731

Net Income Per Limited Partner

Net Income Per Limited Partner Unit and Cash Distributions	6 Months Ended
	Jun. 30, 2018
Equity [Abstract]
Net Income Per Limited Partner Unit and Cash Distributions	Net Income Per Limited Partner Unit and Cash Distributions We determined basic and diluted net income per limited partner unit as follows: Three Months Ended Six Months Ended 2018 2017 2018 2017 (in millions, except per unit amounts) Net income attributable to controlling interests $ 381 $ 328 $ 788 $ 645 Less: Net income attributable to: General partner’s interest in general partner units—2% (a) — 7 — 13 General partner’s interest in incentive distribution rights (a) — 87 — 170 Limited partners’ interest in net income attributable to common units $ 381 $ 234 $ 788 $ 462 Weighted average limited partner units outstanding—basic and diluted 485 310 465 310 Net income per limited partner unit—basic and diluted $ 0.78 $ 0.75 $ 1.69 $ 1.49 ______________ (a) General partner units and incentive distribution rights (IDRs) were converted to common units of Spectra Energy Partners as a result of the Equity Restructuring Agreement dated January 21, 2018 (Equity Restructuring Agreement). See Note 13 for additional information. Our partnership agreement requires that, within 60 days after the end of each quarter, we distribute all of our Available Cash, as defined below, to unitholders of record on the applicable record date. Available Cash. Available Cash, for any quarter, consists of all cash and cash equivalents on hand at the end of that quarter: • less the amount of cash reserves established by the general partner to: • provide for the proper conduct of business, • comply with applicable law, any debt instrument or other agreement, or • provide funds for distributions for any one or more of the next four quarters, • plus, if the general partner so determines, all or a portion of cash and cash equivalents on hand on the date of determination of Available Cash for the quarter; • provided, however, that disbursements made by us or any of our subsidiaries or cash reserves established, increased or reduced after the end of that quarter but on or before the date of determination of Available Cash for that quarter shall be deemed to have been made, established, increased or reduced, for purposes of determining Available Cash, within that quarter if our general partner so determines .

Variable Interest Entities

Variable Interest Entities	6 Months Ended
	Jun. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Variable Interest Entity Disclosure	Variable Interest Entities Sabal Trail. We own a 50% interest in Sabal Trail Transmission, LLC (Sabal Trail), a joint venture that operates a pipeline originating in Alabama that transports natural gas to Florida. On April 30, 2018, Sabal Trail issued $500 million in aggregate principal amount of 4.246% senior notes due in 2028, $600 million in aggregate principal amount of 4.682% senior notes due in 2038 and $400 million in aggregate principal amount of 4.832% senior notes due in 2048. Sabal Trail distributed net proceeds from the offering to its partners as a partial reimbursement of construction and development costs incurred by the partners. The net distribution made to us was $744 million and was used to pay down short-term borrowings. As of June 30, 2018, Sabal Trail is no longer a variable interest entity (VIE) due to Sabal Trail having sufficient equity at risk to finance its activities based on reconsideration triggered by to Sabal Trail's debt issuance and the distributions made to its members in April 2018. NEXUS. We own a 50% interest in NEXUS Gas Transmission, LLC (NEXUS), a joint venture that is constructing a greenfield natural gas pipeline from Ohio to Michigan and leasing capacity on third party pipelines in order to provide transportation of Appalachian Basin natural gas to markets in Ohio, Michigan, and the Dawn Hub in Ontario, Canada through the Vector Pipeline. NEXUS is a VIE due to insufficient equity at risk to finance its activities. We determined that we are not the primary beneficiary because the power to direct the activities of NEXUS that most significantly impact its economic performance is shared. We account for NEXUS under the equity method. Our maximum exposure to loss is $1.3 billion . We have an investment in NEXUS of $869 million and $640 million as of June 30, 2018 and December 31, 2017 , respectively, classified as Investments in and loans to unconsolidated affiliates on our Condensed Consolidated Balance Sheets. In 2016, we issued performance guarantees to a third party and an affiliate on behalf of NEXUS. See Note 12 for further discussion of the guarantee arrangement. PennEast. In 2017, we purchased an additional 10% interest in PennEast Pipeline Company, LLC (PennEast) from PSEG Power Gas Holdings, LLC, increasing our ownership interest in PennEast to 20% . PennEast is a joint venture that is proposing to construct a natural gas pipeline originating in northeastern Pennsylvania, and ending near Pennington, Mercer County, New Jersey. PennEast is a VIE due to insufficient equity at risk to finance its activities. We determined that we are not the primary beneficiary because the power to direct the activities of PennEast that most significantly impact its economic performance is shared. We account for PennEast under the equity method. Our maximum exposure to loss is $279 million . We have an investment in PennEast of $66 million and $55 million as of June 30, 2018 and December 31, 2017 , respectively, classified as Investments in and loans to unconsolidated affiliates on our Condensed Consolidated Balance Sheets. The maximum exposure to loss for these entities is limited to our current equity investment and the remaining expected contributions for each joint venture.

Marketable Securities and Restr

Marketable Securities and Restricted Funds	6 Months Ended
	Jun. 30, 2018
Investments, Debt and Equity Securities [Abstract]
Marketable Securities and Restricted Funds	Marketable Securities and Restricted Funds We routinely invest excess cash and various restricted balances in securities such as commercial paper, corporate debt securities, and other money market securities in the United States, as well as equity securities in Canada. We do not purchase marketable securities for speculative purposes, therefore we do not have any securities classified as trading securities. While we do not routinely sell marketable securities prior to their scheduled maturity dates, some of our investments may be held and restricted for the purposes of funding future capital expenditures and National Energy Board (NEB) regulatory requirements, so these investments are classified as AFS marketable securities as they may occasionally be sold prior to their scheduled maturity dates due to the unexpected timing of cash needs. Initial investments in securities are classified as purchases of the respective type of securities (AFS marketable securities or held-to-maturity (HTM) marketable securities). Maturities of AFS securities are presented within Net cash used in investing activities within the Condensed Consolidated Statements of Cash Flows. AFS Securities. We had $3 million of AFS securities classified as Regulatory and other assets on the Condensed Consolidated Balance Sheets as of June 30, 2018 and December 31, 2017 . At June 30, 2018 and December 31, 2017 , these investments include $3 million of restricted funds held and collected from customers for Canadian pipeline abandonment in accordance with the NEB's regulatory requirements, as well as less than $1 million of restricted funds related to certain construction projects as of December 31, 2017 . At June 30, 2018 , the weighted-average contractual maturity of outstanding AFS securities was less than one year . There were no material gross unrecognized holding gains or losses associated with investments in AFS securities at June 30, 2018 or December 31, 2017 . HTM Securities. All of our HTM securities are restricted funds. We had $3 million money market securities classified as Other assets, net on the Condensed Consolidated Balance Sheets as of June 30, 2018 and December 31, 2017 . These securities are restricted pursuant to certain Express-Platte pipeline system debt agreements. At June 30, 2018 , the weighted-average contractual maturity of outstanding HTM securities was less than one year . There were no material gross unrecognized holding gains or losses associated with investments in HTM securities at June 30, 2018 or December 31, 2017 . Other Restricted Funds. In addition to the AFS and HTM securities that were restricted funds as described above, we had other restricted funds totaling $2 million and $4 million classified as Regulatory and other assets on the Condensed Consolidated Balance Sheets at June 30, 2018 and December 31, 2017 , respectively. These restricted funds are related to certain construction projects. Effective January 1, 2018, we adopted ASU 2016-18 on a retrospective basis. As a result, changes in restricted cash and restricted cash equivalents, which include HTM securities and other restricted funds discussed above, have been included within Cash and cash equivalents when reconciling the opening and closing period amounts shown on our Condensed Consolidated Statements of Cash Flows. Changes in restricted funds that are not restricted cash or restricted cash equivalents are presented within Net cash used in investing activities on our Condensed Consolidated Statements of Cash Flows. See Note 2 for additional information.

Debt and Credit Facility

Debt and Credit Facility	6 Months Ended
	Jun. 30, 2018
Debt Disclosure [Abstract]
Debt Disclosure [Text Block]	Debt Credit Facility Maturity Date (a) Total Facility Draws (b) Available (in millions) Spectra Energy Partners, LP 2022 $ 2,500 $ 1,161 $ 1,339 ______________ (a) Includes $336 million of commitments that expire in 2021. (b) Includes facility draws and commercial paper issuances that are back-stopped by the credit facility. The issuances of commercial paper, letters of credit and revolving borrowings reduce the amount available under the credit facility. As of June 30, 2018 , there were no letters of credit issued or revolving borrowings outstanding under the credit facility. Our commercial paper program provides for the issuance of up to an aggregate principal amount $2.5 billion of commercial paper and is supported by the availability of long-term committed credit facilities and therefore have been classified as long-term debt as of June 30, 2018 and December 31, 2017 , respectively. Our credit facility agreement and term debt indentures include common events of default and covenant provisions, including a financial covenant, whereby accelerated repayment and/or termination of the agreement may result if we were to default on payment or violate certain covenants. As of June 30, 2018 , we were in compliance with those covenants. Debt Issuances . On January 9, 2018, Texas Eastern Transmission, LP (Texas Eastern), an indirect subsidiary of Spectra Energy Partners, issued $400 million in aggregate principal amount of 3.50% senior notes due in 2028 and $400 million in aggregate principal amount of 4.15% senior notes due in 2048. Texas Eastern used a portion of the net proceeds from the offering to fund expansion projects and capital expenditures on the Texas Eastern pipeline system. In addition, Texas Eastern used a portion of the net proceeds from the offering to repay funds we advanced to Texas Eastern in September 2017, which Texas Eastern used to repay a $400 million debt maturity. We used the proceeds received to repay commercial paper and credit facility borrowings, which were incurred primarily to fund Texas Eastern’s capital expenditures, as well as those of our other subsidiaries.

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements The following presents, for each of the fair value hierarchy levels, assets and liabilities that are measured at fair value on a recurring basis as of June 30, 2018 and December 31, 2017 : Description Condensed Consolidated Balance Sheet Caption June 30, 2018 Total Level 1 Level 2 Level 3 (in millions) Interest rate swaps Other assets, net 22 $ — $ 22 $ — Commodity swaps Other assets, net 1 — — 1 Canadian equity securities Regulatory and other assets 3 3 — — Interest rate swaps Regulatory and other assets 6 — 6 — Commodity swaps Regulatory and other assets 1 — — 1 Total Assets $ 33 $ 3 $ 28 $ 2 Interest rate swaps Current liabilities — other $ 3 $ — $ 3 $ — Interest rate swaps Regulatory and other liabilities 7 — 7 — Total Liabilities $ 10 $ — $ 10 $ — Description Condensed Consolidated Balance Sheet Caption December 31, 2017 Total Level 1 Level 2 Level 3 (in millions) Canadian equity securities Regulatory and other assets $ 3 $ 3 $ — $ — Interest rate swaps Other assets, net 4 — 4 — Commodity swaps Other assets, net 2 — — 2 Total Assets $ 9 $ 3 $ 4 $ 2 Interest rate swaps Current liabilities — other $ 3 $ — $ 3 $ — Interest rate swaps Regulatory and other liabilities 5 — 5 — Total Liabilities $ 8 $ — $ 8 $ — Level 1 Level 1 valuations represent quoted unadjusted prices for identical instruments in active markets. Level 2 Fair values of our financial instruments that are actively traded in the secondary market, including our long-term debt, are determined based on market-based prices. These Level 2 valuations may include inputs such as quoted market prices of the exact or similar instruments, broker or dealer quotations, or alternative pricing sources that may include models or matrix pricing tools, with reasonable levels of price transparency. For interest rate swaps, we utilize data obtained from a third-party source for the determination of fair value. Both the future cash flows for the fixed-leg and floating-leg of our swaps are discounted to present value. Level 3 Level 3 valuation techniques include the use of pricing models, discounted cash flow methodologies or similar techniques where at least one significant model assumption or input is unobservable. Level 3 financial instruments also include those for which the determination of fair value requires significant management judgment or estimation. Financial Instruments The fair values of financial instruments that are recorded and carried at book value are summarized in the following table. Judgment is required in interpreting market data to develop the estimates of fair value. These estimates are not necessarily indicative of the amounts we could have realized in current markets. June 30, 2018 December 31, 2017 Condensed Consolidated Balance Sheets Book Value Approximate Fair Value Book Value Approximate Fair Value (in millions) Note receivable, noncurrent (a) $ 71 $ 71 $ 71 $ 71 Long-term debt, including current maturities (b) 6,650 6,639 5,850 6,211 ______________ (a) Included within Investments in and loans to unconsolidated affiliates. (b) Excludes variable rate debt, unamortized items and fair value hedge carrying value adjustments. The fair value of our fixed-rate long-term debt is determined based on market-based prices as described in the Level 2 valuation technique described above and is classified as Level 2. The fair values of cash and cash equivalents, restricted cash, short-term investments, accounts receivable, note receivable-noncurrent, accounts payable, short-term money market securities, commercial paper, credit facility borrowings and long-term variable-rate debt are not materially different from their carrying amounts because of the short-term nature of these instruments or because the stated rates approximate market rates.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Environmental We are subject to various U.S. federal, state and local laws and regulations, as well as Canadian federal and provincial laws, relating to the protection of the environment. These laws and regulations can change from time to time, imposing new obligations on us. Environmental risk is inherent to liquid hydrocarbon and natural gas pipeline operations, and we and our affiliates are, at times, subject to environmental remediation at various contaminated sites. We manage this environmental risk through appropriate environmental policies and practices to minimize any impact our operations may have on the environment. To the extent that we are unable to recover payment for environmental liabilities from insurance or other potentially responsible parties, we will be responsible for payment of liabilities arising from environmental incidents associated with the operating activities of our liquids and natural gas businesses. Litigation We are subject to various legal and regulatory actions and proceedings which arise in the normal course of business, including interventions in regulatory proceedings and challenges to regulatory approvals and permits by special interest groups. While the final outcome of such actions and proceedings cannot be predicted with certainty, management believes that the resolution of such actions and proceedings will not have a material impact on our condensed consolidated financial position or results of operations.

Guarantees

Guarantees	6 Months Ended
	Jun. 30, 2018
Guarantees [Abstract]
Guarantees	Guarantees We have various financial guarantees which are issued in the normal course of business. We enter into these arrangements to facilitate a commercial transaction with a third party by enhancing the value of the transaction to the third party. To varying degrees, these guarantees involve elements of performance and credit risk, which are not included on our Condensed Consolidated Balance Sheets. The possibility of having to perform under these guarantees is largely dependent upon future operations of various subsidiaries, investees and other third parties, or the occurrence of certain future events. In December 2016, we issued performance guarantees to a third party and an affiliate on behalf of an equity method investee. These guarantees were issued to enable the equity method investee to enter into long-term transportation contracts with the third party. While the likelihood is remote, the maximum potential amount of future payments we could have been required to make as of June 30, 2018 was $107 million . These performance guarantees expire in 2032 . As of June 30, 2018 , the amounts recorded for the guarantees described above are not material, either individually or in the aggregate.

Issuances of Common Units

Issuances of Common Units	6 Months Ended
	Jun. 30, 2018
Issuances of Common Units [Abstract]
Issuances of Common Units	Issuances of Common Units On January 21, 2018, we entered into the Equity Restructuring Agreement with SEP GP, our general partner pursuant to which the IDRs and the 2% general partner interest in us held by that entity were converted into 172,500,000 newly issued common units and a non-economic general partner interest in us.

New Accounting Pronouncements

New Accounting Pronouncements	6 Months Ended
	Jun. 30, 2018
Accounting Changes and Error Corrections [Abstract]
New Accounting Pronouncements	New Accounting Pronouncements Adoption of New Standards Clarifying Guidance on Derecognition and Partial Sales of Nonfinancial Assets Effective January 1, 2018, we adopted Accounting Standards Update (ASU) 2017-05 on a modified retrospective basis. The new standard clarifies the scope provisions of nonfinancial assets and how to allocate consideration to each distinct asset, and amends the guidance for derecognition of a distinct nonfinancial asset in partial sale transactions. The adoption of this accounting update did not have a material impact on our Condensed Consolidated Financial Statements. Clarifying the Presentation of Restricted Cash in the Statement of Cash Flows Effective January 1, 2018, we adopted ASU 2016-18 on a retrospective basis. The new standard clarifies guidance on the classification and presentation of changes in restricted cash and restricted cash equivalents within the Condensed Consolidated Statements of Cash Flows. The amendments require that changes in restricted cash and restricted cash equivalents be included within Cash and cash equivalents when reconciling the opening and closing period amounts shown on the Condensed Consolidated Statements of Cash Flows. For current and comparative periods, we amended the presentation in the Condensed Consolidated Statements of Cash Flows to include restricted cash and restricted cash equivalents with Cash and cash equivalents. The following table shows the changes in beginning and ending Cash, cash equivalents and restricted cash as a result of adopting ASU 2016-18: June 30, 2018 December 31, 2017 June 30, 2017 December 31, 2016 (in millions) Cash and cash equivalents $ 96 $ 107 $ 153 $ 216 Restricted cash in Other assets, net 3 3 3 3 Restricted cash in Regulatory and other assets 2 4 3 14 Cash, cash equivalents and restricted cash $ 101 $ 114 $ 159 $ 233 Simplifying Cash Flow Classification Effective January 1, 2018, we adopted ASU 2016-15 on a retrospective basis. The new standard reduces diversity in practice of how certain cash receipts and cash payments are classified in the Condensed Consolidated Statement of Cash Flows. The new guidance addresses eight specific presentation issues. We assessed each of the eight specific presentation issues and determined that the adoption of this ASU did not have a material impact on our Condensed Consolidated Financial Statements. Recognition and Measurement of Financial Assets and Liabilities Effective January 1, 2018, we adopted ASU 2016-01 on a prospective basis. The new standard addresses certain aspects of recognition, measurement, presentation and disclosure of financial assets and liabilities. Investments in equity securities, excluding equity method and consolidated investments, are no longer classified as trading or available-for-sale (AFS) securities. All investments in equity securities with readily determinable fair values are classified as investments at fair value through net income. Investments in equity securities without readily determinable fair values are measured using the fair value measurement alternative and are recorded at cost minus impairment, if any, plus or minus changes resulting from observable price changes in orderly transactions for an identical or similar investment of the same issuer. Investments in equity securities measured using the fair value measurement alternative are reviewed for indicators of impairment each reporting period. Fair value of financial assets and liabilities is measured using the exit price notion. The adoption of this accounting update did not have a material impact on our Condensed Consolidated Financial Statements. Revenue from Contracts with Customers Effective January 1, 2018, we adopted ASU 2014-09 on a modified retrospective basis to contracts that were not yet completed at the date of initial application. The new standard was issued with the intent of significantly enhancing consistency and comparability of revenue recognition practices across entities and industries. The new standard establishes a single, principles-based, five-step model to be applied to all contracts with customers and introduces new and enhanced disclosure requirements. It also requires the use of more estimates and judgments than the previous standards. The adoption of this new standard did not have a material impact on our Condensed Consolidated Financial Statements. See Note 4 for additional information. Future Accounting Policy Changes Improvements to Accounting for Hedging Activities ASU 2017-12 was issued in August 2017 with the objective of better aligning a company’s risk management activities and the resulting hedge accounting reflected in the financial statements. The amendments allow cash flow hedging of contractually specified components in financial and non-financial items. Under the new guidance, hedge ineffectiveness is no longer required to be measured and hedging instruments’ fair value changes will be recorded in the same income statement line as the hedged item. The ASU also allows the initial quantitative hedge effectiveness assessment to be performed at any time before the end of the quarter in which the hedge is designated. After initial quantitative testing is performed, an ongoing qualitative effectiveness assessment is permitted. The accounting update is effective January 1, 2019, with early adoption permitted, and is to be applied on a modified retrospective basis. We are currently assessing the impact of the new standard on our Condensed Consolidated Financial Statements. Accounting for Credit Losses ASU 2016-13 was issued in June 2016 with the intent of providing financial statement users with more useful information about the expected credit losses on financial instruments and other commitments to extend credit held by a reporting entity at each reporting date. Current treatment uses the incurred loss methodology for recognizing credit losses that delays the recognition until it is probable a loss has been incurred. The accounting update adds a new impairment model, known as the current expected credit loss model, which is based on expected losses rather than incurred losses. Under the new guidance, an entity will recognize as an allowance its estimate of expected credit losses, which the Financial Accounting Standards Board believes will result in more timely recognition of such losses. The accounting update is effective January 1, 2020. We are currently assessing the impact of the new standard on our Condensed Consolidated Financial Statements. Recognition of Leases ASU 2016-02 was issued in February 2016 with the intent to increase transparency and comparability among organizations. It requires lessees of operating lease arrangements to recognize lease assets and lease liabilities on the statement of financial position and disclose additional key information about lease agreements. The accounting update also replaces the current definition of a lease and requires that an arrangement be recognized as a lease when a customer has the right to obtain substantially all of the economic benefits from the use of an asset, as well as the right to direct the use of the asset. We will adopt the new standard on January 1, 2019 and we intend to apply the transition practical expedients offered in connection with this update. The election to apply the package of practical expedients allows an entity to not apply the new lease standard to the prior year comparative periods in the year of adoption. Application of the package of practical expedients permits entities not to reassess whether any expired or existing contracts contain leases, their lease classification, or any related initial direct costs. Further, ASU 2018-01 was issued in January 2018 to address stakeholder concerns about the costs and complexity of complying with the transition provisions of the new lease requirements as they relate to land easements. The amendments provide an optional transition practical expedient to not evaluate existing or expired land easements that were not previously accounted for as leases under existing guidance. We intend to elect this practical expedient in connection with the adoption of the new lease requirements.

Revenue from contracts with cus

Revenue from contracts with customers (Notes)	6 Months Ended
	Jun. 30, 2018
Revenue Contracts [Abstract]
Revenue from Contract with Customer [Text Block]	4. Revenue from Contracts with Customers Major Products and Services U.S. Transmission Liquids Consolidated (in millions) Three Months Ended June 30, 2018 Transportation of natural gas $ 575 $ — $ 575 Transportation of crude oil — 97 97 Storage of natural gas 47 5 52 Total revenue from contracts with customers 622 102 724 Other revenue 2 — 2 Intersegment revenue — — — Total revenue $ 624 $ 102 $ 726 Six Months Ended June 30, 2018 Transportation of natural gas $ 1,189 $ — $ 1,189 Transportation of crude oil — 195 195 Storage of natural gas and other 102 15 117 Total revenue from contracts with customers 1,291 210 1,501 Other revenue 4 — 4 Intersegment revenue — — — Total revenue $ 1,295 $ 210 $ 1,505 We disaggregate revenue into categories which represent our principal performance obligations within each business segment because these revenue categories represent the most significant revenue streams in each segment and consequently are considered to be the most relevant revenue information for management to consider in evaluating performance. Contract Balances Accounts Receivable Contract Assets Contract Liabilities (in millions) Balance at adoption date $ 265 $ — $ 65 Balance at reporting date 248 — 65 Contract liabilities primarily relate to deferred revenue. There were no material changes in contract liabilities during the three and six months ended June 30, 2018 . Recognition and Measurement of Revenue U.S. Transmission Liquids Consolidated Three months ended June 30, 2018 (in millions) Revenue from products and services transferred over time - crude oil and natural gas transportation and storage $ 622 $ 102 $ 724 Six months ended June 30, 2018 Revenue from products and services transferred over time - crude oil and natural gas transportation and storage $ 1,291 $ 210 $ 1,501 Revenue to be Recognized from Unfulfilled Performance Obligations Total revenue from performance obligations expected to be fulfilled in future periods is $22.0 billion , of which $1.3 billion and $2.4 billion is expected to be recognized during the remaining six months ending December 31, 2018 and year ending December 31, 2019 , respectively. Revenues from contracts with customers which have an original expected duration of one year or less are excluded from these amounts.

Risk Management and Hedging Act

Risk Management and Hedging Activities Risk Management and Hedging Activities (Notes)	6 Months Ended
	Jun. 30, 2018
Risk Management and Hedging Activities Disclosure [Abstract]
Derivative Instruments and Hedging Activities Disclosure [Text Block]	Risk Management and Hedging Activities Changes in interest rates expose us to risk as a result of our issuance of variable and fixed-rate debt and commercial paper. We are exposed to foreign currency risk from the Canadian portion of the Express-Platte pipeline. We employ established policies and procedures to manage our risks associated with these market fluctuations, which may include the use of derivatives, mostly around interest rate exposures. Total Interest Rate Derivative Instruments We generally have a policy of entering into individual International Swaps and Derivatives Association, Inc. agreements, or other similar derivative agreements, with the majority of our financial derivative counterparties. These agreements provide for the net settlement of derivative instruments outstanding with specific counterparties in the event of bankruptcy or other significant credit events, and reduces our credit risk exposure on financial derivative asset positions outstanding with the counterparties in those circumstances. The following table summarizes the maximum potential settlement in the event of these specific circumstances. All amounts are presented gross on the Condensed Consolidated Balance Sheets: June 30, 2018 December 31, 2017 Gross Amounts Presented in the Condensed Consolidated Balance Sheet Amounts Available for Offset Net Amount Gross Amounts Presented in the Condensed Consolidated Balance Sheet Amounts Available for Offset Net Amount Description (in millions) Assets $ 28 $ (1 ) $ 27 $ 4 $ (1 ) $ 3 Liabilities (10 ) 1 (9 ) (8 ) 1 (7 ) Fair Value Hedges At June 30, 2018 , we had “pay floating - receive fixed” interest rate swaps outstanding with a total notional amount of $900 million to hedge against changes in the fair value of our fixed-rate financial instruments that arise as a result of changes in market interest rates . These swaps also allow us to transform a portion of the underlying interest payments related to our long-term debt securities from fixed-rate to variable-rate interest payments in order to achieve our desired mix of fixed and variable-rate debt. Our "pay floating - received fixed" interest rate derivative instruments are designated and qualify as fair value hedges. The gain or loss on the derivative as well as the offsetting loss or gain on the hedged item attributable to the hedged risk is recognized in the Condensed Consolidated Statements of Income. During the six months ended June 30, 2018 , the amounts recognized were $8 million loss on the fair value hedges and offsetting $8 million gain on long-term debt. Cash Flow Hedges Our earnings and cash flows are also exposed to variability in longer term interest rates ahead of anticipated fixed rate debt issuances. Forward starting interest rate swaps are used to hedge against the effect of future interest rate movements. Since the third quarter of 2017, we have entered into pre-issuance interest rate swaps which are designated and qualified as cash flow hedges. The information of these cash flow swaps are presented as follows: Fair Value at Date of Maturity & Contract Type Accounting Treatment Average Interest Rate Notional Amount June 30, 2018 December 31, 2017 (in millions) Contracts maturing in 2018 Cash Flow Hedge 2.51 % $ 560 $ 22 $ 1 Contracts maturing in 2020 Cash Flow Hedge 2.70 % 250 6 (3 ) We estimate that $2 million of Accumulated Other Comprehensive Income will be reclassified into net income in the next 12 months related to these swaps. The effects of derivative instruments on the Condensed Consolidated Statements of Income and the Condensed Consolidated Statements of Comprehensive Income are shown as follows: Amount of unrealized gain recognized in Other Comprehensive Income Three Months Ended Six Months Ended 2018 2017 2018 2017 (in millions) (in millions) Cash flow hedges - interest rate swaps $ 9 $ — $ 35 $ — Non-qualifying Hedges Our earnings and cash flows are exposed to changes in commodity prices as a result of our ownership interests in certain assets. In July 2017, we entered into a power swap to fix a portion of the variable price exposure for power costs from the Canadian portion of our Express-Platte pipeline system until 2020. As a result, we recognized an unrealized loss of $1 million and less than $1 million included in Operating, maintenance and other on the Condensed Consolidated Statements of Income during the three and six months ended June 30, 2018 , respectively and hedge assets of $2 million included in Other assets, net and Regulatory and other assets on the Condensed Consolidated Balance Sheets at June 30, 2018 .

Marketable Securities and Res20

Marketable Securities and Restricted Funds Marketable Securities (Policies)	6 Months Ended
	Jun. 30, 2018
Marketable Securities [Abstract]
Marketable Securities, Policy [Policy Text Block]	We routinely invest excess cash and various restricted balances in securities such as commercial paper, corporate debt securities, and other money market securities in the United States, as well as equity securities in Canada. We do not purchase marketable securities for speculative purposes, therefore we do not have any securities classified as trading securities. While we do not routinely sell marketable securities prior to their scheduled maturity dates, some of our investments may be held and restricted for the purposes of funding future capital expenditures and National Energy Board (NEB) regulatory requirements, so these investments are classified as AFS marketable securities as they may occasionally be sold prior to their scheduled maturity dates due to the unexpected timing of cash needs. Initial investments in securities are classified as purchases of the respective type of securities (AFS marketable securities or held-to-maturity (HTM) marketable securities). Maturities of AFS securities are presented within Net cash used in investing activities within the Condensed Consolidated Statements of Cash Flows.

Net Income Per Limited Partne21

Net Income Per Limited Partner Unit and Cash Distributions (Tables)	6 Months Ended
	Jun. 30, 2018
Equity [Abstract]
Net Income Per Limited Partner Unit Calculations	: Three Months Ended Six Months Ended 2018 2017 2018 2017 (in millions, except per unit amounts) Net income attributable to controlling interests $ 381 $ 328 $ 788 $ 645 Less: Net income attributable to: General partner’s interest in general partner units—2% (a) — 7 — 13 General partner’s interest in incentive distribution rights (a) — 87 — 170 Limited partners’ interest in net income attributable to common units $ 381 $ 234 $ 788 $ 462 Weighted average limited partner units outstanding—basic and diluted 485 310 465 310 Net income per limited partner unit—basic and diluted $ 0.78 $ 0.75 $ 1.69 $ 1.49 ______________ (a) General partner units and incentive distribution rights (IDRs) were converted to common units of Spectra Energy Partners as a result of the Equity Restructuring Agreement dated January 21, 2018 (Equity Restructuring Agreement). See Note 13 for additional information.

Debt and Credit Facility (Table

Debt and Credit Facility (Tables)	6 Months Ended
	Jun. 30, 2018
Debt Disclosure [Abstract]
Debt and Credit Facility Summary	Credit Facility Maturity Date (a) Total Facility Draws (b) Available (in millions) Spectra Energy Partners, LP 2022 $ 2,500 $ 1,161 $ 1,339

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2018
Fair Value Disclosures [Abstract]
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis	The following presents, for each of the fair value hierarchy levels, assets and liabilities that are measured at fair value on a recurring basis as of June 30, 2018 and December 31, 2017 : Description Condensed Consolidated Balance Sheet Caption June 30, 2018 Total Level 1 Level 2 Level 3 (in millions) Interest rate swaps Other assets, net 22 $ — $ 22 $ — Commodity swaps Other assets, net 1 — — 1 Canadian equity securities Regulatory and other assets 3 3 — — Interest rate swaps Regulatory and other assets 6 — 6 — Commodity swaps Regulatory and other assets 1 — — 1 Total Assets $ 33 $ 3 $ 28 $ 2 Interest rate swaps Current liabilities — other $ 3 $ — $ 3 $ — Interest rate swaps Regulatory and other liabilities 7 — 7 — Total Liabilities $ 10 $ — $ 10 $ — Description Condensed Consolidated Balance Sheet Caption December 31, 2017 Total Level 1 Level 2 Level 3 (in millions) Canadian equity securities Regulatory and other assets $ 3 $ 3 $ — $ — Interest rate swaps Other assets, net 4 — 4 — Commodity swaps Other assets, net 2 — — 2 Total Assets $ 9 $ 3 $ 4 $ 2 Interest rate swaps Current liabilities — other $ 3 $ — $ 3 $ — Interest rate swaps Regulatory and other liabilities 5 — 5 — Total Liabilities $ 8 $ — $ 8 $ —
Fair Value Measurement, Policy [Policy Text Block]	Level 1 Level 1 valuations represent quoted unadjusted prices for identical instruments in active markets. Level 2 Fair values of our financial instruments that are actively traded in the secondary market, including our long-term debt, are determined based on market-based prices. These Level 2 valuations may include inputs such as quoted market prices of the exact or similar instruments, broker or dealer quotations, or alternative pricing sources that may include models or matrix pricing tools, with reasonable levels of price transparency. For interest rate swaps, we utilize data obtained from a third-party source for the determination of fair value. Both the future cash flows for the fixed-leg and floating-leg of our swaps are discounted to present value. Level 3 Level 3 valuation techniques include the use of pricing models, discounted cash flow methodologies or similar techniques where at least one significant model assumption or input is unobservable. Level 3 financial instruments also include those for which the determination of fair value requires significant management judgment or estimation.
Fair Values of Financial Instruments That are Recorded and Carried at Book Value	The fair values of financial instruments that are recorded and carried at book value are summarized in the following table. Judgment is required in interpreting market data to develop the estimates of fair value. These estimates are not necessarily indicative of the amounts we could have realized in current markets. June 30, 2018 December 31, 2017 Condensed Consolidated Balance Sheets Book Value Approximate Fair Value Book Value Approximate Fair Value (in millions) Note receivable, noncurrent (a) $ 71 $ 71 $ 71 $ 71 Long-term debt, including current maturities (b) 6,650 6,639 5,850 6,211 ______________ (a) Included within Investments in and loans to unconsolidated affiliates. (b) Excludes variable rate debt, unamortized items and fair value hedge carrying value adjustme

General (Details)

General (Details)	Jun. 30, 2018
Enbridge Inc.
Business Acquisition
Ownership percentage by parent	83.00%
Publicly Owned
Business Acquisition
Ownership percentage by public	17.00%

Business Segments (Additional I

Business Segments (Additional Information) (Details)	6 Months Ended
	Jun. 30, 2018reportable_segments
Segment Reporting [Abstract]
Number of Reportable Segments	2

Business Segment Data (Details)

Business Segment Data (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Segment Reporting Information
Total operating revenues	$ 726	$ 695	$ 1,505	$ 1,395
Depreciation, Depletion and Amortization	90	87
Depreciation, Depletion and Amortization, Nonproduction	90	87	179	172
Interest expense	85	60	170	116
Interest income and other	3	0	4	1
Earnings from continuing operations before income taxes	398	372	821	731
Total Operating Segments
Segment Reporting Information
Total operating revenues	726	695	1,505	1,395
Depreciation, Depletion and Amortization	90	87
Depreciation, Depletion and Amortization, Nonproduction			179	172
Earnings before interest taxes depreciation and amortization	572	544	1,169	1,089
US Transmission [Member]
Segment Reporting Information
Total operating revenues	624	592	1,295	1,188
Depreciation, Depletion and Amortization	82	79
Depreciation, Depletion and Amortization, Nonproduction			163	156
Earnings before interest taxes depreciation and amortization	505	480	1,027	959
Liquids [Member]
Segment Reporting Information
Total operating revenues	102	103	210	207
Depreciation, Depletion and Amortization	8	8
Depreciation, Depletion and Amortization, Nonproduction			16	16
Earnings before interest taxes depreciation and amortization	67	64	142	130
Other Segments [Member]
Segment Reporting Information
Earnings before interest taxes depreciation and amortization	$ (2)	$ (25)	$ (3)	$ (71)

Net Income Per Limited Partne27

Net Income Per Limited Partner Unit and Cash Distributions (Details) - USD ($) $ / shares in Units, shares in Millions, $ 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]
Net income attributable to controlling interests	$ 381	$ 328	$ 788	$ 645
Net income attributable to general partner	0	94	0	183
Limited partners’ interest in net income attributable to common units	$ 381	$ 234	$ 788	$ 462
Weighted average limited partner units outstanding—basic and diluted	485	310	465	310
Net income per limited partner unit—basic and diluted	$ 0.78	$ 0.75	$ 1.69	$ 1.49
Partnership Interest
Related Party Transaction [Line Items]
Net income attributable to general partner	$ 0	$ 7	$ 0	$ 13
Incentive Distribution Rights
Related Party Transaction [Line Items]
Net income attributable to general partner	$ 0	$ 87	$ 0	$ 170

Variable Interest Entities (Det

Variable Interest Entities (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2018	Apr. 30, 2018	Dec. 31, 2017
Nexus
Variable Interest Entity [Line Items]
Variable Interest Entity, Qualitative or Quantitative Information, Ownership Percentage	50.00%
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	$ 1,300
Investments	$ 869		$ 640
PennEast Pipeline
Variable Interest Entity [Line Items]
Variable Interest Entity, Qualitative or Quantitative Information, Ownership Percentage	20.00%
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	$ 279
Investments	$ 66		$ 55
Sabal Trail
Variable Interest Entity [Line Items]
Limited Liability Company (LLC) or Limited Partnership (LP), Managing Member or General Partner, Ownership Interest	50.00%
Senior Unsecured Notes Four Point Six Eight Two Percent Due Twenty Thirty Eight [Domain] | Sabal Trail
Variable Interest Entity [Line Items]
Unsecured Debt		$ 600
Senior Unsecured Notes Four Point Eight Three Two Percent Due Twenty Forty Eight [Domain] | Sabal Trail
Variable Interest Entity [Line Items]
Unsecured Debt		400
Senior Unsecured Notes Four Point Two Four Six Percent Due Twenty Twenty Eight [Domain] | Sabal Trail
Variable Interest Entity [Line Items]
Unsecured Debt		$ 500

Marketable Securities and Res29

Marketable Securities and Restricted Funds - Schedule of Available-for-Sale Securities (Details) - USD ($) $ in Millions	3 Months Ended
	Jun. 30, 2018	Dec. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Accumulated Gross Unrealized Gain (Loss), before Tax	$ 0
Investments and Other Assets - Other
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities	3
Canadian Pipeline Abandonment Requirement | Investments and Other Assets - Other
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities	$ 3
Project Costs | Investments and Other Assets - Other
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities		$ 1
Available-for-sale Securities | Maximum
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, contractual maturity	1 year

Marketable Securities and Res30

Marketable Securities and Restricted Funds - Schedule of Held-to-Maturity Securities (Details) $ in Millions	3 Months Ended
	Jun. 30, 2018USD ($)
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity Securities, Accumulated Unrecognized Holding Gain	$ 0
Current Assets - Other | Money Market Funds
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity Securities, Fair Value	$ 3
Held-to-maturity Securities | Maximum
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity securities, contractual maturity	1 year

Marketable Securities and Res31

Marketable Securities and Restricted Funds Marketable Securities and Restricted Funds - Other Restricted Funds (Details) $ in Millions	Jun. 30, 2018USD ($)
Project Costs | Investments and Other Assets - Other
Gain (Loss) on Investments [Line Items]
Restricted Cash and Cash Equivalents, Noncurrent	$ 2

Debt and Credit Facility (Addit

Debt and Credit Facility (Additional Information) (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2018	Jan. 09, 2018
Line of Credit Facility [Line Items]
Line of Credit Facility Maturity Yr	2,022
Line of Credit Facility, Maximum Borrowing Capacity	$ 2,500
Draws (b)	1,161
Available	$ 1,339
Senior Unsecured Notes Three Point Five Percent Due Twenty Twenty Eight [Member] | Texas Eastern Transmission Lp [Member]
Line of Credit Facility [Line Items]
Total Facility		$ 400
Senior Unsecured Notes Four Point One Five Percent Due Twenty Twenty Fourty Eight [Member] | Texas Eastern Transmission Lp [Member]
Line of Credit Facility [Line Items]
Total Facility		$ 400

Fair Value Measurements - Fair

Fair Value Measurements - Fair Value Hierarchy Levels, Assets that are Measured at Fair Value on a Recurring Basis (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Financial Instruments [Line Items]
Assets, Fair Value Disclosure	$ 33	$ 9
Liabilities, Fair Value Disclosure, Recurring	10	8
Fair Value, Inputs, Level 1
Financial Instruments [Line Items]
Assets, Fair Value Disclosure	3	3
Fair Value, Inputs, Level 2
Financial Instruments [Line Items]
Assets, Fair Value Disclosure	28	4
Liabilities, Fair Value Disclosure, Recurring	10	8
Fair Value, Inputs, Level 3 [Member]
Financial Instruments [Line Items]
Assets, Fair Value Disclosure	2	2
Interest Rate Swap [Member] | Other Current Assets [Member]
Financial Instruments [Line Items]
Assets, Fair Value Disclosure	22	4
Interest Rate Swap [Member] | Other Current Assets [Member] | Fair Value, Inputs, Level 2
Financial Instruments [Line Items]
Assets, Fair Value Disclosure	22	4
Interest Rate Swap [Member] | Regulatory Assets and Deferred Debits [Member]
Financial Instruments [Line Items]
Assets, Fair Value Disclosure	6
Interest Rate Swap [Member] | Regulatory Assets and Deferred Debits [Member] | Fair Value, Inputs, Level 2
Financial Instruments [Line Items]
Assets, Fair Value Disclosure	6
Interest Rate Swap [Member] | Other Current Liabilities [Member]
Financial Instruments [Line Items]
Liabilities, Fair Value Disclosure, Recurring	3	3
Interest Rate Swap [Member] | Other Current Liabilities [Member] | Fair Value, Inputs, Level 2
Financial Instruments [Line Items]
Liabilities, Fair Value Disclosure, Recurring		3
Financial and Nonfinancial Liabilities, Fair Value Disclosure	3
Interest Rate Swap [Member] | Other Noncurrent Liabilities [Member]
Financial Instruments [Line Items]
Liabilities, Fair Value Disclosure, Recurring	7	5
Interest Rate Swap [Member] | Other Noncurrent Liabilities [Member] | Fair Value, Inputs, Level 2
Financial Instruments [Line Items]
Liabilities, Fair Value Disclosure, Recurring	7	5
Commodity Contract [Member] | Other Current Assets [Member]
Financial Instruments [Line Items]
Assets, Fair Value Disclosure	1	2
Commodity Contract [Member] | Other Noncurrent Assets [Member]
Financial Instruments [Line Items]
Assets, Fair Value Disclosure	1
Commodity Contract [Member] | Other Noncurrent Assets [Member] | Fair Value, Inputs, Level 3 [Member]
Financial Instruments [Line Items]
Assets, Fair Value Disclosure	1	2
CANADA | Canadian Equity Securities | Other Noncurrent Assets [Member]
Financial Instruments [Line Items]
Assets, Fair Value Disclosure	3	3
CANADA | Canadian Equity Securities | Other Noncurrent Assets [Member] | Fair Value, Inputs, Level 1
Financial Instruments [Line Items]
Assets, Fair Value Disclosure	$ 3	$ 3

Fair Value Measurements - Fai34

Fair Value Measurements - Fair Values of Financial Instruments Recorded and Carried at Book Value (Details) - USD ($) $ in Millions		Jun. 30, 2018	Dec. 31, 2017
Book Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Notes Receivable, Fair Value Disclosure	[1]	$ 71	$ 71
Long-term debt, including current maturities	[1]	6,650
Approximate Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Notes Receivable, Fair Value Disclosure	[1]	71	$ 71
Long-term debt, including current maturities	[1]	$ 6,639
[1]	variable rate debt, unamortized items and fair value hedge carrying value adjustments.The fai

Guarantees (Details)

Guarantees (Details) $ in Millions	6 Months Ended
	Jun. 30, 2018USD ($)
Guarantees [Abstract]
Guarantor Obligations, Maximum Exposure, Undiscounted	$ 107
Guarantor Obligations, Term	2,032

Issuances of Common Units (Addi

Issuances of Common Units (Additional Information) (Detail) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jan. 21, 2018
Issuances of Common Units [Line Items]
Common Unit, Issued			172,500,000
Proceeds from issuance of common units	$ 0	$ 87

New Accounting Pronouncements P

New Accounting Pronouncements Presentation of Restricted Cash (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017	Dec. 31, 2016
Restricted Cash and Cash Equivalents Items [Line Items]
Cash and cash equivalents	$ 96	$ 107
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	101	114	$ 159	$ 233
Cash and Cash Equivalents [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	$ 101	$ 114	$ 159	$ 233

Revenue from contracts with c38

Revenue from contracts with customers (Details) - USD ($) $ in Millions	3 Months Ended			6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2018	Jun. 30, 2017
Disaggregation of Revenue [Line Items]
Storage of natural gas and other	$ 54	$ 57		$ 121	$ 118
Total operating revenues	726	695		1,505	1,395
US Transmission [Member]
Disaggregation of Revenue [Line Items]
Transportation of natural gas			$ 575	1,189
Transportation of crude oil			0	0
Storage of natural gas and other	47			102
Contracts Revenue	622		622	1,291
Results of Operations, Revenue, Other	2			4
Total operating revenues	624	592		1,295	1,188
Liquids [Member]
Disaggregation of Revenue [Line Items]
Transportation of natural gas	0			0
Transportation of crude oil	97			195
Storage of natural gas and other	5			15
Contracts Revenue	102		102	210
Results of Operations, Revenue, Other	0			0
Total operating revenues	102	$ 103		210	$ 207
Operating Segments
Disaggregation of Revenue [Line Items]
Transportation of natural gas	575			1,189
Transportation of crude oil	97			195
Storage of natural gas and other	52			117
Contracts Revenue	724		$ 724	1,501
Results of Operations, Revenue, Other	2			4
Total operating revenues	726			1,505
Intersegment Eliminations [Member] | US Transmission [Member]
Disaggregation of Revenue [Line Items]
Contracts Revenue	0			0
Intersegment Eliminations [Member] | Liquids [Member]
Disaggregation of Revenue [Line Items]
Contracts Revenue	0			0
Intersegment Eliminations [Member] | Operating Segments
Disaggregation of Revenue [Line Items]
Contracts Revenue	$ 0			$ 0

Revenue from contracts with c39

Revenue from contracts with customers Timing of recognition of revenues (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2016	Jun. 30, 2018
Liquids [Member]
Revenue from External Customer [Line Items]
Contracts Revenue	$ 102	$ 102	$ 210
Operating Segments
Revenue from External Customer [Line Items]
Contracts Revenue	724	724	1,501
US Transmission [Member]
Revenue from External Customer [Line Items]
Contracts Revenue	$ 622	$ 622	$ 1,291

Revenue from contracts with c40

Revenue from contracts with customers Contract balances (Details) - Type of Adoption [Domain] - USD ($) $ in Millions	Jun. 30, 2018	Jan. 01, 2018
contract balances [Line Items]
Receivables, Long-term Contracts or Programs	$ 248	$ 265
Contract with Customer, Asset, Net	0	0
Contract with Customer, Liability	$ 65	$ 65

Revenue from contracts with c41

Revenue from contracts with customers Revenue to be recognized from unfulfilled obligations (Details) - USD ($) $ in Billions	Dec. 31, 2019	Dec. 31, 2018	Jun. 30, 2018
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation	$ 2.4	$ 1.3	$ 22

Subsequent Events (Details)

Subsequent Events (Details) - Sabal Trail Transmission, LLC [Member] $ in Millions	Apr. 30, 2018USD ($)
Senior Unsecured Notes Four Point Two Four Six Percent Due Twenty Twenty Eight [Domain]
Subsequent Event [Line Items]
Unsecured Debt	$ 500
Senior Unsecured Notes Four Point Six Eight Two Percent Due Twenty Thirty Eight [Domain]
Subsequent Event [Line Items]
Unsecured Debt	600
Senior Unsecured Notes Four Point Eight Three Two Percent Due Twenty Forty Eight [Domain]
Subsequent Event [Line Items]
Unsecured Debt	$ 400

Risk Management and Hedging A43

Risk Management and Hedging Activities (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		11 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 01, 2020	Dec. 01, 2018	Dec. 31, 2017
Derivative [Line Items]
Derivative Liability, Fair Value, Gross Asset	$ (10)		$ (10)				$ (8)
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	1		1				1
Derivative Liability, Noncurrent	(9)		(9)				(7)
Description of Interest Rate Cash Flow Hedge Activities					250	560
Interest Rate Cash Flow Hedge Asset at Fair Value	22		22				1
Interest Rate Cash Flow Hedge Liability at Fair Value	6		6				3
Increase (Decrease) in Fair Value of Interest Rate Fair Value Hedging Instruments			8
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge			8
Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net	2		2
Unrealized Gain (Loss) on Commodity Contracts			1
Derivative Instruments Not Designated as Hedging Instruments, Asset, at Fair Value	2		2
Interest Rate Swap [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset	28		28				4
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	(1)		(1)				(1)
Derivative Asset, Noncurrent	27		27				$ 3
Interest Rate Swap [Member] | Interest Expense [Member] | Cash Flow Hedging [Member]
Derivative [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	9	$ 0	35	$ 0
Interest Rate Swap [Member] | Pay floating - receive fixed interest rate swap [Member]
Derivative [Line Items]
Derivative, Notional Amount	$ 900		$ 900
Contracts maturing in 2018 [Member]
Derivative [Line Items]
Description of Interest Rate Derivative Activities						0.0251
Contracts maturing in 2020 [Member]
Derivative [Line Items]
Description of Interest Rate Derivative Activities					0.0270

Uncategorized Items - sep-20180

Label	Element	Value
Noncontrolling Interest, Increase from Sale of Parent Equity Interest	us-gaap_NoncontrollingInterestIncreaseFromSaleOfParentEquityInterest	$ 1,000,000
Noncontrolling Interest [Member]
Noncontrolling Interest, Increase from Sale of Parent Equity Interest	us-gaap_NoncontrollingInterestIncreaseFromSaleOfParentEquityInterest	1,000,000
Cash and Cash Equivalents [Member]
Cash and Cash Equivalents, at Carrying Value	us-gaap_CashAndCashEquivalentsAtCarryingValue	216,000,000
Cash and Cash Equivalents, at Carrying Value	us-gaap_CashAndCashEquivalentsAtCarryingValue	153,000,000
Cash and Cash Equivalents, at Carrying Value	us-gaap_CashAndCashEquivalentsAtCarryingValue	107,000,000
Cash and Cash Equivalents, at Carrying Value	us-gaap_CashAndCashEquivalentsAtCarryingValue