Spectra Energy 10-K 25 Feb 16 2014 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2015	Jan. 31, 2016	Jun. 30, 2015
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2015
Document Fiscal Year Focus	2,014
Document Fiscal Period Focus	FY
Trading Symbol	SE
Entity Registrant Name	SPECTRA ENERGY CORP.
Entity Central Index Key	1,373,835
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		671,500,270
Entity Public Float			$ 22,000,000,000

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2015		Dec. 31, 2014		Dec. 31, 2013
Operating Revenues
Transportation, storage and processing of natural gas	$ 3,225		$ 3,291		$ 3,128
Distribution of natural gas	1,320		1,583		1,577
Sales of natural gas liquids	209		497		440
Transportation of crude oil	357		302		224
Other	123		230		149
Total operating revenues	5,234		5,903		5,518
Operating Expenses
Natural gas and petroleum products purchased	835		1,219		1,139
Operating, maintenance and other	1,500		1,571		1,568
Depreciation and amortization	764		796		772
Property and other taxes	353		393		373
Impairment of goodwill and other	349		0		0
Total operating expenses	3,801		3,979		3,852
Operating Income	1,433		1,924		1,666
Other Income and Expenses
Earnings (loss) from equity investments	(290)		361		445
Other income and expenses, net	114		59		124
Total other income and expenses	(176)		420		569
Interest Expense	636		679		657
Earnings Before Income Taxes	621		1,665		1,578
Income Tax Expense	161		382		419
Net Income	460		1,283		1,159
Net Income—Noncontrolling Interests	264		201		121
Net Income—Controlling Interests	$ 196		$ 1,082		$ 1,038
Weighted-average shares outstanding
Basic (in shares)	671		671		669
Diluted (in shares)	672		672		671
Earnings per share
Basic (in usd per share)	$ 0.29	[1]	$ 1.61	[1]	$ 1.55
Diluted (in usd per share)	0.29	[1]	1.61	[1]	1.55
Common Stock, Dividends, Per Share, Declared	$ 1.48		$ 1.375		$ 1.22
[1]	Quarterly earnings-per-share amounts are stand-alone calculations and may not be additive to full-year amounts due to rounding.

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Net Income	$ 460	$ 1,283	$ 1,159
Other comprehensive income (loss):
Foreign currency translation adjustments	(950)	(548)	(494)
Non-cash mark-to-market net gain on hedges	0	4	7
Reclassification of cash flow hedges into earnings	0	5	7
Pension and benefits impact (net of tax benefit (expense) of $1, $14 and $(88), respectively)	5	(47)	203
Other	1	0	2
Total other comprehensive income (loss)	(944)	(586)	(275)
Total Comprehensive Income (Loss), net of tax	(484)	697	884
Less: Comprehensive Income—Noncontrolling Interests	251	194	114
Comprehensive Income (Loss)—Controlling Interests	$ (735)	$ 503	$ 770

Consolidated Statements of Com4

Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement of Comprehensive Income [Abstract]
Tax benefit (expense) on pension and benefits impact	$ 1	$ 14	$ (88)

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions		Dec. 31, 2015	Dec. 31, 2014
Current Assets
Cash and cash equivalents		$ 213	$ 215
Receivables (net of allowance for doubtful accounts of $11 at December 31, 2015 and 2014)		806	1,336
Inventory		307	313
Fuel tracker		41	102
Other		281	366
Total current assets		1,648	2,332
Investments and Other Assets
Investments in and loans to unconsolidated affiliates		2,592	2,966
Goodwill		4,154	4,714
Other		310	327
Total investments and other assets		7,056	8,007
Property, Plant and Equipment
Cost		29,843	29,211
Less accumulated depreciation and amortization		6,925	6,904
Net property, plant and equipment		22,918	22,307
Regulatory Assets and Deferred Debits		1,301	1,352
Total Assets		32,923	33,998
Current Liabilities
Accounts payable		511	458
Commercial paper	[1],[2]	1,112	1,583
Taxes accrued		78	91
Interest accrued		179	181
Current maturities of long-term debt		652	327
Other		860	1,169
Total current liabilities		3,392	3,809
Long-term Debt		12,892	12,727
Deferred Credits and Other Liabilities
Deferred income taxes		5,445	5,405
Regulatory and other		1,323	1,401
Total deferred credits and other liabilities		$ 6,768	$ 6,806
Commitments and Contingencies
Preferred Stock of Subsidiaries		$ 339	$ 258
Equity
Preferred stock, $0.001 par, 22 million shares authorized, no shares outstanding		0	0
Common stock, $0.001 par, 1 billion shares authorized, 671 million shares outstanding at December 31, 2015 and 2014		1	1
Additional paid-in capital		5,053	4,956
Retained earnings		1,741	2,541
Accumulated other comprehensive (loss) income		(269)	662
Total controlling interests		6,526	8,160
Noncontrolling interests		3,006	2,238
Total equity		9,532	10,398
Total Liabilities and Equity		$ 32,923	$ 33,998
[1]	The weighted-average days to maturity was 12 days as of December 31, 2015 and 14 days as of December 31, 2014.
[2]	Weighted-average rate on outstanding commercial paper was 0.9% at December 31, 2015 and 0.6% at December 31, 2014.

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Receivables, allowance for doubtful accounts	$ 11	$ 11
Preferred stock, par value (in usd per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized	22,000,000	22,000,000
Preferred stock, shares outstanding	0	0
Common stock, par value (in usd per share)	$ 0.001	$ 0.001
Common stock, shares authorized	1,000,000,000	1,000,000,000
Common stock, shares outstanding	671,000,000	671,000,000

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 460	$ 1,283	$ 1,159
Depreciation and amortization	778	809	787
Impairment charges	349	0	0
Adjustments to reconcile net income to net cash provided by operating activities:
Deferred income tax expense	88	388	421
(Earnings) loss from equity investments	290	(361)	(445)
Distributions from equity investments	161	380	324
Decrease (increase) in
Receivables	141	(9)	(94)
Inventory	(40)	(106)	17
Other current assets	43	(143)	(88)
Increase (decrease) in
Accounts payable	26	25	(2)
Taxes accrued	23	28	(8)
Other current liabilities	(15)	3	101
Other, assets	(106)	(33)	(111)
Other, liabilities	49	(43)	(31)
Net cash provided by operating activities	2,247	2,221	2,030
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(2,848)	(2,028)	(1,947)
Investments in and loans to unconsolidated affiliates	(124)	(259)	(312)
Acquisitions, net of cash acquired	0	0	(1,254)
Purchases of held-to-maturity securities	(668)	(790)	(985)
Proceeds from sales and maturities of held-to-maturity securities	695	815	1,023
Purchases of available-for-sale securities	(95)	(13)	(5,878)
Proceeds from sales and maturities of available-for-sale securities	87	7	6,024
Distributions from equity investments	451	266	87
Distribution to equity investment	(248)	0	(71)
Repayment of loan to equity investment	0	0	71
Other changes in restricted funds	(33)	(1)	2
Other	1	0	4
Net cash used in investing activities	(2,782)	(2,003)	(3,236)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt	1,585	1,028	4,372
Payments for the redemption of long-term debt	(285)	(1,184)	(2,139)
Net increase (decrease) in commercial paper	(439)	574	(206)
Distributions to noncontrolling interests	(198)	(175)	(144)
Contributions from noncontrolling interests	248	145	23
Proceeds from the issuance of Spectra Energy Partners, LP common units	546	327	214
Proceeds from the issuance of Westcoast Energy, Inc. preferred stock	84	0	0
Dividends paid on common stock	(996)	(925)	(821)
Other	(5)	11	17
Net cash provided by (used in) financing activities	540	(199)	1,316
Effect of exchange rate changes on cash	(7)	(5)	(3)
Net increase (decrease) in cash and cash equivalents	(2)	14	107
Cash and cash equivalents at beginning of period	215	201	94
Cash and cash equivalents at end of period	213	215	201
Supplemental Disclosures
Cash paid for interest, net of amount capitalized	623	684	625
Net cash paid (refunds received) for income taxes	29	(8)	43
Property, plant and equipment non-cash accruals	$ 192	$ 125	$ 112

Consolidated Statements of Equi

Consolidated Statements of Equity - USD ($) $ in Millions	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Foreign Currency Translation Adjustments	Other	Noncontrolling Interests
Beginning Balance at Dec. 31, 2012	$ 9,843	$ 1	$ 5,297	$ 2,165	$ 2,044	$ (535)	$ 871
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	1,159			1,038			121
Other comprehensive income (loss)	(275)				(487)	219	(7)
Dividends on common stock	(820)			(820)
Stock-based compensation	19		19
Distributions to noncontrolling interests	(144)						(144)
Contributions from noncontrolling interests	23						23
Spectra Energy common stock issued	23		23
Spectra Energy Partners, LP common units issued/retired	189		42				147
Transfer of interests in subsidiaries to Spectra Energy Partners, LP	306		(511)				817
Other, net	0		(1)				1
Ending Balance at Dec. 31, 2013	10,323	1	4,869	2,383	1,557	(316)	1,829
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	1,283			1,082			201
Other comprehensive income (loss)	(586)				(541)	(38)	(7)
Dividends on common stock	(924)			(924)
Stock-based compensation	19		19
Distributions to noncontrolling interests	(175)						(175)
Contributions from noncontrolling interests	145						145
Spectra Energy common stock issued	11		11
Spectra Energy Partners, LP common units issued/retired	297		49				248
Transfer of interests in subsidiaries to Spectra Energy Partners, LP	2		3				(1)
Other, net	3		5				(2)
Ending Balance at Dec. 31, 2014	10,398	1	4,956	2,541	1,016	(354)	2,238
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	460			196			264
Other comprehensive income (loss)	(944)				(937)	6	(13)
Dividends on common stock	(996)			(996)
Stock-based compensation	21		21
Distributions to noncontrolling interests	(200)						(200)
Contributions from noncontrolling interests	248						248
Spectra Energy common stock issued	3		3
Spectra Energy Partners, LP common units issued/retired	530		(105)				635
Transfer of interests in subsidiaries	0		166				(166)
Other, net	12		12				0
Ending Balance at Dec. 31, 2015	$ 9,532	$ 1	$ 5,053	$ 1,741	$ 79	$ (348)	$ 3,006

Summary of Operations and Signi

Summary of Operations and Significant Accounting Policies	12 Months Ended
	Dec. 31, 2015
Accounting Policies [Abstract]
Summary of Operations and Significant Accounting Policies	Summary of Operations and Significant Accounting Policies The terms “we,” “our,” “us” and “Spectra Energy” as used in this report refer collectively to Spectra Energy Corp 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. The term “Spectra Energy Partners” refers to our Spectra Energy Partners operating segment. The term “SEP” refers to Spectra Energy Partners, LP, our master limited partnership. Nature of Operations. Spectra Energy Corp, through its subsidiaries and equity affiliates, owns and operates a large and diversified portfolio of complementary natural gas-related energy assets, and owns and operates a crude oil pipeline system that connects Canadian and U.S. producers to refineries in the U.S. Rocky Mountain and Midwest regions. We currently operate in three key areas of the natural gas industry: gathering and processing, transmission and storage, and distribution. We provide transmission and storage of natural gas to customers in various regions of the northeastern and southeastern U.S., the Maritime Provinces in Canada, the Pacific Northwest in the U.S. and Canada, and in the province of Ontario, Canada. We also provide natural gas sales and distribution services to retail customers in Ontario, and natural gas gathering and processing services to customers in western Canada. We also own a 50% interest in DCP Midstream, LLC (DCP Midstream), based in Denver, Colorado, one of the leading natural gas gatherers in the U.S. and one of the largest U.S. producers and marketers of natural gas liquids (NGLs). Basis of Presentation. The accompanying Consolidated Financial Statements include our accounts and the accounts of our majority-owned subsidiaries, after eliminating intercompany transactions and balances. Use of Estimates. To conform with generally accepted accounting principles (GAAP) in the U.S., we make estimates and assumptions that affect the amounts reported in the Consolidated Financial Statements and Notes to Consolidated Financial Statements. Although these estimates are based on our best available knowledge at the time, actual results could differ. Fair Value Measurements. We measure the fair value of financial assets and liabilities by maximizing the use of observable inputs and minimizing the use of unobservable inputs. Fair value is the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Cost-Based Regulation. The economic effects of regulation can result in a regulated company recording assets for costs that have been or are expected to be approved for recovery from customers or recording liabilities for amounts that are expected to be returned to customers or for instances where the regulator provides current rates that are intended to recover costs that are expected to be incurred in the future. Accordingly, we record assets and liabilities that result from the regulated ratemaking process that may not be recorded under GAAP for non-regulated entities. We continually assess whether regulatory assets are probable of future recovery by considering factors such as applicable regulatory changes and recent rate orders to other regulated entities. Based on this assessment, we believe our existing regulatory assets are probable of recovery. These regulatory assets and liabilities are mostly classified in the Consolidated Balance Sheets as Regulatory Assets and Deferred Debits, and Deferred Credits and Other Liabilities—Regulatory and Other. We evaluate our regulated assets, and consider factors such as regulatory changes and the effect of competition. If cost-based regulation ends or competition increases, we may have to reduce our asset balances to reflect a market basis less than cost and write-off the associated regulatory assets and liabilities. See Note 5 for further discussion. Foreign Currency Translation. The Canadian dollar has been determined to be the functional currency of our Canadian operations based on an assessment of the economic circumstances of those operations. Assets and liabilities of our Canadian operations are translated into U.S. dollars at current exchange rates. Translation adjustments resulting from fluctuations in exchange rates are included as a separate component of Other Comprehensive Income on the Consolidated Statements of Comprehensive Income. Revenue and expense accounts of these operations are translated at average monthly exchange rates prevailing during the periods. Gains and losses arising from transactions denominated in currencies other than the functional currency are included in the results of operations of the period in which they occur. Foreign currency transaction losses totaled $ 6 million in 2015 , and gains totaled $3 million in 2014 and $1 million in 2013 , and are included in Other Income and Expenses, Net on the Consolidated Statements of Operations. Deferred U.S. taxes related to translation gains and losses have not been provided on those Canadian operations where we expect the earnings to be indefinitely reinvested. Revenue Recognition. Revenues from the transmission, storage, processing, distribution and sales of natural gas, from the sales of NGLs and from the transportation and storage of crude oil are generally recognized when either the service is provided or the product is delivered. Revenues related to these services provided or products delivered but not yet billed are estimated each month. These estimates are generally based on contract data, regulatory information, estimated distribution usage based on historical data adjusted for heating degree days, commodity prices and preliminary throughput and allocation measurements. Final bills for the current month are billed and collected in the following month. Differences between actual and estimated unbilled revenues are immaterial. There were no customers accounting for 10% or more of consolidated revenues during 2015 , 2014 or 2013 . We also have certain customer contracts with billed amounts that decline annually over the terms of the contracts. Differences between the amounts billed and recognized are deferred on the Consolidated Balance Sheets. Stock-Based Compensation. For employee awards, equity-classified and liability-classified stock-based compensation cost is measured at the grant date based on the fair value of the award. Liability-classified stock-based compensation cost is remeasured at each reporting period until settlement. Related compensation expense is recognized over the requisite service period, which generally begins on the date the award is granted through the earlier of the date the award vests, the date the employee becomes retirement-eligible or the date the market or performance condition of the award is met. Awards, including stock options, granted to employees that are retirement-eligible are deemed to have vested immediately upon issuance, and therefore, compensation cost for those awards is recognized on the date such awards are granted. See Note 22 for further discussion. Pension and Other Post-Retirement Benefits. We fully recognize the overfunded or underfunded status of our consolidating subsidiaries’ pension and other post-retirement benefit plans as Investments and Other Assets—Other, Current Liabilities—Other or Deferred Credits and Other Liabilities—Regulatory and Other in the Consolidated Balance Sheets, as appropriate. A plan’s funded status is the difference between the fair value of plan assets and the plan’s projected benefit obligation. We record deferred plan costs and income (unrecognized losses and gains, and unrecognized prior service costs and credits) in Accumulated Other Comprehensive Income (AOCI) on the Consolidated Statements of Equity, until they are amortized and recognized as a component of benefit expense within Operating, Maintenance and Other in the Consolidated Statements of Operations. See Note 23 for further discussion. Allowance for Funds Used During Construction (AFUDC). AFUDC, which represents the estimated debt and equity costs of capital funds necessary to finance the construction of certain new regulated facilities, consists of two components, an equity component and an interest expense component. The equity component is a non-cash item. After construction is completed, we are permitted to recover these costs through inclusion in the rate base and in the depreciation provision. AFUDC is capitalized as a component of Property, Plant and Equipment—Cost in the Consolidated Balance Sheets, with offsetting credits to the Consolidated Statements of Operations through Other Income and Expenses, Net for the equity component and Interest Expense for the interest expense component. The total amount of AFUDC included in the Consolidated Statements of Operations was $143 million in 2015 (an equity component of $111 million and an interest expense component of $32 million ), $72 million in 2014 (an equity component of $53 million and an interest expense component of $19 million ) and $155 million in 2013 (an equity component of $105 million and an interest expense component of $50 million ). Income Taxes. Deferred income taxes are recognized for differences between the financial reporting and tax bases of assets and liabilities at enacted statutory tax rates in effect for the years in which the differences are expected to reverse. The effect on deferred taxes of a change in tax rates is recognized in income in the period that includes the enactment date. Actual income taxes could vary from these estimates due to future changes in income tax law or results from the final review of tax returns by federal, state or foreign tax authorities. Financial statement effects on tax positions are recognized in the period in which it is more likely than not that the position will be sustained upon examination, the position is effectively settled or when the statute of limitations to challenge the position has expired. Interest and penalties related to unrecognized tax benefits are recorded as interest expense and other expense, respectively. Cash and Cash Equivalents. Highly liquid investments with original maturities of three months or less at the date of acquisition are considered cash equivalents, except for the investments that were pledged as collateral against long-term debt as discussed in Note 15 and any investments that are considered restricted funds. Inventory. Inventory consists of natural gas and NGLs held in storage for transmission and processing, and also includes materials and supplies. Natural gas inventories primarily relate to the Distribution segment in Canada and are valued at costs approved by the regulator, the Ontario Energy Board (OEB). The difference between the approved price and the actual cost of gas purchased is recorded in either Fuel Tracker or Other Current Liabilities, as appropriate, for future disposition with customers, subject to approval by the OEB. The remaining inventory is recorded at the lower of cost or market, primarily using average cost. Natural Gas Imbalances. The Consolidated Balance Sheets include in-kind balances as a result of differences in gas volumes received and delivered for customers. Since settlement of certain imbalances is in-kind, changes in their balances do not have an effect on our Consolidated Statements of Cash Flows. Receivables include $291 million and $642 million as of December 31, 2015 and December 31, 2014, respectively, and Other Current Liabilities include $287 million and $634 million as of December 31, 2015 and December 31, 2014, respectively, related to gas imbalances. Most natural gas volumes owed to or by us are valued at natural gas market index prices as of the balance sheet dates. Risk Management and Hedging Activities and Financial Instruments. Currently, our use of derivative instruments is primarily limited to interest rate positions and commodity pricing. All derivative instruments that do not qualify for the normal purchases and normal sales exception are recorded on the Consolidated Balance Sheets at fair value. Cash inflows and outflows related to derivative instruments are a component of Cash Flows From Operating Activities in the accompanying Consolidated Statements of Cash Flows. Cash Flow and Fair Value Hedges. Qualifying energy commodity and other derivatives may be designated as either a hedge of a forecasted transaction (cash flow hedge) or a hedge of a recognized asset, liability or firm commitment (fair value hedge). For all hedge contracts, we prepare documentation of the hedge in accordance with accounting standards and assess whether the hedge contract is highly effective using regression analysis, both at inception and on a quarterly basis, in offsetting changes in cash flows or fair values of hedged items. We document hedging activity by instrument type (futures or swaps) and risk management strategy (commodity price risk or interest rate risk). For derivatives designated as fair value hedges, we recognize the gain or loss on the derivative instrument, as well as the offsetting gain or loss on the hedged item in earnings, to the extent effective, in the current period. In the event the hedge is not effective, there is no offsetting gain or loss recognized in earnings for the hedged item. All derivatives designated and accounted for as hedges are classified in the same category as the item being hedged in the Consolidated Statements of Cash Flows. All components of each derivative gain or loss are included in the assessment of hedge effectiveness. Investments. We may actively invest a portion of our available cash and restricted funds balances in various financial instruments, including taxable or tax-exempt debt securities. In addition, we invest in short-term money market securities, some of which are restricted due to debt collateral or insurance requirements. Investments in available-for-sale (AFS) securities are carried at fair value and investments in held-to-maturity (HTM) securities are carried at cost. Investments in money market securities are also accounted for at fair value. Realized gains and losses, and dividend and interest income related to these securities, including any amortization of discounts or premiums arising at acquisition, are included in earnings. The costs of securities sold are determined using the specific identification method. Purchases and sales of AFS and HTM securities are presented on a gross basis within Cash Flows From Investing Activities in the accompanying Consolidated Statements of Cash Flows. Goodwill. We perform our goodwill impairment test annually and evaluate goodwill when events or changes in circumstances indicate that its carrying value may not be recoverable. In 2015 we recorded a goodwill impairment charge of $270 million for British Columbia (BC) Field Services and $63 million for Empress NGL operations associated with the Westcoast Energy, Inc. (Westcoast) acquisition in 2002. No impairments of goodwill were recorded in 2014 or 2013 . See Note 11 for further discussion. We perform our annual review for goodwill impairment at the reporting unit level, which is identified by assessing whether the components of our operating segments constitute businesses for which discrete financial information is available, whether segment management regularly reviews the operating results of those components and whether the economic and regulatory characteristics are similar. We determined that our reporting units are equivalent to our reportable segments, except for the reporting units of our Western Canada Transmission & Processing and Spectra Energy Partners reportable segments, which are one level below. As permitted under accounting guidance on testing goodwill for impairment, we perform either a qualitative assessment or a quantitative assessment of each of our reporting units based on management’s judgment. With respect to our qualitative assessments, we consider events and circumstances specific to us, such as macroeconomic conditions, industry and market considerations, cost factors and overall financial performance, when evaluating whether it is more likely than not that the fair values of our reporting units are less than their respective carrying amounts. In connection with our quantitative assessments, we primarily use a discounted cash flow analysis to determine the fair values of those reporting units. Key assumptions in the determination of fair value included the use of an appropriate discount rate and estimated future cash flows. In estimating cash flows, we incorporate expected long-term growth rates in key markets served by our operations, regulatory stability, the ability to renew contracts, commodity prices (where appropriate) and foreign currency exchange rates, as well as other factors that affect our reporting units’ revenue, expense and capital expenditure projections. If the carrying amount of the reporting unit exceeds its fair value, a comparison of the fair value and carrying value of the goodwill of that reporting unit needs to be performed. If the carrying value of the goodwill of a reporting unit exceeds the implied fair value of that goodwill, an impairment loss is recognized in an amount equal to the excess. Additional impairment tests are performed between the annual reviews if events or changes in circumstances make it more likely than not that the fair value of a reporting unit is below its carrying amount. Property, Plant and Equipment. Property, plant and equipment is stated at historical cost less accumulated depreciation. We capitalize all construction-related direct labor and material costs, as well as indirect construction costs. Indirect costs include general engineering, taxes and the cost of funds used during construction. The costs of renewals and betterments that extend the useful life or increase the expected output of property, plant and equipment are also capitalized. The costs of repairs, replacements and major maintenance projects that do not extend the useful life or increase the expected output of property, plant and equipment are expensed as incurred. Depreciation is generally computed over the asset’s estimated useful life using the straight-line method. When we retire regulated property, plant and equipment, we charge the original cost plus the cost of retirement, less salvage value, to accumulated depreciation and amortization. When we sell entire regulated operating units or retire non-regulated properties, the cost is removed from the property account and the related accumulated depreciation and amortization accounts are reduced. Any gain or loss is recorded in earnings, unless otherwise required by the applicable regulatory body. Preliminary Project Costs. Project development costs, including expenditures for preliminary surveys, plans, investigations, environmental studies, regulatory applications and other costs incurred for the purpose of determining the feasibility of capital expansion projects, are capitalized for rate-regulated enterprises when it is determined that recovery of such costs through regulated revenues of the completed project is probable. Any inception-to-date costs of the project that were initially expensed are reversed and capitalized as Property, Plant and Equipment. Long-Lived Asset Impairments. We evaluate whether long-lived assets, excluding goodwill, have been impaired when circumstances indicate the carrying value of those assets may not be recoverable. For such long-lived assets, an impairment exists when its carrying value exceeds the sum of estimates of the undiscounted cash flows expected to result from the use and eventual disposition of the asset. When alternative courses of action to recover the carrying amount of a long-lived asset are under consideration, a probability-weighted approach is used in developing estimates of future undiscounted cash flows. If the carrying value of the long-lived asset is not recoverable based on these estimated future undiscounted cash flows, an impairment loss is measured as the excess of the asset’s carrying value over its fair value, such that the asset’s carrying value is adjusted to its estimated fair value. We assess the fair value of long-lived assets using commonly accepted techniques and may use more than one source. Sources to determine fair value include, but are not limited to, recent third-party comparable sales, internally developed discounted cash flow analyses and analyses from outside advisors. Significant changes in market conditions resulting from events such as changes in natural gas available to our systems, the condition of an asset, a change in our intent to utilize the asset or a significant change in contracted revenues or regulatory recoveries would generally require us to reassess the cash flows related to the long-lived assets. Asset Retirement Obligations. We recognize asset retirement obligations (AROs) for legal commitments associated with the retirement of long-lived assets that result from the acquisition, construction, development and/or normal use of the asset and conditional AROs in which the timing or method of settlement are conditional on a future event that may or may not be within our control. The fair value of a liability for an ARO is recognized in the period in which it is incurred if a reasonable estimate of fair value can be made and is added to the carrying amount of the associated asset. This additional carrying amount is depreciated over the estimated useful life of the asset. Unamortized Debt Premium, Discount and Expense. Premiums, discounts and expenses incurred with the issuance of outstanding long-term debt are amortized over the terms of the debt issues. Any call premiums or unamortized expenses associated with refinancing higher-cost debt obligations to finance regulated assets and operations are amortized consistent with regulatory treatment of those items, where appropriate. Environmental Expenditures. We expense environmental expenditures related to conditions caused by past operations that do not generate current or future revenues. Environmental expenditures related to operations that generate current or future revenues are expensed or capitalized, as appropriate. Undiscounted liabilities are recorded when the necessity for environmental remediation becomes probable and the costs can be reasonably estimated, or when other potential environmental liabilities are reasonably estimable and probable. Captive Insurance Reserves. We have captive insurance subsidiaries which provide insurance coverage to our consolidated subsidiaries as well as certain equity affiliates, on a limited basis, for various business risks and losses, such as workers compensation, property, business interruption and general liability. Liabilities include provisions for estimated losses incurred but not yet reported, as well as provisions for known claims which have been estimated on a claims-incurred basis. Incurred but not yet reported reserve estimates involve the use of assumptions and are based upon historical loss experience, industry data and other actuarial assumptions. Reserve estimates are adjusted in future periods as actual losses differ from historical experience. Guarantees. Upon issuance or material modification of a guarantee made by us, we recognize a liability for the estimated fair value of the obligation we assume under that guarantee, if any. Fair value is estimated using a probability-weighted approach. We reduce the obligation over the term of the guarantee or related contract in a systematic and rational method as risk is reduced under the obligation. Accounting For Sales of Stock by a Subsidiary. Sales of stock by a consolidated subsidiary are accounted for as equity transactions in those instances where a change in control does not take place. Segment Reporting. Operating segments are components of an enterprise for which separate financial information is available and evaluated regularly by the chief operating decision maker (CODM) in deciding how to allocate resources and evaluate performance. Two or more operating segments may be aggregated into a single reportable segment provided certain criteria are met. There is no such aggregation within our defined business segments. A description of our reportable segments, consistent with how business results are reported internally to management, and the disclosure of segment information is presented in Note 4. Consolidated Statements of Cash Flows. Cash flows from discontinued operations are combined with cash flows from continuing operations within operating, investing and financing cash flows. Cash received from insurance proceeds are classified depending on the activity that resulted in the insurance proceeds. For example, business interruption insurance proceeds are included as a component of operating activities while insurance proceeds from damaged property are included as a component of investing activities. With respect to cash overdrafts, book overdrafts are included within operating cash flows while bank overdrafts, if any, are included within financing cash flows. Distributions from Equity Investments. We consider distributions received from equity investments which do not exceed cumulative equity in earnings subsequent to the date of investment to be a return on investment and classify these amounts as Cash Flows From Operating Activities within the accompanying Consolidated Statements of Cash Flows. Cumulative distributions received in excess of cumulative equity in earnings subsequent to the date of investment are considered to be a return of investment and are classified as Cash Flows From Investing Activities. New Accounting Pronouncements. The following new Accounting Standards Updates (ASUs) were adopted during 2015 and the effect of such adoption has been presented in the accompanying Consolidated Financial Statements: In April 2014, the Financial Accounting Standards Board (FASB) issued ASU No. 2014-08, “ Presentation of Financial Statements (Topic 205) and Property, Plant, and Equipment (Topic 360): Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity.” This ASU revises the definition of discontinued operations by limiting discontinued operations reporting to disposals of components of an entity that represent strategic shifts that have or will have a major effect on an entity’s operations and financial results, removing the lack of continuing involvement criteria and requiring discontinued operations reporting for the disposal of an equity method investment that meets the definition of discontinued operations. The update also requires expanded disclosures for discontinued operations, and disclosure of pretax profit or loss of certain individually significant components of an entity that do not qualify for discontinued operations reporting. This ASU was effective for us on January 1, 2015 and did not have a material impact on our consolidated results of operations, financial position or cash flows. In April 2015, the FASB issued ASU No. 2015-03, “ Interest-Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs, ” which requires that debt issuance costs be presented in the balance sheet as a direct deduction from the carrying amount of the related debt liability, rather than as a deferred charge asset. We adopted this standard on December 31, 2015. The adoption of this ASU resulted in the retrospective adjustment of the December 31, 2014 Consolidated Balance Sheet, which resulted in the presentation of $42 million of debt issuance costs previously reported in Regulatory Assets and Deferred Debits as a reduction of Long-term Debt on our Consolidated Balance Sheet. In addition, $46 million of debt issuance costs are presented as a reduction of Long-term Debt on our December 31, 2015 Consolidated Balance Sheet. In November 2015, the FASB issued ASU No. 2015-17, “ Accounting for Income Taxes (Topic 740): Balance Sheet Classification of Deferred Taxes .” This ASU simplifies the balance sheet presentation of deferred income taxes by requiring deferred tax liabilities and assets be classified as noncurrent in a classified balance sheet. We adopted this standard on December 31, 2015 and applied it prospectively. The adoption of this ASU did not have a material impact on our consolidated results of operations, financial position, or cash flow. Pending. The following new accounting pronouncements have been issued but not yet adopted: In February 2015, the FASB issued ASU No. 2015-02, “Consolidation (Topic 810): Amendments to the Consolidation Analysis,” which makes changes to both the variable interest model and the voting model. These changes will require re-evaluation of certain entities for consolidation and will require us to revise our documentation regarding the consolidation or deconsolidation of such entities. This ASU is effective for us on January 1, 2016 and is not expected to have a material impact on our consolidated results of operations, financial position or cash flow. In July 2015, the FASB issued ASU No. 2015-11, “ Inventory (Topic 330): Simplifying the Measurement of Inventory, ” which simplifies the subsequent measurement of inventory by requiring inventory to be measured at the lower of cost and net realizable value. This ASU is effective for us January 1, 2016 and is not expected to have a material impact on our consolidated results of operations, financial position or cash flow. In July 2015, the FASB decided to defer the effective date of the revenue standard ASU No. 2014-09, “ Revenue from Contracts with Customers (Topic 606), ” for one year and to permit entities to early adopt the standard as of the original effective date. ASU No. 2014-09 supersedes the revenue recognition requirements of “ Revenue Recognition (Topic 605) ” and clarifies the principles of recognizing revenue. This ASU is effective for us January 1, 2018. We are currently evaluating this ASU and its potential impact on us. In September 2015, the FASB issued ASU No. 2015-16, “ Business Combinations (Topic 805): Simplifying the Accounting for Measurement-Period Adjustments, ” to simplify accounting for adjustments made to provisional amounts recognized in a business combination and to eliminate the retrospective accounting for those adjustments. This ASU is effective for us January 1, 2016 and is not expected to have a material impact on our consolidated results of operations, financial position or cash flow. In January 2016, the FASB issued ASU 2016-01 , "Financial Instruments--Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities," which amends the classification and measurement of financial instruments. Changes primarily affect the accounting for equity investments, financial liabilities under the fair value option, and the presentation and disclosure requirements for financial instruments. This ASU is effective for us beginning after December 15, 2017. Early adoption is not permitted. We are currently evaluating this ASU and its potential impact on us. 2014 . There were no significant accounting pronouncements issued during 2014 that had a material impact on our consolidated results of operations, financial position or cash flows. 2013 . There were no significant accounting pronouncements issued during 2013 that had a material impact on our consolidated results of operations, financial position or cash flows.

Spectra Energy Partners, LP

Spectra Energy Partners, LP	12 Months Ended
	Dec. 31, 2015
Related Party Transactions [Abstract]
Spectra Energy Partners, LP	Spectra Energy Partners, LP SEP is our natural gas infrastructure and crude oil pipeline master limited partnership. As of December 31, 2015 , Spectra Energy owned 78% of SEP, including a 2% general partner interest. Sand Hills and Southern Hills. On October 30, 2015, Spectra Energy acquired SEP’s 33.3% ownership interests in DCP Sand Hills Pipeline, LLC (Sand Hills) and DCP Southern Hills Pipeline, LLC (Southern Hills). In consideration for this transaction, SEP retired 21,560,000 of our limited partner units and 440,000 of our general partner units in SEP. This will result in the reduction of any associated distribution payable to Spectra Energy, beginning in 2016. There will also be a reduction in the aggregate quarterly distributions, if any, to Spectra Energy (as holder of incentive distribution rights), by $4 million per quarter for a period of 12 consecutive quarters, which commenced with the quarter ending on December 31, 2015 and will end with the quarter ending on September 30, 2018. U.S. Assets Dropdown. In 2013, Spectra Energy entered into a contribution agreement with SEP (the Contribution Agreement), pursuant to which Spectra Energy agreed to contribute to SEP substantially all of Spectra Energy’s interests in its subsidiaries that own U.S. transmission and storage and liquids assets, including its remaining 60% interest in the U.S. portion of Express-Platte, and to assign to SEP its interests in certain related contracts (collectively, the U.S. Assets Dropdown). In 2013, Spectra Energy completed the closing of substantially all of the U.S. Assets Dropdown. This first of three planned transactions consisted of all the contributed entities contemplated in the Contribution Agreement, excluding a 25.05% ownership interest in Southeast Supply Header, LLC (SESH) and a 1% ownership interest in Steckman Ridge, LP (Steckman Ridge). Consideration to Spectra Energy for the 2013 closing included $2.3 billion in cash, assumption by SEP (indirectly by acquisition of the contributed entities) of approximately $2.4 billion of third-party indebtedness of the contributed entities, 167.6 million newly issued SEP limited partner units and 3.4 million newly issued general partner units. This transfer of assets between entities under common control resulted in a decrease to Additional Paid-in Capital of $733 million ( $458 million net of tax) and an increase to Equity—Noncontrolling Interests of $733 million on the Consolidated Balance Sheet in 2013. The change in Equity—Noncontrolling Interests primarily represents the public unitholders’ share of the increase in SEP’s equity as a result of the issuance of additional units to Spectra Energy, less the effects of the resulting decrease in the public unitholders’ ownership percentage of SEP. Spectra Energy’s ownership in SEP increased as a result of the transaction. In November 2014, Spectra Energy completed the second of three planned transactions related to the U.S Assets Dropdown. This transaction consisted of contributing an additional 24.95% ownership interest in SESH and the remaining 1% interest in Steckman Ridge to SEP. Consideration to Spectra Energy was approximately 4.3 million newly issued SEP common units. Also, in connection with this transaction, SEP issued approximately 86,000 of newly issued general partner units to Spectra Energy in exchange for the same amount of common units in order to maintain Spectra Energy’s 2% general partner interest in SEP. This transfer of assets between entities under common control resulted in a decrease to Additional Paid-in Capital of $ 29 million ( $16 million net of tax) and an increase to Equity—Noncontrolling Interests of $29 million on the Consolidated Balance Sheet in 2014. The change in Equity—Noncontrolling Interests primarily represents the public unitholders’ share of the increase in SEP’s equity as a result of the issuance of additional units to Spectra Energy, less the effects of the resulting decrease in the public unitholders’ ownership percentage of SEP. Spectra Energy’s ownership in SEP increased as a result of the transaction. On November 4, 2015, the third, and final, transaction related to the U.S. Assets Dropdown occurred. Spectra Energy contributed the remaining 0.1% interest in SESH to SEP. Total consideration to Spectra Energy was 17,114 newly issued SEP common units. Also, in connection with this third transaction, SEP issued 342 general partner units to Spectra Energy in exchange for the same amount of common units in order to maintain Spectra Energy's 2% general partner interest in SEP. The contributed assets provide transportation and storage of natural gas, crude oil, and natural gas liquids for customers in various regions of the U.S. and in Alberta, Canada. The contributed assets included after all stages of the U.S. Assets Dropdown consisted of: • a 100% ownership interest in Texas Eastern Transmission, LP (Texas Eastern) • a 100% ownership interest in Algonquin Gas Transmission, LLC (Algonquin) • Spectra Energy’s remaining 60% ownership interest in the U.S. portion of Express-Platte • Spectra Energy’s remaining 38.77% ownership interest in Maritimes & Northeast Pipeline, L.L.C. • a 33.3% ownership interest in Sand Hills • a 33.3% ownership interest in Southern Hills • Spectra Energy’s remaining 1% ownership interest in Gulfstream Natural Gas System, LLC (Gulfstream) • a 50% ownership interest in SESH • a 100% ownership interest in Bobcat Gas Storage • Spectra Energy’s remaining 50% of Market Hub Partners Holding • a 50% ownership interest in Steckman Ridge • Texas Eastern’s and Express-Platte’s storage facilities Express-Platte. In August 2013, Spectra Energy contributed a 40% interest in the U.S. portion of Express-Platte and sold a 100% ownership interest in the Canadian portion to SEP. Aggregate consideration for the transactions consisted of $410 million in cash and 7.2 million of newly issued SEP partnership units. This transfer of assets between entities, under common control, resulted in a decrease to Additional Paid-in Capital of $84 million ( $53 million net of tax) and an increase to Equity—Noncontrolling Interest of $84 million . The change in Equity—Noncontrolling Interests primarily represents the public unitholders’ share of the increase in SEP equity as a result of the issuance of additional units to Spectra Energy, less the effects of the resulting decrease in the public unitholders’ ownership percentage. Sales of SEP Common Units. SEP has entered into equity distribution agreements for its at-the-market offering program, pursuant to which SEP may offer and sell, through sales agents, common units representing limited partner interests at prices it deems appropriate having aggregate offering prices ranging from $400 million to up to $ 1 billion . Sales of common units, if any, will be made by means of ordinary brokers’ transactions on the New York Stock Exchange, in block transactions, or as otherwise agreed to between SEP and the sales agent. SEP intends to use the net proceeds from sales under the program for general partnership purposes, which may include debt repayment, future acquisitions and capital expenditures. Under this program SEP issued 12.0 million , 6.4 million and 0.6 million common units to the public in 2015, 2014 and 2013, respectively, for total net proceeds of $546 million , $327 million and $24 million , respectively. In 2015 and 2014, SEP also issued 245,000 and 132,000 general partner units, respectively, to Spectra Energy. In 2013 , SEP issued 5.2 million common units to the public, representing limited partner interests, and 0.1 million general partner units to Spectra Energy. Total net proceeds to SEP were $193 million (net proceeds to Spectra Energy were $190 million ). Net proceeds to SEP were temporarily invested in restricted available-for-sale securities until the U.S. Assets Dropdown, at which time the funds were used to pay for a portion of the dropdown transaction. In connection with the sale of the units, a $61 million gain ( $38 million net of tax) to Additional Paid-in Capital and a $128 million increase in Equity—Noncontrolling Interests were recorded in 2013.

Acquisitions and Dispositions

Acquisitions and Dispositions	12 Months Ended
	Dec. 31, 2015
Business Combinations [Abstract]
Acquisitions and Dispositions	Acquisitions and Dispositions Acquisitions. We consolidate assets and liabilities from acquisitions as of the purchase date and include earnings from acquisitions in consolidated earnings after the purchase date. Assets acquired and liabilities assumed are recorded at estimated fair values on the date of acquisition. The purchase price less the estimated fair value of the acquired assets and liabilities meeting the definition of a “business” is recorded as goodwill. The allocation of the purchase price may be adjusted if additional information is received during the allocation period, which generally does not exceed one year from the consummation date. Sand Hills and Southern Hills. On October 30, 2015 Spectra Energy acquired SEP’s 33.3% ownership interests in Sand Hills and Southern Hills. In consideration for this transaction, SEP retired 21,560,000 of our limited partner units and 440,000 of our general partner units in SEP. See Note 2 for further discussion. This transfer of assets between entities under common control resulted in an increase to Additional Paid-in Capital of $166 million and a decrease to Equity-Noncontrolling Interests of $166 million on the Consolidated Balance Sheet in 2015. The change in Equity-Noncontrolling Interests primarily represents the public unitholders’ share of the decrease in SEP’s equity as a result of the retirement of units previously held by us, less the effects of the resulting increase in the public unitholders’ ownership percentage of SEP. Spectra Energy’s ownership in SEP decreased as a result of the transaction. In 2013, subsidiaries of Spectra Energy contributed their 33.3% direct interests in Sand Hills and Southern Hills to SEP in connection with the U.S. Assets Dropdown. At the time of this contribution, DCP Midstream Partners, LP (DCP Partners), DCP Midstream’s master limited partnership, and Phillips 66 also each owned direct one-third ownership interests in the two pipelines. The Sand Hills pipeline provides NGL transportation from the Permian and Eagle Ford basins to the premium NGL markets on the Gulf Coast. The Southern Hills pipeline provides NGL transportation from the Midcontinent to Mont Belvieu, Texas. See Note 2 for further discussion. Express-Platte. In March 2013 , we acquired 100% of the ownership interests in the Express-Platte crude oil pipeline system for $1.5 billion , consisting of $1.25 billion in cash and $260 million of acquired debt, before working capital adjustments. The Express-Platte pipeline system, which begins in Hardisty, Alberta, and terminates in Wood River, Illinois, is comprised of both the Express and Platte crude oil pipelines. The Express pipeline carries crude oil to U.S. refining markets in the Rockies area, including Montana, Wyoming, Colorado and Utah. The Platte pipeline, which interconnects with Express pipeline in Casper, Wyoming, transports crude oil predominantly from the Bakken shale and western Canada to refineries in the Midwest. In 2013, subsidiaries of Spectra Energy contributed a 100% interest in the U.S. portion of Express-Platte and sold a 100% ownership interest in the Canadian portion to SEP. See Note 2 for further discussion. The following table summarizes the fair values of the assets and liabilities acquired as of the date of the acquisition: Purchase Price Allocation (in millions) Cash purchase price $ 1,250 Working capital and other purchase adjustments 71 Total 1,321 Cash 67 Receivables 25 Other current assets 9 Property, plant and equipment 1,251 Accounts payable (18 ) Other current liabilities (17 ) Deferred credits and other liabilities (259 ) Long-term debt, including current portion (260 ) Total assets acquired/liabilities assumed 798 Goodwill $ 523 The purchase price is greater than the sum of fair values of the net assets acquired, resulting in goodwill as noted above. The goodwill reflects the value of the strategic location of the pipeline and the opportunity to grow the business. Goodwill related to the acquisition of Express-Platte is not deductible for income tax purposes. The allocation of the fair values of assets and liabilities acquired related to the acquisition of Express-Platte was finalized in the first quarter of 2014, resulting in the following adjustments to amounts reported as of December 31, 2013: a $60 million decrease in Property, Plant and Equipment, a $1 million decrease in Other Current Assets and a $24 million decrease in Deferred Credits and Other Liabilities, resulting in a $37 million increase in Goodwill. Dispositions. As discussed above, on October 30, 2015 we acquired SEP’s 33.3% ownership interests in Sand Hills and Southern Hills. We immediately contributed our 33.3% interests in Sand Hills and Southern Hills to DCP Midstream. The contribution is reflected as a non-cash transaction in the statement of cash flows. After this contribution, DCP Midstream and DCP Partners each hold a direct one-third ownership interest in the two pipelines. The remaining one-third direct ownership interest continues to be held by Phillips 66. In consideration for this transaction, we increased our basis in the net equity of DCP Midstream and retained our 50% ownership interest.

Business Segments

Business Segments	12 Months Ended
	Dec. 31, 2015
Segment Reporting [Abstract]
Business Segments	Business Segments We manage our business in four reportable segments: Spectra Energy Partners, Distribution, Western Canada Transmission & Processing and Field Services. The remainder of our business operations is presented as “Other,” and consists of unallocated corporate costs and employee benefit plan assets and liabilities, 100%-owned captive insurance subsidiaries and other miscellaneous activities. Our CODM regularly reviews financial information about each of these segments in deciding how to allocate resources and evaluate performance. There is no aggregation within our reportable business segments. Spectra Energy's presentation of its Spectra Energy Partners segment is reflective of the parent-level focus by our CODM, considering the resource allocation and governance provisions associated with SEP’s master limited partnership structure. SEP maintains a capital and cash management structure that is separate from Spectra Energy’s, is self-funding and maintains its own lines of bank credit and cash management accounts. From a Spectra Energy perspective, our CODM evaluates the Spectra Energy Partners segment as a whole, without regard to any of SEP’s individual businesses. Spectra Energy Partners provides transmission, storage and gathering of natural gas, as well as the transportation of crude oil and NGLs through interstate pipeline systems for customers in various regions of the midwestern, northeastern and southern U.S. and Canada. The natural gas transmission and storage operations are primarily subject to the rules and regulations of the Federal Energy Regulatory Commission (FERC). The crude oil transportation operations are primarily subject to regulation by the FERC in the U.S. and the National Energy Board (NEB) in Canada. Our Spectra Energy Partners segment is composed of the operations of SEP, less governance costs, which are included in “Other.” Distribution provides retail natural gas distribution service in Ontario, Canada, as well as natural gas transmission and storage services to other utilities and energy market participants. These services are provided by Union Gas Limited (Union Gas), and are primarily subject to the rules and regulations of the OEB. Western Canada Transmission & Processing provides transmission of natural gas, natural gas gathering and processing services, and NGL extraction, fractionation, transportation, storage and marketing to customers in western Canada, the northern tier of the U.S. and the Maritime Provinces in Canada. This segment conducts business mostly through BC Pipeline, BC Field Services, Empress NGL operations, Canadian Midstream, and Maritimes & Northeast Pipeline Limited Partnership (M&N Canada). BC Pipeline, BC Field Services and M&N Canada operations are primarily subject to the rules and regulations of the NEB. Field Services gathers, compresses, treats, processes, transports, stores and sells natural gas, produces, fractionates, transports, stores and sells NGLs, recovers and sells condensate, and trades and markets natural gas and NGLs. It conducts operations through DCP Midstream, which is owned 50% by us and 50% by Phillips 66. DCP Midstream gathers raw natural gas through gathering systems connecting to several interstate and intrastate natural gas and NGL pipeline systems, one natural gas storage facility and one NGL storage facility. DCP Midstream operates in a diverse number of regions, including the Permian Basin, Eagle Ford, Niobrara/DJ Basin and the Midcontinent. DCP Partners is a publicly traded master limited partnership, of which DCP Midstream acts as general partner. As of December 31, 2015, DCP Midstream had an approximate 21% ownership interest in DCP Partners, including DCP Midstream’s limited partner and general partner interests. Our reportable segments offer different products and services and are managed separately as business units. Management evaluates segment performance based on earnings before interest, taxes, depreciation and amortization (EBITDA). Cash, cash equivalents and short-term investments are managed at the parent-company levels, so the associated gains and losses from foreign currency transactions and interest and dividend income are excluded from the segments’ EBITDA. Our segment EBITDA may not be comparable to similarly titled measures of other companies because other companies may not calculate EBITDA in the same manner. Transactions between reportable segments are accounted for on the same basis as transactions with unaffiliated third parties. Business Segment Data Unaffiliated Revenues Intersegment Revenues Total Operating Revenues Segment EBITDA/ Consolidated Earnings before Income Taxes Depreciation and Amortization Capital and Investment Expenditures (a,b) Assets (in millions) 2015 Spectra Energy Partners $ 2,455 $ — $ 2,455 $ 1,905 $ 297 $ 2,007 $ 18,983 Distribution 1,527 — 1,527 473 176 544 5,209 Western Canada Transmission & Processing 1,242 43 1,285 491 243 360 5,909 Field Services — — — (461 ) — — 1,660 Total reportable segments 5,224 43 5,267 2,408 716 2,911 31,761 Other 10 63 73 (384 ) 48 61 1,226 Eliminations — (106 ) (106 ) — — — (64 ) Depreciation and amortization — — — 764 — — — Interest expense — — — 636 — — — Interest income and other (c) — — — (3 ) — — — Total consolidated $ 5,234 $ — $ 5,234 $ 621 $ 764 $ 2,972 $ 32,923 2014 Spectra Energy Partners $ 2,269 $ — $ 2,269 $ 1,669 $ 290 $ 1,241 $ 17,850 Distribution 1,843 — 1,843 552 192 427 6,055 Western Canada Transmission & Processing 1,781 121 1,902 754 271 473 6,913 Field Services — — — 217 — — 1,345 Total reportable segments 5,893 121 6,014 3,192 753 2,141 32,163 Other 10 62 72 (58 ) 43 146 1,893 Eliminations — (183 ) (183 ) — — — (58 ) Depreciation and amortization — — — 796 — — — Interest expense — — — 679 — — — Interest income and other (c) — — — 6 — — — Total consolidated $ 5,903 $ — $ 5,903 $ 1,665 $ 796 $ 2,287 $ 33,998 2013 Spectra Energy Partners $ 1,964 $ 1 $ 1,965 $ 1,433 $ 263 $ 1,299 $ 16,783 Distribution 1,848 — 1,848 574 199 357 6,000 Western Canada Transmission & Processing 1,694 73 1,767 736 272 561 7,157 Field Services — — — 343 — — 1,365 Total reportable segments 5,506 74 5,580 3,086 734 2,217 31,305 Other 12 60 72 (86 ) 38 42 2,680 Eliminations — (134 ) (134 ) — — — (499 ) Depreciation and amortization — — — 772 — — — Interest expense — — — 657 — — — Interest income and other (c) — — — 7 — — — Total consolidated $ 5,518 $ — $ 5,518 $ 1,578 $ 772 $ 2,259 $ 33,486 __________ (a) Excludes the $1,254 million cash outlay for the acquisition of Express-Platte in 2013, part of Spectra Energy Partners. (b) Excludes a $71 million loan to an equity investment in 2013 at Spectra Energy Partners. (c) Includes foreign currency transaction gains and losses related to segment EBITDA. Geographic Data U.S. Canada Consolidated (in millions) 2015 Consolidated revenues $ 2,389 $ 2,845 $ 5,234 Consolidated long-lived assets 17,549 10,979 28,528 2014 Consolidated revenues 2,212 3,691 5,903 Consolidated long-lived assets 15,834 12,715 28,549 2013 Consolidated revenues 1,926 3,592 5,518 Consolidated long-lived assets 14,963 13,247 28,210

Regulatory Matters

Regulatory Matters	12 Months Ended
	Dec. 31, 2015
Regulated Operations [Abstract]
Regulatory Matters	Regulatory Matters Regulatory Assets and Liabilities We record assets and liabilities that result from the regulated ratemaking process that would not be recorded under U.S. GAAP for non-regulated entities. See Note 1 for further discussion. The following items are reflected in the consolidated balance sheets. All regulatory assets and liabilities are excluded from rate base unless otherwise noted below. Recovery/Refund Period December 31, 2015 2014 (in millions) Regulatory Assets Under-recovery of fuel costs (c) — $ 41 $ 44 Gas purchase costs (c) — — 57 Other — 73 46 Total Regulatory Assets—Current (a) 114 147 Net regulatory asset related to income taxes (d,e) 2 years - remaining life of asset 1,215 1,271 Project development costs (d) Through 2036 9 10 Vacation accrual (d) Various 23 22 Deferred debt expense/premium (d) Various 23 31 Other Various 13 13 Total Regulatory Assets—Non Current (b) 1,283 1,347 Total Regulatory Assets $ 1,397 $ 1,494 Regulatory Liabilities Gas purchase costs (c) — $ 48 $ — Other (d) — 32 59 Total Regulatory Liabilities—Current (a) 80 59 Removal costs (d) Exceeds remaining life of asset 258 326 Pipeline rate credit Life of associated liability 24 25 Other (d) Various 23 20 Total Regulatory Liabilities—Non Current (b) 305 371 Total Regulatory Liabilities $ 385 $ 430 ________ (a) Included in Inventory, Fuel Tracker, Current Assets—Other or Current Liabilities—Other. (b) Included in Regulatory Assets and Deferred Debits or Deferred Credits and Other Liabilities—Regulatory and Other. (c) Includes costs settled in cash annually through transportation rates in accordance with FERC and/or OEB gas tariffs. (d) All or a portion of the balance is included in rate base. (e) All amounts are expected to be included in future rate filings. Union Gas. Union Gas has regulatory assets of $291 million as of December 31, 2015 and $303 million as of December 31, 2014 related to deferred income tax liabilities. Under the current OEB-authorized rate structure, income tax costs are recovered in rates based on the current income tax payable and do not include accruals for deferred income tax. However, as income taxes become payable as a result of the reversal of timing differences that created the deferred income taxes, it is expected that rates will be adjusted to recover these taxes. Since substantially all of these timing differences are related to property, plant and equipment costs, recovery of these regulatory assets is expected to occur over the life of those assets. Union Gas has regulatory liabilities associated with plant removal costs of $258 million as of December 31, 2015 and $322 million as of December 31, 2014 . These regulatory liabilities represent collections from customers under approved rates for future asset removal activities that are expected to occur associated with its regulated facilities. In addition, Union Gas has regulatory liabilities of $48 million as of December 31, 2015 and regulatory assets of $57 million as of December 31, 2014 representing gas cost collections from customers under approved rates that vary from actual cost of gas for the associated periods. Union Gas files an application quarterly with the OEB to ensure that customers’ rates are updated to reflect published forward-market prices. The difference between the approved and the actual cost of gas is deferred for future repayment to or refund from customers. BC Pipeline and BC Field Services. The BC Pipeline and BC Field Services businesses in western Canada have regulatory assets of $727 million as of December 31, 2015 and $795 million as of December 31, 2014 related to deferred income tax liabilities. Under the current NEB-authorized rate structure, income tax costs are recovered in tolls based on the current income tax payable and do not include accruals for deferred income tax. However, as income taxes become payable as a result of the reversal of timing differences that created the deferred income taxes, it is expected that transportation and field services tolls will be adjusted to recover these taxes. Since most of these timing differences are related to property, plant and equipment costs, this recovery is expected to occur over the life of those assets. When evaluating the recoverability of the BC Pipelines’ and BC Field Services’ regulatory assets, we take into consideration the NEB regulatory environment, natural gas reserve estimates for reserves located or expected to be located near these assets, the ability to remain competitive in the markets served and projected demand growth estimates for the areas served by the BC Pipeline and BC Field Services businesses. Based on current evaluation of these factors, we believe that recovery of these tax costs is probable over the periods described above. Rate Related Information Union Gas. In December 2015, Union Gas filed an application with the OEB for the disposition of the 2014 energy conservation deferral and variance account balances. As a result of this application, Union Gas has a receivable from customers of approximately $8 million as of December 31, 2015 and $9 million as of December 31, 2014, which is reflected as Current Assets—Other on the Consolidated Balance Sheets. A hearing and decision from the OEB is expected in 2016.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Income Tax Expense Components 2015 2014 2013 (in millions) Current income taxes Federal $ — $ 1 $ (32 ) State 13 3 4 Foreign 60 (10 ) 26 Total current income taxes 73 (6 ) (2 ) Deferred income taxes Federal 145 335 353 State (18 ) (17 ) 69 Foreign (39 ) 70 (1 ) Total deferred income taxes 88 388 421 Total income tax expense $ 161 $ 382 $ 419 Earnings before Income Taxes 2015 2014 2013 (in millions) Domestic $ 636 $ 1,108 $ 1,059 Foreign (15 ) 557 519 Total earnings before income taxes $ 621 $ 1,665 $ 1,578 Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to Actual Income Tax Expense 2015 2014 2013 (in millions) Income tax expense, computed at the statutory rate of 35% $ 217 $ 583 $ 552 State income tax, net of federal income tax effect 12 25 20 Tax differential on foreign earnings (44 ) (125 ) (147 ) Noncontrolling interests (92 ) (70 ) (42 ) Valuation allowance 1 2 (3 ) Goodwill impairment 91 — — Revaluation of accumulated deferred state taxes (12 ) (25 ) 31 Other items, net (12 ) (8 ) 8 Total income tax expense $ 161 $ 382 $ 419 Effective tax rate 25.9 % 22.9 % 26.6 % Net Deferred Income Tax Liability Components December 31, 2015 2014 (in millions) Deferred credits and other liabilities $ 275 $ 225 Net operating loss carryforward 295 158 Other 36 53 Total deferred income tax assets 606 436 Valuation allowance (27 ) (29 ) Net deferred income tax assets 579 407 Investments and other assets (1,605 ) (1,531 ) Accelerated depreciation rates (4,035 ) (3,875 ) Regulatory assets and deferred debits (384 ) (426 ) Total deferred income tax liabilities (6,024 ) (5,832 ) Total net deferred income tax liabilities $ (5,445 ) $ (5,425 ) The above deferred tax amounts have been classified in the Consolidated Balance Sheets as follows: December 31, 2015 2014 (in millions) Other current liabilities $ — $ (20 ) Deferred credits and other liabilities (5,445 ) (5,405 ) Total net deferred income tax liabilities $ (5,445 ) $ (5,425 ) At December 31, 2015 , we had a federal net operating loss carryforward, net of unrecognized tax benefits, of $726 million that expires at various times beginning in 2021 . The deferred tax asset attributable to the federal net operating losses, net of unrecognized tax benefits, is $254 million . At December 31, 2015 we also had a state net operating loss carryforward of approximately $381 million that expires at various times beginning in 2016 . The deferred tax asset attributable to the state net operating loss carryovers is $20 million , net of federal impacts and unrecognized tax benefits, at December 31, 2015 . We had valuation allowances of $9 million at both December 31, 2015 and 2014 against the deferred tax asset related to the federal net operating loss carryforward. We had valuation allowances of $1 million and less than $1 million at December 31, 2015 and 2014, respectively, against the deferred tax asset related to the state net operating loss carryforward and other state tax credits. At December 31, 2015 , we had a foreign net operating loss carryforward of $80 million that expires at various times beginning in 2026 . The deferred tax asset attributable to the foreign net operating loss is $21 million . We had valuation allowances of $1 million and less than $1 million at December 31, 2015 and 2014, respectively, against the deferred tax asset related to the foreign net operating loss carryforward and property, plant and equipment. At December 31, 2015 , we also had a foreign capital loss carryforward of $124 million with an indefinite expiration period. The deferred tax asset attributable to the foreign capital loss carryforward is $16 million . We had valuation allowances of $16 million and $20 million at December 31, 2015 and 2014 , respectively, against the deferred tax asset related to the foreign capital loss carryforward. Reconciliation of Gross Unrecognized Income Tax Benefits 2015 2014 2013 (in millions) Balance at beginning of period $ 50 $ 76 $ 80 Increases related to prior year tax positions 10 10 7 Decreases related to prior year tax positions (1 ) (6 ) (17 ) Increases related to current year tax positions 30 1 2 Settlements — — (3 ) Lapse of statute of limitations (4 ) (30 ) 9 Foreign currency translation (3 ) (1 ) (2 ) Balance at end of period $ 82 $ 50 $ 76 Unrecognized tax benefits totaled $82 million at December 31, 2015 . Of this, $39 million would reduce the annual effective tax rate if recognized on or after January 1, 2016. We recorded a net increase of $32 million in gross unrecognized tax benefits during 2015 . This was a result of $22 million attributable to deferred tax liabilities, foreign currency exchange rate fluctuations and a $10 million increase in income tax expense. We recognize potential accrued interest and penalties related to unrecognized tax benefits as interest expense and as other expense, respectively. We recognized interest expense of $2 million in 2015 and interest income of $2 million in 2014 related to unrecognized tax benefits. Accrued interest and penalties totaled $21 million at December 31, 2015 and $19 million at December 31, 2014 . Although uncertain, we believe it is reasonably possible that the total amount of unrecognized tax benefits could decrease by $30 million to $40 million prior to December 31, 2016. We remain subject to examination for Canada income tax return filings for years 2009 through 2014 and U.S. federal income tax return filings for years 2011 through 2014 . A limited number of state tax return filings remain subject to examination for years 2007 through 2014 . We have foreign subsidiaries’ undistributed earnings of approximately $1.5 billion at December 31, 2015 that are indefinitely invested outside the U.S. and, accordingly, no U.S. federal or state income taxes have been provided on those earnings. Upon distribution of those earnings, we may be subject to both foreign withholding taxes and U.S. income taxes, net of allowable foreign tax credits. The amount of such additional taxes would be dependent on several factors, including the size and timing of the distribution and the availability of foreign tax credits. As a result, the determination of the potential amount of unrecognized withholding and deferred income taxes is not practicable.

Earnings per Common Share

Earnings per Common Share	12 Months Ended
	Dec. 31, 2015
Earnings Per Share [Abstract]
Earnings per Common Share	Earnings per Common Share Basic earnings per common share (EPS) is computed by dividing net income from controlling interests by the weighted-average number of common shares outstanding during the period. Diluted EPS is computed by dividing net income from controlling interests by the diluted weighted-average number of common shares outstanding during the period. Diluted EPS reflects the potential dilution that could occur if securities or other agreements to issue common stock, such as stock options, stock-based performance unit awards and phantom stock awards, were exercised, settled or converted into common stock. Weighted-average shares used to calculate diluted EPS includes the effect of certain options and restricted stock awards. In 2015, 2014 and 2013, there were no options or stock awards that were not included in the calculation of diluted EPS. The following table presents our basic and diluted EPS calculations: 2015 2014 2013 (in millions, except per-share amounts) Net income—controlling interests $ 196 $ 1,082 $ 1,038 Weighted-average common shares outstanding Basic 671 671 669 Diluted 672 672 671 Basic and diluted earnings per common share $ 0.29 $ 1.61 $ 1.55

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income	12 Months Ended
	Dec. 31, 2015
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated Other Comprehensive Income	Accumulated Other Comprehensive Income (Loss) The following table presents the net of tax changes in AOCI by component and amounts reclassified out of AOCI to Net Income, excluding amounts attributable to noncontrolling interests: Foreign Currency Translation Adjustments Pension and Post-retirement Benefit Plan Obligations Gas Purchase Contract Hedges Other Total Accumulated Other Comprehensive Income (Loss) (in millions) December 31, 2013 $ 1,557 $ (304 ) $ (11 ) $ (1 ) $ 1,241 Reclassified to net income — — 4 1 5 Other AOCI activity (541 ) (47 ) 4 — (584 ) December 31, 2014 1,016 (351 ) (3 ) — 662 Other AOCI activity (937 ) 5 — 1 (931 ) December 31, 2015 $ 79 $ (346 ) $ (3 ) $ 1 $ (269 ) Reclassifications to Net Income are primarily included in Other Income and Expenses, Net on our Consolidated Statements of Operations.

Inventory

Inventory	12 Months Ended
	Dec. 31, 2015
Inventory Disclosure [Abstract]
Inventory	Inventory The components of inventory are as follows: December 31, 2015 2014 (in millions) Natural gas $ 217 $ 211 NGLs 23 28 Materials and supplies 67 74 Total inventory $ 307 $ 313 Our inventory at our Empress operations at Western Canada Transmission & Processing is subject to lower of cost or market. As such, we recorded non-cash charges totaling $14 million in 2015 and $19 million in 2014 ( $10 million and $14 million after tax, respectively) to Natural Gas and Petroleum Products Purchased on the Consolidated Statements of Operations to reduce propane inventory to estimated net realizable value.

Investments in and Loans to Unc

Investments in and Loans to Unconsolidated Affiliates and Related Party Transactions	12 Months Ended
	Dec. 31, 2015
Investments in and Advances to Affiliates, Schedule of Investments [Abstract]
Investments in and Loans to Unconsolidated Affiliates and Related Party Transactions	Investments in and Loans to Unconsolidated Affiliates and Related Party Transactions Investments in affiliates for which we are not the primary beneficiary, but over which we have significant influence, are accounted for using the equity method. As of December 31, 2015 and 2014 , the carrying amounts of investments in affiliates approximated the amounts of underlying equity in net assets, with the exception of DCP Midstream in 2015, which relates to a contribution of assets recorded at carrying value. We received distributions from our equity investments of $612 million in 2015 , $646 million in 2014 and $411 million in 2013 . Cumulative undistributed earnings of unconsolidated affiliates totaled $28 million at December 31, 2015 and $482 million at December 31, 2014 . Spectra Energy Partners. As of December 31, 2015 , our Spectra Energy Partners segment investments were mostly comprised of a 39% effective interest in Gulfstream, a 39% effective interest in SESH, and a 39% effective interest in Steckman Ridge. On November 4, 2015, we contributed our remaining 0.1% interest in SESH to SEP. Total consideration to Spectra Energy was 17,114 newly issued SEP common units. This was the last of three planned transactions related to the U.S. Assets Dropdown. Also, in connection with this transaction, SEP issued 342 general partner units to Spectra Energy in exchange for the same amount of common units in order to maintain Spectra Energy's 2% general partner interest in SEP. We have a loan outstanding to Steckman Ridge in connection with the construction of its storage facilities. The loan carries market-based interest rates and is due the earlier of October 1, 2023 or coincident with the closing of any long-term financings by Steckman Ridge. The loan receivable from Steckman Ridge, including accrued interest, totaled $71 million at December 31, 2015 and 2014 . We recorded interest income on the Steckman Ridge loan of $1 million in 2015 , 2014 and 2013 . On October 30, 2015, Spectra Energy acquired SEP’s 33.3% ownership interests in Sand Hills and Southern Hills. In consideration for this transaction, SEP retired 21,560,000 of our limited partner units and 440,000 of our general partner units in SEP. This resulted in the reduction of any associated distribution payable to us, beginning in 2016. There will also be a reduction in the aggregate quarterly distributions, if any, to us (as holder of incentive distribution rights), by $4 million per quarter for a period of 12 consecutive quarters, which commenced with the quarter ending on December 31, 2015 and will end with the quarter ending on September 30, 2018. Field Services. Our most significant investment in unconsolidated affiliates is our 50% investment in DCP Midstream, which is accounted for under the equity method of accounting. DCP Midstream is a limited liability company which is a pass-through entity for U.S. income tax purposes. DCP Midstream also owns an entity which files its own federal, foreign and state income tax returns. Income tax expense related to that entity is included in the income tax expense of DCP Midstream. Therefore, DCP Midstream’s net income attributable to members’ interests does not include income taxes for earnings which are passed through to the members based upon their ownership percentage. We recognize the tax effects of our share of DCP Midstream’s pass-through earnings in Income Tax Expense in the Consolidated Statements of Operations. DCP Partners issues, from time to time, limited partner units to the public, which are recorded by DCP Midstream directly to its equity. Our proportionate 50% share of gains from those issuances, totaling $2 million in 2015 , $73 million in 2014 and $98 million in 2013 , are reflected in Earnings (Loss) from Equity Investments in the Consolidated Statements of Operations. Due to the significant downturn in commodity prices, DCP Midstream performed a goodwill impairment test and other asset impairment tests in 2015. The impairment tests were based on internal discounted cash flow models taking into account various observable and unobservable factors, such as prices, volumes, expenses and discount rate. The impairment tests resulted in DCP Midstream’s recognition of a $460 million goodwill impairment and $342 million in other asset impairments, net of tax, which reduced our equity earnings from DCP Midstream by $231 million after-tax for 2015. Due to the impairments recognized by DCP Midstream, we assessed our equity investment in DCP Midstream and determined that our equity investment in DCP Midstream was not impaired. As previously discussed, on October 30, 2015, we contributed our 33.3% interests in Sand Hills and Southern Hills acquired from SEP to DCP Midstream. In consideration for this transaction, we increased our basis in the net equity of DCP Midstream and retained our 50% ownership interest. Investments in and Loans to Unconsolidated Affiliates December 31, 2015 December 31, 2014 Domestic International Total Domestic International Total (in millions) Spectra Energy Partners $ 904 $ — $ 904 $ 1,588 $ — $ 1,588 Distribution — 11 11 — 14 14 Western Canada Transmission & Processing — 17 17 — 18 18 Field Services 1,660 — 1,660 1,345 — 1,345 Other — — — 1 — 1 Total $ 2,564 $ 28 $ 2,592 $ 2,934 $ 32 $ 2,966 Equity in Earnings of Unconsolidated Affiliates 2015 2014 2013 Domestic International Total Domestic International Total Domestic International Total (in millions) Spectra Energy Partners $ 167 $ — $ 167 $ 133 $ — $ 133 $ 90 $ — $ 90 Distribution — 1 1 — 1 1 — 1 1 Western Canada Transmission & Processing — 2 2 — 1 1 — (1 ) (1 ) Field Services (461 ) — (461 ) 217 — 217 343 — 343 Other 1 — 1 9 — 9 12 — 12 Total $ (293 ) $ 3 $ (290 ) $ 359 $ 2 $ 361 $ 445 $ — $ 445 Summarized Combined Financial Information of Unconsolidated Affiliates (Presented at 100%) Statements of Operations 2015 2014 2013 DCP Midstream Other Total DCP Midstream Other Total DCP Midstream Other Total (in millions) Operating revenues $ 7,420 $ 767 $ 8,187 $ 14,013 $ 744 $ 14,757 $ 12,038 $ 558 $ 12,596 Operating expenses 8,227 288 8,515 13,262 319 13,581 11,230 261 11,491 Operating income (807 ) 479 (328 ) 751 425 1,176 808 297 1,105 Net income (843 ) 393 (450 ) 536 332 868 584 206 790 Net income attributable to members’ interests (929 ) 393 (536 ) 288 332 620 491 206 697 Balance Sheets December 31, 2015 December 31, 2014 DCP Midstream Other Total DCP Midstream Other Total (in millions) Current assets $ 800 $ 498 $ 1,298 $ 1,380 $ 241 $ 1,621 Non-current assets 13,094 3,265 16,359 12,299 5,358 17,657 Current liabilities (896 ) (387 ) (1,283 ) (2,938 ) (632 ) (3,570 ) Non-current liabilities (5,894 ) (1,679 ) (7,573 ) (5,538 ) (1,197 ) (6,735 ) Equity—total 7,104 1,697 8,801 5,203 3,770 8,973 Equity—noncontrolling interests (2,404 ) — (2,404 ) (2,578 ) — (2,578 ) Equity—controlling interests $ 4,700 $ 1,697 $ 6,397 $ 2,625 $ 3,770 $ 6,395 Related Party Transactions DCP Midstream . DCP Midstream processes certain of our pipeline customers’ gas to meet gas quality specifications in order to be transported on our Texas Eastern system. DCP Midstream processes the gas and sells the NGLs that are extracted from the gas. A portion of the proceeds from those sales are retained by DCP Midstream and the balance is remitted to us. We received proceeds of $46 million in 2015, $79 million in 2014 and $48 million in 2013 from DCP Midstream related to those sales, classified as Operating Revenues—Other in our Consolidated Statements of Operations. In addition to the above, we recorded other revenues from DCP Midstream and its affiliates totaling $4 million in 2015 and $9 million in 2014 and 2013, primarily within Transportation, Storage and Processing of Natural Gas, and $4 million in 2015, $7 million in 2014 and $8 million in 2013 within Sales of Natural Gas Liquids. We had accounts receivable from DCP Midstream and its affiliates of $1 million at December 31, 2015 and December 31, 2014. We received no distributions from DCP Midstream during 2015. We received distributions from DCP Midstream of $237 million in 2014 and $215 million in 2013, classified as Cash Flows from Operating Activities—Distributions from Equity Investments. Gulfstream . During the third quarter of 2015, Gulfstream issued unsecured debt of $800 million to fund the repayment of its current debt. Gulfstream distributed $396 million of proceeds to us, classified as Cash Flows from Investing Activities—Distributions from Equity Investments, of which we contributed $248 million back to Gulfstream in 2015, classified as Cash Flows from Investing Activities—Loan to Equity Investment, as the current debt matured and of which we plan to contribute the remaining $148 million in the first half of 2016. At December 31, 2015 , our Consolidated Balance Sheets include $148 million in Current Liabilities—Other related to this matter. SESH. In 2014, SESH issued unsecured debt of $400 million to fund the repayment of its current debt. SESH distributed $200 million of proceeds to us, classified as Cash Flows from Investing Activities—Distributions from Equity Investments, of which we contributed $200 million back to SESH during 2014, classified as Cash Flows from Investing Activities—Investments in and Loans to Unconsolidated Affiliates, as the current debt matured. Other. We provide certain administrative and other services to certain other operating entities. We recorded recoveries of costs from these affiliates of $28 million in 2015 , $38 million in 2014 and $68 million in 2013 . We also recorded recoveries of costs associated with a project of $139 million in 2015. Outstanding receivables from these affiliates totaled $11 million at December 31, 2015 and $1 million at December 31, 2014 . See also Notes 3, 16 and 18 for additional related party information.

Goodwill

Goodwill	12 Months Ended
	Dec. 31, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	Goodwill The following table presents activity within goodwill based on a segment basis: Spectra Energy Partners Distribution Western Canada Transmission & Processing Total (in millions) December 31, 2013 $ 3,215 $ 824 $ 771 $ 4,810 Adjustment to acquisition of Express-Platte 37 — — 37 Foreign currency translation (8 ) (65 ) (60 ) (133 ) December 31, 2014 3,244 759 711 4,714 Impairment of goodwill — — (333 ) (333 ) Foreign currency translation (12 ) (110 ) (105 ) (227 ) December 31, 2015 $ 3,232 $ 649 $ 273 $ 4,154 See Note 3 for discussion of the acquisition of Express-Platte and an adjustment to Goodwill recorded in the first quarter of 2014 related to the acquisition. The following remaining goodwill amounts originating from the acquisition of Westcoast in 2002 are included as segment assets within “Other” in the segment data presented in Note 4: December 31, 2015 2014 (in millions) Distribution $ 646 $ 757 Western Canada Transmission & Processing 246 677 Due to the sustained downturn in commodity prices, we performed a goodwill impairment test for BC Field Services and Empress in the fourth quarter of 2015. The impairment test was based on a combination of an income approach and a market approach for which the inputs are classified as Level 3. The impairment test resulted in recognition of a $270 million goodwill impairment for BC Field Services and a $63 million goodwill impairment for Empress which resulted in a total goodwill impairment of $333 million . No triggering events occurred during the period from April 1, 2015 through December 31, 2015 that warranted re-testing for goodwill impairment except for the BC Field Services reporting unit and Empress reporting unit. See Note 10 for discussion related to the partial impairment of goodwill recognized by DCP Midstream.

Marketable Securities and Restr

Marketable Securities and Restricted Funds [Text Block]	12 Months Ended
	Dec. 31, 2015
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, bankers acceptances, corporate debt securities, treasury bills and money market funds in the U.S. and 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 insurance purposes and capital expenditures, 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 HTM marketable securities). Maturities of securities are classified within proceeds from sales and maturities of securities in the Consolidated Statements of Cash Flows. AFS Securities. AFS securities are as follows: Estimated Fair Value December 31, 2015 2014 (in millions) Corporate debt securities $ 31 $ 23 Money market funds — 1 Total available-for-sale securities $ 31 $ 24 Our AFS securities are classified on the Consolidated Balance Sheets as follows: Estimated Fair Value December 31, 2015 2014 (in millions) Restricted funds Investments and other assets—other $ 11 $ 1 Non-restricted funds Current assets—other 20 3 Investments and other assets—other — 20 Total available-for-sale securities $ 31 $ 24 At December 31, 2015 , the weighted–average contractual maturity of outstanding AFS securities was less than one year . There were no material gross unrealized holding gains or losses associated with investments in AFS securities at December 31, 2015 or 2014 . HTM Securities. All of our HTM securities are as follows: Estimated Fair Value December 31, Description Consolidated Balance Sheet Caption 2015 2014 (in millions) Bankers acceptances Current assets—other $ 30 $ 38 Canadian government securities Current assets—other 24 30 Money market funds Current assets—other 3 3 Canadian government securities Investments and other assets—other 50 101 Bankers acceptances Investments and other assets—other 12 — Total held-to-maturity securities $ 119 $ 172 All of our HTM securities are restricted funds pursuant to certain M&N Canada and Express-Platte (our crude oil pipeline system) debt agreements. The funds restricted for M&N Canada, plus future cash from operations that would otherwise be available for distribution to the partners of M&N Canada, are required to be placed in escrow until the balance in escrow is sufficient to fund all future debt service on the M&N Canada 6.90% senior secured notes. There are sufficient funds held in escrow to fund all future debt service on these M&N Canada notes as of December 31, 2015 . At December 31, 2015 , 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 December 31, 2015 or 2014 . Other Restricted Funds . In addition to the portions of the AFS and HTM securities that were restricted funds as described above, we had other restricted funds totaling $11 million at December 31, 2015 and $13 million at December 31, 2014 classified as Current Assets—Other. These restricted funds are related to additional amounts for insurance. We also had other restricted funds totaling $38 million at December 31, 2015 and $6 million at December 31, 2014 classified as Investments and Other Assets—Other. $24 million of these restricted funds are related to funds held and collected from customers for Canadian pipeline abandonment in accordance with the NEB’s regulatory requirements and $14 million are related to certain construction projects. Changes in restricted balances are presented within Cash Flows from Investing Activities on our Consolidated Statements of Cash Flows. Interest income. Interest income totaled $3 million in 2015 , $4 million in 2014 and $6 million 2013 , and is included in Other Income and Expenses, Net on the Consolidated Statements of Operations.

Property, Plant and Equipment

Property, Plant and Equipment	12 Months Ended
	Dec. 31, 2015
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	Property, Plant and Equipment Estimated Useful Life December 31, 2015 2014 (years) (in millions) Plant Natural gas transmission 15–100 $ 15,690 $ 15,001 Natural gas distribution 25-60 2,651 2,971 Gathering and processing facilities 25-40 4,178 4,765 Natural gas storage 10–122 2,137 2,162 Crude oil transportation and storage 25–75 1,206 1,169 Land rights and rights of way 21–122 591 568 Other buildings and improvements 10–50 149 132 Equipment 3–40 301 343 Vehicles 5–20 102 114 Land — 138 150 Construction in process — 1,919 1,113 Software 4–10 439 387 Other 5–82 342 336 Total property, plant and equipment 29,843 29,211 Total accumulated depreciation (6,527 ) (6,543 ) Total accumulated amortization (398 ) (361 ) Total net property, plant and equipment $ 22,918 $ 22,307 We had no material capital leases at December 31, 2015 or 2014 . Almost 85% of our property, plant and equipment is regulated with estimated useful lives based on rates approved by the applicable regulatory authorities in the U.S. and Canada: the FERC, the NEB and the OEB. Composite weighted-average depreciation rates were 2.72% for 2015 , 2.82% for 2014 and 2.96% for 2013 . Amortization expense of intangible assets totaled $79 million in 2015 , $74 million in 2014 and $65 million in 2013 . Estimated amortization expense for the next five years follows: Estimated Amortization Expense (in millions) 2016 $ 84 2017 80 2018 54 2019 35 2020 28

Asset Retirement Obligations

Asset Retirement Obligations	12 Months Ended
	Dec. 31, 2015
Asset Retirement Obligation Disclosure [Abstract]
Asset Retirement Obligations	Asset Retirement Obligations Our AROs relate mostly to the retirement of certain gathering pipelines and processing facilities, obligations related to right-of-way agreements and contractual leases for land use. However, we have determined that a significant portion of our assets have an indeterminate life, and as such, the fair values of those associated retirement obligations are not reasonably estimable. These assets include onshore and some offshore pipelines, and certain processing plants and distribution facilities, whose retirement dates will depend mostly on the various natural gas supply sources that connect to our systems and the ongoing demand for natural gas usage in the markets we serve. We expect these supply sources and market demands to continue for the foreseeable future, therefore we are unable to estimate retirement dates that would result in asset retirement obligations. AROs are adjusted each period for liabilities incurred or settled during the period, accretion expense, any revisions made to the estimated cash flows and dispositions of businesses. In 2015, SEP revised the estimated future cash flow assumptions for its ARO liabilities due to a reduction in the remaining estimated life of certain Texas Eastern offshore facilities which resulted in an increase to ARO liabilities of $32 million . In 2014, Western Canada Transmission & Processing revised the estimated future cash flow assumptions relating to asbestos abatement at its processing plants which resulted in an increase to ARO liabilities of $44 million . Reconciliation of Changes in Asset Retirement Obligation Liabilities 2015 2014 (in millions) Balance at beginning of year $ 400 $ 350 Accretion expense 17 16 Revisions in estimated cash flows (a) 72 72 Foreign currency exchange impact (62 ) (28 ) Liabilities settled (9 ) (10 ) Balance at end of year (b) $ 418 $ 400 ________ (a) Reflects revised assumptions regarding ARO Liabilities due to a reduction in the remaining estimated life of certain Texas Eastern offshore facilities in 2015 and asbestos abatement at Western Canada Transmission & Processing in 2014. (b) Amounts included in Deferred Credits and Other Liabilities in the Consolidated Balance Sheets.

Debt and Credit Facilities

Debt and Credit Facilities	12 Months Ended
	Dec. 31, 2015
Debt Disclosure [Abstract]
Debt and Credit Facilities	Debt and Credit Facilities Summary of Debt and Related Terms December 31, 2015 2014 Spectra Energy Capital, LLC (in millions) 6.20% senior unsecured notes due April 2018 $ 500 $ 500 6.75% senior unsecured notes due July 2018 150 150 Variable-rate senior unsecured term loan due November 2018 300 300 8.00% senior unsecured notes due October 2019 500 500 5.65% senior unsecured notes due March 2020 300 300 3.30% senior unsecured notes due March 2023 650 650 6.75% senior unsecured notes due February 2032 240 240 7.50% senior unsecured notes due September 2038 250 250 Total Spectra Energy Capital, LLC Debt 2,890 2,890 SEP SEP 2.95% senior unsecured notes due June 2016 250 250 SEP 2.95% senior unsecured notes due September 2018 500 500 SEP variable-rate senior unsecured term loan due November 2018 400 400 SEP 4.60% senior unsecured notes due June 2021 250 250 SEP 4.75% senior unsecured notes due March 2024 1,000 1,000 SEP 3.50% senior unsecured notes due March 2025 500 — SEP 5.95% senior unsecured notes due September 2043 400 400 SEP 4.50% senior unsecured notes due March 2045 500 — Texas Eastern 6.00% senior unsecured notes due September 2017 400 400 Texas Eastern 4.13% senior unsecured notes due December 2020 300 300 Texas Eastern 2.80% senior unsecured notes due October 2022 500 500 Texas Eastern 7.00% senior unsecured notes due July 2032 450 450 Algonquin 3.51% senior notes due July 2024 350 350 East Tennessee Natural Gas, LLC 3.10% senior notes due December 2024 200 200 Express-Platte 6.09% senior secured notes due January 2020 110 110 Express-Platte 7.39% subordinated secured notes due 2015 to 2019 42 74 Total SEP Debt 6,152 5,184 Westcoast 8.50% debentures due November 2015 — 108 3.28% medium-term notes due January 2016 181 215 8.50% debentures due September 2018 108 129 5.60% medium-term notes due January 2019 217 258 9.90% debentures due January 2020 72 86 4.57% medium-term notes due July 2020 181 215 3.88% medium-term notes due October 2021 108 129 3.12% medium-term notes due December 2022 181 215 3.43% medium-term notes due September 2024 253 301 8.85% debentures due July 2025 108 129 8.80% medium-term notes due November 2025 18 22 3.77% medium-term notes due December 2025 217 — 7.30% debentures due December 2026 90 108 6.75% medium-term notes due December 2027 108 129 7.15% medium-term notes due March 2031 145 172 4.79% medium-term notes due October 2041 145 129 M&N Canada 6.90% senior secured notes due 2015 to 2019 75 112 M&N Canada 4.34% senior secured notes due 2015 to 2019 47 83 Other 2 2 Total Westcoast Debt $ 2,256 $ 2,542 December 31, 2015 2014 Union Gas (in millions) 11.50% debentures due August 2015 $ — $ 129 4.64% medium-term notes due June 2016 145 172 9.70% debentures due November 2017 90 108 5.35% medium-term notes due April 2018 145 172 8.75% debentures due August 2018 90 108 8.65% senior debentures due October 2018 54 64 2.76% medium-term notes due June 2021 145 172 4.85% medium-term notes due April 2022 90 108 3.79% medium-term notes due July 2023 181 215 3.19% medium-term notes due September 2025 145 — 8.65% debentures due November 2025 90 108 5.46% medium-term notes due September 2036 119 142 6.05% medium-term notes due September 2038 216 258 5.20% medium-term notes due July 2040 181 215 4.88% medium-term notes due June 2041 217 258 4.20% medium-term notes due June 2044 361 215 Total Union Gas Debt 2,269 2,444 Total Long-term debt principal (including current maturities) 13,567 13,060 Change in fair value of debt hedged 22 17 Unamortized debt discount, net (22 ) (12 ) Unamortized capitalized debt issuance costs (a) (46 ) (42 ) Other unamortized items 4 7 Total other non-principal amounts (42 ) (30 ) Commercial paper (b) 1,112 1,583 Capital Leases 19 24 Total debt (including capital lease obligations) (c) 14,656 14,637 Current maturities of long-term debt (652 ) (327 ) Commercial paper (d) (1,112 ) (1,583 ) Total long-term debt (including capital lease obligations) $ 12,892 $ 12,727 ______ (a) Reflects implementation of ASU No. 2015-03 as discussed in Note 1. (b) The weighted-average days to maturity was 12 days as of December 31, 2015 and 14 days as of December 31, 2014 . (c) As of December 31, 2015 and 2014 , respectively, $4,681 million and $5,264 million of debt was denominated in Canadian dollars. (d) Weighted-average rate on outstanding commercial paper was 0.9% at December 31, 2015 and 0.6% at December 31, 2014 . Secured Debt. Secured debt, totaling $274 million as of December 31, 2015 , includes project financings for M&N Canada and Express-Platte. Ownership interests in M&N Canada and certain of its accounts, revenues, business contracts and other assets are pledged as collateral. Express-Platte notes payable are secured by the assignment of the Express-Platte transportation receivables and by the Canadian portion of the Express-Platte pipeline system assets. Floating Rate Debt. Debt included approximately $1,812 million of floating-rate debt as of December 31, 2015 and $2,283 million as of December 31, 2014 . The weighted average interest rate of borrowings outstanding that contained floating rates was 1.15% at December 31, 2015 and 0.8% at December 31, 2014 . Annual Maturities December 31, 2015 (in millions) 2016 $ 650 2017 543 2018 2,277 2019 745 2020 963 Thereafter 8,408 Total long-term debt, including current maturities (a) $ 13,586 __________ (a) Excludes commercial paper of $1,112 million . Includes capital leases of $19 million . We have the ability under certain debt facilities to call and repay the obligations prior to scheduled maturities. Therefore, the actual timing of future cash repayments could be materially different than presented above. Available Credit Facilities and Restrictive Debt Covenants Expiration Total Commercial Paper Outstanding at December 31, 2015 Available (in millions) Spectra Energy Capital, LLC (a) 2019 $ 1,000 $ 481 $ 519 SEP (b) 2019 2,000 476 1,524 Westcoast (c) 2019 289 6 283 Union Gas (d) 2019 361 149 212 Total $ 3,650 $ 1,112 $ 2,538 __________ (a) Revolving credit facility contains a covenant requiring the Spectra Energy consolidated debt-to-total capitalization ratio, as defined in the agreement, to not exceed 65% . Per the terms of the agreement, collateralized debt is excluded from the calculation of the ratio. This ratio was 59.6% at December 31, 2015 . (b) Revolving credit facility contains a covenant that requires SEP to maintain a ratio of total Consolidated Indebtedness-to-Consolidated EBITDA, as defined in the agreement, of 5.0 to 1 or less. As of December 31, 2015 , this ratio was 3.6 to 1. (c) U.S. dollar equivalent at December 31, 2015 . The revolving credit facility is 400 million Canadian dollars and contains a covenant that requires the Westcoast non-consolidated debt-to-total capitalization ratio to not exceed 75% . The ratio was 35.4% at December 31, 2015 . (d) U.S. dollar equivalent at December 31, 2015 . The revolving credit facility is 500 million Canadian dollars and contains a covenant that requires the Union Gas debt-to-total capitalization ratio to not exceed 75% and a provision which requires Union Gas to repay all borrowings under the facility for a period of two days during the second quarter of each year. The ratio was 67.8% at December 31, 2015 . The issuances of commercial paper, letters of credit and revolving borrowings reduce the amounts available under the credit facilities. As of December 31, 2015 , there were no letters of credit issued or revolving borrowings outstanding under the credit facilities. Our credit agreements contain various covenants, including the maintenance of certain financial ratios. Failure to meet those covenants beyond applicable grace periods could result in accelerated due dates and/or termination of the agreements. As of December 31, 2015 , we were in compliance with those covenants. In addition, our credit agreements allow for acceleration of payments or termination of the agreements due to nonpayment, or in some cases, due to the acceleration of other significant indebtedness of the borrower or some of its subsidiaries. Our debt and credit agreements do not contain provisions that trigger an acceleration of indebtedness based solely on the occurrence of a material adverse change in our financial condition or results of operations. As noted above, the terms of our Spectra Capital, LLC (Spectra Capital) credit agreements require our consolidated debt-to-total capitalization ratio, as defined in the agreement, to be 65% or lower. Per the terms of the agreements, collateralized debt is excluded from the calculation of the ratio. This ratio was 59.6% at December 31, 2015 . Approximately $7.9 billion of our equity (net assets) was considered restricted at December 31, 2015 , representing the minimum amount of equity required to maintain the 65% consolidated debt-to-total capitalization ratio.

Preferred Stock of Subsidiaries

Preferred Stock of Subsidiaries	12 Months Ended
	Dec. 31, 2015
Equity [Abstract]
Preferred Stock of Subsidiaries	Preferred Stock of Subsidiaries Westcoast and Union Gas have outstanding preferred shares owned by third parties that are generally not redeemable prior to specified redemption dates. On or after those dates, the shares may be redeemed, in whole or in part, for cash at the option of Westcoast and Union Gas, as applicable. The shares are not subject to any sinking fund or mandatory redemption and are not convertible into common shares. As redemption of the shares is not solely within our control, we have classified the preferred stock of subsidiaries as temporary equity on our Consolidated Balance Sheets. Dividends are cumulative and payable quarterly, and are included in Net Income—Noncontrolling Interests in the Consolidated Statements of Operations. Approximately 78% of the outstanding preferred shares are redeemable at the option of Westcoast and Union Gas, as applicable. On December 15, 2015, Westcoast issued 4.6 million Cumulative 5-Year Minimum Rate Reset Redeemable First Preferred Shares, Series 10 for an aggregate principle amount of 115 million Canadian dollars (approximately $84 million as of the issuance date). Net proceeds from the issuance were used to fund capital expenditures, to refinance maturing debt obligations and for other corporate purposes.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2015
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 and recorded at fair value on a recurring basis: Description Consolidated Balance Sheet Caption December 31, 2015 Total Level 1 Level 2 Level 3 (in millions) Corporate debt securities Cash and cash equivalents $ 137 $ — $ 137 $ — Corporate debt securities Current assets — other 20 — 20 — Commodity derivatives Current assets — other 36 — — 36 Commodity derivatives Investments and other assets — other 5 — — 5 Corporate debt securities Investments and other assets — other 11 — 11 — Interest rate swaps Investments and other assets — other 37 — 37 — Total Assets $ 246 $ — $ 205 $ 41 Description Consolidated Balance Sheet Caption December 31, 2014 Total Level 1 Level 2 Level 3 (in millions) Corporate debt securities Cash and cash equivalents $ 85 $ — $ 85 $ — Corporate debt securities Current assets — other 3 — 3 — Commodity derivatives Current assets — other 57 — — 57 Interest rate swaps Current assets — other 2 — 2 — Commodity derivatives Investments and other assets — other 21 — — 21 Corporate debt securities Investments and other assets — other 20 — 20 — Interest rate swaps Investments and other assets — other 22 — 22 — Money market funds Investments and other assets — other 1 1 — — Total Assets $ 211 $ 1 $ 132 $ 78 The following presents changes in Level 3 assets and liabilities that are measured at fair value on a recurring basis using significant unobservable inputs: 2015 2014 (in millions) Derivative assets (liabilities) Fair value, beginning of period $ 78 $ (3 ) Total gains (losses): Included in earnings 43 91 Included in other comprehensive income (10 ) 5 Purchases (3 ) — Settlements (67 ) (15 ) Fair value, end of period $ 41 $ 78 Unrealized gains (losses) relating to instruments held at the end of the period $ (19 ) $ 56 Level 1 Level 1 valuations represent quoted unadjusted prices for identical instruments in active markets. Level 2 Valuation Techniques 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 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. In addition, credit default swap rates are used to develop the adjustment for credit risk embedded in our positions. We believe that since some of the inputs and assumptions for the calculations of fair value are derived from observable market data, a Level 2 classification is appropriate. Level 3 Valuation Techniques 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. The derivative financial instruments reported in Level 3 at December 31, 2015 consist of NGL revenue swap contracts related to the Empress assets in Western Canada Transmission & Processing. As of December 31, 2015 , we reported certain of our NGL basis swaps at fair value using Level 3 inputs due to such derivatives not having observable market prices for substantially the full term of the derivative asset or liability. For valuations that include both observable and unobservable inputs, if the unobservable input is determined to be significant to the overall inputs, the entire valuation is categorized in Level 3. This includes derivatives valued using indicative price quotations whose contract length extends into unobservable periods. The fair value of these NGL basis swaps is determined using a discounted cash flow valuation technique based on a forward commodity basis curve. For these derivatives, the primary input to the valuation model is the forward commodity basis curve, which is based on observable or public data sources and extrapolated when observable prices are not available. The significant unobservable inputs used in the fair value measurements of our Level 3 derivatives are the forward natural gas basis curves, for which a significant portion of the derivative’s term is beyond available forward pricing. At December 31, 2015 , a 10¢ per gallon movement in underlying forward NGL prices would affect the estimated fair value of our NGL derivatives by $15 million . This calculated amount does not take into account any other changes to the fair value measurement calculation. 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. December 31, 2015 2014 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) 13,567 13,891 13,060 14,446 __________ (a) Included within Investments in and Loans to Unconsolidated Affiliates. (b) Excludes capital leases, unamortized items and fair value hedge carrying value adjustments. The fair value of our 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, notes receivable—noncurrent, accounts payable and commercial paper 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. During the fourth quarter of 2015 , we recorded goodwill impairment charges on BC Field Services and Empress reporting units of $270 million and $63 million , respectively. See Note 11 for further discussion. There were no material adjustments to assets and liabilities measured at fair value on a nonrecurring basis in 2014 .

Risk Management and Hedging Act

Risk Management and Hedging Activities	12 Months Ended
	Dec. 31, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Risk Management and Hedging Activities	Risk Management and Hedging Activities We are exposed to the impact of market fluctuations in the prices of NGLs and natural gas purchased as a result of our investment in DCP Midstream, the ownership of the NGL marketing operations in western Canada and processing operations associated with our U.S. pipeline assets. Exposure to interest rate risk exists as a result of the issuance of variable and fixed-rate debt and commercial paper. We are exposed to foreign currency risk from our Canadian operations. 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 and commodity exposures. DCP Midstream manages their direct exposure to market prices separate from Spectra Energy, and utilizes various risk management strategies, including the use of commodity derivatives. Other than the commodity derivatives and interest rate swaps as described below, we did not have any significant derivatives outstanding during the year ended December 31, 2015 . Derivative Portfolio Carrying Value as of December 31, 2015 Maturities in 2016 Maturities Maturities in 2018 Maturities in 2019 and Thereafter Total Carrying Value (in millions) Derivatives designated as hedging instruments Interest rate swaps $ — $ 2 $ 12 $ 23 $ 37 Total derivatives designated as hedging instruments — 2 12 23 37 Derivatives not designated as hedging instruments Commodity derivatives 36 5 — — 41 Total derivatives not designated as hedging instruments 36 5 — — 41 Total derivative instruments $ 36 $ 7 $ 12 $ 23 $ 78 These amounts represent the combination of amounts presented as assets for non-cash gains on mark-to-market and hedging transactions on our Consolidated Balance Sheet and do not include any derivative positions of DCP Midstream. See Note 17 for information regarding the presentation of these derivative positions on our Consolidated Balance Sheets. Commodity Derivatives. Our NGL marketing operations are exposed to market fluctuations in the prices of natural gas and NGLs related to natural gas processing and marketing activities. We closely monitor the potential effects of commodity price changes and may choose to enter into contracts to protect margins for a portion of future sales and fuel expenses by using financial commodity instruments, such as swaps, forward contracts and options. Effective January 2014, we implemented a commodity price risk management program at Western Canada Transmission & Processing’s Empress NGL business and elected to not apply cash flow hedge accounting. At December 31, 2015 , we had commodity mark-to-market derivatives outstanding with a total notional amount of 152 million gallons. The longest dated commodity derivative contract we currently have expires in 2018 . Information about our commodity derivatives that had netting or rights of offset arrangements are as follows: December 31, 2015 Gross Amounts Gross Amounts Offset Net Amount Presented in the Consolidated Balance Sheets Description (in millions) Assets $ 104 $ 63 $ 41 Liabilities 63 63 — Substantially all of our commodity derivative agreements outstanding at December 31, 2015 have provisions that require collateral to be posted in the amount of the net liability position if one of our credit ratings falls below investment grade. Information regarding the impacts of commodity derivatives on our Consolidated Statements of Operations is as follows: Derivatives Consolidated Statements of Operations Caption 2015 2014 2013 (in millions) Commodity derivatives Sales of natural gas liquids $ 40 $ 93 $ — Interest Rate Swaps. Changes in interest rates expose us to risk as a result of our issuance of variable and fixed-rate debt and commercial paper. We manage our interest rate exposure by limiting our variable-rate exposures to percentages of total debt and by monitoring the effects of market changes in interest rates. We also enter into financial derivative instruments, including, but not limited to, interest rate swaps and rate lock agreements to manage and mitigate interest rate risk exposure. For interest rate derivative instruments that 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 included in Interest Expense on the Consolidated Statements of Operations. There were no significant amounts of gains or losses, either effective or ineffective, recognized in net income or other comprehensive income in 2015 , 2014 or 2013 . At December 31, 2015 , we had “pay floating — receive fixed” interest rate swaps outstanding with a total notional amount of $2,000 million to hedge against changes in the fair value of our fixed-rate debt 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 fixed-rate debt securities into variable-rate interest payments in order to achieve our desired mix of fixed and variable-rate debt. Information about our interest rate swaps that had netting or rights of offset arrangements are as follows: December 31, 2015 December 31, 2014 Gross Amounts Presented in the Consolidated Balance Sheets Amounts Not Offset in the Consolidated Balance Sheets Net Amount Gross Amounts Presented in the Consolidated Balance Sheets Amounts Not Offset in the Consolidated Balance Sheets Net Amount Description (in millions) Assets $ 37 $ — $ 37 $ 24 $ — $ 24 Foreign Currency Risk. We are exposed to foreign currency risk from investments and operations in Canada. To mitigate risks associated with foreign currency fluctuations, contracts may be denominated in or indexed to the U.S. dollar and/or local inflation rates, or investments may be naturally hedged through debt denominated or issued in the foreign currency. To monitor our currency exchange rate risks, we use sensitivity analysis, which measures the effect of devaluation of the Canadian dollar. Credit Risk. Our principal customers for natural gas transmission and crude oil transportation, storage and gathering and processing services are industrial end-users, marketers, exploration and production companies, local distribution companies and utilities located throughout the U.S. and Canada. We have concentrations of receivables from natural gas utilities and their affiliates, industrial customers and marketers throughout these regions, as well as retail distribution customers in Canada. These concentrations of customers may affect our overall credit risk in that risk factors can negatively affect the credit quality of the entire sector. Where exposed to credit risk, we analyze the customers’ financial condition prior to entering into an agreement, establish credit limits and monitor the appropriateness of those limits on an ongoing basis. We also obtain parental guarantees, cash deposits or letters of credit from customers to provide credit support, where appropriate, based on our financial analysis of the customer and the regulatory or contractual terms and conditions applicable to each contract.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies General Insurance We carry, either directly or through our captive insurance companies, insurance coverages consistent with companies engaged in similar commercial operations with similar type properties. Our insurance program includes (1) commercial general and excess liability insurance for liabilities to third parties for bodily injury and property damage resulting from our operations; (2) workers’ compensation liability coverage to required statutory limits; (3) automobile liability insurance for all owned, non-owned and hired vehicles covering liabilities to third parties for bodily injury and property damage; (4) insurance policies in support of the indemnification provisions of our by-laws; and (5) property insurance, including machinery breakdown, on an all-risk-replacement valued basis, onshore business interruption and extra expense. All coverages are subject to certain deductibles, terms and conditions common for companies with similar types of operations. Environmental We are subject to various U.S. federal, state and local laws and regulations, as well as Canadian federal and provincial laws, regarding air and water quality, hazardous and solid waste disposal and other environmental matters. These laws and regulations can change from time to time, imposing new obligations on us. Like others in the energy industry, we and our affiliates are responsible for environmental remediation at various contaminated sites. These include some properties that are part of our ongoing operations, sites formerly owned or used by us, and sites owned by third parties. Remediation typically involves management of contaminated soils and may involve groundwater remediation. Managed in conjunction with relevant federal, state/provincial and local agencies, activities vary with site conditions and locations, remedial requirements, complexity and sharing of responsibility. If remediation activities involve statutory joint and several liability provisions, strict liability, or cost recovery or contribution actions, we or our affiliates could potentially be held responsible for contamination caused by other parties. In some instances, we may share liability associated with contamination with other potentially responsible parties, and may also benefit from contractual indemnities that cover some or all cleanup costs. All of these sites generally are managed in the normal course of business or affiliated operations. We believe that there are no matters outstanding that upon resolution will have a material effect on our consolidated results of operations, financial position or cash flows. Included in Deferred Credits and Other Liabilities—Regulatory and Other on the Consolidated Balance Sheets are undiscounted liabilities related to extended environmental-related activities totaling $8 million as of December 31, 2015 and $10 million as of December 31, 2014 . These liabilities represent provisions for costs associated with remediation activities at some of our current and former sites, as well as other environmental contingent liabilities. Litigation Litigation and Legal Proceedings. We are involved in legal, tax and regulatory proceedings in various forums arising in the ordinary course of business, including matters regarding contract and payment claims, some of which involve substantial monetary amounts. We have insurance coverage for certain of these losses should they be incurred. We believe that the final disposition of these proceedings will not have a material effect on our consolidated results of operations, financial position or cash flows. Legal costs related to the defense of loss contingencies are expensed as incurred. We had no material reserves for legal matters recorded as of December 31, 2015 or 2014 related to litigation. Other Commitments and Contingencies See Note 20 for a discussion of guarantees and indemnifications. Operating Lease Commitments We lease assets in various areas of our operations. Consolidated rental expense for operating leases classified in Operating Income was $47 million in 2015 and $38 million for both 2014 and 2013 , which is included in Operating, Maintenance and Other on the Consolidated Statements of Operations. The following is a summary of future minimum lease payments under operating leases which at inception had noncancellable terms of more than one year. We had no material capital lease commitments as of December 31, 2015 or 2014 . Long-term Operating Leases (in millions) 2016 $ 49 2017 41 2018 39 2019 35 2020 31 Thereafter 139 Total future minimum lease payments $ 334

Guarantees and Indemnifications

Guarantees and Indemnifications	12 Months Ended
	Dec. 31, 2015
Guarantees [Abstract]
Guarantees and Indemnifications	Guarantees and Indemnifications We have various financial guarantees and indemnifications which are issued in the normal course of business. As discussed below, these contracts include financial guarantees, stand-by letters of credit, debt guarantees, surety bonds and indemnifications. 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 Consolidated Balance Sheets. The possibility of having to perform under these guarantees and indemnifications is largely dependent upon future operations of various subsidiaries, investees and other third parties, or the occurrence of certain future events. We have issued performance guarantees to customers and other third parties that guarantee the payment and performance of other parties, including certain non-100%-owned entities. In connection with our spin-off from Duke Energy Corporation (Duke Energy) in 2007, certain guarantees that were previously issued by us were assigned to, or replaced by, Duke Energy as guarantor in 2006. For any remaining guarantees of other Duke Energy obligations, Duke Energy has indemnified us against any losses incurred under these guarantee arrangements. The maximum potential amount of future payments we could have been required to make under these performance guarantees as of December 31, 2015 was approximately $406 million , which has been indemnified by Duke Energy as discussed above. One of these outstanding performance guarantees, which has a maximum potential amount of future payment of $201 million , expires in 2028 . The remaining guarantees have no contractual expirations. We have also issued joint and several guarantees to some of the Duke/Fluor Daniel (D/FD) project owners, guaranteeing the performance of D/FD under its engineering, procurement and construction contracts and other contractual commitments in place at the time of our spin-off from Duke Energy. D/FD is one of the entities transferred to Duke Energy in connection with our spin-off. Substantially all of these guarantees have no contractual expiration and no stated maximum amount of future payments that we could be required to make. Fluor Enterprises Inc., as 50% owner in D/FD, issued similar joint and several guarantees to the same D/FD project owners. Westcoast, a 100% -owned subsidiary, has issued performance guarantees to third parties guaranteeing the performance of unconsolidated entities, such as equity method investments, and of entities previously sold by Westcoast to third parties. Those guarantees require Westcoast to make payment to the guaranteed third party upon the failure of such unconsolidated or sold entity to make payment under some of its contractual obligations, such as debt agreements, purchase contracts and leases. Certain guarantees that were previously issued by Westcoast for obligations of entities that remained a part of Duke Energy are considered guarantees of third party performance; however, Duke Energy has indemnified us against any losses incurred under these guarantee arrangements. We have entered into various indemnification agreements related to purchase and sale agreements and other types of contractual agreements with vendors and other third parties. These agreements typically cover environmental, litigation and other matters, as well as breaches of representations, warranties and covenants. Typically, claims may be made by third parties for various periods of time, depending on the nature of the claim. Our potential exposure under these indemnification agreements can range from a specified amount, such as the purchase price, to an unlimited dollar amount, depending on the nature of the claim and the particular transaction. We are unable to estimate the total potential amount of future payments under these indemnification agreements due to several factors, such as the unlimited exposure under certain guarantees. As of December 31, 2015 , the amounts recorded for the guarantees and indemnifications described above are not material, both individually and in the aggregate.

Effects of Changes in Noncontro

Effects of Changes in Noncontrolling Interests Ownership	12 Months Ended
	Dec. 31, 2015
Noncontrolling Interest [Abstract]
Changes In Noncontrolling Interests Ownership [Text Block]	Effects of Changes in Noncontrolling Interests Ownership The following table presents the effects of changes in our ownership interests in non-100%-owned consolidated subsidiaries: 2015 2014 2013 (in millions) Net income—controlling interests $ 196 $ 1,082 $ 1,038 Increase (decrease) in additional paid-in capital resulting from issuances/retirements of SEP units (a) (105 ) 49 42 Total net income—controlling interests and changes in equity—controlling interests $ 91 $ 1,131 $ 1,080 ________________ (a) See Note 2 for further discussion.

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation	Stock-Based Compensation The Spectra Energy Corp 2007 Long-Term Incentive Plan (the 2007 LTIP), as amended and restated, provides for the granting of stock options, restricted and unrestricted stock awards and units, and other equity-based awards, to employees and other key individuals who perform services for us. A maximum of 40 million shares of common stock may be awarded under the 2007 LTIP. Restricted, performance and phantom awards granted under the 2007 LTIP typically become 100% vested on the three -year anniversary of the grant date. Equity-classified and liability-classified stock-based compensation cost is measured at the grant date based on the fair value of the award. Liability-classified stock-based compensation cost is re-measured at each reporting period until settlement. Related compensation expense is recognized over the requisite service period, which generally begins on the date the award is granted through the earlier of the date the award becomes vested, the date the employee becomes retirement-eligible, or the date the market or performance condition is met. Options granted under the 2007 LTIP are issued with exercise prices equal to the fair market value of our common stock on the grant date, have ten -year terms and generally vest over a three -year term. Compensation expense related to stock options is recognized over the requisite service period. The requisite service period for stock options is the same as the vesting period, with the exception of retirement eligible employees, who have shorter requisite service periods ending when the employees become retirement eligible. We issue new shares upon exercising or vesting of share-based awards. The Black-Scholes option-pricing model is used to estimate the fair value of options at grant date. All outstanding stock options are fully vested, and as a result, we do not expect to recognize future compensation costs related to these stock options. We recorded pre-tax stock-based compensation expense as follows, the components of which are described further below: 2015 2014 2013 (in millions) Phantom awards $ 11 $ 14 $ 13 Performance awards 18 13 33 Total $ 29 $ 27 $ 46 The tax benefit in Net Income associated with the recorded stock-based compensation expense was $7 million in both 2015 and 2014 , and $8 million 2013 . We recognized tax benefits from stock-based compensation cost of approximately $1 million in 2015 , $3 million in 2014 and $5 million in 2013 in Additional Paid-in Capital. Awards Activity Performance Awards Phantom Awards Units Weighted Average Grant Date Fair Value Units Weighted Average Grant Date Fair Value (thousands) (thousands) Outstanding at December 31, 2014 1,775 $ 35 1,281 $ 33 Granted 564 48 395 36 Vested (2 ) 41 (428 ) 31 Forfeited (635 ) 22 (36 ) 30 Outstanding at December 31, 2015 1,702 39 1,212 28 Awards expected to vest 1,608 39 1,176 28 Performance Awards Under the 2007 LTIP, we can also grant stock-based performance awards. The performance awards generally vest over three years at the earliest, if performance metrics are met. The liability-classified awards will be settled in cash at vesting. We granted 564,300 equity-classified awards during 2015 , 557,100 during 2014 and 356,600 during 2013 , with fair values of $27 million in 2015 , $26 million in 2014 and $13 million in 2013 . We did not grant liability-classified awards during 2015 or 2014 ; however, we granted 343,700 during 2013 , with a fair value of $13 million . Of the unvested and outstanding performance awards granted, 1,689,640 awards contain market conditions based on the total shareholder return of Spectra Energy common stock relative to a pre-defined peer group, and 12,900 awards contain performance conditions based on EBITDA performance of one subsidiary company. The equity-classified and liability-classified awards with market conditions are valued using the Monte Carlo valuation method. The liability-classified awards are remeasured at each reporting period until settlement. Weighted-Average Assumptions for Stock-Based Performance Awards 2015 2014 2013 Risk-free rate of return 1.1% 0.7% 0.4% Expected life 3 years 3 years 3 years Expected volatility—Spectra Energy 18% 20% 21% Expected volatility—peer group 13%-27% 14%–32% 13%–33% Market index (a) N/A N/A 16% _________ (a) Beginning in 2014, the valuation model was refined to use an alternate analytical approach to project future stock prices in order to improve consistency and efficiency. The improved approach does not require the use of a market index assumption to determine the future stock price used in the valuation model. As such, the volatility of the market index assumption will not be presented going forward. Based on our assessment, it was determined that this refinement did not have a significant impact on the fair value of the shares for all periods presented. The risk-free rate of return was determined based on a yield of three -year U.S. Treasury bonds on the grant date. The expected volatility was established based on historical volatility over three years using daily stock price observations. Because the award payout includes dividend equivalents, no dividend yield assumption is required. The total fair value of the shares vested was less than $1 million in 2015 , $20 million in 2014 and $19 million in 2013 . As of December 31, 2015 , we expect to recognize $26 million of future compensation cost related to outstanding performance awards over a weighted-average period of less than one year. Phantom Awards Under the 2007 LTIP, we can also grant stock-based phantom awards. The phantom awards generally vest over three years. The liability-classified awards will be settled in cash at vesting. We awarded 39,200 equity-classified awards to our employees in 2015 , 101,500 in 2014 and 474,500 in 2013 , with fair values of $1 million , $4 million and $14 million , respectively. We awarded 356,100 liability-classified awards to our employees in 2015 and 353,000 in 2014 , with fair values of $13 million for both 2015 and 2014 . The liability-classified awards are remeasured at each reporting period until settlement. The total fair value of the shares vested was $13 million in 2015 , $11 million in 2014 and $14 million in 2013 . As of December 31, 2015 , we expect to recognize $12 million of future compensation cost related to phantom awards over a weighted-average period of less than two years. Stock Option Activity Options Weighted- Average Exercise Price Weighted- Average Remaining Life Aggregate Intrinsic Value (in thousands) (in years) (in millions) Outstanding at December 31, 2014 1,102 $ 25 2.0 $ 12 Exercised (134 ) 23 Forfeited or expired (10 ) 23 Outstanding at December 31, 2015 958 26 1.2 — Exercisable at December 31, 2015 958 26 1.2 — We did not award any non-qualified stock options to employees during 2015 , 2014 or 2013 . The total intrinsic value of options exercised was $1 million in 2015 , $6 million in 2014 and $21 million in 2013 . Cash received by us from options exercised was $3 million in 2015 , $11 million in 2014 and $43 million in 2013 . All stock options are fully vested, and as a result, we do not expect to recognize future compensation costs related to these stock options.

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2015
Compensation and Retirement Disclosure [Abstract]
Employee Benefit Plans	Employee Benefit Plans Retirement Plans. We have a qualified non-contributory defined benefit (DB) retirement plan for U.S. employees (U.S. Qualified Pension Plan). This plan covers U.S. employees using a cash balance formula. Under a cash balance formula, a plan participant accumulates a retirement benefit consisting of pay credits that are based upon a percentage (which may vary with age and years of service) of current eligible earnings and current interest credits. We also maintain non-qualified, non-contributory, unfunded defined benefit plans (U.S. Non-Qualified Pension Plans) which cover certain current and former U.S. executives. The U.S. Non-Qualified Pension Plans have no plan assets. There are other non-qualified plans such as savings and deferred compensation plans which cover certain current and former U.S. executives. Pursuant to trust agreements, Spectra Energy has set aside funds for certain of the above non-qualified plans in several trusts. Although these funds are restrictive in nature, they remain a component of our general assets and are subject to the claims of creditors. These trust funds totaling $18 million as of December 31, 2015 and $17 million as of December 31, 2014 , invested in money market funds and valued using a Level 1 hierarchy level, are considered AFS securities and are classified as Investments and Other Assets—Other on the Consolidated Balance Sheets. In addition, our Westcoast subsidiary maintains qualified and non-qualified, contributory and non-contributory DB (Canadian Qualified Pension Plan and Canadian Non-Qualified Pension Plan, respectively) and defined contribution (Canadian DC) retirement plans covering substantially all employees of our Canadian operations. The DB plans provide retirement benefits based on each plan participant’s years of service and final average earnings. Under the Canadian DC plan, company contributions are determined according to the terms of the plan and based on each plan participant’s age, years of service and current eligible earnings. We also provide non-qualified DB supplemental pensions to all employees who retire under a DB qualified pension plan and whose pension is limited by the maximum pension limits under the Income Tax Act (Canada). We report our Canadian benefit plans separate from the U.S. plans due to differences in actuarial assumptions. Our policy is to fund our retirement plans, where applicable, on an actuarial basis to provide assets sufficient to meet benefits to be paid to plan participants or as required by legislation or plan terms. We made contributions to our U.S. Qualified and Non-Qualified Pension Plans of $22 million in 2015 , $21 million in 2014 and $22 million in 2013 . We made total contributions to our Canadian Qualified and Non-Qualified Pension Plans of $22 million in 2015 , $36 million in 2014 and $80 million in 2013 . Contributions of $8 million in 2015 and $9 million in both 2014 and 2013 were made to our Canadian DC plan. We anticipate that in 2016 we will make total contributions of approximately $22 million to the U.S. Qualified and Non-Qualified Pension Plans, approximately $16 million to the Canadian Qualified and Non-Qualified Pension Plans and approximately $8 million to the Canadian DC Plan. Actuarial gains and losses are amortized over the average remaining service period of active employees. The average remaining service period of active employees covered by the U.S. Qualified and Non-Qualified Pension Plans is 11 years. The average remaining service periods of active employees covered by the Canadian Qualified and Non-Qualified Pension Plans is 11 years. We determine the market-related value of plan assets using a calculated value that recognizes changes in fair value of the plan assets over five years for the U.S. plans and over three years for the Canadian plans. Qualified and Non-Qualified Pension Plans Change in Projected Benefit Obligation and Change in Fair Value of Plan Assets U.S. Canada 2015 2014 2015 2014 (in millions) Change in Projected Benefit Obligation Projected benefit obligation, beginning of period $ 586 $ 575 $ 1,202 $ 1,131 Service cost 19 19 28 25 Interest cost 24 24 43 52 Actuarial loss (gain) (18 ) 13 (3 ) 143 Participant contributions — — 5 5 Benefits paid (40 ) (45 ) (47 ) (49 ) Foreign currency translation effect — — (194 ) (105 ) Projected benefit obligation, end of period 571 586 1,034 1,202 Change in Fair Value of Plan Assets Plan assets, beginning of period 551 531 1,050 1,040 Actual return on plan assets (1 ) 44 52 115 Benefits paid (40 ) (45 ) (47 ) (49 ) Employer contributions 22 21 22 36 Plan participants’ contributions — — 5 5 Expected non-investment expenses — — (3 ) (3 ) Foreign currency translation effect — — (171 ) (94 ) Plan assets, end of period 532 551 908 1,050 Net amount recognized $ (39 ) $ (35 ) $ (126 ) $ (152 ) Accumulated Benefit Obligation $ 549 $ 567 $ 967 $ 1,123 U.S. Canada 2015 2014 2015 2014 (in millions) Net amount recognized Current Liabilities - Other $ (2 ) $ (2 ) $ (5 ) $ (6 ) Deferred Credits and Other Liabilities - Regulatory and Other (37 ) (33 ) (142 ) (165 ) Other Assets - Other — — 21 19 Total net amount recognized $ (39 ) $ (35 ) $ (126 ) $ (152 ) The tables above include certain nonqualified pension plans that are unfunded. Those U.S. plans had projected benefit obligations of $23 million at December 31, 2015 and $22 million at December 31, 2014 . Those Canadian plans had projected benefit obligations of $103 million at December 31, 2015 and $117 million at December 31, 2014 . At December 31, 2015 , U.S. plans with accumulated benefit obligations in excess of plan assets had projected benefit obligations of $23 million , accumulated benefit obligations of $20 million and no plan assets. Canadian plans with accumulated benefit obligations in excess of plan assets had projected benefit obligations of $340 million , accumulated benefit obligations of $316 million and plan assets with a fair value of $215 million . Amounts Recognized in Accumulated Other Comprehensive Income U.S. Canada December 31, December 31, 2015 2014 2015 2014 (in millions) Net actuarial loss $ 156 $ 141 $ 330 $ 345 Prior service cost — — 5 6 Total amount recognized in AOCI $ 156 $ 141 $ 335 $ 351 Components of Net Periodic Pension Costs U.S. Canada 2015 2014 2013 2015 2014 2013 (in millions) Net Periodic Pension Cost Service cost benefit earned $ 19 $ 19 $ 19 $ 31 $ 29 $ 33 Interest cost on projected benefit obligation 24 24 21 43 52 50 Expected return on plan assets (42 ) (39 ) (33 ) (65 ) (69 ) (66 ) Amortization of prior service cost — — — 1 2 2 Amortization of loss 10 13 20 25 22 35 Net periodic pension cost 11 17 27 35 36 54 Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income Current year actuarial loss (gain) 25 8 (69 ) 10 93 (133 ) Amortization of actuarial loss (10 ) (13 ) (20 ) (25 ) (22 ) (35 ) Amortization of prior service credit — — — (1 ) (2 ) (2 ) Total recognized in other comprehensive income 15 (5 ) (89 ) (16 ) 69 (170 ) Total Recognized in Net Periodic Pension Cost and Other Comprehensive Income $ 26 $ 12 $ (62 ) $ 19 $ 105 $ (116 ) In 2016, approximately $7 million of actuarial losses for the U.S. plans and $17 million for the Canadian plans will be amortized from AOCI on the Consolidated Balance Sheets into net periodic pension cost, and approximately $1 million of prior service credits will be amortized from AOCI into net periodic pension costs for the Canadian plans. Assumptions Used for Pension Benefits Accounting U.S. Canada 2015 2014 2013 2015 2014 2013 Benefit Obligations Discount rate 4.58 % 4.10 % 4.31 % 4.03 % 4.00 % 4.81 % Salary increase 4.00 4.00 4.61 3.00 3.25 3.25 Net Periodic Benefit Cost Discount rate 4.10 4.31 3.55 4.00 4.81 4.15 Salary increase 4.00 4.61 4.61 3.25 3.25 3.25 Expected long-term rate of return on plan assets 8.00 8.00 7.40 7.40 7.40 7.10 The discount rates used to determine the benefit obligations are the rates at which the benefit obligations could be effectively settled. The discount rates for our U.S. and Canadian plans are developed from yields on available high-quality bonds in each country and reflect each plan’s expected cash flows. The long-term rates of return for the U.S. and Canadian plan assets as of December 31, 2015 were developed using weighted-average calculations of expected returns based primarily on future expected returns across classes considering the use of active asset managers applied against the U.S. and Canadian plans’ respective targeted asset mix. Qualified Pension Plan Assets U.S. Canada Asset Category Target Allocation December 31, Target Allocation December 31, 2015 2014 2015 2014 U.S. equity securities 23 % 22 % 31 % 17 % 18 % 17 % Canadian equity securities — — — 25 24 25 Other equity securities 10 10 11 13 13 13 Fixed income securities 57 57 48 45 45 45 Other investments 10 11 10 — — — Total 100 % 100 % 100 % 100 % 100 % 100 % Pension plan assets are maintained in master trusts in both the U.S. and Canada. The investment objective of the master trusts is to achieve reasonable returns on trust assets, subject to a prudent level of portfolio risk, for the purpose of enhancing the security of benefits for plan participants. The asset allocation targets were set after considering the investment objective and the risk profile with respect to the trusts. Equities are held for their high expected return. Other equity and fixed income securities are held for diversification. Investments within asset classes are diversified to achieve broad market participation and reduce the effects of individual managers or investments. We regularly review our actual asset allocation and periodically rebalance our investments to the targeted allocation when considered appropriate. The following table summarizes the fair values of pension plan assets recorded at each fair value hierarchy level, as determined in accordance with the valuation techniques described in Note 17: U.S. Canada Total Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 (in millions) December 31, 2015 Cash and cash equivalents $ 2 $ 2 $ — $ — $ 3 $ 3 $ — $ — Equity securities 171 171 — — 501 221 280 — Fixed income securities 304 304 — — 404 404 — — Other 55 — — 55 — — — — Total $ 532 $ 477 $ — $ 55 $ 908 $ 628 $ 280 $ — December 31, 2014 Cash and cash equivalents $ 3 $ 3 $ — $ — $ 3 $ 3 $ — $ — Equity securities 233 233 — — 576 342 234 — Fixed income securities 262 262 — — 471 471 — — Other 53 — — 53 — — — — Total $ 551 $ 498 $ — $ 53 $ 1,050 $ 816 $ 234 $ — The following presents changes in Level 3 assets that are measured at fair value on a recurring basis using significant unobservable inputs: U.S. 2015 2014 (in millions) Fair value, beginning of period $ 53 $ 49 Gain (loss) included in other comprehensive income 2 4 Fair value, end of period $ 55 $ 53 Expected Benefit Payments U.S. Canada (in millions) 2016 $ 84 $ 44 2017 49 47 2018 47 49 2019 49 51 2020 50 54 2021 – 2025 233 297 Other Post-Retirement Benefit Plans U.S. Other Post-Retirement Benefits. We provide certain health care and life insurance benefits for retired employees on a contributory and non-contributory basis. Employees are eligible for these benefits if they have met age and service requirements at retirement, as defined in the plans. These benefit costs are accrued over an employee’s active service period to the date of full benefits eligibility. Actuarial gains and losses are amortized over the average remaining service period of the active employees of 14 years. We determine the market-related value of the plan assets using a calculated value that recognizes changes in fair value of the plan assets over five years for the U.S. plans. Canadian Other Post-Retirement Benefits. We provide health care and life insurance benefits for retired employees on a non-contributory basis for our Canadian operations predominantly under defined contribution plans. Employees are eligible for these benefits if they have met age and service requirements at retirement, as defined in the plans. The Canadian plans are not funded. Other Post-Retirement Benefit Plans — Change in Projected Benefit Obligation and Fair Value of Plan Assets U.S. Canada 2015 2014 2015 2014 (in millions) Change in Benefit Obligation Accumulated post-retirement benefit obligation, beginning of period $ 172 $ 184 $ 133 $ 133 Service cost 1 1 4 4 Interest cost 7 8 5 6 Plan participants’ contributions 3 2 — — Actuarial loss (gain) 1 (7 ) (11 ) 7 Medicare subsidy receivable 2 2 — — Benefits paid (20 ) (18 ) (4 ) (4 ) Foreign currency translation effect — — (20 ) (13 ) Accumulated post-retirement benefit obligation, end of period 166 172 107 133 Change in Fair Value of Plan Assets Plan assets, beginning of period 92 87 — — Actual return on plan assets 1 7 — — Benefits paid (20 ) (18 ) (4 ) (4 ) Employer contributions 12 14 4 4 Plan participants’ contributions 3 2 — — Plan assets, end of period 88 92 — — Net amount recognized (a) $ (78 ) $ (80 ) $ (107 ) $ (133 ) _______ (a) Recognized primarily in Deferred Credits and Other Liabilities—Regulatory and Other in the Consolidated Balance Sheets. Other Post-Retirement Benefit Plans — Amounts Recognized in Accumulated Other Comprehensive Income U.S. Canada December 31, December 31, 2015 2014 2015 2014 (in millions) Prior service credit $ — $ — $ (3 ) $ (4 ) Net actuarial loss (gain) 3 (4 ) 1 12 Total amount recognized in AOCI $ 3 $ (4 ) $ (2 ) $ 8 In 2016 , approximately $1 million of prior service costs will be amortized from AOCI into net periodic pension costs for the Canadian plans. U.S. Canada 2015 2014 2013 2015 2014 2013 (in millions) Other Post-Retirement Benefit Plans — Components of Net Periodic Benefit Cost Service cost benefit earned $ 1 $ 1 $ 1 $ 4 $ 4 $ 5 Interest cost on accumulated post-retirement benefit obligation 7 8 7 5 6 6 Expected return on plan assets (6 ) (5 ) (4 ) — — — Amortization of prior service credit — — — (1 ) (1 ) (1 ) Amortization of loss — 1 2 — — — Net periodic other post-retirement benefit cost 2 5 6 8 9 10 Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income Current year actuarial loss (gain) 7 (9 ) (18 ) (11 ) 6 (13 ) Amortization of actuarial loss — (1 ) (2 ) — — — Amortization of prior service credit — — — 1 1 1 Total recognized in other comprehensive income 7 (10 ) (20 ) (10 ) 7 (12 ) Total recognized in net periodic benefit cost and other comprehensive income $ 9 $ (5 ) $ (14 ) $ (2 ) $ 16 $ (2 ) Other Post-Retirement Benefits Plans — Assumptions Used for Benefits Accounting U.S. Canada 2015 2014 2013 2015 2014 2013 Benefit Obligations Discount rate 4.53 % 4.08 % 4.46 % 4.03 % 4.00 % 4.83 % Salary increase 4.00 4.00 4.61 3.00 3.25 3.25 Net Periodic Benefit Cost Discount rate 4.08 4.46 3.70 4.00 4.83 4.20 Salary increase 4.00 4.61 4.61 3.25 3.25 3.25 Expected return on plan assets 6.83 6.98 6.51 N/A N/A N/A The discount rates used to determine the post-retirement obligations are the rates at which the benefit obligations could be effectively settled. The discount rates for our U.S. and Canadian plans are developed from yields on available high-quality bonds in each country and reflect each plan’s expected cash flows. Assumed Health Care Cost Trend Rates U.S. Canada 2015 2014 2015 2014 Health care cost trend rate assumed for next year 7.00% 7.00% 5.50% 6.00% Rate to which the cost trend is assumed to decline 5.00% 5.00% 5.00% 5.00% Year that the rate reaches the ultimate trend rate 2020 2019 2017 2017 Sensitivity to Changes in Assumed Health Care Cost Trend Rates U.S. Canada 1% Point Increase 1% Point Decrease 1% Point Increase 1% Point Decrease (in millions) Effect on total service and interest costs $ — $ — $ 1 $ (1 ) Effect on post-retirement benefit obligations 7 (6 ) 5 (5 ) Other Post-Retirement Plan Assets U.S. Asset Category December 31, 2015 2014 Cash and cash equivalents 3 % — % Equity securities 45 48 Fixed income securities 46 47 Other assets 6 5 Total 100 % 100 % A portion of our other post-retirement plan assets is maintained within the U.S. master trust discussed under the pension plans above. We invest other post-retirement plan assets in the Spectra Energy Corp Employee Benefits Trust (VEBA I) and the Spectra Energy Corp Post-Retirement Medical Benefits Trust (VEBA II). The investment objective of the VEBAs is to achieve sufficient returns on trust assets, subject to a prudent level of portfolio risk, for the purpose of promoting the security of plan benefits for participants. The VEBA trusts are passively managed. The asset allocation table above includes the other post-retirement benefit assets held in the master trusts, VEBA I and VEBA II. The following table summarizes the fair values of the other post-retirement plan assets recorded at each fair value hierarchy level as determined in accordance with the valuation techniques described in Note 17: U.S. VEBA I and VEBA II Trusts Master Trust Total Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 (in millions) December 31, 2015 Cash and cash equivalents $ 3 $ 3 $ — $ — $ — $ — $ — $ — Equity securities 24 — 24 — 15 15 — — Fixed income securities 14 — 14 — 26 26 — — Other investments — — — — 5 — — 5 Total $ 41 $ 3 $ 38 $ — $ 46 $ 41 $ — $ 5 December 31, 2014 Equity securities $ 25 $ — $ 25 $ — $ 20 $ 20 $ — $ — Fixed income securities 21 — 21 — 22 22 — — Other investments — — — — 4 — — 4 Total $ 46 $ — $ 46 $ — $ 46 $ 42 $ — $ 4 The following presents changes in Level 3 assets that are measured at fair value on a recurring basis using significant unobservable inputs: U.S. 2015 2014 (in millions) Fair value, beginning of period $ 4 $ 4 Unrealized gain included in other comprehensive income 1 — Fair value, end of period $ 5 $ 4 Other Post-Retirement Benefit Plans — Payments and Receipts We expect to make future benefit payments, which reflect expected future service, as appropriate. As our plans provide benefits that are actuarially equivalent to the benefits received by Medicare recipients, we expect to receive future subsidies under Medicare Part D. The following benefit payments and subsidies are expected to be paid (or received) over each of the next five years and thereafter. Benefit Payments Medicare Part D Subsidy Receipts U.S. Canada U.S. (in millions) 2016 $ 16 $ 4 $ (1 ) 2017 15 4 (1 ) 2018 15 4 (1 ) 2019 15 4 (1 ) 2020 14 5 (1 ) 2021 – 2025 61 26 (5 ) We anticipate making no contributions to the U.S. plans and $4 million to the Canadian plans in 2016 . Retirement/Savings Plan In addition to the retirement plans discussed above, we also have defined contribution employee savings plans available to both U.S. and Canadian employees. Employees may participate in a matching contribution where we match a certain percentage of before-tax employee contributions of up to 6% of eligible pay per pay period for U.S. employees and up to 5% of eligible pay per pay period for Canadian employees. We expensed pre-tax employer matching contributions of $15 million in 2015 and 2014 , and $14 million in 2013 for U.S employees, and $13 million in 2015 , 2014 and 2013 for Canadian employees.

Consolidating Financial Informa

Consolidating Financial Information	12 Months Ended
	Dec. 31, 2015
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Consolidating Financial Information	Condensed Consolidating Financial Information Spectra Energy Corp has agreed to fully and unconditionally guarantee the payment of principal and interest under all series of notes outstanding under the Senior Indenture of Spectra Capital, a 100%-owned, consolidated subsidiary. In accordance with the Securities and Exchange Commission rules, the following condensed consolidating financial information is presented. The information shown for Spectra Energy Corp and Spectra Capital is presented utilizing the equity method of accounting for investments in subsidiaries, as required. The non-guarantor subsidiaries column represents all consolidated subsidiaries of Spectra Capital. This information should be read in conjunction with our accompanying Consolidated Financial Statements and notes thereto. Spectra Energy Corp Condensed Consolidating Statement of Operations Year Ended December 31, 2015 (In millions) Spectra Energy Corp Spectra Capital Non-Guarantor Subsidiaries Eliminations Consolidated Total operating revenues $ — $ — $ 5,237 $ (3 ) $ 5,234 Total operating expenses 6 (4 ) 3,802 (3 ) 3,801 Operating income (loss) (6 ) 4 1,435 — 1,433 Loss from equity investments — — (290 ) — (290 ) Equity in earnings of consolidated subsidiaries 161 573 — (734 ) — Other income and expenses, net — 1 113 — 114 Interest expense — 244 392 — 636 Earnings before income taxes 155 334 866 (734 ) 621 Income tax expense (benefit) (41 ) 173 29 — 161 Net income 196 161 837 (734 ) 460 Net income—noncontrolling interests — — 264 — 264 Net income—controlling interests $ 196 $ 161 $ 573 $ (734 ) $ 196 Spectra Energy Corp Condensed Consolidating Statement of Operations Year Ended December 31, 2014 (In millions) Spectra Energy Corp Spectra Capital Non-Guarantor Subsidiaries Eliminations Consolidated Total operating revenues $ — $ — $ 5,906 $ (3 ) $ 5,903 Total operating expenses 6 1 3,975 (3 ) 3,979 Operating income (loss) (6 ) (1 ) 1,931 — 1,924 Earnings from equity investments — — 361 — 361 Equity in earnings of consolidated subsidiaries 1,054 1,651 — (2,705 ) — Other income and expenses, net (2 ) 9 52 — 59 Interest expense — 253 426 — 679 Earnings before income taxes 1,046 1,406 1,918 (2,705 ) 1,665 Income tax expense (benefit) (36 ) 352 66 — 382 Net income 1,082 1,054 1,852 (2,705 ) 1,283 Net income—noncontrolling interests — — 201 — 201 Net income—controlling interests $ 1,082 $ 1,054 $ 1,651 $ (2,705 ) $ 1,082 Spectra Energy Corp Condensed Consolidating Statement of Operations Year Ended December 31, 2013 (In millions) Spectra Energy Corp Spectra Capital Non-Guarantor Subsidiaries Eliminations Consolidated Total operating revenues $ — $ — $ 5,521 $ (3 ) $ 5,518 Total operating expenses 8 3 3,844 (3 ) 3,852 Operating income (loss) (8 ) (3 ) 1,677 — 1,666 Earnings from equity investments — — 445 — 445 Equity in earnings of consolidated subsidiaries 1,015 1,649 — (2,664 ) — Other income and expenses, net 1 15 108 — 124 Interest expense — 216 441 — 657 Earnings before income taxes 1,008 1,445 1,789 (2,664 ) 1,578 Income tax expense (benefit) (30 ) 430 19 — 419 Net income 1,038 1,015 1,770 (2,664 ) 1,159 Net income—noncontrolling interests — — 121 — 121 Net income—controlling interests $ 1,038 $ 1,015 $ 1,649 $ (2,664 ) $ 1,038 Spectra Energy Corp Condensed Consolidating Statements of Comprehensive Income (In millions) Spectra Energy Corp Spectra Capital Non-Guarantor Subsidiaries Eliminations Consolidated Year Ended December 31, 2015 Net income $ 196 $ 161 $ 837 $ (734 ) $ 460 Other comprehensive income (loss) (14 ) 1 (931 ) — (944 ) Total comprehensive income (loss), net of tax 182 162 (94 ) (734 ) (484 ) Less: comprehensive income—noncontrolling interests — — 251 — 251 Comprehensive income (loss)—controlling interests $ 182 $ 162 $ (345 ) $ (734 ) $ (735 ) Year Ended December 31, 2014 Net income $ 1,082 $ 1,054 $ 1,852 $ (2,705 ) $ 1,283 Other comprehensive income (loss) 9 1 (596 ) — (586 ) Total comprehensive income, net of tax 1,091 1,055 1,256 (2,705 ) 697 Less: comprehensive income—noncontrolling interests — — 194 — 194 Comprehensive income—controlling interests $ 1,091 $ 1,055 $ 1,062 $ (2,705 ) $ 503 Year Ended December 31, 2013 Net income $ 1,038 $ 1,015 $ 1,770 $ (2,664 ) $ 1,159 Other comprehensive income (loss) 69 2 (346 ) — (275 ) Total comprehensive income, net of tax 1,107 1,017 1,424 (2,664 ) 884 Less: comprehensive income—noncontrolling interests — — 114 — 114 Comprehensive income—controlling interests $ 1,107 $ 1,017 $ 1,310 $ (2,664 ) $ 770 Spectra Energy Corp Condensed Consolidating Balance Sheet December 31, 2015 (In millions) Spectra Energy Corp Spectra Capital Non-Guarantor Subsidiaries Eliminations Consolidated Cash and cash equivalents $ — $ 1 $ 212 $ — $ 213 Receivables—consolidated subsidiaries 15 6 13 (34 ) — Notes receivable—current—consolidated subsidiaries — — 387 (387 ) — Receivables—other 2 — 804 — 806 Other current assets 25 — 604 — 629 Total current assets 42 7 2,020 (421 ) 1,648 Investments in and loans to unconsolidated affiliates — — 2,592 — 2,592 Investments in consolidated subsidiaries 13,919 19,161 — (33,080 ) — Advances receivable—consolidated subsidiaries — 5,273 1,326 (6,599 ) — Notes receivable—consolidated subsidiaries — — 2,800 (2,800 ) — Goodwill — — 4,154 — 4,154 Other assets 41 27 242 — 310 Net property, plant and equipment — — 22,918 — 22,918 Regulatory assets and deferred debits 3 3 1,295 — 1,301 Total Assets $ 14,005 $ 24,471 $ 37,347 $ (42,900 ) $ 32,923 Accounts payable $ 2 $ 3 $ 506 $ — $ 511 Accounts payable—consolidated subsidiaries 4 28 2 (34 ) — Commercial paper — 481 631 — 1,112 Short-term borrowings—consolidated subsidiaries — 387 — (387 ) — Taxes accrued 5 — 73 — 78 Current maturities of long-term debt — — 652 — 652 Other current liabilities 102 48 889 — 1,039 Total current liabilities 113 947 2,753 (421 ) 3,392 Long-term debt — 2,891 10,001 — 12,892 Advances payable—consolidated subsidiaries 6,599 — — (6,599 ) — Notes payable—consolidated subsidiaries — 2,800 — (2,800 ) — Deferred credits and other liabilities 767 3,914 2,087 — 6,768 Preferred stock of subsidiaries — — 339 — 339 Equity Controlling interests 6,526 13,919 19,161 (33,080 ) 6,526 Noncontrolling interests — — 3,006 — 3,006 Total equity 6,526 13,919 22,167 (33,080 ) 9,532 Total Liabilities and Equity $ 14,005 $ 24,471 $ 37,347 $ (42,900 ) $ 32,923 Spectra Energy Corp Condensed Consolidating Balance Sheet December 31, 2014 (In millions) Spectra Energy Corp Spectra Capital Non-Guarantor Subsidiaries Eliminations Consolidated Cash and cash equivalents $ — $ 1 $ 214 $ — $ 215 Receivables—consolidated subsidiaries 18 — 11 (29 ) — Receivables—other 2 — 1,334 — 1,336 Other current assets 71 2 708 — 781 Total current assets 91 3 2,267 (29 ) 2,332 Investments in and loans to unconsolidated affiliates — — 2,966 — 2,966 Investments in consolidated subsidiaries 14,531 20,562 — (35,093 ) — Advances receivable—consolidated subsidiaries — 4,683 898 (5,581 ) — Notes receivable—consolidated subsidiaries — — 3,198 (3,198 ) — Goodwill — — 4,714 — 4,714 Other assets 38 22 267 — 327 Net property, plant and equipment — — 22,307 — 22,307 Regulatory assets and deferred debits 4 5 1,343 — 1,352 Total Assets $ 14,664 $ 25,275 $ 37,960 $ (43,901 ) $ 33,998 Accounts payable $ 3 $ — $ 455 $ — $ 458 Accounts payable—consolidated subsidiaries — 17 12 (29 ) — Commercial paper — 398 1,185 — 1,583 Short-term borrowings—consolidated subsidiaries — 398 — (398 ) — Taxes accrued 5 — 86 — 91 Current maturities of long-term debt — — 327 — 327 Other current liabilities 96 54 1,200 — 1,350 Total current liabilities 104 867 3,265 (427 ) 3,809 Long-term debt — 2,890 9,837 — 12,727 Advances payable—consolidated subsidiaries 5,581 — — (5,581 ) — Notes payable—consolidated subsidiaries — 2,800 — (2,800 ) — Deferred credits and other liabilities 819 4,187 1,800 — 6,806 Preferred stock of subsidiaries — — 258 — 258 Equity Controlling interests 8,160 14,531 20,562 (35,093 ) 8,160 Noncontrolling interests — — 2,238 — 2,238 Total equity 8,160 14,531 22,800 (35,093 ) 10,398 Total Liabilities and Equity $ 14,664 $ 25,275 $ 37,960 $ (43,901 ) $ 33,998 Spectra Energy Corp Condensed Consolidating Statement of Cash Flows Year Ended December 31, 2015 (In millions) Spectra Energy Corp Spectra Capital Non-Guarantor Subsidiaries Eliminations Consolidated CASH FLOWS FROM OPERATING ACTIVITIES Net income $ 196 $ 161 $ 837 $ (734 ) $ 460 Adjustments to reconcile net income to net cash provided by (used in) operating activities: Depreciation and amortization — — 778 — 778 Impairment charges — — 349 — 349 Loss from equity investments — — 290 — 290 Equity in earnings of consolidated subsidiaries (161 ) (573 ) — 734 — Distributions from equity investments — — 161 — 161 Other 187 33 (11 ) — 209 Net cash provided by (used in) operating activities 222 (379 ) 2,404 — 2,247 CASH FLOWS FROM INVESTING ACTIVITIES Capital expenditures — — (2,848 ) — (2,848 ) Investments in and loans to unconsolidated affiliates — — (124 ) — (124 ) Purchases of held-to-maturity securities — — (668 ) — (668 ) Proceeds from sales and maturities of held-to-maturity securities — — 695 — 695 Purchases of available-for-sale securities — — (95 ) — (95 ) Proceeds from sales and maturities of available-for-sale securities — — 87 — 87 Distributions from equity investments — — 451 — 451 Advances (to) from affiliates (240 ) 296 — (56 ) — Loan to equity investment — — (248 ) — (248 ) Other changes in restricted funds — — (33 ) — (33 ) Other — — 1 — 1 Net cash provided by (used in) investing activities (240 ) 296 (2,782 ) (56 ) (2,782 ) CASH FLOWS FROM FINANCING ACTIVITIES Proceeds from the issuance of long-term debt — — 1,585 — 1,585 Payments for the redemption of long-term debt — — (285 ) — (285 ) Net increase (decrease) in commercial paper — 83 (522 ) — (439 ) Distributions to noncontrolling interests — — (198 ) — (198 ) Contributions from noncontrolling interests — — 248 — 248 Proceeds from the issuance of SEP common units — — 546 — 546 Proceeds from the issuance of Westcoast preferred stock — — 84 — 84 Dividends paid on common stock (996 ) — — — (996 ) Distributions and advances from (to) affiliates 1,018 — (1,074 ) 56 — Other (4 ) — (1 ) — (5 ) Net cash provided by financing activities 18 83 383 56 540 Effect of exchange rate changes on cash — — (7 ) — (7 ) Net decrease in cash and cash equivalents — — (2 ) — (2 ) Cash and cash equivalents at beginning of period — 1 214 — 215 Cash and cash equivalents at end of period $ — $ 1 $ 212 $ — $ 213 Spectra Energy Corp Condensed Consolidating Statement of Cash Flows Year Ended December 31, 2014 (In millions) Spectra Energy Corp Spectra Capital Non-Guarantor Subsidiaries Eliminations Consolidated CASH FLOWS FROM OPERATING ACTIVITIES Net income $ 1,082 $ 1,054 $ 1,852 $ (2,705 ) $ 1,283 Adjustments to reconcile net income to net cash provided by (used in) operating activities: Depreciation and amortization — — 809 — 809 Earnings from equity investments — — (361 ) — (361 ) Equity in earnings of consolidated subsidiaries (1,054 ) (1,651 ) — 2,705 — Distributions from equity investments — — 380 — 380 Other 14 304 (208 ) — 110 Net cash provided by (used in) operating activities 42 (293 ) 2,472 — 2,221 CASH FLOWS FROM INVESTING ACTIVITIES Capital expenditures — — (2,028 ) — (2,028 ) Investments in and loans to unconsolidated affiliates — — (259 ) — (259 ) Purchases of held-to-maturity securities — — (790 ) — (790 ) Proceeds from sales and maturities of held-to-maturity securities — — 815 — 815 Purchases of available-for-sale securities — — (13 ) — (13 ) Proceeds from sales and maturities of available-for-sale securities — — 7 — 7 Distributions from equity investments — — 266 — 266 Advances from affiliates 92 495 — (587 ) — Other changes in restricted funds — — (1 ) — (1 ) Net cash provided by (used in) investing activities 92 495 (2,003 ) (587 ) (2,003 ) CASH FLOWS FROM FINANCING ACTIVITIES Proceeds from the issuance of long-term debt — 300 728 — 1,028 Payments for the redemption of long-term debt — (557 ) (627 ) — (1,184 ) Net increase in commercial paper — 54 520 — 574 Distributions to noncontrolling interests — — (175 ) — (175 ) Contributions from noncontrolling interests — — 145 — 145 Proceeds from the issuance of SEP common units — — 327 — 327 Dividends paid on common stock (925 ) — — — (925 ) Distributions and advances from (to) affiliates 777 (10 ) (1,354 ) 587 — Other 14 — (3 ) — 11 Net cash used in financing activities (134 ) (213 ) (439 ) 587 (199 ) Effect of exchange rate changes on cash — — (5 ) — (5 ) Net increase (decrease) in cash and cash equivalents — (11 ) 25 — 14 Cash and cash equivalents at beginning of period — 12 189 — 201 Cash and cash equivalents at end of period $ — $ 1 $ 214 $ — $ 215 Spectra Energy Corp Condensed Consolidating Statement of Cash Flows Year Ended December 31, 2013 (In millions) Spectra Energy Corp Spectra Capital (a) Non-Guarantor Subsidiaries (a) Eliminations Consolidated CASH FLOWS FROM OPERATING ACTIVITIES Net income $ 1,038 $ 1,015 $ 1,770 $ (2,664 ) $ 1,159 Adjustments to reconcile net income to net cash provided by (used in) operating activities: Depreciation and amortization — — 787 — 787 Earnings from equity investments — — (445 ) — (445 ) Equity in earnings of consolidated subsidiaries (1,015 ) (1,649 ) — 2,664 — Distributions from equity investments — — 324 — 324 Other (2 ) 478 (271 ) — 205 Net cash provided by (used in) operating activities 21 (156 ) 2,165 — 2,030 CASH FLOWS FROM INVESTING ACTIVITIES Capital expenditures — — (1,947 ) — (1,947 ) Investments in and loans to unconsolidated affiliates — — (312 ) — (312 ) Acquisitions, net of cash acquired — — (1,254 ) — (1,254 ) Purchases of held-to-maturity securities — — (985 ) — (985 ) Proceeds from sales and maturities of held-to-maturity securities — — 1,023 — 1,023 Purchases of available-for-sale securities — — (5,878 ) — (5,878 ) Proceeds from sales and maturities of available-for-sale securities — — 6,024 — 6,024 Distributions from equity investments — — 87 — 87 Advances to affiliates (75 ) (1,856 ) — 1,931 — Loan to equity investment — — (71 ) — (71 ) Repayment of loan to equity investment — 71 — — 71 Other changes in restricted funds — — 2 — 2 Other — — 4 — 4 Net cash used in investing activities (75 ) (1,785 ) (3,307 ) 1,931 (3,236 ) CASH FLOWS FROM FINANCING ACTIVITIES Proceeds from the issuance of long-term debt — 1,848 2,524 — 4,372 Payments for the redemption of long-term debt — (1,944 ) (195 ) — (2,139 ) Net decrease in commercial paper — (170 ) (36 ) — (206 ) Net increase in short-term borrowings - consolidated subsidiaries — (497 ) — 497 — Distributions to noncontrolling interests — — (144 ) — (144 ) Contributions from noncontrolling interests — — 23 — 23 Proceeds from the issuance of SEP common units — — 214 — 214 Dividends paid on common stock (821 ) — — — (821 ) Distributions and advances from (to) affiliates 847 2,718 (1,137 ) (2,428 ) — Other 28 (5 ) (6 ) — 17 Net cash provided by financing activities 54 1,950 1,243 (1,931 ) 1,316 Effect of exchange rate changes on cash — — (3 ) — (3 ) Net increase in cash and cash equivalents — 9 98 — 107 Cash and cash equivalents at beginning of period — 3 91 — 94 Cash and cash equivalents at end of period $ — $ 12 $ 189 $ — $ 201 ____________ (a) Excludes the effects of $3,869 million of non-cash equitizations of advances receivable owed to Spectra Capital.

Quarterly Financial Data (Unaud

Quarterly Financial Data (Unaudited)	12 Months Ended
	Dec. 31, 2015
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Data (Unaudited)	Quarterly Financial Data (Unaudited) First Quarter Second Quarter Third Quarter Fourth Quarter Total (in millions, except per share amounts) 2015 Operating revenues $ 1,623 $ 1,192 $ 1,103 $ 1,316 $ 5,234 Operating income 541 406 389 97 1,433 Net income (loss) 325 80 243 (188 ) 460 Net income (loss)—controlling interests 267 18 174 (263 ) 196 Earnings (loss) per share (a) Basic and diluted 0.40 0.03 0.26 (0.39 ) 0.29 2014 Operating revenues $ 1,843 $ 1,253 $ 1,207 $ 1,600 $ 5,903 Operating income 639 338 382 565 1,924 Net income 467 188 254 374 1,283 Net income—controlling interests 419 146 201 316 1,082 Earnings per share (a) Basic 0.63 0.22 0.30 0.47 1.61 Diluted 0.62 0.22 0.30 0.47 1.61 ___________ (a) Quarterly earnings-per-share amounts are stand-alone calculations and may not be additive to full-year amounts due to rounding. Unusual or Infrequent Items Due to the significant downturn in commodity prices, DCP Midstream performed a goodwill impairment test and other asset impairment tests in 2015. The impairment tests resulted in DCP Midstream’s recognition of a $460 million goodwill impairment and $342 million in other asset impairments, net of tax, which reduced our equity earnings from DCP Midstream by $231 million after-tax for 2015. Due to the asset impairment recognized by DCP Midstream, we assessed our equity investment in DCP Midstream and determined that our equity investment in DCP Midstream was not impaired. During the fourth quarter of 2015, we recorded goodwill impairments associated with the acquisition of Westcoast in 2002 for BC Field Services and the Empress NGL Operations, which impacted net income by $270 million and $63 million , respectively. The impairments are included in Impairment of Goodwill and Other on the Consolidated Statement of Operations. See Note 11 for further discussion.

SCHEDULE II-VALUATION AND QUALI

SCHEDULE II-VALUATION AND QUALIFYING ACCOUNTS AND RESERVES	12 Months Ended
	Dec. 31, 2015
Valuation and Qualifying Accounts [Abstract]
SCHEDULE II-VALUATION AND QUALIFYING ACCOUNTS AND RESERVES	SPECTRA ENERGY CORP SCHEDULE II—VALUATION AND QUALIFYING ACCOUNTS AND RESERVES Balance at Beginning of Period Additions: Deductions (a) Balance at End of Period Charged to Expense Charged to Other Accounts (in millions) December 31, 2015 Allowance for doubtful accounts $ 11 $ 7 $ — $ 7 $ 11 Other (b) 113 36 24 39 134 $ 124 $ 43 $ 24 $ 46 $ 145 December 31, 2014 Allowance for doubtful accounts $ 10 $ 6 $ — $ 5 $ 11 Other (b) 164 29 — 80 113 $ 174 $ 35 $ — $ 85 $ 124 December 31, 2013 Allowance for doubtful accounts $ 13 $ 7 $ — $ 10 $ 10 Other (b) 181 21 — 38 164 $ 194 $ 28 $ — $ 48 $ 174 _________ (a) Principally cash payments and reserve reversals. (b) Principally income tax, insurance-related, litigation and other reserves, included primarily in Deferred Credits and Other Liabilities—Regulatory and Other on the Consolidated Balance Sheets.

Summary of Operations and Sig35

Summary of Operations and Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2015
Accounting Policies [Abstract]
Use of Estimates	Use of Estimates. To conform with generally accepted accounting principles (GAAP) in the U.S., we make estimates and assumptions that affect the amounts reported in the Consolidated Financial Statements and Notes to Consolidated Financial Statements. Although these estimates are based on our best available knowledge at the time, actual results could differ.
Fair Value Measurements	Fair Value Measurements. We measure the fair value of financial assets and liabilities by maximizing the use of observable inputs and minimizing the use of unobservable inputs. Fair value is the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date.
Cost-Based Regulation	Cost-Based Regulation. The economic effects of regulation can result in a regulated company recording assets for costs that have been or are expected to be approved for recovery from customers or recording liabilities for amounts that are expected to be returned to customers or for instances where the regulator provides current rates that are intended to recover costs that are expected to be incurred in the future. Accordingly, we record assets and liabilities that result from the regulated ratemaking process that may not be recorded under GAAP for non-regulated entities. We continually assess whether regulatory assets are probable of future recovery by considering factors such as applicable regulatory changes and recent rate orders to other regulated entities. Based on this assessment, we believe our existing regulatory assets are probable of recovery. These regulatory assets and liabilities are mostly classified in the Consolidated Balance Sheets as Regulatory Assets and Deferred Debits, and Deferred Credits and Other Liabilities—Regulatory and Other. We evaluate our regulated assets, and consider factors such as regulatory changes and the effect of competition. If cost-based regulation ends or competition increases, we may have to reduce our asset balances to reflect a market basis less than cost and write-off the associated regulatory assets and liabilities. See Note 5 for further discussion.
Foreign Currency Translation	Foreign Currency Translation. The Canadian dollar has been determined to be the functional currency of our Canadian operations based on an assessment of the economic circumstances of those operations. Assets and liabilities of our Canadian operations are translated into U.S. dollars at current exchange rates. Translation adjustments resulting from fluctuations in exchange rates are included as a separate component of Other Comprehensive Income on the Consolidated Statements of Comprehensive Income. Revenue and expense accounts of these operations are translated at average monthly exchange rates prevailing during the periods. Gains and losses arising from transactions denominated in currencies other than the functional currency are included in the results of operations of the period in which they occur. Foreign currency transaction losses totaled $ 6 million in 2015 , and gains totaled $3 million in 2014 and $1 million in 2013 , and are included in Other Income and Expenses, Net on the Consolidated Statements of Operations. Deferred U.S. taxes related to translation gains and losses have not been provided on those Canadian operations where we expect the earnings to be indefinitely reinvested.
Revenue Recognition	Revenue Recognition. Revenues from the transmission, storage, processing, distribution and sales of natural gas, from the sales of NGLs and from the transportation and storage of crude oil are generally recognized when either the service is provided or the product is delivered. Revenues related to these services provided or products delivered but not yet billed are estimated each month. These estimates are generally based on contract data, regulatory information, estimated distribution usage based on historical data adjusted for heating degree days, commodity prices and preliminary throughput and allocation measurements. Final bills for the current month are billed and collected in the following month. Differences between actual and estimated unbilled revenues are immaterial. There were no customers accounting for 10% or more of consolidated revenues during 2015 , 2014 or 2013 . We also have certain customer contracts with billed amounts that decline annually over the terms of the contracts. Differences between the amounts billed and recognized are deferred on the Consolidated Balance Sheets.
Stock-Based Compensation	Stock-Based Compensation. For employee awards, equity-classified and liability-classified stock-based compensation cost is measured at the grant date based on the fair value of the award. Liability-classified stock-based compensation cost is remeasured at each reporting period until settlement. Related compensation expense is recognized over the requisite service period, which generally begins on the date the award is granted through the earlier of the date the award vests, the date the employee becomes retirement-eligible or the date the market or performance condition of the award is met. Awards, including stock options, granted to employees that are retirement-eligible are deemed to have vested immediately upon issuance, and therefore, compensation cost for those awards is recognized on the date such awards are granted. See Note 22 for further discussion.
Pension and Other Post-Retirement Benefits	Pension and Other Post-Retirement Benefits. We fully recognize the overfunded or underfunded status of our consolidating subsidiaries’ pension and other post-retirement benefit plans as Investments and Other Assets—Other, Current Liabilities—Other or Deferred Credits and Other Liabilities—Regulatory and Other in the Consolidated Balance Sheets, as appropriate. A plan’s funded status is the difference between the fair value of plan assets and the plan’s projected benefit obligation. We record deferred plan costs and income (unrecognized losses and gains, and unrecognized prior service costs and credits) in Accumulated Other Comprehensive Income (AOCI) on the Consolidated Statements of Equity, until they are amortized and recognized as a component of benefit expense within Operating, Maintenance and Other in the Consolidated Statements of Operations. See Note 23 for further discussion.
Allowance for Funds Used During Construction (AFUDC)	Allowance for Funds Used During Construction (AFUDC). AFUDC, which represents the estimated debt and equity costs of capital funds necessary to finance the construction of certain new regulated facilities, consists of two components, an equity component and an interest expense component. The equity component is a non-cash item. After construction is completed, we are permitted to recover these costs through inclusion in the rate base and in the depreciation provision. AFUDC is capitalized as a component of Property, Plant and Equipment—Cost in the Consolidated Balance Sheets, with offsetting credits to the Consolidated Statements of Operations through Other Income and Expenses, Net for the equity component and Interest Expense for the interest expense component. The total amount of AFUDC included in the Consolidated Statements of Operations was $143 million in 2015 (an equity component of $111 million and an interest expense component of $32 million ), $72 million in 2014 (an equity component of $53 million and an interest expense component of $19 million ) and $155 million in 2013 (an equity component of $105 million and an interest expense component of $50 million ).
Income Taxes	Income Taxes. Deferred income taxes are recognized for differences between the financial reporting and tax bases of assets and liabilities at enacted statutory tax rates in effect for the years in which the differences are expected to reverse. The effect on deferred taxes of a change in tax rates is recognized in income in the period that includes the enactment date. Actual income taxes could vary from these estimates due to future changes in income tax law or results from the final review of tax returns by federal, state or foreign tax authorities. Financial statement effects on tax positions are recognized in the period in which it is more likely than not that the position will be sustained upon examination, the position is effectively settled or when the statute of limitations to challenge the position has expired. Interest and penalties related to unrecognized tax benefits are recorded as interest expense and other expense, respectively.
Cash and Cash Equivalents	Cash and Cash Equivalents. Highly liquid investments with original maturities of three months or less at the date of acquisition are considered cash equivalents, except for the investments that were pledged as collateral against long-term debt as discussed in Note 15 and any investments that are considered restricted funds
Inventory	Inventory. Inventory consists of natural gas and NGLs held in storage for transmission and processing, and also includes materials and supplies. Natural gas inventories primarily relate to the Distribution segment in Canada and are valued at costs approved by the regulator, the Ontario Energy Board (OEB). The difference between the approved price and the actual cost of gas purchased is recorded in either Fuel Tracker or Other Current Liabilities, as appropriate, for future disposition with customers, subject to approval by the OEB. The remaining inventory is recorded at the lower of cost or market, primarily using average cost.
Natural Gas Imbalances	Natural Gas Imbalances. The Consolidated Balance Sheets include in-kind balances as a result of differences in gas volumes received and delivered for customers. Since settlement of certain imbalances is in-kind, changes in their balances do not have an effect on our Consolidated Statements of Cash Flows. Receivables include $291 million and $642 million as of December 31, 2015 and December 31, 2014, respectively, and Other Current Liabilities include $287 million and $634 million as of December 31, 2015 and December 31, 2014, respectively, related to gas imbalances. Most natural gas volumes owed to or by us are valued at natural gas market index prices as of the balance sheet dates.
Fair Value Measurement, Policy	Level 1 Level 1 valuations represent quoted unadjusted prices for identical instruments in active markets. Level 2 Valuation Techniques 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 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. In addition, credit default swap rates are used to develop the adjustment for credit risk embedded in our positions. We believe that since some of the inputs and assumptions for the calculations of fair value are derived from observable market data, a Level 2 classification is appropriate. Level 3 Valuation Techniques 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. The derivative financial instruments reported in Level 3 at December 31, 2015 consist of NGL revenue swap contracts related to the Empress assets in Western Canada Transmission & Processing. As of December 31, 2015 , we reported certain of our NGL basis swaps at fair value using Level 3 inputs due to such derivatives not having observable market prices for substantially the full term of the derivative asset or liability. For valuations that include both observable and unobservable inputs, if the unobservable input is determined to be significant to the overall inputs, the entire valuation is categorized in Level 3. This includes derivatives valued using indicative price quotations whose contract length extends into unobservable periods. The fair value of these NGL basis swaps is determined using a discounted cash flow valuation technique based on a forward commodity basis curve. For these derivatives, the primary input to the valuation model is the forward commodity basis curve, which is based on observable or public data sources and extrapolated when observable prices are not available. The significant unobservable inputs used in the fair value measurements of our Level 3 derivatives are the forward natural gas basis curves, for which a significant portion of the derivative’s term is beyond available forward pricing. At December 31, 2015 , a 10¢ per gallon movement in underlying forward NGL prices would affect the estimated fair value of our NGL derivatives by $15 million . This calculated amount does not take into account any other changes to the fair value measurement calculation.
Risk Management and Hedging Activities and Financial Instruments	Risk Management and Hedging Activities and Financial Instruments. Currently, our use of derivative instruments is primarily limited to interest rate positions and commodity pricing. All derivative instruments that do not qualify for the normal purchases and normal sales exception are recorded on the Consolidated Balance Sheets at fair value. Cash inflows and outflows related to derivative instruments are a component of Cash Flows From Operating Activities in the accompanying Consolidated Statements of Cash Flows. Cash Flow and Fair Value Hedges. Qualifying energy commodity and other derivatives may be designated as either a hedge of a forecasted transaction (cash flow hedge) or a hedge of a recognized asset, liability or firm commitment (fair value hedge). For all hedge contracts, we prepare documentation of the hedge in accordance with accounting standards and assess whether the hedge contract is highly effective using regression analysis, both at inception and on a quarterly basis, in offsetting changes in cash flows or fair values of hedged items. We document hedging activity by instrument type (futures or swaps) and risk management strategy (commodity price risk or interest rate risk). For derivatives designated as fair value hedges, we recognize the gain or loss on the derivative instrument, as well as the offsetting gain or loss on the hedged item in earnings, to the extent effective, in the current period. In the event the hedge is not effective, there is no offsetting gain or loss recognized in earnings for the hedged item. All derivatives designated and accounted for as hedges are classified in the same category as the item being hedged in the Consolidated Statements of Cash Flows. All components of each derivative gain or loss are included in the assessment of hedge effectiveness.
Investments	Investments. We may actively invest a portion of our available cash and restricted funds balances in various financial instruments, including taxable or tax-exempt debt securities. In addition, we invest in short-term money market securities, some of which are restricted due to debt collateral or insurance requirements. Investments in available-for-sale (AFS) securities are carried at fair value and investments in held-to-maturity (HTM) securities are carried at cost. Investments in money market securities are also accounted for at fair value. Realized gains and losses, and dividend and interest income related to these securities, including any amortization of discounts or premiums arising at acquisition, are included in earnings. The costs of securities sold are determined using the specific identification method. Purchases and sales of AFS and HTM securities are presented on a gross basis within Cash Flows From Investing Activities in the accompanying Consolidated Statements of Cash Flows.
Goodwill	Goodwill. We perform our goodwill impairment test annually and evaluate goodwill when events or changes in circumstances indicate that its carrying value may not be recoverable. In 2015 we recorded a goodwill impairment charge of $270 million for British Columbia (BC) Field Services and $63 million for Empress NGL operations associated with the Westcoast Energy, Inc. (Westcoast) acquisition in 2002. No impairments of goodwill were recorded in 2014 or 2013 . See Note 11 for further discussion. We perform our annual review for goodwill impairment at the reporting unit level, which is identified by assessing whether the components of our operating segments constitute businesses for which discrete financial information is available, whether segment management regularly reviews the operating results of those components and whether the economic and regulatory characteristics are similar. We determined that our reporting units are equivalent to our reportable segments, except for the reporting units of our Western Canada Transmission & Processing and Spectra Energy Partners reportable segments, which are one level below. As permitted under accounting guidance on testing goodwill for impairment, we perform either a qualitative assessment or a quantitative assessment of each of our reporting units based on management’s judgment. With respect to our qualitative assessments, we consider events and circumstances specific to us, such as macroeconomic conditions, industry and market considerations, cost factors and overall financial performance, when evaluating whether it is more likely than not that the fair values of our reporting units are less than their respective carrying amounts. In connection with our quantitative assessments, we primarily use a discounted cash flow analysis to determine the fair values of those reporting units. Key assumptions in the determination of fair value included the use of an appropriate discount rate and estimated future cash flows. In estimating cash flows, we incorporate expected long-term growth rates in key markets served by our operations, regulatory stability, the ability to renew contracts, commodity prices (where appropriate) and foreign currency exchange rates, as well as other factors that affect our reporting units’ revenue, expense and capital expenditure projections. If the carrying amount of the reporting unit exceeds its fair value, a comparison of the fair value and carrying value of the goodwill of that reporting unit needs to be performed. If the carrying value of the goodwill of a reporting unit exceeds the implied fair value of that goodwill, an impairment loss is recognized in an amount equal to the excess. Additional impairment tests are performed between the annual reviews if events or changes in circumstances make it more likely than not that the fair value of a reporting unit is below its carrying amount.
Property, Plant and Equipment	Property, Plant and Equipment. Property, plant and equipment is stated at historical cost less accumulated depreciation. We capitalize all construction-related direct labor and material costs, as well as indirect construction costs. Indirect costs include general engineering, taxes and the cost of funds used during construction. The costs of renewals and betterments that extend the useful life or increase the expected output of property, plant and equipment are also capitalized. The costs of repairs, replacements and major maintenance projects that do not extend the useful life or increase the expected output of property, plant and equipment are expensed as incurred. Depreciation is generally computed over the asset’s estimated useful life using the straight-line method. When we retire regulated property, plant and equipment, we charge the original cost plus the cost of retirement, less salvage value, to accumulated depreciation and amortization. When we sell entire regulated operating units or retire non-regulated properties, the cost is removed from the property account and the related accumulated depreciation and amortization accounts are reduced. Any gain or loss is recorded in earnings, unless otherwise required by the applicable regulatory body.
Preliminary Project Costs	Preliminary Project Costs. Project development costs, including expenditures for preliminary surveys, plans, investigations, environmental studies, regulatory applications and other costs incurred for the purpose of determining the feasibility of capital expansion projects, are capitalized for rate-regulated enterprises when it is determined that recovery of such costs through regulated revenues of the completed project is probable. Any inception-to-date costs of the project that were initially expensed are reversed and capitalized as Property, Plant and Equipment.
Long-Lived Asset Impairments	Long-Lived Asset Impairments. We evaluate whether long-lived assets, excluding goodwill, have been impaired when circumstances indicate the carrying value of those assets may not be recoverable. For such long-lived assets, an impairment exists when its carrying value exceeds the sum of estimates of the undiscounted cash flows expected to result from the use and eventual disposition of the asset. When alternative courses of action to recover the carrying amount of a long-lived asset are under consideration, a probability-weighted approach is used in developing estimates of future undiscounted cash flows. If the carrying value of the long-lived asset is not recoverable based on these estimated future undiscounted cash flows, an impairment loss is measured as the excess of the asset’s carrying value over its fair value, such that the asset’s carrying value is adjusted to its estimated fair value. We assess the fair value of long-lived assets using commonly accepted techniques and may use more than one source. Sources to determine fair value include, but are not limited to, recent third-party comparable sales, internally developed discounted cash flow analyses and analyses from outside advisors. Significant changes in market conditions resulting from events such as changes in natural gas available to our systems, the condition of an asset, a change in our intent to utilize the asset or a significant change in contracted revenues or regulatory recoveries would generally require us to reassess the cash flows related to the long-lived assets.
Asset Retirement Obligations	Asset Retirement Obligations. We recognize asset retirement obligations (AROs) for legal commitments associated with the retirement of long-lived assets that result from the acquisition, construction, development and/or normal use of the asset and conditional AROs in which the timing or method of settlement are conditional on a future event that may or may not be within our control. The fair value of a liability for an ARO is recognized in the period in which it is incurred if a reasonable estimate of fair value can be made and is added to the carrying amount of the associated asset. This additional carrying amount is depreciated over the estimated useful life of the asset.
Unamortized Debt Premium, Discount and Expense	Unamortized Debt Premium, Discount and Expense. Premiums, discounts and expenses incurred with the issuance of outstanding long-term debt are amortized over the terms of the debt issues. Any call premiums or unamortized expenses associated with refinancing higher-cost debt obligations to finance regulated assets and operations are amortized consistent with regulatory treatment of those items, where appropriate.
Environmental Expenditures	Environmental Expenditures. We expense environmental expenditures related to conditions caused by past operations that do not generate current or future revenues. Environmental expenditures related to operations that generate current or future revenues are expensed or capitalized, as appropriate. Undiscounted liabilities are recorded when the necessity for environmental remediation becomes probable and the costs can be reasonably estimated, or when other potential environmental liabilities are reasonably estimable and probable.
Captive Insurance Reserves	Captive Insurance Reserves. We have captive insurance subsidiaries which provide insurance coverage to our consolidated subsidiaries as well as certain equity affiliates, on a limited basis, for various business risks and losses, such as workers compensation, property, business interruption and general liability. Liabilities include provisions for estimated losses incurred but not yet reported, as well as provisions for known claims which have been estimated on a claims-incurred basis. Incurred but not yet reported reserve estimates involve the use of assumptions and are based upon historical loss experience, industry data and other actuarial assumptions. Reserve estimates are adjusted in future periods as actual losses differ from historical experience.
Guarantees	Guarantees. Upon issuance or material modification of a guarantee made by us, we recognize a liability for the estimated fair value of the obligation we assume under that guarantee, if any. Fair value is estimated using a probability-weighted approach. We reduce the obligation over the term of the guarantee or related contract in a systematic and rational method as risk is reduced under the obligation.
Accounting For Sales of Stock by a Subsidiary	Accounting For Sales of Stock by a Subsidiary. Sales of stock by a consolidated subsidiary are accounted for as equity transactions in those instances where a change in control does not take place.
Segment Reporting	Segment Reporting. Operating segments are components of an enterprise for which separate financial information is available and evaluated regularly by the chief operating decision maker (CODM) in deciding how to allocate resources and evaluate performance. Two or more operating segments may be aggregated into a single reportable segment provided certain criteria are met. There is no such aggregation within our defined business segments. A description of our reportable segments, consistent with how business results are reported internally to management, and the disclosure of segment information is presented in Note 4.
Consolidated Statements of Cash Flows	Consolidated Statements of Cash Flows. Cash flows from discontinued operations are combined with cash flows from continuing operations within operating, investing and financing cash flows. Cash received from insurance proceeds are classified depending on the activity that resulted in the insurance proceeds. For example, business interruption insurance proceeds are included as a component of operating activities while insurance proceeds from damaged property are included as a component of investing activities. With respect to cash overdrafts, book overdrafts are included within operating cash flows while bank overdrafts, if any, are included within financing cash flows.
Distributions from Unconsolidated Affiliates	Distributions from Equity Investments. We consider distributions received from equity investments which do not exceed cumulative equity in earnings subsequent to the date of investment to be a return on investment and classify these amounts as Cash Flows From Operating Activities within the accompanying Consolidated Statements of Cash Flows. Cumulative distributions received in excess of cumulative equity in earnings subsequent to the date of investment are considered to be a return of investment and are classified as Cash Flows From Investing Activities.
New Accounting Pronouncements	New Accounting Pronouncements. The following new Accounting Standards Updates (ASUs) were adopted during 2015 and the effect of such adoption has been presented in the accompanying Consolidated Financial Statements: In April 2014, the Financial Accounting Standards Board (FASB) issued ASU No. 2014-08, “ Presentation of Financial Statements (Topic 205) and Property, Plant, and Equipment (Topic 360): Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity.” This ASU revises the definition of discontinued operations by limiting discontinued operations reporting to disposals of components of an entity that represent strategic shifts that have or will have a major effect on an entity’s operations and financial results, removing the lack of continuing involvement criteria and requiring discontinued operations reporting for the disposal of an equity method investment that meets the definition of discontinued operations. The update also requires expanded disclosures for discontinued operations, and disclosure of pretax profit or loss of certain individually significant components of an entity that do not qualify for discontinued operations reporting. This ASU was effective for us on January 1, 2015 and did not have a material impact on our consolidated results of operations, financial position or cash flows. In April 2015, the FASB issued ASU No. 2015-03, “ Interest-Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs, ” which requires that debt issuance costs be presented in the balance sheet as a direct deduction from the carrying amount of the related debt liability, rather than as a deferred charge asset. We adopted this standard on December 31, 2015. The adoption of this ASU resulted in the retrospective adjustment of the December 31, 2014 Consolidated Balance Sheet, which resulted in the presentation of $42 million of debt issuance costs previously reported in Regulatory Assets and Deferred Debits as a reduction of Long-term Debt on our Consolidated Balance Sheet. In addition, $46 million of debt issuance costs are presented as a reduction of Long-term Debt on our December 31, 2015 Consolidated Balance Sheet. In November 2015, the FASB issued ASU No. 2015-17, “ Accounting for Income Taxes (Topic 740): Balance Sheet Classification of Deferred Taxes .” This ASU simplifies the balance sheet presentation of deferred income taxes by requiring deferred tax liabilities and assets be classified as noncurrent in a classified balance sheet. We adopted this standard on December 31, 2015 and applied it prospectively. The adoption of this ASU did not have a material impact on our consolidated results of operations, financial position, or cash flow. Pending. The following new accounting pronouncements have been issued but not yet adopted: In February 2015, the FASB issued ASU No. 2015-02, “Consolidation (Topic 810): Amendments to the Consolidation Analysis,” which makes changes to both the variable interest model and the voting model. These changes will require re-evaluation of certain entities for consolidation and will require us to revise our documentation regarding the consolidation or deconsolidation of such entities. This ASU is effective for us on January 1, 2016 and is not expected to have a material impact on our consolidated results of operations, financial position or cash flow. In July 2015, the FASB issued ASU No. 2015-11, “ Inventory (Topic 330): Simplifying the Measurement of Inventory, ” which simplifies the subsequent measurement of inventory by requiring inventory to be measured at the lower of cost and net realizable value. This ASU is effective for us January 1, 2016 and is not expected to have a material impact on our consolidated results of operations, financial position or cash flow. In July 2015, the FASB decided to defer the effective date of the revenue standard ASU No. 2014-09, “ Revenue from Contracts with Customers (Topic 606), ” for one year and to permit entities to early adopt the standard as of the original effective date. ASU No. 2014-09 supersedes the revenue recognition requirements of “ Revenue Recognition (Topic 605) ” and clarifies the principles of recognizing revenue. This ASU is effective for us January 1, 2018. We are currently evaluating this ASU and its potential impact on us. In September 2015, the FASB issued ASU No. 2015-16, “ Business Combinations (Topic 805): Simplifying the Accounting for Measurement-Period Adjustments, ” to simplify accounting for adjustments made to provisional amounts recognized in a business combination and to eliminate the retrospective accounting for those adjustments. This ASU is effective for us January 1, 2016 and is not expected to have a material impact on our consolidated results of operations, financial position or cash flow. In January 2016, the FASB issued ASU 2016-01 , "Financial Instruments--Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities," which amends the classification and measurement of financial instruments. Changes primarily affect the accounting for equity investments, financial liabilities under the fair value option, and the presentation and disclosure requirements for financial instruments. This ASU is effective for us beginning after December 15, 2017. Early adoption is not permitted. We are currently evaluating this ASU and its potential impact on us. 2014 . There were no significant accounting pronouncements issued during 2014 that had a material impact on our consolidated results of operations, financial position or cash flows. 2013 . There were no significant accounting pronouncements issued during 2013 that had a material impact on our consolidated results of operations, financial position or cash flows.

Acquisitions and Dispositions (

Acquisitions and Dispositions (Tables)	12 Months Ended
	Dec. 31, 2015
Business Combinations [Abstract]
Summary of Fair Values of Assets and Liabilities Acquired	The following table summarizes the fair values of the assets and liabilities acquired as of the date of the acquisition: Purchase Price Allocation (in millions) Cash purchase price $ 1,250 Working capital and other purchase adjustments 71 Total 1,321 Cash 67 Receivables 25 Other current assets 9 Property, plant and equipment 1,251 Accounts payable (18 ) Other current liabilities (17 ) Deferred credits and other liabilities (259 ) Long-term debt, including current portion (260 ) Total assets acquired/liabilities assumed 798 Goodwill $ 523

Business Segments (Tables)

Business Segments (Tables)	12 Months Ended
	Dec. 31, 2015
Segment Reporting [Abstract]
Business Segment Data	Business Segment Data Unaffiliated Revenues Intersegment Revenues Total Operating Revenues Segment EBITDA/ Consolidated Earnings before Income Taxes Depreciation and Amortization Capital and Investment Expenditures (a,b) Assets (in millions) 2015 Spectra Energy Partners $ 2,455 $ — $ 2,455 $ 1,905 $ 297 $ 2,007 $ 18,983 Distribution 1,527 — 1,527 473 176 544 5,209 Western Canada Transmission & Processing 1,242 43 1,285 491 243 360 5,909 Field Services — — — (461 ) — — 1,660 Total reportable segments 5,224 43 5,267 2,408 716 2,911 31,761 Other 10 63 73 (384 ) 48 61 1,226 Eliminations — (106 ) (106 ) — — — (64 ) Depreciation and amortization — — — 764 — — — Interest expense — — — 636 — — — Interest income and other (c) — — — (3 ) — — — Total consolidated $ 5,234 $ — $ 5,234 $ 621 $ 764 $ 2,972 $ 32,923 2014 Spectra Energy Partners $ 2,269 $ — $ 2,269 $ 1,669 $ 290 $ 1,241 $ 17,850 Distribution 1,843 — 1,843 552 192 427 6,055 Western Canada Transmission & Processing 1,781 121 1,902 754 271 473 6,913 Field Services — — — 217 — — 1,345 Total reportable segments 5,893 121 6,014 3,192 753 2,141 32,163 Other 10 62 72 (58 ) 43 146 1,893 Eliminations — (183 ) (183 ) — — — (58 ) Depreciation and amortization — — — 796 — — — Interest expense — — — 679 — — — Interest income and other (c) — — — 6 — — — Total consolidated $ 5,903 $ — $ 5,903 $ 1,665 $ 796 $ 2,287 $ 33,998 2013 Spectra Energy Partners $ 1,964 $ 1 $ 1,965 $ 1,433 $ 263 $ 1,299 $ 16,783 Distribution 1,848 — 1,848 574 199 357 6,000 Western Canada Transmission & Processing 1,694 73 1,767 736 272 561 7,157 Field Services — — — 343 — — 1,365 Total reportable segments 5,506 74 5,580 3,086 734 2,217 31,305 Other 12 60 72 (86 ) 38 42 2,680 Eliminations — (134 ) (134 ) — — — (499 ) Depreciation and amortization — — — 772 — — — Interest expense — — — 657 — — — Interest income and other (c) — — — 7 — — — Total consolidated $ 5,518 $ — $ 5,518 $ 1,578 $ 772 $ 2,259 $ 33,486
Geographic Data	Geographic Data U.S. Canada Consolidated (in millions) 2015 Consolidated revenues $ 2,389 $ 2,845 $ 5,234 Consolidated long-lived assets 17,549 10,979 28,528 2014 Consolidated revenues 2,212 3,691 5,903 Consolidated long-lived assets 15,834 12,715 28,549 2013 Consolidated revenues 1,926 3,592 5,518 Consolidated long-lived assets 14,963 13,247 28,210

Regulatory Matters (Tables)

Regulatory Matters (Tables)	12 Months Ended
	Dec. 31, 2015
Regulated Operations [Abstract]
Regulatory Assets and Liabilities	The following items are reflected in the consolidated balance sheets. All regulatory assets and liabilities are excluded from rate base unless otherwise noted below. Recovery/Refund Period December 31, 2015 2014 (in millions) Regulatory Assets Under-recovery of fuel costs (c) — $ 41 $ 44 Gas purchase costs (c) — — 57 Other — 73 46 Total Regulatory Assets—Current (a) 114 147 Net regulatory asset related to income taxes (d,e) 2 years - remaining life of asset 1,215 1,271 Project development costs (d) Through 2036 9 10 Vacation accrual (d) Various 23 22 Deferred debt expense/premium (d) Various 23 31 Other Various 13 13 Total Regulatory Assets—Non Current (b) 1,283 1,347 Total Regulatory Assets $ 1,397 $ 1,494 Regulatory Liabilities Gas purchase costs (c) — $ 48 $ — Other (d) — 32 59 Total Regulatory Liabilities—Current (a) 80 59 Removal costs (d) Exceeds remaining life of asset 258 326 Pipeline rate credit Life of associated liability 24 25 Other (d) Various 23 20 Total Regulatory Liabilities—Non Current (b) 305 371 Total Regulatory Liabilities $ 385 $ 430 ________ (a) Included in Inventory, Fuel Tracker, Current Assets—Other or Current Liabilities—Other. (b) Included in Regulatory Assets and Deferred Debits or Deferred Credits and Other Liabilities—Regulatory and Other. (c) Includes costs settled in cash annually through transportation rates in accordance with FERC and/or OEB gas tariffs. (d) All or a portion of the balance is included in rate base. (e) All amounts are expected to be included in future rate filings.

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Income Tax Expense Components	Income Tax Expense Components 2015 2014 2013 (in millions) Current income taxes Federal $ — $ 1 $ (32 ) State 13 3 4 Foreign 60 (10 ) 26 Total current income taxes 73 (6 ) (2 ) Deferred income taxes Federal 145 335 353 State (18 ) (17 ) 69 Foreign (39 ) 70 (1 ) Total deferred income taxes 88 388 421 Total income tax expense $ 161 $ 382 $ 419
Earnings from Continuing Operations before Income Taxes	Earnings before Income Taxes 2015 2014 2013 (in millions) Domestic $ 636 $ 1,108 $ 1,059 Foreign (15 ) 557 519 Total earnings before income taxes $ 621 $ 1,665 $ 1,578
Reconciliation of Income Tax Expense at U.S. Federal Statutory Tax Rate to Actual Income Tax Expense from Continuing Operations	Reconciliation of Income Tax Expense at the U.S. Federal Statutory Tax Rate to Actual Income Tax Expense 2015 2014 2013 (in millions) Income tax expense, computed at the statutory rate of 35% $ 217 $ 583 $ 552 State income tax, net of federal income tax effect 12 25 20 Tax differential on foreign earnings (44 ) (125 ) (147 ) Noncontrolling interests (92 ) (70 ) (42 ) Valuation allowance 1 2 (3 ) Goodwill impairment 91 — — Revaluation of accumulated deferred state taxes (12 ) (25 ) 31 Other items, net (12 ) (8 ) 8 Total income tax expense $ 161 $ 382 $ 419 Effective tax rate 25.9 % 22.9 % 26.6 %
Net Deferred Income Tax Liability Components	Net Deferred Income Tax Liability Components December 31, 2015 2014 (in millions) Deferred credits and other liabilities $ 275 $ 225 Net operating loss carryforward 295 158 Other 36 53 Total deferred income tax assets 606 436 Valuation allowance (27 ) (29 ) Net deferred income tax assets 579 407 Investments and other assets (1,605 ) (1,531 ) Accelerated depreciation rates (4,035 ) (3,875 ) Regulatory assets and deferred debits (384 ) (426 ) Total deferred income tax liabilities (6,024 ) (5,832 ) Total net deferred income tax liabilities $ (5,445 ) $ (5,425 )
Deferred Tax Amounts Classified in Consolidated Balance Sheets	The above deferred tax amounts have been classified in the Consolidated Balance Sheets as follows: December 31, 2015 2014 (in millions) Other current liabilities $ — $ (20 ) Deferred credits and other liabilities (5,445 ) (5,405 ) Total net deferred income tax liabilities $ (5,445 ) $ (5,425 )
Reconciliation of Gross Unrecognized Income Tax Benefits	Reconciliation of Gross Unrecognized Income Tax Benefits 2015 2014 2013 (in millions) Balance at beginning of period $ 50 $ 76 $ 80 Increases related to prior year tax positions 10 10 7 Decreases related to prior year tax positions (1 ) (6 ) (17 ) Increases related to current year tax positions 30 1 2 Settlements — — (3 ) Lapse of statute of limitations (4 ) (30 ) 9 Foreign currency translation (3 ) (1 ) (2 ) Balance at end of period $ 82 $ 50 $ 76

Earnings per Common Share (Tabl

Earnings per Common Share (Tables)	12 Months Ended
	Dec. 31, 2015
Earnings Per Share [Abstract]
Basic and Diluted EPS Calculations	The following table presents our basic and diluted EPS calculations: 2015 2014 2013 (in millions, except per-share amounts) Net income—controlling interests $ 196 $ 1,082 $ 1,038 Weighted-average common shares outstanding Basic 671 671 669 Diluted 672 672 671 Basic and diluted earnings per common share $ 0.29 $ 1.61 $ 1.55

Accumulated Other Comprehensi41

Accumulated Other Comprehensive Income (Tables)	12 Months Ended
	Dec. 31, 2015
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Schedule of Accumulated Other Comprehensive Income (Loss)	The following table presents the net of tax changes in AOCI by component and amounts reclassified out of AOCI to Net Income, excluding amounts attributable to noncontrolling interests: Foreign Currency Translation Adjustments Pension and Post-retirement Benefit Plan Obligations Gas Purchase Contract Hedges Other Total Accumulated Other Comprehensive Income (Loss) (in millions) December 31, 2013 $ 1,557 $ (304 ) $ (11 ) $ (1 ) $ 1,241 Reclassified to net income — — 4 1 5 Other AOCI activity (541 ) (47 ) 4 — (584 ) December 31, 2014 1,016 (351 ) (3 ) — 662 Other AOCI activity (937 ) 5 — 1 (931 ) December 31, 2015 $ 79 $ (346 ) $ (3 ) $ 1 $ (269 )

Inventory (Tables)

Inventory (Tables)	12 Months Ended
	Dec. 31, 2015
Inventory Disclosure [Abstract]
Components of Inventory	The components of inventory are as follows: December 31, 2015 2014 (in millions) Natural gas $ 217 $ 211 NGLs 23 28 Materials and supplies 67 74 Total inventory $ 307 $ 313

Investments in and Loans to U43

Investments in and Loans to Unconsolidated Affiliates and Related Party Transactions (Tables)	12 Months Ended
	Dec. 31, 2015
Investments in and Advances to Affiliates, Schedule of Investments [Abstract]
Investments in and Advances to Affiliates [Table Text Block]	Investments in and Loans to Unconsolidated Affiliates December 31, 2015 December 31, 2014 Domestic International Total Domestic International Total (in millions) Spectra Energy Partners $ 904 $ — $ 904 $ 1,588 $ — $ 1,588 Distribution — 11 11 — 14 14 Western Canada Transmission & Processing — 17 17 — 18 18 Field Services 1,660 — 1,660 1,345 — 1,345 Other — — — 1 — 1 Total $ 2,564 $ 28 $ 2,592 $ 2,934 $ 32 $ 2,966
Schedule Of Equity In Earnings Of Unconsolidated Affiliates [Text Block]	Equity in Earnings of Unconsolidated Affiliates 2015 2014 2013 Domestic International Total Domestic International Total Domestic International Total (in millions) Spectra Energy Partners $ 167 $ — $ 167 $ 133 $ — $ 133 $ 90 $ — $ 90 Distribution — 1 1 — 1 1 — 1 1 Western Canada Transmission & Processing — 2 2 — 1 1 — (1 ) (1 ) Field Services (461 ) — (461 ) 217 — 217 343 — 343 Other 1 — 1 9 — 9 12 — 12 Total $ (293 ) $ 3 $ (290 ) $ 359 $ 2 $ 361 $ 445 $ — $ 445
Equity Method Investment, Summarized Financial Information, Income Statement [Table Text Block]	Summarized Combined Financial Information of Unconsolidated Affiliates (Presented at 100%) Statements of Operations 2015 2014 2013 DCP Midstream Other Total DCP Midstream Other Total DCP Midstream Other Total (in millions) Operating revenues $ 7,420 $ 767 $ 8,187 $ 14,013 $ 744 $ 14,757 $ 12,038 $ 558 $ 12,596 Operating expenses 8,227 288 8,515 13,262 319 13,581 11,230 261 11,491 Operating income (807 ) 479 (328 ) 751 425 1,176 808 297 1,105 Net income (843 ) 393 (450 ) 536 332 868 584 206 790 Net income attributable to members’ interests (929 ) 393 (536 ) 288 332 620 491 206 697
Equity Method Investment, Summarized Financial Information, Balance Sheets [Table Text Block]	Balance Sheets December 31, 2015 December 31, 2014 DCP Midstream Other Total DCP Midstream Other Total (in millions) Current assets $ 800 $ 498 $ 1,298 $ 1,380 $ 241 $ 1,621 Non-current assets 13,094 3,265 16,359 12,299 5,358 17,657 Current liabilities (896 ) (387 ) (1,283 ) (2,938 ) (632 ) (3,570 ) Non-current liabilities (5,894 ) (1,679 ) (7,573 ) (5,538 ) (1,197 ) (6,735 ) Equity—total 7,104 1,697 8,801 5,203 3,770 8,973 Equity—noncontrolling interests (2,404 ) — (2,404 ) (2,578 ) — (2,578 ) Equity—controlling interests $ 4,700 $ 1,697 $ 6,397 $ 2,625 $ 3,770 $ 6,395

Goodwill (Tables)

Goodwill (Tables)	12 Months Ended
	Dec. 31, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Components and Activity within Goodwill	The following table presents activity within goodwill based on a segment basis: Spectra Energy Partners Distribution Western Canada Transmission & Processing Total (in millions) December 31, 2013 $ 3,215 $ 824 $ 771 $ 4,810 Adjustment to acquisition of Express-Platte 37 — — 37 Foreign currency translation (8 ) (65 ) (60 ) (133 ) December 31, 2014 3,244 759 711 4,714 Impairment of goodwill — — (333 ) (333 ) Foreign currency translation (12 ) (110 ) (105 ) (227 ) December 31, 2015 $ 3,232 $ 649 $ 273 $ 4,154
Goodwill Amounts Originating from Acquisition of Westcoast Energy Inc.	The following remaining goodwill amounts originating from the acquisition of Westcoast in 2002 are included as segment assets within “Other” in the segment data presented in Note 4: December 31, 2015 2014 (in millions) Distribution $ 646 $ 757 Western Canada Transmission & Processing 246 677

Marketable Securities and Res45

Marketable Securities and Restricted Funds (Tables)	12 Months Ended
	Dec. 31, 2015
Investments, Debt and Equity Securities [Abstract]
Estimated Fair Values of Available for Sale Securities	AFS Securities. AFS securities are as follows: Estimated Fair Value December 31, 2015 2014 (in millions) Corporate debt securities $ 31 $ 23 Money market funds — 1 Total available-for-sale securities $ 31 $ 24
Fair Value, by Balance Sheet Grouping	Our AFS securities are classified on the Consolidated Balance Sheets as follows: Estimated Fair Value December 31, 2015 2014 (in millions) Restricted funds Investments and other assets—other $ 11 $ 1 Non-restricted funds Current assets—other 20 3 Investments and other assets—other — 20 Total available-for-sale securities $ 31 $ 24 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. December 31, 2015 2014 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) 13,567 13,891 13,060 14,446 __________ (a) Included within Investments in and Loans to Unconsolidated Affiliates. (b) Excludes capital leases, unamortized items and fair value hedge carrying value adjustments.
Estimated Fair Values of Held to Maturity Marketable Securities	HTM Securities. All of our HTM securities are as follows: Estimated Fair Value December 31, Description Consolidated Balance Sheet Caption 2015 2014 (in millions) Bankers acceptances Current assets—other $ 30 $ 38 Canadian government securities Current assets—other 24 30 Money market funds Current assets—other 3 3 Canadian government securities Investments and other assets—other 50 101 Bankers acceptances Investments and other assets—other 12 — Total held-to-maturity securities $ 119 $ 172

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	12 Months Ended
	Dec. 31, 2015
Property, Plant and Equipment [Abstract]
Property Plant and Equipment	Estimated Useful Life December 31, 2015 2014 (years) (in millions) Plant Natural gas transmission 15–100 $ 15,690 $ 15,001 Natural gas distribution 25-60 2,651 2,971 Gathering and processing facilities 25-40 4,178 4,765 Natural gas storage 10–122 2,137 2,162 Crude oil transportation and storage 25–75 1,206 1,169 Land rights and rights of way 21–122 591 568 Other buildings and improvements 10–50 149 132 Equipment 3–40 301 343 Vehicles 5–20 102 114 Land — 138 150 Construction in process — 1,919 1,113 Software 4–10 439 387 Other 5–82 342 336 Total property, plant and equipment 29,843 29,211 Total accumulated depreciation (6,527 ) (6,543 ) Total accumulated amortization (398 ) (361 ) Total net property, plant and equipment $ 22,918 $ 22,307
Estimated Amortization Expense for Next Five Years	Estimated amortization expense for the next five years follows: Estimated Amortization Expense (in millions) 2016 $ 84 2017 80 2018 54 2019 35 2020 28

Asset Retirement Obligations (T

Asset Retirement Obligations (Tables)	12 Months Ended
	Dec. 31, 2015
Asset Retirement Obligation Disclosure [Abstract]
Reconciliation of Changes in Asset Retirement Obligation Liabilities	Reconciliation of Changes in Asset Retirement Obligation Liabilities 2015 2014 (in millions) Balance at beginning of year $ 400 $ 350 Accretion expense 17 16 Revisions in estimated cash flows (a) 72 72 Foreign currency exchange impact (62 ) (28 ) Liabilities settled (9 ) (10 ) Balance at end of year (b) $ 418 $ 400 ________ (a) Reflects revised assumptions regarding ARO Liabilities due to a reduction in the remaining estimated life of certain Texas Eastern offshore facilities in 2015 and asbestos abatement at Western Canada Transmission & Processing in 2014. (b) Amounts included in Deferred Credits and Other Liabilities in the Consolidated Balance Sheets.

Debt and Credit Facilities (Tab

Debt and Credit Facilities (Tables)	12 Months Ended
	Dec. 31, 2015
Debt Disclosure [Abstract]
Summary of Debt and Related Terms	Summary of Debt and Related Terms December 31, 2015 2014 Spectra Energy Capital, LLC (in millions) 6.20% senior unsecured notes due April 2018 $ 500 $ 500 6.75% senior unsecured notes due July 2018 150 150 Variable-rate senior unsecured term loan due November 2018 300 300 8.00% senior unsecured notes due October 2019 500 500 5.65% senior unsecured notes due March 2020 300 300 3.30% senior unsecured notes due March 2023 650 650 6.75% senior unsecured notes due February 2032 240 240 7.50% senior unsecured notes due September 2038 250 250 Total Spectra Energy Capital, LLC Debt 2,890 2,890 SEP SEP 2.95% senior unsecured notes due June 2016 250 250 SEP 2.95% senior unsecured notes due September 2018 500 500 SEP variable-rate senior unsecured term loan due November 2018 400 400 SEP 4.60% senior unsecured notes due June 2021 250 250 SEP 4.75% senior unsecured notes due March 2024 1,000 1,000 SEP 3.50% senior unsecured notes due March 2025 500 — SEP 5.95% senior unsecured notes due September 2043 400 400 SEP 4.50% senior unsecured notes due March 2045 500 — Texas Eastern 6.00% senior unsecured notes due September 2017 400 400 Texas Eastern 4.13% senior unsecured notes due December 2020 300 300 Texas Eastern 2.80% senior unsecured notes due October 2022 500 500 Texas Eastern 7.00% senior unsecured notes due July 2032 450 450 Algonquin 3.51% senior notes due July 2024 350 350 East Tennessee Natural Gas, LLC 3.10% senior notes due December 2024 200 200 Express-Platte 6.09% senior secured notes due January 2020 110 110 Express-Platte 7.39% subordinated secured notes due 2015 to 2019 42 74 Total SEP Debt 6,152 5,184 Westcoast 8.50% debentures due November 2015 — 108 3.28% medium-term notes due January 2016 181 215 8.50% debentures due September 2018 108 129 5.60% medium-term notes due January 2019 217 258 9.90% debentures due January 2020 72 86 4.57% medium-term notes due July 2020 181 215 3.88% medium-term notes due October 2021 108 129 3.12% medium-term notes due December 2022 181 215 3.43% medium-term notes due September 2024 253 301 8.85% debentures due July 2025 108 129 8.80% medium-term notes due November 2025 18 22 3.77% medium-term notes due December 2025 217 — 7.30% debentures due December 2026 90 108 6.75% medium-term notes due December 2027 108 129 7.15% medium-term notes due March 2031 145 172 4.79% medium-term notes due October 2041 145 129 M&N Canada 6.90% senior secured notes due 2015 to 2019 75 112 M&N Canada 4.34% senior secured notes due 2015 to 2019 47 83 Other 2 2 Total Westcoast Debt $ 2,256 $ 2,542 December 31, 2015 2014 Union Gas (in millions) 11.50% debentures due August 2015 $ — $ 129 4.64% medium-term notes due June 2016 145 172 9.70% debentures due November 2017 90 108 5.35% medium-term notes due April 2018 145 172 8.75% debentures due August 2018 90 108 8.65% senior debentures due October 2018 54 64 2.76% medium-term notes due June 2021 145 172 4.85% medium-term notes due April 2022 90 108 3.79% medium-term notes due July 2023 181 215 3.19% medium-term notes due September 2025 145 — 8.65% debentures due November 2025 90 108 5.46% medium-term notes due September 2036 119 142 6.05% medium-term notes due September 2038 216 258 5.20% medium-term notes due July 2040 181 215 4.88% medium-term notes due June 2041 217 258 4.20% medium-term notes due June 2044 361 215 Total Union Gas Debt 2,269 2,444 Total Long-term debt principal (including current maturities) 13,567 13,060 Change in fair value of debt hedged 22 17 Unamortized debt discount, net (22 ) (12 ) Unamortized capitalized debt issuance costs (a) (46 ) (42 ) Other unamortized items 4 7 Total other non-principal amounts (42 ) (30 ) Commercial paper (b) 1,112 1,583 Capital Leases 19 24 Total debt (including capital lease obligations) (c) 14,656 14,637 Current maturities of long-term debt (652 ) (327 ) Commercial paper (d) (1,112 ) (1,583 ) Total long-term debt (including capital lease obligations) $ 12,892 $ 12,727 ______ (a) Reflects implementation of ASU No. 2015-03 as discussed in Note 1. (b) The weighted-average days to maturity was 12 days as of December 31, 2015 and 14 days as of December 31, 2014 . (c) As of December 31, 2015 and 2014 , respectively, $4,681 million and $5,264 million of debt was denominated in Canadian dollars. (d) Weighted-average rate on outstanding commercial paper was 0.9% at December 31, 2015 and 0.6% at December 31, 2014 .
Annual Maturities	Annual Maturities December 31, 2015 (in millions) 2016 $ 650 2017 543 2018 2,277 2019 745 2020 963 Thereafter 8,408 Total long-term debt, including current maturities (a) $ 13,586 __________ (a) Excludes commercial paper of $1,112 million . Includes capital leases of $19 million .
Available Credit Facilities and Restrictive Debt Covenants	Available Credit Facilities and Restrictive Debt Covenants Expiration Total Commercial Paper Outstanding at December 31, 2015 Available (in millions) Spectra Energy Capital, LLC (a) 2019 $ 1,000 $ 481 $ 519 SEP (b) 2019 2,000 476 1,524 Westcoast (c) 2019 289 6 283 Union Gas (d) 2019 361 149 212 Total $ 3,650 $ 1,112 $ 2,538 __________ (a) Revolving credit facility contains a covenant requiring the Spectra Energy consolidated debt-to-total capitalization ratio, as defined in the agreement, to not exceed 65% . Per the terms of the agreement, collateralized debt is excluded from the calculation of the ratio. This ratio was 59.6% at December 31, 2015 . (b) Revolving credit facility contains a covenant that requires SEP to maintain a ratio of total Consolidated Indebtedness-to-Consolidated EBITDA, as defined in the agreement, of 5.0 to 1 or less. As of December 31, 2015 , this ratio was 3.6 to 1. (c) U.S. dollar equivalent at December 31, 2015 . The revolving credit facility is 400 million Canadian dollars and contains a covenant that requires the Westcoast non-consolidated debt-to-total capitalization ratio to not exceed 75% . The ratio was 35.4% at December 31, 2015 . (d) U.S. dollar equivalent at December 31, 2015 . The revolving credit facility is 500 million Canadian dollars and contains a covenant that requires the Union Gas debt-to-total capitalization ratio to not exceed 75% and a provision which requires Union Gas to repay all borrowings under the facility for a period of two days during the second quarter of each year. The ratio was 67.8% at December 31, 2015 .

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2015
Fair Value Disclosures [Abstract]
Assets and Liabilities Measured at Fair Value on Recurring Basis with Fair Value Hierarchy Levels	The following presents, for each of the fair value hierarchy levels, assets and liabilities that are measured and recorded at fair value on a recurring basis: Description Consolidated Balance Sheet Caption December 31, 2015 Total Level 1 Level 2 Level 3 (in millions) Corporate debt securities Cash and cash equivalents $ 137 $ — $ 137 $ — Corporate debt securities Current assets — other 20 — 20 — Commodity derivatives Current assets — other 36 — — 36 Commodity derivatives Investments and other assets — other 5 — — 5 Corporate debt securities Investments and other assets — other 11 — 11 — Interest rate swaps Investments and other assets — other 37 — 37 — Total Assets $ 246 $ — $ 205 $ 41 Description Consolidated Balance Sheet Caption December 31, 2014 Total Level 1 Level 2 Level 3 (in millions) Corporate debt securities Cash and cash equivalents $ 85 $ — $ 85 $ — Corporate debt securities Current assets — other 3 — 3 — Commodity derivatives Current assets — other 57 — — 57 Interest rate swaps Current assets — other 2 — 2 — Commodity derivatives Investments and other assets — other 21 — — 21 Corporate debt securities Investments and other assets — other 20 — 20 — Interest rate swaps Investments and other assets — other 22 — 22 — Money market funds Investments and other assets — other 1 1 — — Total Assets $ 211 $ 1 $ 132 $ 78
Changes in Level 3 Assets and Liabilities that are Measured at Fair Value on a Recurring Basis using Significant Unobservable Inputs	The following presents changes in Level 3 assets and liabilities that are measured at fair value on a recurring basis using significant unobservable inputs: 2015 2014 (in millions) Derivative assets (liabilities) Fair value, beginning of period $ 78 $ (3 ) Total gains (losses): Included in earnings 43 91 Included in other comprehensive income (10 ) 5 Purchases (3 ) — Settlements (67 ) (15 ) Fair value, end of period $ 41 $ 78 Unrealized gains (losses) relating to instruments held at the end of the period $ (19 ) $ 56
Fair Value of Financial Instruments Recorded and Carried at Book Value	Our AFS securities are classified on the Consolidated Balance Sheets as follows: Estimated Fair Value December 31, 2015 2014 (in millions) Restricted funds Investments and other assets—other $ 11 $ 1 Non-restricted funds Current assets—other 20 3 Investments and other assets—other — 20 Total available-for-sale securities $ 31 $ 24 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. December 31, 2015 2014 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) 13,567 13,891 13,060 14,446 __________ (a) Included within Investments in and Loans to Unconsolidated Affiliates. (b) Excludes capital leases, unamortized items and fair value hedge carrying value adjustments.

Risk Management and Hedging A50

Risk Management and Hedging Activities (Tables)	12 Months Ended
	Dec. 31, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Portfolio Carrying Value	Derivative Portfolio Carrying Value as of December 31, 2015 Maturities in 2016 Maturities Maturities in 2018 Maturities in 2019 and Thereafter Total Carrying Value (in millions) Derivatives designated as hedging instruments Interest rate swaps $ — $ 2 $ 12 $ 23 $ 37 Total derivatives designated as hedging instruments — 2 12 23 37 Derivatives not designated as hedging instruments Commodity derivatives 36 5 — — 41 Total derivatives not designated as hedging instruments 36 5 — — 41 Total derivative instruments $ 36 $ 7 $ 12 $ 23 $ 78
Commodity Derivative Assets and Liabilities Offsetting Table	Information about our commodity derivatives that had netting or rights of offset arrangements are as follows: December 31, 2015 Gross Amounts Gross Amounts Offset Net Amount Presented in the Consolidated Balance Sheets Description (in millions) Assets $ 104 $ 63 $ 41 Liabilities 63 63 —
Commodity derivative impact	Information regarding the impacts of commodity derivatives on our Consolidated Statements of Operations is as follows: Derivatives Consolidated Statements of Operations Caption 2015 2014 2013 (in millions) Commodity derivatives Sales of natural gas liquids $ 40 $ 93 $ —
Schedule of Derivative Instruments in Statement of Financial Position, Fair Value	Information about our interest rate swaps that had netting or rights of offset arrangements are as follows: December 31, 2015 December 31, 2014 Gross Amounts Presented in the Consolidated Balance Sheets Amounts Not Offset in the Consolidated Balance Sheets Net Amount Gross Amounts Presented in the Consolidated Balance Sheets Amounts Not Offset in the Consolidated Balance Sheets Net Amount Description (in millions) Assets $ 37 $ — $ 37 $ 24 $ — $ 24

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Summary of Future Minimum Lease Payments Under Operating Leases	The following is a summary of future minimum lease payments under operating leases which at inception had noncancellable terms of more than one year. We had no material capital lease commitments as of December 31, 2015 or 2014 . Long-term Operating Leases (in millions) 2016 $ 49 2017 41 2018 39 2019 35 2020 31 Thereafter 139 Total future minimum lease payments $ 334

Effects of Changes in Noncont52

Effects of Changes in Noncontrolling Interests Ownership Effects of Changes in Noncontrolling Interests Ownership (Tables)	12 Months Ended
	Dec. 31, 2015
Effects of changes in Noncontrolling Interest [Abstract]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net	The following table presents the effects of changes in our ownership interests in non-100%-owned consolidated subsidiaries: 2015 2014 2013 (in millions) Net income—controlling interests $ 196 $ 1,082 $ 1,038 Increase (decrease) in additional paid-in capital resulting from issuances/retirements of SEP units (a) (105 ) 49 42 Total net income—controlling interests and changes in equity—controlling interests $ 91 $ 1,131 $ 1,080 ________________ (a) See Note 2 for further discussion.

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2015
Components of Pre-Tax Stock Based Compensation Expense in Continuing Operations	We recorded pre-tax stock-based compensation expense as follows, the components of which are described further below: 2015 2014 2013 (in millions) Phantom awards $ 11 $ 14 $ 13 Performance awards 18 13 33 Total $ 29 $ 27 $ 46
Stock Awards Activity	Awards Activity Performance Awards Phantom Awards Units Weighted Average Grant Date Fair Value Units Weighted Average Grant Date Fair Value (thousands) (thousands) Outstanding at December 31, 2014 1,775 $ 35 1,281 $ 33 Granted 564 48 395 36 Vested (2 ) 41 (428 ) 31 Forfeited (635 ) 22 (36 ) 30 Outstanding at December 31, 2015 1,702 39 1,212 28 Awards expected to vest 1,608 39 1,176 28
Stock Option Activity	Stock Option Activity Options Weighted- Average Exercise Price Weighted- Average Remaining Life Aggregate Intrinsic Value (in thousands) (in years) (in millions) Outstanding at December 31, 2014 1,102 $ 25 2.0 $ 12 Exercised (134 ) 23 Forfeited or expired (10 ) 23 Outstanding at December 31, 2015 958 26 1.2 — Exercisable at December 31, 2015 958 26 1.2 —
Performance awards
Weighted Average Assumptions	Weighted-Average Assumptions for Stock-Based Performance Awards 2015 2014 2013 Risk-free rate of return 1.1% 0.7% 0.4% Expected life 3 years 3 years 3 years Expected volatility—Spectra Energy 18% 20% 21% Expected volatility—peer group 13%-27% 14%–32% 13%–33% Market index (a) N/A N/A 16% _________ (a) Beginning in 2014, the valuation model was refined to use an alternate analytical approach to project future stock prices in order to improve consistency and efficiency. The improved approach does not require the use of a market index assumption to determine the future stock price used in the valuation model. As such, the volatility of the market index assumption will not be presented going forward. Based on our assessment, it was determined that this refinement did not have a significant impact on the fair value of the shares for all periods presented.

Employee Benefit Plans (Tables)

Employee Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2015
Change in Projected Benefit Obligation and Change in Fair Value of Plan Assets	Change in Projected Benefit Obligation and Change in Fair Value of Plan Assets U.S. Canada 2015 2014 2015 2014 (in millions) Change in Projected Benefit Obligation Projected benefit obligation, beginning of period $ 586 $ 575 $ 1,202 $ 1,131 Service cost 19 19 28 25 Interest cost 24 24 43 52 Actuarial loss (gain) (18 ) 13 (3 ) 143 Participant contributions — — 5 5 Benefits paid (40 ) (45 ) (47 ) (49 ) Foreign currency translation effect — — (194 ) (105 ) Projected benefit obligation, end of period 571 586 1,034 1,202 Change in Fair Value of Plan Assets Plan assets, beginning of period 551 531 1,050 1,040 Actual return on plan assets (1 ) 44 52 115 Benefits paid (40 ) (45 ) (47 ) (49 ) Employer contributions 22 21 22 36 Plan participants’ contributions — — 5 5 Expected non-investment expenses — — (3 ) (3 ) Foreign currency translation effect — — (171 ) (94 ) Plan assets, end of period 532 551 908 1,050 Net amount recognized $ (39 ) $ (35 ) $ (126 ) $ (152 ) Accumulated Benefit Obligation $ 549 $ 567 $ 967 $ 1,123 U.S. Canada 2015 2014 2015 2014 (in millions) Net amount recognized Current Liabilities - Other $ (2 ) $ (2 ) $ (5 ) $ (6 ) Deferred Credits and Other Liabilities - Regulatory and Other (37 ) (33 ) (142 ) (165 ) Other Assets - Other — — 21 19 Total net amount recognized $ (39 ) $ (35 ) $ (126 ) $ (152 )
Amounts Recognized in Accumulated Other Comprehensive Income	Amounts Recognized in Accumulated Other Comprehensive Income U.S. Canada December 31, December 31, 2015 2014 2015 2014 (in millions) Net actuarial loss $ 156 $ 141 $ 330 $ 345 Prior service cost — — 5 6 Total amount recognized in AOCI $ 156 $ 141 $ 335 $ 351
Components of Net Periodic Cost	Components of Net Periodic Pension Costs U.S. Canada 2015 2014 2013 2015 2014 2013 (in millions) Net Periodic Pension Cost Service cost benefit earned $ 19 $ 19 $ 19 $ 31 $ 29 $ 33 Interest cost on projected benefit obligation 24 24 21 43 52 50 Expected return on plan assets (42 ) (39 ) (33 ) (65 ) (69 ) (66 ) Amortization of prior service cost — — — 1 2 2 Amortization of loss 10 13 20 25 22 35 Net periodic pension cost 11 17 27 35 36 54 Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income Current year actuarial loss (gain) 25 8 (69 ) 10 93 (133 ) Amortization of actuarial loss (10 ) (13 ) (20 ) (25 ) (22 ) (35 ) Amortization of prior service credit — — — (1 ) (2 ) (2 ) Total recognized in other comprehensive income 15 (5 ) (89 ) (16 ) 69 (170 ) Total Recognized in Net Periodic Pension Cost and Other Comprehensive Income $ 26 $ 12 $ (62 ) $ 19 $ 105 $ (116 )
Assumptions Used for Benefits Accounting	Assumptions Used for Pension Benefits Accounting U.S. Canada 2015 2014 2013 2015 2014 2013 Benefit Obligations Discount rate 4.58 % 4.10 % 4.31 % 4.03 % 4.00 % 4.81 % Salary increase 4.00 4.00 4.61 3.00 3.25 3.25 Net Periodic Benefit Cost Discount rate 4.10 4.31 3.55 4.00 4.81 4.15 Salary increase 4.00 4.61 4.61 3.25 3.25 3.25 Expected long-term rate of return on plan assets 8.00 8.00 7.40 7.40 7.40 7.10
Assumed Health Care Cost Trend Rates	Assumed Health Care Cost Trend Rates U.S. Canada 2015 2014 2015 2014 Health care cost trend rate assumed for next year 7.00% 7.00% 5.50% 6.00% Rate to which the cost trend is assumed to decline 5.00% 5.00% 5.00% 5.00% Year that the rate reaches the ultimate trend rate 2020 2019 2017 2017
Sensitivity to Changes in Assumed Health Care Cost Trend Rates	Sensitivity to Changes in Assumed Health Care Cost Trend Rates U.S. Canada 1% Point Increase 1% Point Decrease 1% Point Increase 1% Point Decrease (in millions) Effect on total service and interest costs $ — $ — $ 1 $ (1 ) Effect on post-retirement benefit obligations 7 (6 ) 5 (5 )
Qualified pension plans
Changes in Level 3 Assets That are Measured at Fair Value on Recurring Basis Using Significant Unobservable Inputs	The following presents changes in Level 3 assets that are measured at fair value on a recurring basis using significant unobservable inputs: U.S. 2015 2014 (in millions) Fair value, beginning of period $ 53 $ 49 Gain (loss) included in other comprehensive income 2 4 Fair value, end of period $ 55 $ 53
Pension Plans, Defined Benefit | Qualified pension plans
Target Allocation of Plan Assets	Qualified Pension Plan Assets U.S. Canada Asset Category Target Allocation December 31, Target Allocation December 31, 2015 2014 2015 2014 U.S. equity securities 23 % 22 % 31 % 17 % 18 % 17 % Canadian equity securities — — — 25 24 25 Other equity securities 10 10 11 13 13 13 Fixed income securities 57 57 48 45 45 45 Other investments 10 11 10 — — — Total 100 % 100 % 100 % 100 % 100 % 100 %
Fair Value of Plan Assets	The following table summarizes the fair values of pension plan assets recorded at each fair value hierarchy level, as determined in accordance with the valuation techniques described in Note 17: U.S. Canada Total Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 (in millions) December 31, 2015 Cash and cash equivalents $ 2 $ 2 $ — $ — $ 3 $ 3 $ — $ — Equity securities 171 171 — — 501 221 280 — Fixed income securities 304 304 — — 404 404 — — Other 55 — — 55 — — — — Total $ 532 $ 477 $ — $ 55 $ 908 $ 628 $ 280 $ — December 31, 2014 Cash and cash equivalents $ 3 $ 3 $ — $ — $ 3 $ 3 $ — $ — Equity securities 233 233 — — 576 342 234 — Fixed income securities 262 262 — — 471 471 — — Other 53 — — 53 — — — — Total $ 551 $ 498 $ — $ 53 $ 1,050 $ 816 $ 234 $ —
Expected Benefit Payments	Expected Benefit Payments U.S. Canada (in millions) 2016 $ 84 $ 44 2017 49 47 2018 47 49 2019 49 51 2020 50 54 2021 – 2025 233 297
U.S. and Canada Other Post-Retirement Benefits
Change in Projected Benefit Obligation and Change in Fair Value of Plan Assets	Other Post-Retirement Benefit Plans — Change in Projected Benefit Obligation and Fair Value of Plan Assets U.S. Canada 2015 2014 2015 2014 (in millions) Change in Benefit Obligation Accumulated post-retirement benefit obligation, beginning of period $ 172 $ 184 $ 133 $ 133 Service cost 1 1 4 4 Interest cost 7 8 5 6 Plan participants’ contributions 3 2 — — Actuarial loss (gain) 1 (7 ) (11 ) 7 Medicare subsidy receivable 2 2 — — Benefits paid (20 ) (18 ) (4 ) (4 ) Foreign currency translation effect — — (20 ) (13 ) Accumulated post-retirement benefit obligation, end of period 166 172 107 133 Change in Fair Value of Plan Assets Plan assets, beginning of period 92 87 — — Actual return on plan assets 1 7 — — Benefits paid (20 ) (18 ) (4 ) (4 ) Employer contributions 12 14 4 4 Plan participants’ contributions 3 2 — — Plan assets, end of period 88 92 — — Net amount recognized (a) $ (78 ) $ (80 ) $ (107 ) $ (133 ) _______ (a) Recognized primarily in Deferred Credits and Other Liabilities—Regulatory and Other in the Consolidated Balance Sheets.
Amounts Recognized in Accumulated Other Comprehensive Income	Other Post-Retirement Benefit Plans — Amounts Recognized in Accumulated Other Comprehensive Income U.S. Canada December 31, December 31, 2015 2014 2015 2014 (in millions) Prior service credit $ — $ — $ (3 ) $ (4 ) Net actuarial loss (gain) 3 (4 ) 1 12 Total amount recognized in AOCI $ 3 $ (4 ) $ (2 ) $ 8
Components of Net Periodic Cost	U.S. Canada 2015 2014 2013 2015 2014 2013 (in millions) Other Post-Retirement Benefit Plans — Components of Net Periodic Benefit Cost Service cost benefit earned $ 1 $ 1 $ 1 $ 4 $ 4 $ 5 Interest cost on accumulated post-retirement benefit obligation 7 8 7 5 6 6 Expected return on plan assets (6 ) (5 ) (4 ) — — — Amortization of prior service credit — — — (1 ) (1 ) (1 ) Amortization of loss — 1 2 — — — Net periodic other post-retirement benefit cost 2 5 6 8 9 10 Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income Current year actuarial loss (gain) 7 (9 ) (18 ) (11 ) 6 (13 ) Amortization of actuarial loss — (1 ) (2 ) — — — Amortization of prior service credit — — — 1 1 1 Total recognized in other comprehensive income 7 (10 ) (20 ) (10 ) 7 (12 ) Total recognized in net periodic benefit cost and other comprehensive income $ 9 $ (5 ) $ (14 ) $ (2 ) $ 16 $ (2 )
Assumptions Used for Benefits Accounting	Other Post-Retirement Benefits Plans — Assumptions Used for Benefits Accounting U.S. Canada 2015 2014 2013 2015 2014 2013 Benefit Obligations Discount rate 4.53 % 4.08 % 4.46 % 4.03 % 4.00 % 4.83 % Salary increase 4.00 4.00 4.61 3.00 3.25 3.25 Net Periodic Benefit Cost Discount rate 4.08 4.46 3.70 4.00 4.83 4.20 Salary increase 4.00 4.61 4.61 3.25 3.25 3.25 Expected return on plan assets 6.83 6.98 6.51 N/A N/A N/A
Target Allocation of Plan Assets	Other Post-Retirement Plan Assets U.S. Asset Category December 31, 2015 2014 Cash and cash equivalents 3 % — % Equity securities 45 48 Fixed income securities 46 47 Other assets 6 5 Total 100 % 100 %
Fair Value of Plan Assets	The asset allocation table above includes the other post-retirement benefit assets held in the master trusts, VEBA I and VEBA II.
Expected Benefit Payments	The following benefit payments and subsidies are expected to be paid (or received) over each of the next five years and thereafter. Benefit Payments Medicare Part D Subsidy Receipts U.S. Canada U.S. (in millions) 2016 $ 16 $ 4 $ (1 ) 2017 15 4 (1 ) 2018 15 4 (1 ) 2019 15 4 (1 ) 2020 14 5 (1 ) 2021 – 2025 61 26 (5 )
U.S.
Changes in Level 3 Assets That are Measured at Fair Value on Recurring Basis Using Significant Unobservable Inputs	The following presents changes in Level 3 assets that are measured at fair value on a recurring basis using significant unobservable inputs: U.S. 2015 2014 (in millions) Fair value, beginning of period $ 4 $ 4 Unrealized gain included in other comprehensive income 1 — Fair value, end of period $ 5 $ 4

Consolidating Financial Infor55

Consolidating Financial Information (Tables)	12 Months Ended
	Dec. 31, 2015
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Condensed Consolidating Statement of Operations	Spectra Energy Corp Condensed Consolidating Statement of Operations Year Ended December 31, 2015 (In millions) Spectra Energy Corp Spectra Capital Non-Guarantor Subsidiaries Eliminations Consolidated Total operating revenues $ — $ — $ 5,237 $ (3 ) $ 5,234 Total operating expenses 6 (4 ) 3,802 (3 ) 3,801 Operating income (loss) (6 ) 4 1,435 — 1,433 Loss from equity investments — — (290 ) — (290 ) Equity in earnings of consolidated subsidiaries 161 573 — (734 ) — Other income and expenses, net — 1 113 — 114 Interest expense — 244 392 — 636 Earnings before income taxes 155 334 866 (734 ) 621 Income tax expense (benefit) (41 ) 173 29 — 161 Net income 196 161 837 (734 ) 460 Net income—noncontrolling interests — — 264 — 264 Net income—controlling interests $ 196 $ 161 $ 573 $ (734 ) $ 196 Spectra Energy Corp Condensed Consolidating Statement of Operations Year Ended December 31, 2014 (In millions) Spectra Energy Corp Spectra Capital Non-Guarantor Subsidiaries Eliminations Consolidated Total operating revenues $ — $ — $ 5,906 $ (3 ) $ 5,903 Total operating expenses 6 1 3,975 (3 ) 3,979 Operating income (loss) (6 ) (1 ) 1,931 — 1,924 Earnings from equity investments — — 361 — 361 Equity in earnings of consolidated subsidiaries 1,054 1,651 — (2,705 ) — Other income and expenses, net (2 ) 9 52 — 59 Interest expense — 253 426 — 679 Earnings before income taxes 1,046 1,406 1,918 (2,705 ) 1,665 Income tax expense (benefit) (36 ) 352 66 — 382 Net income 1,082 1,054 1,852 (2,705 ) 1,283 Net income—noncontrolling interests — — 201 — 201 Net income—controlling interests $ 1,082 $ 1,054 $ 1,651 $ (2,705 ) $ 1,082 Spectra Energy Corp Condensed Consolidating Statement of Operations Year Ended December 31, 2013 (In millions) Spectra Energy Corp Spectra Capital Non-Guarantor Subsidiaries Eliminations Consolidated Total operating revenues $ — $ — $ 5,521 $ (3 ) $ 5,518 Total operating expenses 8 3 3,844 (3 ) 3,852 Operating income (loss) (8 ) (3 ) 1,677 — 1,666 Earnings from equity investments — — 445 — 445 Equity in earnings of consolidated subsidiaries 1,015 1,649 — (2,664 ) — Other income and expenses, net 1 15 108 — 124 Interest expense — 216 441 — 657 Earnings before income taxes 1,008 1,445 1,789 (2,664 ) 1,578 Income tax expense (benefit) (30 ) 430 19 — 419 Net income 1,038 1,015 1,770 (2,664 ) 1,159 Net income—noncontrolling interests — — 121 — 121 Net income—controlling interests $ 1,038 $ 1,015 $ 1,649 $ (2,664 ) $ 1,038
Condensed Consolidating Statement of Comprehensive Income	Spectra Energy Corp Condensed Consolidating Statements of Comprehensive Income (In millions) Spectra Energy Corp Spectra Capital Non-Guarantor Subsidiaries Eliminations Consolidated Year Ended December 31, 2015 Net income $ 196 $ 161 $ 837 $ (734 ) $ 460 Other comprehensive income (loss) (14 ) 1 (931 ) — (944 ) Total comprehensive income (loss), net of tax 182 162 (94 ) (734 ) (484 ) Less: comprehensive income—noncontrolling interests — — 251 — 251 Comprehensive income (loss)—controlling interests $ 182 $ 162 $ (345 ) $ (734 ) $ (735 ) Year Ended December 31, 2014 Net income $ 1,082 $ 1,054 $ 1,852 $ (2,705 ) $ 1,283 Other comprehensive income (loss) 9 1 (596 ) — (586 ) Total comprehensive income, net of tax 1,091 1,055 1,256 (2,705 ) 697 Less: comprehensive income—noncontrolling interests — — 194 — 194 Comprehensive income—controlling interests $ 1,091 $ 1,055 $ 1,062 $ (2,705 ) $ 503 Year Ended December 31, 2013 Net income $ 1,038 $ 1,015 $ 1,770 $ (2,664 ) $ 1,159 Other comprehensive income (loss) 69 2 (346 ) — (275 ) Total comprehensive income, net of tax 1,107 1,017 1,424 (2,664 ) 884 Less: comprehensive income—noncontrolling interests — — 114 — 114 Comprehensive income—controlling interests $ 1,107 $ 1,017 $ 1,310 $ (2,664 ) $ 770
Condensed Consolidating Balance Sheet	Spectra Energy Corp Condensed Consolidating Balance Sheet December 31, 2015 (In millions) Spectra Energy Corp Spectra Capital Non-Guarantor Subsidiaries Eliminations Consolidated Cash and cash equivalents $ — $ 1 $ 212 $ — $ 213 Receivables—consolidated subsidiaries 15 6 13 (34 ) — Notes receivable—current—consolidated subsidiaries — — 387 (387 ) — Receivables—other 2 — 804 — 806 Other current assets 25 — 604 — 629 Total current assets 42 7 2,020 (421 ) 1,648 Investments in and loans to unconsolidated affiliates — — 2,592 — 2,592 Investments in consolidated subsidiaries 13,919 19,161 — (33,080 ) — Advances receivable—consolidated subsidiaries — 5,273 1,326 (6,599 ) — Notes receivable—consolidated subsidiaries — — 2,800 (2,800 ) — Goodwill — — 4,154 — 4,154 Other assets 41 27 242 — 310 Net property, plant and equipment — — 22,918 — 22,918 Regulatory assets and deferred debits 3 3 1,295 — 1,301 Total Assets $ 14,005 $ 24,471 $ 37,347 $ (42,900 ) $ 32,923 Accounts payable $ 2 $ 3 $ 506 $ — $ 511 Accounts payable—consolidated subsidiaries 4 28 2 (34 ) — Commercial paper — 481 631 — 1,112 Short-term borrowings—consolidated subsidiaries — 387 — (387 ) — Taxes accrued 5 — 73 — 78 Current maturities of long-term debt — — 652 — 652 Other current liabilities 102 48 889 — 1,039 Total current liabilities 113 947 2,753 (421 ) 3,392 Long-term debt — 2,891 10,001 — 12,892 Advances payable—consolidated subsidiaries 6,599 — — (6,599 ) — Notes payable—consolidated subsidiaries — 2,800 — (2,800 ) — Deferred credits and other liabilities 767 3,914 2,087 — 6,768 Preferred stock of subsidiaries — — 339 — 339 Equity Controlling interests 6,526 13,919 19,161 (33,080 ) 6,526 Noncontrolling interests — — 3,006 — 3,006 Total equity 6,526 13,919 22,167 (33,080 ) 9,532 Total Liabilities and Equity $ 14,005 $ 24,471 $ 37,347 $ (42,900 ) $ 32,923 Spectra Energy Corp Condensed Consolidating Balance Sheet December 31, 2014 (In millions) Spectra Energy Corp Spectra Capital Non-Guarantor Subsidiaries Eliminations Consolidated Cash and cash equivalents $ — $ 1 $ 214 $ — $ 215 Receivables—consolidated subsidiaries 18 — 11 (29 ) — Receivables—other 2 — 1,334 — 1,336 Other current assets 71 2 708 — 781 Total current assets 91 3 2,267 (29 ) 2,332 Investments in and loans to unconsolidated affiliates — — 2,966 — 2,966 Investments in consolidated subsidiaries 14,531 20,562 — (35,093 ) — Advances receivable—consolidated subsidiaries — 4,683 898 (5,581 ) — Notes receivable—consolidated subsidiaries — — 3,198 (3,198 ) — Goodwill — — 4,714 — 4,714 Other assets 38 22 267 — 327 Net property, plant and equipment — — 22,307 — 22,307 Regulatory assets and deferred debits 4 5 1,343 — 1,352 Total Assets $ 14,664 $ 25,275 $ 37,960 $ (43,901 ) $ 33,998 Accounts payable $ 3 $ — $ 455 $ — $ 458 Accounts payable—consolidated subsidiaries — 17 12 (29 ) — Commercial paper — 398 1,185 — 1,583 Short-term borrowings—consolidated subsidiaries — 398 — (398 ) — Taxes accrued 5 — 86 — 91 Current maturities of long-term debt — — 327 — 327 Other current liabilities 96 54 1,200 — 1,350 Total current liabilities 104 867 3,265 (427 ) 3,809 Long-term debt — 2,890 9,837 — 12,727 Advances payable—consolidated subsidiaries 5,581 — — (5,581 ) — Notes payable—consolidated subsidiaries — 2,800 — (2,800 ) — Deferred credits and other liabilities 819 4,187 1,800 — 6,806 Preferred stock of subsidiaries — — 258 — 258 Equity Controlling interests 8,160 14,531 20,562 (35,093 ) 8,160 Noncontrolling interests — — 2,238 — 2,238 Total equity 8,160 14,531 22,800 (35,093 ) 10,398 Total Liabilities and Equity $ 14,664 $ 25,275 $ 37,960 $ (43,901 ) $ 33,998
Condensed Consolidating Statement of Cash Flows	Spectra Energy Corp Condensed Consolidating Statement of Cash Flows Year Ended December 31, 2015 (In millions) Spectra Energy Corp Spectra Capital Non-Guarantor Subsidiaries Eliminations Consolidated CASH FLOWS FROM OPERATING ACTIVITIES Net income $ 196 $ 161 $ 837 $ (734 ) $ 460 Adjustments to reconcile net income to net cash provided by (used in) operating activities: Depreciation and amortization — — 778 — 778 Impairment charges — — 349 — 349 Loss from equity investments — — 290 — 290 Equity in earnings of consolidated subsidiaries (161 ) (573 ) — 734 — Distributions from equity investments — — 161 — 161 Other 187 33 (11 ) — 209 Net cash provided by (used in) operating activities 222 (379 ) 2,404 — 2,247 CASH FLOWS FROM INVESTING ACTIVITIES Capital expenditures — — (2,848 ) — (2,848 ) Investments in and loans to unconsolidated affiliates — — (124 ) — (124 ) Purchases of held-to-maturity securities — — (668 ) — (668 ) Proceeds from sales and maturities of held-to-maturity securities — — 695 — 695 Purchases of available-for-sale securities — — (95 ) — (95 ) Proceeds from sales and maturities of available-for-sale securities — — 87 — 87 Distributions from equity investments — — 451 — 451 Advances (to) from affiliates (240 ) 296 — (56 ) — Loan to equity investment — — (248 ) — (248 ) Other changes in restricted funds — — (33 ) — (33 ) Other — — 1 — 1 Net cash provided by (used in) investing activities (240 ) 296 (2,782 ) (56 ) (2,782 ) CASH FLOWS FROM FINANCING ACTIVITIES Proceeds from the issuance of long-term debt — — 1,585 — 1,585 Payments for the redemption of long-term debt — — (285 ) — (285 ) Net increase (decrease) in commercial paper — 83 (522 ) — (439 ) Distributions to noncontrolling interests — — (198 ) — (198 ) Contributions from noncontrolling interests — — 248 — 248 Proceeds from the issuance of SEP common units — — 546 — 546 Proceeds from the issuance of Westcoast preferred stock — — 84 — 84 Dividends paid on common stock (996 ) — — — (996 ) Distributions and advances from (to) affiliates 1,018 — (1,074 ) 56 — Other (4 ) — (1 ) — (5 ) Net cash provided by financing activities 18 83 383 56 540 Effect of exchange rate changes on cash — — (7 ) — (7 ) Net decrease in cash and cash equivalents — — (2 ) — (2 ) Cash and cash equivalents at beginning of period — 1 214 — 215 Cash and cash equivalents at end of period $ — $ 1 $ 212 $ — $ 213 Spectra Energy Corp Condensed Consolidating Statement of Cash Flows Year Ended December 31, 2014 (In millions) Spectra Energy Corp Spectra Capital Non-Guarantor Subsidiaries Eliminations Consolidated CASH FLOWS FROM OPERATING ACTIVITIES Net income $ 1,082 $ 1,054 $ 1,852 $ (2,705 ) $ 1,283 Adjustments to reconcile net income to net cash provided by (used in) operating activities: Depreciation and amortization — — 809 — 809 Earnings from equity investments — — (361 ) — (361 ) Equity in earnings of consolidated subsidiaries (1,054 ) (1,651 ) — 2,705 — Distributions from equity investments — — 380 — 380 Other 14 304 (208 ) — 110 Net cash provided by (used in) operating activities 42 (293 ) 2,472 — 2,221 CASH FLOWS FROM INVESTING ACTIVITIES Capital expenditures — — (2,028 ) — (2,028 ) Investments in and loans to unconsolidated affiliates — — (259 ) — (259 ) Purchases of held-to-maturity securities — — (790 ) — (790 ) Proceeds from sales and maturities of held-to-maturity securities — — 815 — 815 Purchases of available-for-sale securities — — (13 ) — (13 ) Proceeds from sales and maturities of available-for-sale securities — — 7 — 7 Distributions from equity investments — — 266 — 266 Advances from affiliates 92 495 — (587 ) — Other changes in restricted funds — — (1 ) — (1 ) Net cash provided by (used in) investing activities 92 495 (2,003 ) (587 ) (2,003 ) CASH FLOWS FROM FINANCING ACTIVITIES Proceeds from the issuance of long-term debt — 300 728 — 1,028 Payments for the redemption of long-term debt — (557 ) (627 ) — (1,184 ) Net increase in commercial paper — 54 520 — 574 Distributions to noncontrolling interests — — (175 ) — (175 ) Contributions from noncontrolling interests — — 145 — 145 Proceeds from the issuance of SEP common units — — 327 — 327 Dividends paid on common stock (925 ) — — — (925 ) Distributions and advances from (to) affiliates 777 (10 ) (1,354 ) 587 — Other 14 — (3 ) — 11 Net cash used in financing activities (134 ) (213 ) (439 ) 587 (199 ) Effect of exchange rate changes on cash — — (5 ) — (5 ) Net increase (decrease) in cash and cash equivalents — (11 ) 25 — 14 Cash and cash equivalents at beginning of period — 12 189 — 201 Cash and cash equivalents at end of period $ — $ 1 $ 214 $ — $ 215 Spectra Energy Corp Condensed Consolidating Statement of Cash Flows Year Ended December 31, 2013 (In millions) Spectra Energy Corp Spectra Capital (a) Non-Guarantor Subsidiaries (a) Eliminations Consolidated CASH FLOWS FROM OPERATING ACTIVITIES Net income $ 1,038 $ 1,015 $ 1,770 $ (2,664 ) $ 1,159 Adjustments to reconcile net income to net cash provided by (used in) operating activities: Depreciation and amortization — — 787 — 787 Earnings from equity investments — — (445 ) — (445 ) Equity in earnings of consolidated subsidiaries (1,015 ) (1,649 ) — 2,664 — Distributions from equity investments — — 324 — 324 Other (2 ) 478 (271 ) — 205 Net cash provided by (used in) operating activities 21 (156 ) 2,165 — 2,030 CASH FLOWS FROM INVESTING ACTIVITIES Capital expenditures — — (1,947 ) — (1,947 ) Investments in and loans to unconsolidated affiliates — — (312 ) — (312 ) Acquisitions, net of cash acquired — — (1,254 ) — (1,254 ) Purchases of held-to-maturity securities — — (985 ) — (985 ) Proceeds from sales and maturities of held-to-maturity securities — — 1,023 — 1,023 Purchases of available-for-sale securities — — (5,878 ) — (5,878 ) Proceeds from sales and maturities of available-for-sale securities — — 6,024 — 6,024 Distributions from equity investments — — 87 — 87 Advances to affiliates (75 ) (1,856 ) — 1,931 — Loan to equity investment — — (71 ) — (71 ) Repayment of loan to equity investment — 71 — — 71 Other changes in restricted funds — — 2 — 2 Other — — 4 — 4 Net cash used in investing activities (75 ) (1,785 ) (3,307 ) 1,931 (3,236 ) CASH FLOWS FROM FINANCING ACTIVITIES Proceeds from the issuance of long-term debt — 1,848 2,524 — 4,372 Payments for the redemption of long-term debt — (1,944 ) (195 ) — (2,139 ) Net decrease in commercial paper — (170 ) (36 ) — (206 ) Net increase in short-term borrowings - consolidated subsidiaries — (497 ) — 497 — Distributions to noncontrolling interests — — (144 ) — (144 ) Contributions from noncontrolling interests — — 23 — 23 Proceeds from the issuance of SEP common units — — 214 — 214 Dividends paid on common stock (821 ) — — — (821 ) Distributions and advances from (to) affiliates 847 2,718 (1,137 ) (2,428 ) — Other 28 (5 ) (6 ) — 17 Net cash provided by financing activities 54 1,950 1,243 (1,931 ) 1,316 Effect of exchange rate changes on cash — — (3 ) — (3 ) Net increase in cash and cash equivalents — 9 98 — 107 Cash and cash equivalents at beginning of period — 3 91 — 94 Cash and cash equivalents at end of period $ — $ 12 $ 189 $ — $ 201 ____________ (a) Excludes the effects of $3,869 million of non-cash equitizations of advances receivable owed to Spectra Capital.

Quarterly Financial Data (Una56

Quarterly Financial Data (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2015
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Data	First Quarter Second Quarter Third Quarter Fourth Quarter Total (in millions, except per share amounts) 2015 Operating revenues $ 1,623 $ 1,192 $ 1,103 $ 1,316 $ 5,234 Operating income 541 406 389 97 1,433 Net income (loss) 325 80 243 (188 ) 460 Net income (loss)—controlling interests 267 18 174 (263 ) 196 Earnings (loss) per share (a) Basic and diluted 0.40 0.03 0.26 (0.39 ) 0.29 2014 Operating revenues $ 1,843 $ 1,253 $ 1,207 $ 1,600 $ 5,903 Operating income 639 338 382 565 1,924 Net income 467 188 254 374 1,283 Net income—controlling interests 419 146 201 316 1,082 Earnings per share (a) Basic 0.63 0.22 0.30 0.47 1.61 Diluted 0.62 0.22 0.30 0.47 1.61 ___________ (a) Quarterly earnings-per-share amounts are stand-alone calculations and may not be additive to full-year amounts due to rounding.

Summary of Operations and Sig57

Summary of Operations and Significant Accounting Policies (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015		Dec. 31, 2014	Dec. 31, 2013
Significant Accounting Policies [Line Items]
Percentage of consolidated revenues by customer	There were no customers accounting for 10% or more of consolidated revenues during 2015, 2014 or 2013.		There were no customers accounting for 10% or more of consolidated revenues during 2015, 2014 or 2013.	There were no customers accounting for 10% or more of consolidated revenues during 2015, 2014 or 2013.
Allowance for funds used during construction	$ 143		$ 72	$ 155
Equity component of allowance for funds used during construction	111		53	105
Interest expense component of allowance for funds used during construction	32		19	50
Receivables, net	806		1,336
Current Liabilities-Other	860		1,169
Unamortized Debt Issuance Expense	46	[1]	42
Goodwill, Impairment Loss	333		0	0
BC Pipeline and BC Field Services
Significant Accounting Policies [Line Items]
Goodwill, Impairment Loss	270
Empress
Significant Accounting Policies [Line Items]
Goodwill, Impairment Loss	63
Natural Gas Imbalances
Significant Accounting Policies [Line Items]
Receivables, net	291		642
Current Liabilities-Other	287		634
Other Expense
Significant Accounting Policies [Line Items]
Foreign currency transaction gains (losses)	$ 6		3	$ 1
DCP Midstream, LLC
Significant Accounting Policies [Line Items]
Equity Method Investment, Ownership Percentage	50.00%
Restatement Adjustment [Member]
Significant Accounting Policies [Line Items]
Unamortized Debt Issuance Expense	$ 46		$ 42
[1]	Reflects implementation of ASU No. 2015-03 as discussed in Note 1.

Spectra Energy Partners, LP - A

Spectra Energy Partners, LP - Additional Information (Detail) - USD ($) $ in Millions	Nov. 04, 2015	Oct. 30, 2015	Nov. 30, 2014	Nov. 30, 2013	Aug. 31, 2013	Apr. 30, 2013	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Nov. 03, 2014	Nov. 01, 2013
Spectra Energy Partners, LP
Related Party Transaction [Line Items]
Partners' Capital Account, Units, Sale of Units							12,000,000	6,400,000	600,000
Proceeds from Issuance or Sale of Equity						$ 193	$ 546	$ 327	$ 24
Partners Capital Account Sale Of Units Net Of Tax						$ 190
General Partner | Spectra Energy Partners, LP
Related Party Transaction [Line Items]
Partners' Capital Account, Units, Sale of Units						100,000	245,000	132,000
Limited Partner | Spectra Energy Partners, LP
Related Party Transaction [Line Items]
Partners' Capital Account, Units, Sale of Units						5,200,000
Spectra Energy Partners, LP
Related Party Transaction [Line Items]
Percentage of ownership interests							78.00%
Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Non-current Liabilities Long Term Debt Including Current Portion											$ 2,400
Equity interest issued (in shares)	17,114		4,300,000						167,600,000
General partner units issued (in shares)	342									86,000	3,400,000
Partners' Capital Account, Sale of Units			$ 29						$ 733
Partners Capital Account Sale Of Units Net Of Tax			16						458
Noncontrolling Interest, Period Increase (Decrease)			$ 29						$ 733
Percentage of Voting Rights Contributed									60.00%
Payments to Acquire Businesses, Gross									$ 2,300
Spectra Energy Partners, LP | SandHills SouthernHills NGL Pipelines
Related Party Transaction [Line Items]
Percentage of Voting Rights Contributed							33.30%
Spectra Energy Partners, LP | Bobcat
Related Party Transaction [Line Items]
Percentage of Voting Rights Contributed							100.00%
Spectra Energy Partners, LP | Texas Eastern
Related Party Transaction [Line Items]
Percentage of Voting Rights Contributed							100.00%
Spectra Energy Partners, LP | Southeast Supply Header
Related Party Transaction [Line Items]
Business Acquisition, Percentage of Voting Interests NOT acquired									25.05%
Percentage of Voting Rights Contributed	0.10%		24.95%				50.00%
Spectra Energy Partners, LP | Algonquin
Related Party Transaction [Line Items]
Percentage of Voting Rights Contributed							100.00%
Spectra Energy Partners, LP | Maritimes Northeast Pipeline Llc
Related Party Transaction [Line Items]
Percentage of Voting Rights Contributed							38.77%
Spectra Energy Partners, LP | Gulfstream
Related Party Transaction [Line Items]
Percentage of Voting Rights Contributed							1.00%
Spectra Energy Partners, LP | Market Hub Partners Holdings
Related Party Transaction [Line Items]
Percentage of Voting Rights Contributed							50.00%
Spectra Energy Partners, LP | Steckman Ridge LP
Related Party Transaction [Line Items]
Business Acquisition, Percentage of Voting Interests NOT acquired									1.00%
Percentage of Voting Rights Contributed			1.00%				50.00%
Spectra Energy Partners, LP | General Partner
Related Party Transaction [Line Items]
Percentage of ownership interests	2.00%						2.00%
Percentage of Voting Rights Maintained			2.00%
United States | Spectra Energy Partners, LP | Express Platte Pipeline System
Related Party Transaction [Line Items]
Percentage of Voting Rights Contributed							60.00%
SandHills SouthernHills NGL Pipelines | Spectra Energy Partners, LP
Related Party Transaction [Line Items]
Business Acquisition, Percentage of Voting Interests Acquired		33.30%
SandHills SouthernHills NGL Pipelines | Spectra Energy Partners, LP | General Partner
Related Party Transaction [Line Items]
Partners' Capital Account, Units, Redeemed		440,000
SandHills SouthernHills NGL Pipelines | Spectra Energy Partners, LP | Limited Partner
Related Party Transaction [Line Items]
Partners' Capital Account, Units, Redeemed		21,560,000
Express Platte Pipeline System | Spectra Energy Partners, LP
Related Party Transaction [Line Items]
Payments to Acquire Businesses, Gross					$ 410
Express Platte Pipeline System | Spectra Energy Partners, LP
Related Party Transaction [Line Items]
Equity interest issued (in shares)					7,200,000
Partners' Capital Account, Sale of Units					$ 84
Partners Capital Account Sale Of Units Net Of Tax					53
Noncontrolling Interest, Period Increase (Decrease)					$ 84
Express Platte Pipeline System | United States | Spectra Energy Partners, LP
Related Party Transaction [Line Items]
Percentage of Voting Rights Contributed					40.00%
Express Platte Pipeline System | Canada | Spectra Energy Partners, LP
Related Party Transaction [Line Items]
Percentage of voting rights sold					100.00%
Additional Paid-in Capital | Spectra Energy Partners, LP
Related Party Transaction [Line Items]
Partners' Capital Account, Sale of Units									$ 61
Partners Capital Account Sale Of Units Net Of Tax									38
Noncontrolling Interests | Spectra Energy Partners, LP
Related Party Transaction [Line Items]
Noncontrolling Interest, Increase from Subsidiary Equity Issuance									$ 128
Minimum | Spectra Energy Partners, LP
Related Party Transaction [Line Items]
Proceeds from Issuance or Sale of Equity				$ 400
Maximum | Spectra Energy Partners, LP
Related Party Transaction [Line Items]
Proceeds from Issuance or Sale of Equity				$ 1,000
Reduction in Quarterly Distribution [Member] | SandHills SouthernHills NGL Pipelines | Spectra Energy Partners, LP
Related Party Transaction [Line Items]
Proceeds from Contributions from Affiliates		$ 4

Acquisitions and Dispositions -

Acquisitions and Dispositions - Additional Information (Detail) - USD ($) $ in Millions	Oct. 30, 2015	Mar. 14, 2013	Mar. 31, 2013	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Mar. 31, 2014
Business Acquisition [Line Items]
Acquisitions, net of cash acquired				$ 0	$ 0	$ 1,254
Goodwill				$ 4,154	4,714	$ 4,810
Express Platte
Business Acquisition [Line Items]
Business Acquisition, Percentage of Voting Interests Acquired		100.00%
Business combination, consideration transferred		$ 1,500
Acquisitions, net of cash acquired			$ 1,250
Long-term debt acquired		260
Property, plant and equipment		1,251
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Other		9
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Other		259
Goodwill		523
Cash purchase price		$ 1,250
Sand Hills and Southern Hills
Business Acquisition [Line Items]
Partners' Capital Account, Sale of Units	$ 166
Noncontrolling Interest, Period Increase (Decrease)	$ 166
Spectra Energy Partners, LP | Sand Hills and Southern Hills
Business Acquisition [Line Items]
Business Acquisition, Percentage of Voting Interests Acquired	33.30%
Spectra Energy Partners, LP | United States | Express Platte
Business Acquisition [Line Items]
Percentage of Voting Rights Contributed in Transaction				100.00%
Spectra Energy Partners, LP | Canada | Express Platte
Business Acquisition [Line Items]
Percentage of voting rights sold				100.00%
Change in Approximate Fair Value | Express Platte
Business Acquisition [Line Items]
Property, plant and equipment							$ 60
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Other							1
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Other							24
Goodwill							$ 37
SandHills SouthernHills NGL Pipelines | DCP Midstream, LLC
Business Acquisition [Line Items]
Percentage of Voting Rights Contributed in Transaction	33.30%					33.30%
Limited Partner | Spectra Energy Partners, LP | SandHills SouthernHills NGL Pipelines
Business Acquisition [Line Items]
Partners' Capital Account, Units, Redeemed	21,560,000
General Partner | Spectra Energy Partners, LP | SandHills SouthernHills NGL Pipelines
Business Acquisition [Line Items]
Partners' Capital Account, Units, Redeemed	440,000
Spectra Energy Corp
Business Acquisition [Line Items]
Acquisitions, net of cash acquired						$ 0
Goodwill				$ 0	$ 0
Spectra Energy Corp | DCP Midstream, LLC
Business Acquisition [Line Items]
Equity Method Investment, Ownership Percentage				50.00%

Acquisitions and Dispositions60

Acquisitions and Dispositions - Summary of Fair Values of Assets and Liabilities Acquired (Detail) - USD ($) $ in Millions	Mar. 14, 2013	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Business Acquisition [Line Items]
Goodwill		$ 4,154	$ 4,714	$ 4,810
Express-Platte
Business Acquisition [Line Items]
Cash purchase price	$ 1,250
Working capital and other purchase adjustments	71
Total	1,321
Cash	67
Receivables	25
Other current assets	9
Property, plant and equipment	1,251
Accounts payable	(18)
Other current liabilities	(17)
Deferred credits and other liabilities	(259)
Long-term debt, including current portion	(260)
Total assets acquired/liabilities assumed	798
Goodwill	$ 523

Business Segments - Additional

Business Segments - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2015reportable_segments
Segment Reporting Information [Line Items]
Number of reportable segments	4
DCP Midstream, LLC | DCP Midstream Partners, LP
Segment Reporting Information [Line Items]
Equity Method Investment, Ownership Percentage	21.00%
Phillips 66 | DCP Midstream, LLC
Segment Reporting Information [Line Items]
Equity Method Investment, Ownership Percentage	50.00%
Spectra Energy Corp | DCP Midstream, LLC
Segment Reporting Information [Line Items]
Equity Method Investment, Ownership Percentage	50.00%

Business Segment Data (Detail)

Business Segment Data (Detail) - USD ($) $ in Millions		3 Months Ended								12 Months Ended
		Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting Information [Line Items]
Operating revenues		$ 1,316	$ 1,103	$ 1,192	$ 1,623	$ 1,600	$ 1,207	$ 1,253	$ 1,843	$ 5,234	$ 5,903	$ 5,518
Capital and Investment Expenditures	[1],[2]									2,972	2,287	2,259
Assets		32,923				33,998				32,923	33,998	33,486
Depreciation and amortization										764	796	772
Interest expense										636	679	657
Earnings Before Income Taxes										621	1,665	1,578
Unaffiliated Revenues
Segment Reporting Information [Line Items]
Operating revenues										5,234	5,903	5,518
Intersegment Revenues
Segment Reporting Information [Line Items]
Operating revenues										0	0	0
Operating Segments
Segment Reporting Information [Line Items]
Interest Expense, Other	[3]									(3)
Interest income and other	[3]										6	7
Spectra Energy Partners, LP | Unaffiliated Revenues
Segment Reporting Information [Line Items]
Operating revenues										2,455	2,269	1,964
Spectra Energy Partners, LP | Intersegment Revenues
Segment Reporting Information [Line Items]
Operating revenues										0	0	1
Spectra Energy Partners, LP | Operating Segments
Segment Reporting Information [Line Items]
Operating revenues										2,455	2,269	1,965
Earnings Before Interest Taxes Depreciation And Amortization										1,905	1,669	1,433
Capital and Investment Expenditures	[1],[2]									2,007	1,241	1,299
Assets		18,983				17,850				18,983	17,850	16,783
Depreciation and amortization										297	290	263
Distribution | Unaffiliated Revenues
Segment Reporting Information [Line Items]
Operating revenues										1,527	1,843	1,848
Distribution | Operating Segments
Segment Reporting Information [Line Items]
Operating revenues										1,527	1,843	1,848
Earnings Before Interest Taxes Depreciation And Amortization										473	552	574
Capital and Investment Expenditures	[1],[2]									544	427	357
Assets		5,209				6,055				5,209	6,055	6,000
Depreciation and amortization										176	192	199
Western Canada Transmission & Processing | Unaffiliated Revenues
Segment Reporting Information [Line Items]
Operating revenues										1,242	1,781	1,694
Western Canada Transmission & Processing | Intersegment Revenues
Segment Reporting Information [Line Items]
Operating revenues										43	121	73
Western Canada Transmission & Processing | Operating Segments
Segment Reporting Information [Line Items]
Operating revenues										1,285	1,902	1,767
Earnings Before Interest Taxes Depreciation And Amortization										491	754	736
Capital and Investment Expenditures	[1],[2]									360	473	561
Assets		5,909				6,913				5,909	6,913	7,157
Depreciation and amortization										243	271	272
Field Services | Operating Segments
Segment Reporting Information [Line Items]
Earnings Before Interest Taxes Depreciation And Amortization										(461)	217	343
Assets		1,660				1,345				1,660	1,345	1,365
Total Reportable Segments | Unaffiliated Revenues
Segment Reporting Information [Line Items]
Operating revenues										5,224	5,893	5,506
Total Reportable Segments | Intersegment Revenues
Segment Reporting Information [Line Items]
Operating revenues										43	121	74
Total Reportable Segments | Operating Segments
Segment Reporting Information [Line Items]
Operating revenues										5,267	6,014	5,580
Earnings Before Interest Taxes Depreciation And Amortization										2,408	3,192	3,086
Capital and Investment Expenditures	[1],[2]									2,911	2,141	2,217
Assets		31,761				32,163				31,761	32,163	31,305
Depreciation and amortization										716	753	734
Other | Unaffiliated Revenues
Segment Reporting Information [Line Items]
Operating revenues										10	10	12
Other | Intersegment Revenues
Segment Reporting Information [Line Items]
Operating revenues										63	62	60
Other | Operating Segments
Segment Reporting Information [Line Items]
Operating revenues										73	72	72
Earnings Before Interest Taxes Depreciation And Amortization										(384)	(58)	(86)
Capital and Investment Expenditures	[1],[2]									61	146	42
Assets		1,226				1,893				1,226	1,893	2,680
Depreciation and amortization										48	43	38
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Operating revenues										(106)	(183)	(134)
Assets		$ (64)				$ (58)				(64)	(58)	(499)
Intersegment Eliminations [Member] | Intersegment Revenues
Segment Reporting Information [Line Items]
Operating revenues										$ (106)	$ (183)	$ (134)
[1]	Excludes a $71 million loan to an equity investment in 2013 at Spectra Energy Partners.
[2]	Excludes the $1,254 million cash outlay for the acquisition of Express-Platte in 2013, part of Spectra Energy Partners.
[3]	(c)Includes foreign currency transaction gains and losses related to segment EBITDA.

Business Segment Data (Notes) (

Business Segment Data (Notes) (Detail) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Mar. 31, 2013	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting Information [Line Items]
Purchase price		$ 0	$ 0	$ 1,254
Unconsolidated affiliates | Spectra Energy Partners, LP
Segment Reporting Information [Line Items]
Loans and Leases Receivable, Related Parties				$ 71
Spectra Energy Partners, LP | Express-Platte
Segment Reporting Information [Line Items]
Purchase price	$ 1,254

Business Segments - Geographic

Business Segments - Geographic Data (Detail) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting Information [Line Items]
Consolidated revenues	$ 1,316	$ 1,103	$ 1,192	$ 1,623	$ 1,600	$ 1,207	$ 1,253	$ 1,843	$ 5,234	$ 5,903	$ 5,518
Consolidated long-lived assets	28,528				28,549				28,528	28,549	28,210
United States
Segment Reporting Information [Line Items]
Consolidated revenues									2,389	2,212	1,926
Consolidated long-lived assets	17,549				15,834				17,549	15,834	14,963
Canada
Segment Reporting Information [Line Items]
Consolidated revenues									2,845	3,691	3,592
Consolidated long-lived assets	$ 10,979				$ 12,715				$ 10,979	$ 12,715	$ 13,247

Regulatory Assets and Liabiliti

Regulatory Assets and Liabilities (Detail) - USD ($) $ in Millions		Dec. 31, 2015	Dec. 31, 2014
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory Assets, Current	[1]	$ 114	$ 147
Regulatory Assets, Noncurrent	[2]	1,283	1,347
Regulatory Assets		1,397	1,494
Regulatory Liability, Current	[1]	80	59
Regulatory Liability, Noncurrent	[2]	305	371
Regulatory Liabilities		385	430
Gas purchase costs (c)
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory Liability, Current	[3]	48	0
Other
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory Liability, Current	[4]	32	59
Regulatory Liability, Noncurrent	[4]	23	20
Removal costs
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory Liability, Noncurrent	[4]	258	326
Pipeline rate credit
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory Liability, Noncurrent		24	25
Under-recovery of fuel costs (c)
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory Assets, Current	[3]	41	44
Gas purchase costs (c)
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory Assets, Current	[3]	0	57
Other
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory Assets, Current		73	46
Regulatory Assets, Noncurrent		13	13
Net regulatory asset related to income taxes (d,e)
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory Assets, Noncurrent	[4],[5]	1,215	1,271
Project development costs (d)
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory Assets, Noncurrent		9	10
Vacation accrual (d)
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory Assets, Noncurrent		23	22
Deferred debt expense/premium (d)
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory Assets, Noncurrent	[4]	$ 23	$ 31
[1]	(a)Included in Inventory, Fuel Tracker, Current Assets—Other or Current Liabilities—Other.
[2]	(b)Included in Regulatory Assets and Deferred Debits or Deferred Credits and Other Liabilities—Regulatory and Other.
[3]	(c)Includes costs settled in cash annually through transportation rates in accordance with FERC and/or OEB gas tariffs.
[4]	(d)All or a portion of the balance is included in rate base.
[5]	(e)All amounts are expected to be included in future rate filings.

Regulatory Matters - Additional

Regulatory Matters - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Regulatory Matters [Line Items]
Regulatory assets	$ 1,397	$ 1,494
Regulatory liabilities	385	430
Union Gas Limited | Deferred Income Tax Charge
Regulatory Matters [Line Items]
Regulatory assets	291	303
Union Gas Limited | Customer Receipts
Regulatory Matters [Line Items]
Regulatory assets		57
BC Pipeline and BC Field Services | Deferred Income Tax Charge
Regulatory Matters [Line Items]
Regulatory assets	727	795
Removal costs | Union Gas Limited
Regulatory Matters [Line Items]
Regulatory liabilities	258	322
Customer Receipts | Union Gas Limited
Regulatory Matters [Line Items]
Regulatory liabilities	48
Accounts Receivable [Member] | Union Gas Limited
Regulatory Matters [Line Items]
Public Utilities, Approved Rate Increase (Decrease), Amount	$ 8	$ 9

Income Taxes - Income Tax Expen

Income Taxes - Income Tax Expense Components (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Current income taxes
Federal	$ 0	$ 1	$ (32)
State	13	3	4
Foreign	60	(10)	26
Total current income taxes	73	(6)	(2)
Deferred income taxes
Federal	145	335	353
State	(18)	(17)	69
Foreign	(39)	70	(1)
Total deferred income taxes	88	388	421
Total income tax expense	$ 161	$ 382	$ 419

Income Taxes - Earnings from Co

Income Taxes - Earnings from Continuing Operations before Income Taxes (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Domestic	$ 636	$ 1,108	$ 1,059
Foreign	(15)	557	519
Earnings Before Income Taxes	$ 621	$ 1,665	$ 1,578

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Income Tax Expense at U.S. Federal Statutory Tax Rate to Actual Income Tax Expense from Continuing Operations (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Income tax expense, computed at the statutory rate of 35%	$ 217	$ 583	$ 552
State income tax, net of federal income tax effect	12	25	20
Tax differential on foreign earnings	(44)	(125)	(147)
Noncontrolling interests	(92)	(70)	(42)
Valuation allowance	1	2	(3)
Goodwill impairment	91	0	0
Revaluation of accumulated deferred state taxes	(12)	(25)	31
Other items, net	(12)	(8)	8
Total income tax expense	$ 161	$ 382	$ 419
Effective tax rate	25.90%	22.90%	26.60%
Effective Income Tax Rate Reconciliation, Statutory tax rate	35.00%	35.00%	35.00%

Income Taxes - Net Deferred Inc

Income Taxes - Net Deferred Income Tax Liability Components (Detail) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Deferred credits and other liabilities	$ 275	$ 225
Net operating loss carryforward	295	158
Other	36	53
Total deferred income tax assets	606	436
Valuation allowance	(27)	(29)
Net deferred income tax assets	579	407
Investments and other assets	(1,605)	(1,531)
Accelerated depreciation rates	(4,035)	(3,875)
Regulatory assets and deferred debits	(384)	(426)
Total deferred income tax liabilities	(6,024)	(5,832)
Total net deferred income tax liabilities	$ (5,445)	$ (5,425)

Income Taxes - Deferred Tax Amo

Income Taxes - Deferred Tax Amounts Classified in Consolidated Balance Sheets (Detail) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Other current liabilities	$ 0	$ (20)
Deferred credits and other liabilities	(5,445)	(5,405)
Total net deferred income tax liabilities	$ (5,445)	$ (5,425)

Income Taxes - Reconciliation72

Income Taxes - Reconciliation of Gross Unrecognized Income Tax Benefits (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at beginning of period	$ 50	$ 76	$ 80
Increases related to prior year tax positions	10	10	7
Decreases related to prior year tax positions	(1)	(6)	(17)
Increases related to current year tax positions	30	1	2
Settlements	0	0	(3)
Lapse of statute of limitations	(4)	(30)	9
Foreign currency translation	(3)	(1)	(2)
Balance at end of period	$ 82	$ 50	$ 76

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Contingency [Line Items]
Unrecognized tax benefits	$ 82	$ 50	$ 76	$ 80
Unrecognized tax benefits that would reduce the annual effective tax rate if recognized in next fiscal year	39
Net increase in gross uncertain tax benefits	32
Uncertain tax benefits, deferred tax liabilities and foreign currency exchange rate fluctuations	22
Uncertain tax benefits, increase in income tax expense	10
Interest income related to unrecognized tax benefits	2	2
Accrued interest and penalties related to unrecognized tax benefits	21	19
Undistributed earnings of foreign subsidiaries	1,500
Minimum
Income Tax Contingency [Line Items]
Decrease in Unrecognized Tax Benefits is Reasonably Possible	30
Maximum
Income Tax Contingency [Line Items]
Decrease in Unrecognized Tax Benefits is Reasonably Possible	40
United States
Income Tax Contingency [Line Items]
Net Operating Loss Carryforward	726
Deferred tax asset attributable to the federal net operating loss	$ 254
Valuation allowance against deferred tax asset attributable to net operating loss carryforward		9
United States | Minimum
Income Tax Contingency [Line Items]
Net operating loss carryforwards, expiration date	2,021
Subject to examination income tax return fillings, date	2,011
United States | Maximum
Income Tax Contingency [Line Items]
Subject to examination income tax return fillings, date	2,014
State
Income Tax Contingency [Line Items]
Net Operating Loss Carryforward	$ 381
Deferred tax asset attributable to the state net operating loss carryovers	20
Valuation allowance against deferred tax asset attributable to net operating loss carryforward	$ 1	1
State | Minimum
Income Tax Contingency [Line Items]
Net operating loss carryforwards, expiration date	2,016
Subject to examination income tax return fillings, date	2,007
State | Maximum
Income Tax Contingency [Line Items]
Subject to examination income tax return fillings, date	2,014
Foreign Country
Income Tax Contingency [Line Items]
Net Operating Loss Carryforward	$ 80
Deferred tax asset attributable to foreign net operating loss	21
Valuation allowance against deferred tax asset attributable to net operating loss carryforward	1	1
Capital loss carryforward	$ 124
Capital loss carryforward, expiration date	indefinite
Deferred tax asset attributable to foreign capital loss carryforward	$ 16
Valuation allowance against deferred tax asset related to foreign capital loss carryforward	$ 16	$ 20
Foreign Country | Minimum
Income Tax Contingency [Line Items]
Net operating loss carryforwards, expiration date	2,026
Canada | Minimum
Income Tax Contingency [Line Items]
Subject to examination income tax return fillings, date	2,009
Canada | Maximum
Income Tax Contingency [Line Items]
Subject to examination income tax return fillings, date	2,014

Earnings per Common Share Optio

Earnings per Common Share Options or Stock Awards Not Included in EPS (Details) - shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0	0	0

Earnings per Common Share - Bas

Earnings per Common Share - Basic and Diluted Eps Calculations (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended																12 Months Ended
	Dec. 31, 2015		Sep. 30, 2015		Jun. 30, 2015		Mar. 31, 2015		Dec. 31, 2014		Sep. 30, 2014		Jun. 30, 2014		Mar. 31, 2014		Dec. 31, 2015		Dec. 31, 2014		Dec. 31, 2013
Earnings Per Share [Abstract]
Net Income—Controlling Interests	$ (263)		$ 174		$ 18		$ 267		$ 316		$ 201		$ 146		$ 419		$ 196		$ 1,082		$ 1,038
Weighted average common shares, outstanding
Basic (in shares)																	671		671		669
Diluted (in shares)																	672		672		671
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Basic (in usd per share)	$ (0.39)	[1]	$ 0.26	[1]	$ 0.03	[1]	$ 0.40	[1]	$ 0.47	[1]	$ 0.30	[1]	$ 0.22	[1]	$ 0.63	[1]	$ 0.29	[1]	$ 1.61	[1]	$ 1.55
Diluted (in usd per share)	$ (0.39)	[1]	$ 0.26	[1]	$ 0.03	[1]	$ 0.40	[1]	$ 0.47	[1]	$ 0.30	[1]	$ 0.22	[1]	$ 0.62	[1]	$ 0.29	[1]	$ 1.61	[1]	$ 1.55
[1]	Quarterly earnings-per-share amounts are stand-alone calculations and may not be additive to full-year amounts due to rounding.

Accumulated Other Comprehensi76

Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Increase (Decrease) in Accumulated Other Comprehensive Income [Roll Forward]
Balance at beginning of period	$ 662	$ 1,241
Reclassified to net income		5
Other AOCI activity	(931)	(584)
Balance at end of period	(269)	662
Foreign Currency Translation Adjustments
Increase (Decrease) in Accumulated Other Comprehensive Income [Roll Forward]
Balance at beginning of period	1,016	1,557
Reclassified to net income		0
Other AOCI activity	(937)	(541)
Balance at end of period	79	1,016
Pension and Post-retirement Benefit Plan Obligations
Increase (Decrease) in Accumulated Other Comprehensive Income [Roll Forward]
Balance at beginning of period	(351)	(304)
Reclassified to net income		0
Other AOCI activity	5	(47)
Balance at end of period	(346)	(351)
Gas Purchase Contract Hedges
Increase (Decrease) in Accumulated Other Comprehensive Income [Roll Forward]
Balance at beginning of period	(3)	(11)
Reclassified to net income		4
Other AOCI activity	0	4
Balance at end of period	(3)	(3)
Other
Increase (Decrease) in Accumulated Other Comprehensive Income [Roll Forward]
Balance at beginning of period	0	(1)
Reclassified to net income		1
Other AOCI activity	1	0
Balance at end of period	$ 1	$ 0

Inventory - Components of Inven

Inventory - Components of Inventory (Detail) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Inventory Disclosure [Abstract]
Natural gas	$ 217	$ 211
NGLs	23	28
Materials and supplies	67	74
Total inventory	$ 307	$ 313

Inventory - Additional Informat

Inventory - Additional Information (Detail) - Western Canada Transmission & Processing - Empress Operations - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Inventories [Line Items]
Inventory Write-down	$ 14	$ 19
Inventory Write-down, net of tax	$ 10	$ 14

Investments in and Loans to U79

Investments in and Loans to Unconsolidated Affiliates and Related Party Transactions Investments in and Loans to Unconsolidated Affiliates - Additional Information (Detail) - USD ($) $ in Millions	Nov. 04, 2015	Oct. 30, 2015	Dec. 31, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Schedule of Equity Method Investments [Line Items]
Distributions from equity investments				$ 161	$ 380	$ 324
Distributions From Equity Investments				612	646	411
Retained Earnings, Undistributed Earnings from Equity Method Investees			$ 28	28	482
Earnings (loss) from equity investments				(290)	361	445
Spectra Energy Partners, LP
Schedule of Equity Method Investments [Line Items]
Equity interest issued (in shares)	17,114
General partner units issued (in shares)	342
General Partners' Capital Account Percentage Interest	2.00%
Earnings (loss) from equity investments				$ 167	133	90
Gulfstream | Spectra Energy Partners, LP
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage			39.00%	39.00%
Southeast Supply Header | Spectra Energy Partners, LP
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage			39.00%	39.00%
Percentage of Voting Rights Contributed	0.10%
Steckman Ridge LP | Spectra Energy Partners, LP
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage			39.00%	39.00%
Loans and Leases Receivable, Related Parties			$ 71	$ 71	71
Interest Income, Related Party				$ 1	1	1
DCP Midstream, LLC
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage			50.00%	50.00%
Earnings (loss) from equity investments				$ 2	$ 73	$ 98
Maximum | Steckman Ridge LP
Schedule of Equity Method Investments [Line Items]
Related Party Loan Due Date					Oct. 1, 2023
Reduction in Quarterly Distribution [Member] | SandHills SouthernHills NGL Pipelines | Spectra Energy Partners, LP
Schedule of Equity Method Investments [Line Items]
Proceeds from Contributions from Affiliates		$ 4
Investment Income (Expense) | DCP Midstream, LLC
Schedule of Equity Method Investments [Line Items]
Goodwill Impairment Recorded by Equity Method Investment				460
Other Asset Impairment Recorded by Equity Method Investment			$ 342
Goodwill, Impairment Loss, Net of Tax				$ 231
SandHills SouthernHills NGL Pipelines | DCP Midstream, LLC
Schedule of Equity Method Investments [Line Items]
Percentage of Voting Rights Contributed in Transaction		33.30%
Limited Partner | Spectra Energy Partners, LP | SandHills SouthernHills NGL Pipelines
Schedule of Equity Method Investments [Line Items]
Partners' Capital Account, Units, Redeemed		21,560,000
General Partner | Spectra Energy Partners, LP | SandHills SouthernHills NGL Pipelines
Schedule of Equity Method Investments [Line Items]
Partners' Capital Account, Units, Redeemed		440,000

Investments in and Loans to U80

Investments in and Loans to Unconsolidated Affiliates and Related Party Transactions Investments in and Loans to Unconsolidated Affiliates (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Schedule of Equity Method Investments [Line Items]
Investments in and loans to unconsolidated affiliates	$ 2,592	$ 2,966
Domestic [Member]
Schedule of Equity Method Investments [Line Items]
Investments in and loans to unconsolidated affiliates	2,564	2,934
International [Member]
Schedule of Equity Method Investments [Line Items]
Investments in and loans to unconsolidated affiliates	28	32
Spectra Energy Partners, LP
Schedule of Equity Method Investments [Line Items]
Investments in and loans to unconsolidated affiliates	904	1,588
Spectra Energy Partners, LP | Domestic [Member]
Schedule of Equity Method Investments [Line Items]
Investments in and loans to unconsolidated affiliates	904	1,588
Spectra Energy Partners, LP | International [Member]
Schedule of Equity Method Investments [Line Items]
Investments in and loans to unconsolidated affiliates	0	0
Distribution
Schedule of Equity Method Investments [Line Items]
Investments in and loans to unconsolidated affiliates	11	14
Distribution | Domestic [Member]
Schedule of Equity Method Investments [Line Items]
Investments in and loans to unconsolidated affiliates	0	0
Distribution | International [Member]
Schedule of Equity Method Investments [Line Items]
Investments in and loans to unconsolidated affiliates	11	14
Western Canada Transmission & Processing
Schedule of Equity Method Investments [Line Items]
Investments in and loans to unconsolidated affiliates	17	18
Western Canada Transmission & Processing | Domestic [Member]
Schedule of Equity Method Investments [Line Items]
Investments in and loans to unconsolidated affiliates	0	0
Western Canada Transmission & Processing | International [Member]
Schedule of Equity Method Investments [Line Items]
Investments in and loans to unconsolidated affiliates	17	18
Field Services
Schedule of Equity Method Investments [Line Items]
Investments in and loans to unconsolidated affiliates	1,660	1,345
Field Services | Domestic [Member]
Schedule of Equity Method Investments [Line Items]
Investments in and loans to unconsolidated affiliates	1,660	1,345
Field Services | International [Member]
Schedule of Equity Method Investments [Line Items]
Investments in and loans to unconsolidated affiliates	0	0
Other
Schedule of Equity Method Investments [Line Items]
Investments in and loans to unconsolidated affiliates	0	1
Other | Domestic [Member]
Schedule of Equity Method Investments [Line Items]
Investments in and loans to unconsolidated affiliates	0	1
Other | International [Member]
Schedule of Equity Method Investments [Line Items]
Investments in and loans to unconsolidated affiliates	$ 0	$ 0

Investments in and Loans to U81

Investments in and Loans to Unconsolidated Affiliates and Related Party Transactions Equity in Earnings of Unconsolidated Affiliates (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Schedule of Equity Method Investments [Line Items]
Earnings (loss) from equity investments	$ (290)	$ 361	$ 445
Domestic [Member]
Schedule of Equity Method Investments [Line Items]
Earnings (loss) from equity investments	(293)	359	445
International [Member]
Schedule of Equity Method Investments [Line Items]
Earnings (loss) from equity investments	3	2	0
Spectra Energy Partners, LP
Schedule of Equity Method Investments [Line Items]
Earnings (loss) from equity investments	167	133	90
Spectra Energy Partners, LP | Domestic [Member]
Schedule of Equity Method Investments [Line Items]
Earnings (loss) from equity investments	167	133	90
Spectra Energy Partners, LP | International [Member]
Schedule of Equity Method Investments [Line Items]
Earnings (loss) from equity investments	0	0	0
Distribution
Schedule of Equity Method Investments [Line Items]
Earnings (loss) from equity investments	1	1	1
Distribution | Domestic [Member]
Schedule of Equity Method Investments [Line Items]
Earnings (loss) from equity investments	0	0	0
Distribution | International [Member]
Schedule of Equity Method Investments [Line Items]
Earnings (loss) from equity investments	1	1	1
Western Canada Transmission & Processing
Schedule of Equity Method Investments [Line Items]
Earnings (loss) from equity investments	2	1	(1)
Western Canada Transmission & Processing | Domestic [Member]
Schedule of Equity Method Investments [Line Items]
Earnings (loss) from equity investments	0	0	0
Western Canada Transmission & Processing | International [Member]
Schedule of Equity Method Investments [Line Items]
Earnings (loss) from equity investments	2	1	(1)
Field Services
Schedule of Equity Method Investments [Line Items]
Earnings (loss) from equity investments	(461)	217	343
Field Services | Domestic [Member]
Schedule of Equity Method Investments [Line Items]
Earnings (loss) from equity investments	(461)	217	343
Field Services | International [Member]
Schedule of Equity Method Investments [Line Items]
Earnings (loss) from equity investments	0	0	0
Other
Schedule of Equity Method Investments [Line Items]
Earnings (loss) from equity investments	1	9	12
Other | Domestic [Member]
Schedule of Equity Method Investments [Line Items]
Earnings (loss) from equity investments	1	9	12
Other | International [Member]
Schedule of Equity Method Investments [Line Items]
Earnings (loss) from equity investments	$ 0	$ 0	$ 0

Investments in and Loans to U82

Investments in and Loans to Unconsolidated Affiliates and Related Party Transactions Summarized Statements of Operations of Unconsolidated Affiliates Presented at 100 Percent (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Schedule of Equity Method Investments [Line Items]
Operating Revenues	$ 8,187	$ 14,757	$ 12,596
Operating Expenses	8,515	13,581	11,491
Operating Income	(328)	1,176	1,105
Net Income	(450)	868	790
Net Income Attributable to Members' Interests	(536)	620	697
DCP Midstream, LLC
Schedule of Equity Method Investments [Line Items]
Operating Revenues	7,420	14,013	12,038
Operating Expenses	8,227	13,262	11,230
Operating Income	(807)	751	808
Net Income	(843)	536	584
Net Income Attributable to Members' Interests	(929)	288	491
Other Affiliates [Member]
Schedule of Equity Method Investments [Line Items]
Operating Revenues	767	744	558
Operating Expenses	288	319	261
Operating Income	479	425	297
Net Income	393	332	206
Net Income Attributable to Members' Interests	$ 393	$ 332	$ 206

Investments in and Loans to U83

Investments in and Loans to Unconsolidated Affiliates and Related Party Transactions Summarized Balance Sheets of Unconsolidated Affiliates Presented at 100 Percent (Detail) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Schedule of Equity Method Investments [Line Items]
Current Assets	$ 1,298	$ 1,621
Non-current Assets	16,359	17,657
Current Liabilities	1,283	3,570
Non-current Liabilities	7,573	6,735
Equity - Total	8,801	8,973
Equity - Noncontrolling Interests	(2,404)	(2,578)
Equity - Controlling Interests	6,397	6,395
DCP Midstream, LLC
Schedule of Equity Method Investments [Line Items]
Current Assets	800	1,380
Non-current Assets	13,094	12,299
Current Liabilities	896	2,938
Non-current Liabilities	5,894	5,538
Equity - Total	7,104	5,203
Equity - Noncontrolling Interests	(2,404)	(2,578)
Equity - Controlling Interests	4,700	2,625
Other Affiliates [Member]
Schedule of Equity Method Investments [Line Items]
Current Assets	498	241
Non-current Assets	3,265	5,358
Current Liabilities	387	632
Non-current Liabilities	1,679	1,197
Equity - Total	1,697	3,770
Equity - Noncontrolling Interests	0	0
Equity - Controlling Interests	$ 1,697	$ 3,770

Investments in and Loans to U84

Investments in and Loans to Unconsolidated Affiliates and Related Party Transactions Related Party Transactions (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Related Party Transaction [Line Items]
Distributions from equity investments		$ 161	$ 380	$ 324
Current Liabilities-Other		860	1,169
DCP Midstream, LLC
Related Party Transaction [Line Items]
Accounts Receivable, Related Parties		1	1
Distributions from equity investments			237	215
DCP Midstream, LLC | Other Revenue, Net [Member]
Related Party Transaction [Line Items]
Revenue from Related Parties		46	79	48
DCP Midstream, LLC | Gas Gathering, Transportation, Marketing and Processing Revenue Excluding Sales of Natural Gas Liquids [Member]
Related Party Transaction [Line Items]
Revenue from Related Parties		4	9	9
DCP Midstream, LLC | Sales of Natural Gas Liquids [Member]
Related Party Transaction [Line Items]
Revenue from Related Parties		4	7	8
Gulfstream
Related Party Transaction [Line Items]
Distributions from equity investments	$ 396
Unsecured Debt	$ 800
Payments to Acquire Equity Method Investments		248
Gulfstream unsecured debt maturing 1H2016		148
Current Liabilities-Other		148
SESH [Member]
Related Party Transaction [Line Items]
Distributions from equity investments			200
Unsecured Debt			400
Payments to Acquire Equity Method Investments			200
Other Affiliates [Member]
Related Party Transaction [Line Items]
Recovery of Direct Costs		28	38	$ 68
Due from Related Parties		11	$ 1
Nexus Transmission, LLC [Member]
Related Party Transaction [Line Items]
Recovery of Direct Costs		$ 139

Goodwill - Components and Activ

Goodwill - Components and Activity within Goodwill (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Goodwill [Roll Forward]
Beginning balance	$ 4,714	$ 4,810
Acquisition of Express-Platte		37
Impairment of goodwill	(333)	0	$ 0
Foreign currency translation	(227)	(133)
Ending balance	4,154	4,714	4,810
Spectra Energy Partners, LP
Goodwill [Roll Forward]
Beginning balance	3,244	3,215
Acquisition of Express-Platte		37
Impairment of goodwill	0
Foreign currency translation	(12)	(8)
Ending balance	3,232	3,244	3,215
Distribution
Goodwill [Roll Forward]
Beginning balance	759	824
Acquisition of Express-Platte		0
Impairment of goodwill	0
Foreign currency translation	(110)	(65)
Ending balance	649	759	824
Western Canada Transmission & Processing
Goodwill [Roll Forward]
Beginning balance	711	771
Acquisition of Express-Platte		0
Impairment of goodwill	(333)
Foreign currency translation	(105)	(60)
Ending balance	$ 273	$ 711	$ 771

Goodwill - Amounts Originating

Goodwill - Amounts Originating from Acquisition of Westcoast Energy Inc. (Detail) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Goodwill [Line Items]
Goodwill	$ 4,154	$ 4,714	$ 4,810
Distribution
Goodwill [Line Items]
Goodwill	649	759	824
Western Canada Transmission & Processing
Goodwill [Line Items]
Goodwill	273	711	$ 771
Westcoast Energy Inc. | Distribution
Goodwill [Line Items]
Goodwill	646	757
Westcoast Energy Inc. | Western Canada Transmission & Processing
Goodwill [Line Items]
Goodwill	$ 246	$ 677

Goodwill - Impairment of Goodwi

Goodwill - Impairment of Goodwill (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Goodwill [Line Items]
Goodwill, Impairment Loss	$ 333	$ 0	$ 0
BC Pipeline and BC Field Services
Goodwill [Line Items]
Goodwill, Impairment Loss	270
Empress
Goodwill [Line Items]
Goodwill, Impairment Loss	63
Western Canada Transmission & Processing
Goodwill [Line Items]
Goodwill, Impairment Loss	333
Western Canada Transmission & Processing | BC Pipeline and BC Field Services
Goodwill [Line Items]
Goodwill, Impairment Loss	270
Western Canada Transmission & Processing | Empress
Goodwill [Line Items]
Goodwill, Impairment Loss	$ 63

Marketable Securities and Res88

Marketable Securities and Restricted Funds - Estimated Fair Values of Available for Sale Securities (Detail) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Total available-for-sale securities	$ 31	$ 24
Corporate Debt Securities
Schedule of Available-for-sale Securities [Line Items]
Total available-for-sale securities	31	23
Money Market Funds
Schedule of Available-for-sale Securities [Line Items]
Total available-for-sale securities	$ 0	$ 1

Marketable Securities and Res89

Marketable Securities and Restricted Funds - Restricted and Nonrestricted AFS Securities by Balance Sheet Classification Table Text (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Total available-for-sale securities	$ 31	$ 24
Investments and Other Assets - Other
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Restricted	11	1
Available-for-sale Securities	0	20
Current Assets - Other
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities	$ 20	$ 3

Marketable Securities and Res90

Marketable Securities and Restricted Funds Available for Sale Securities Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Change in Net Unrealized Holding Gain (Loss), Net of Tax	$ 0	$ 0
Available-for-sale Securities [Member] | Maximum
Schedule of Available-for-sale Securities [Line Items]
Weighted Average Contractual Maturity Of Outstanding Securities	1 year

- Estimated Fair Values of Held

- Estimated Fair Values of Held to Maturity Securities (Detail) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Schedule of Held-to-maturity Securities [Line Items]
Total held-to-maturity securities	$ 119	$ 172
Current Assets - Other | Bankers Acceptance
Schedule of Held-to-maturity Securities [Line Items]
Total held-to-maturity securities	30	38
Current Assets - Other | Canadian Government Securities
Schedule of Held-to-maturity Securities [Line Items]
Total held-to-maturity securities	24	30
Current Assets - Other | Money Market Funds
Schedule of Held-to-maturity Securities [Line Items]
Total held-to-maturity securities	3	3
Investments and Other Assets - Other | Bankers Acceptance
Schedule of Held-to-maturity Securities [Line Items]
Total held-to-maturity securities	12	0
Investments and Other Assets - Other | Canadian Government Securities
Schedule of Held-to-maturity Securities [Line Items]
Total held-to-maturity securities	$ 50	$ 101

Marketable Securities and Res92

Marketable Securities and Restricted Funds Held to Maturity Securities Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity Securities, Unrecognized Holding Gain	$ 0	$ 0
M&N Canada six point nine zero percent senior secured notes due 2014 to 2019 [Member] | Maritimes & Northeast Pipeline Limited Partnership [Member]
Schedule of Held-to-maturity Securities [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	6.90%
Held-to-maturity Securities [Member] | Maximum
Schedule of Held-to-maturity Securities [Line Items]
Weighted Average Contractual Maturity Of Outstanding Securities	1 year

Marketable Securities and Res93

Marketable Securities and Restricted Funds Other Restricted Funds Additional Information (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Current Assets - Other
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted Cash and Cash Equivalents, Current	$ 11	$ 13
Investments And Other Assets [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted Cash and Cash Equivalents, Noncurrent	38	$ 6
Project Costs [Member] | Investments And Other Assets [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted Cash and Cash Equivalents, Noncurrent	14
Canadian Pipeline Abandonment Requirement [Member] | Investments And Other Assets [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted Cash and Cash Equivalents, Noncurrent	$ 24

Marketable Securities and Res94

Marketable Securities and Restricted Funds Interest Income Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Other Income [Member]
Net Investment Income [Line Items]
Investment Income, Interest	$ 3	$ 4	$ 6

Property Plant and Equipment (D

Property Plant and Equipment (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	$ 29,843	$ 29,211
Total accumulated depreciation	(6,527)	(6,543)
Total accumulated amortization	(398)	(361)
Net property, plant and equipment	22,918	22,307
Plant | Natural gas transmission
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	$ 15,690	15,001
Plant | Natural gas transmission | Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	15 years
Plant | Natural gas transmission | Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	100 years
Plant | Natural gas distribution
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	$ 2,651	2,971
Plant | Natural gas distribution | Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	25 years
Plant | Natural gas distribution | Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	60 years
Plant | Gathering and processing facilities
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	$ 4,178	4,765
Plant | Gathering and processing facilities | Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	25 years
Plant | Gathering and processing facilities | Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	40 years
Plant | Natural gas storage
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	$ 2,137	2,162
Plant | Natural gas storage | Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	10 years
Plant | Natural gas storage | Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	122 years
Plant | Crude oil transportation and storage
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	$ 1,206	1,169
Plant | Crude oil transportation and storage | Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	30 years
Plant | Crude oil transportation and storage | Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	75 years
Plant | Land rights and rights of way
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	$ 591	568
Plant | Land rights and rights of way | Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	21 years
Plant | Land rights and rights of way | Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	122 years
Plant | Other buildings and improvements
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	$ 149	132
Plant | Other buildings and improvements | Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	10 years
Plant | Other buildings and improvements | Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	50 years
Equipment
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	$ 301	343
Equipment | Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	3 years
Equipment | Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	40 years
Vehicles
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	$ 102	114
Vehicles | Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	5 years
Vehicles | Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	20 years
Land
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	$ 138	150
Construction in process
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	1,919	1,113
Software
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	$ 439	387
Software | Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	4 years
Software | Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	10 years
Other
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	$ 342	$ 336
Other | Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	5 years
Other | Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	82 years

Property, Plant and Equipment -

Property, Plant and Equipment - Estimated Amortization Expense for Next Five Years (Detail) $ in Millions	Dec. 31, 2015USD ($)
Estimated Amortization Expense
2,016	$ 84
2,017	80
2,018	54
2,019	35
2,020	$ 28

Property, Plant And Equipment97

Property, Plant And Equipment - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Abstract]
Capital Leases, Balance Sheet, Assets by Major Class, Net	$ 0	$ 0
Percentage of public utilities property plant and equipment regulated with estimated useful lives based on rates approved by regulatory authorities	85.00%
Composite weighted-average depreciation rates	2.72%	2.82%	2.96%
Amortization expense of intangible assets	$ 79,000,000	$ 74,000,000	$ 65,000,000

Reconciliation of Changes in As

Reconciliation of Changes in Asset Retirement Obligation Liabilities (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015		Dec. 31, 2014
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at beginning of year		$ 400	[1]	$ 350
Accretion expense		17		16
Revisions in estimated cash flows (a)	[2]	72		72
Foreign currency exchange impact		(62)		(28)
Liabilities settled		(9)		(10)
Balance at end of year (b)	[1]	$ 418		$ 400
[1]	Amounts included in Deferred Credits and Other Liabilities in the Consolidated Balance Sheets.
[2]	Reflects revised assumptions regarding ARO Liabilities due to a reduction in the remaining estimated life of certain Texas Eastern offshore facilities in 2015 and asbestos abatement at Western Canada Transmission & Processing in 2014.

Asset Retirement Obligations -

Asset Retirement Obligations - Additional Information (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014
Reconciliation Of Changes In Asset Retirement Obligations [Line Items]
Asset retirement obligation, revision of estimate	[1]	$ 72	$ 72
Spectra Energy Partners, LP
Reconciliation Of Changes In Asset Retirement Obligations [Line Items]
Asset retirement obligation, revision of estimate	[1]	$ 32
Western Canada Transmission & Processing
Reconciliation Of Changes In Asset Retirement Obligations [Line Items]
Asset retirement obligation, revision of estimate	[1]		$ 44
[1]	Reflects revised assumptions regarding ARO Liabilities due to a reduction in the remaining estimated life of certain Texas Eastern offshore facilities in 2015 and asbestos abatement at Western Canada Transmission & Processing in 2014.

Debt and Credit Facilities - Su

Debt and Credit Facilities - Summary of Debt and Related Terms (Detail) - USD ($) $ in Millions		Dec. 31, 2015		Dec. 31, 2014
Debt Instrument [Line Items]
Short-term Debt, Weighted Average Interest Rate		0.90%		0.60%
Long-term debt principal (including current maturities)		$ 13,567		$ 13,060
Change in fair value of debt hedged		22		17
Unamortized debt discount, net		(22)		(12)
Unamortized Debt Issuance Expense		(46)	[1]	(42)
Other unamortized items		4		7
Total other non-principal amounts		(42)		(30)
Commercial paper	[2],[3]	1,112		1,583
Capital Leases		19		24
Total debt (including capital lease obligations)	[4]	14,656		14,637
Current maturities of long-term debt		(652)		(327)
Total long-term debt (including capital lease obligations)		12,892		12,727
Secured debt		274
Spectra Energy Capital, LLC
Debt Instrument [Line Items]
Long-term debt principal (including current maturities)		2,890		2,890
Commercial paper		481		398
Current maturities of long-term debt		0		0
Spectra Energy Capital, LLC | 6.20% senior unsecured notes due April 2018
Debt Instrument [Line Items]
Unsecured Debt		500		500
Spectra Energy Capital, LLC | 6.75% senior unsecured notes due July 2018
Debt Instrument [Line Items]
Unsecured Debt		150		150
Spectra Energy Capital, LLC | Variable-rate senior unsecured term loan due November 2018
Debt Instrument [Line Items]
Unsecured Debt		300		300
Spectra Energy Capital, LLC | 8.00% senior unsecured notes due October 2019
Debt Instrument [Line Items]
Unsecured Debt		500		500
Spectra Energy Capital, LLC | 5.65% senior unsecured notes due March 2020
Debt Instrument [Line Items]
Unsecured Debt		300		300
Spectra Energy Capital, LLC | 3.30% senior unsecured notes due March 2023
Debt Instrument [Line Items]
Unsecured Debt		650		650
Spectra Energy Capital, LLC | 6.75% senior unsecured notes due February 2032
Debt Instrument [Line Items]
Unsecured Debt		240		240
Spectra Energy Capital, LLC | 7.50% senior unsecured notes due September 2038
Debt Instrument [Line Items]
Unsecured Debt		250		250
Spectra Energy Partners, LP
Debt Instrument [Line Items]
Long-term debt principal (including current maturities)		6,152		5,184
Spectra Energy Partners, LP | SEP 2.95% senior unsecured notes due June 2016
Debt Instrument [Line Items]
Unsecured Debt		250		250
Spectra Energy Partners, LP | SEP 2.95% senior unsecured notes due September 2018
Debt Instrument [Line Items]
Unsecured Debt		500		500
Spectra Energy Partners, LP | SEP variable-rate senior unsecured term loan due November 2018
Debt Instrument [Line Items]
Unsecured Debt		400		400
Spectra Energy Partners, LP | SEP 4.60% senior unsecured notes due June 2021
Debt Instrument [Line Items]
Unsecured Debt		250		250
Spectra Energy Partners, LP | SEP 4.75% senior unsecured notes due March 2024
Debt Instrument [Line Items]
Unsecured Debt		1,000		1,000
Spectra Energy Partners, LP | SEP 3.50% senior unsecured notes due March 2025
Debt Instrument [Line Items]
Unsecured Debt		500		0
Spectra Energy Partners, LP | SEP 5.95% senior unsecured notes due September 2043
Debt Instrument [Line Items]
Unsecured Debt		400		400
Spectra Energy Partners, LP | SEP 4.50% senior unsecured notes due March 2045
Debt Instrument [Line Items]
Unsecured Debt		500		0
Texas Eastern | Texas Eastern 6.00% senior unsecured notes due September 2017
Debt Instrument [Line Items]
Unsecured Debt		400		400
Texas Eastern | Texas Eastern 4.13% senior unsecured notes due December 2020
Debt Instrument [Line Items]
Unsecured Debt		300		300
Texas Eastern | Texas Eastern 2.80% senior unsecured notes due October 2022
Debt Instrument [Line Items]
Unsecured Debt		500		500
Texas Eastern | Texas Eastern 7.00% senior unsecured notes due July 2032
Debt Instrument [Line Items]
Unsecured Debt		450		450
Algonquin | Algonquin 3.51% senior notes due July 2024
Debt Instrument [Line Items]
Unsecured Debt		350		350
East Tennessee Natural Gas, LLC | East Tennessee Natural Gas, LLC 3.10% senior notes due December 2024
Debt Instrument [Line Items]
Unsecured Debt		200		200
Express-Platte | Express-Platte 6.09% senior secured notes due January 2020
Debt Instrument [Line Items]
Secured debt		110		110
Express-Platte | Express-Platte 7.39% subordinated secured notes due 2015 to 2019
Debt Instrument [Line Items]
Secured debt		42		74
Westcoast
Debt Instrument [Line Items]
Long-term debt principal (including current maturities)		2,256		2,542
Westcoast | 8.50% debentures due November 2015
Debt Instrument [Line Items]
Unsecured Debt		0		108
Westcoast | 3.28% medium-term notes due January 2016
Debt Instrument [Line Items]
Unsecured Debt		181		215
Westcoast | 8.50% debentures due September 2018
Debt Instrument [Line Items]
Unsecured Debt		108		129
Westcoast | 5.60% medium-term notes due January 2019
Debt Instrument [Line Items]
Unsecured Debt		217		258
Westcoast | 9.90% debentures due January 2020
Debt Instrument [Line Items]
Unsecured Debt		72		86
Westcoast | 4.57% medium-term notes due July 2020
Debt Instrument [Line Items]
Unsecured Debt		181		215
Westcoast | 3.88% medium-term notes due October 2021
Debt Instrument [Line Items]
Unsecured Debt		108		129
Westcoast | 3.12% medium-term notes due December 2022
Debt Instrument [Line Items]
Unsecured Debt		181		215
Westcoast | 3.43% medium-term notes due September 2024
Debt Instrument [Line Items]
Unsecured Debt		253		301
Westcoast | 8.85% debentures due July 2025
Debt Instrument [Line Items]
Unsecured Debt		108		129
Westcoast | 8.80% medium-term notes due November 2025
Debt Instrument [Line Items]
Unsecured Debt		18		22
Westcoast | 3.77% medium-term notes due December 2025
Debt Instrument [Line Items]
Unsecured Debt		217		0
Westcoast | 7.30% debentures due December 2026
Debt Instrument [Line Items]
Unsecured Debt		90		108
Westcoast | 6.75% medium-term notes due December 2027
Debt Instrument [Line Items]
Unsecured Debt		108		129
Westcoast | 7.15% medium-term notes due March 2031
Debt Instrument [Line Items]
Unsecured Debt		145		172
Westcoast | 4.79% medium-term notes due October 2041
Debt Instrument [Line Items]
Unsecured Debt		145		129
Westcoast | Other
Debt Instrument [Line Items]
Unsecured Debt		2		2
M&N Canada | M&N Canada 6.90% senior secured notes due 2015 to 2019
Debt Instrument [Line Items]
Secured debt		75		112
M&N Canada | M&N Canada 4.34% senior secured notes due 2015 to 2019
Debt Instrument [Line Items]
Secured debt		47		83
Union Gas
Debt Instrument [Line Items]
Long-term debt principal (including current maturities)		2,269		2,444
Union Gas | 11.50% debentures due August 2015
Debt Instrument [Line Items]
Unsecured Debt		0		129
Union Gas | 4.64% medium-term notes due June 2016
Debt Instrument [Line Items]
Unsecured Debt		145		172
Union Gas | 9.70% debentures due November 2017
Debt Instrument [Line Items]
Unsecured Debt		90		108
Union Gas | 5.35% medium-term notes due April 2018
Debt Instrument [Line Items]
Unsecured Debt		145		172
Union Gas | 8.75% debentures due August 2018
Debt Instrument [Line Items]
Unsecured Debt		90		108
Union Gas | 8.65% senior debentures due October 2018
Debt Instrument [Line Items]
Unsecured Debt		54		64
Union Gas | 2.76% medium-term notes due June 2021
Debt Instrument [Line Items]
Unsecured Debt		145		172
Union Gas | 4.85% medium-term notes due April 2022
Debt Instrument [Line Items]
Unsecured Debt		90		108
Union Gas | 3.79% medium-term notes due July 2023
Debt Instrument [Line Items]
Unsecured Debt		181		215
Union Gas | 3.19% medium-term notes due September 2025
Debt Instrument [Line Items]
Unsecured Debt		145		0
Union Gas | 8.65% debentures due November 2025
Debt Instrument [Line Items]
Unsecured Debt		90		108
Union Gas | 5.46% medium-term notes due September 2036
Debt Instrument [Line Items]
Unsecured Debt		119		142
Union Gas | 6.05% medium-term notes due September 2038
Debt Instrument [Line Items]
Unsecured Debt		216		258
Union Gas | 5.20% medium-term notes due July 2040
Debt Instrument [Line Items]
Unsecured Debt		181		215
Union Gas | 4.88% medium-term notes due June 2041
Debt Instrument [Line Items]
Unsecured Debt		217		258
Union Gas | 4.20% medium-term notes due June 2044
Debt Instrument [Line Items]
Unsecured Debt		$ 361		$ 215
[1]	Reflects implementation of ASU No. 2015-03 as discussed in Note 1.
[2]	The weighted-average days to maturity was 12 days as of December 31, 2015 and 14 days as of December 31, 2014.
[3]	Weighted-average rate on outstanding commercial paper was 0.9% at December 31, 2015 and 0.6% at December 31, 2014.
[4]	As of December 31, 2015 and 2014, respectively, $4,681 million and $5,264 million of debt was denominated in Canadian dollars.

Debt and Credit Facilities -101

Debt and Credit Facilities - Summary of Debt and Related Terms (Notes) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Commercial paper weighted average life period	12 days	14 days
Short-term Debt, Weighted Average Interest Rate	0.90%	0.60%
Canadian Dollars Denominated
Debt Instrument [Line Items]
Long-term debt	$ 4,681	$ 5,264
Spectra Energy Capital, LLC | 6.20% senior unsecured notes due April 2018
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	6.20%
Debt instrument, maturity date, description	April 2,018
Spectra Energy Capital, LLC | 6.75% senior unsecured notes due July 2018
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	6.75%
Debt instrument, maturity date, description	July 2,018
Spectra Energy Capital, LLC | Variable-rate senior unsecured term loan due November 2018
Debt Instrument [Line Items]
Debt instrument, maturity date, description	November 2,018
Spectra Energy Capital, LLC | 8.00% senior unsecured notes due October 2019
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	8.00%
Debt instrument, maturity date, description	October 2,019
Spectra Energy Capital, LLC | 5.65% senior unsecured notes due March 2020
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	5.65%
Debt instrument, maturity date, description	March 2,020
Spectra Energy Capital, LLC | 3.30% senior unsecured notes due March 2023
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	3.30%
Debt instrument, maturity date, description	March 2,023
Spectra Energy Capital, LLC | 6.75% senior unsecured notes due February 2032
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	6.75%
Debt instrument, maturity date, description	February 2,032
Spectra Energy Capital, LLC | 7.50% senior unsecured notes due September 2038
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	7.50%
Debt instrument, maturity date, description	September 2,038
Spectra Energy Partners, LP | SEP 2.95% senior unsecured notes due June 2016
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	2.95%
Debt instrument, maturity date, description	June 2,016
Spectra Energy Partners, LP | SEP 2.95% senior unsecured notes due September 2018
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	2.95%
Debt instrument, maturity date, description	September 2,018
Spectra Energy Partners, LP | SEP variable-rate senior unsecured term loan due November 2018
Debt Instrument [Line Items]
Debt instrument, maturity date, description	November 2,018
Spectra Energy Partners, LP | SEP 4.60% senior unsecured notes due June 2021
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	4.60%
Debt instrument, maturity date, description	June 2,021
Spectra Energy Partners, LP | SEP 4.75% senior unsecured notes due March 2024
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	4.75%
Debt instrument, maturity date, description	March 2,024
Spectra Energy Partners, LP | SEP 3.50% senior unsecured notes due March 2025
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	3.50%
Debt instrument, maturity date, description	March 2,025
Spectra Energy Partners, LP | SEP 5.95% senior unsecured notes due September 2043
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	5.95%
Debt instrument, maturity date, description	September 2,043
Spectra Energy Partners, LP | SEP 4.50% senior unsecured notes due March 2045
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	4.50%
Debt instrument, maturity date, description	March 2,045
Texas Eastern | Texas Eastern 6.00% senior unsecured notes due September 2017
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	6.00%
Debt instrument, maturity date, description	September 2,017
Texas Eastern | Texas Eastern 4.13% senior unsecured notes due December 2020
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	4.13%
Debt instrument, maturity date, description	December 2,020
Texas Eastern | Texas Eastern 2.80% senior unsecured notes due October 2022
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	2.80%
Debt instrument, maturity date, description	October 2,022
Texas Eastern | Texas Eastern 7.00% senior unsecured notes due July 2032
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	7.00%
Debt instrument, maturity date, description	July 2,032
Algonquin | Algonquin 3.51% senior notes due July 2024
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	3.51%
Debt instrument, maturity date, description	July 2,024
East Tennessee Natural Gas, LLC | East Tennessee Natural Gas, LLC 3.10% senior notes due December 2024
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	3.10%
Debt instrument, maturity date, description	December 2,024
Express-Platte | Express-Platte 6.09% senior secured notes due January 2020
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	6.09%
Debt instrument, maturity date, description	January 2,020
Express-Platte | Express-Platte 7.39% subordinated secured notes due 2015 to 2019
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	7.39%
Debt instrument, maturity date, description	2015 to 2019
Westcoast | 8.50% debentures due November 2015
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	8.50%
Debt instrument, maturity date, description	November 2,015
Westcoast | 3.28% medium-term notes due January 2016
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	3.28%
Debt instrument, maturity date, description	January 2,016
Westcoast | 8.50% debentures due September 2018
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	8.50%
Debt instrument, maturity date, description	September 2,018
Westcoast | 5.60% medium-term notes due January 2019
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	5.60%
Debt instrument, maturity date, description	January 2,019
Westcoast | 9.90% debentures due January 2020
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	9.90%
Debt instrument, maturity date, description	January 2,020
Westcoast | 4.57% medium-term notes due July 2020
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	4.57%
Debt instrument, maturity date, description	July 2,020
Westcoast | 3.88% medium-term notes due October 2021
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	3.88%
Debt instrument, maturity date, description	October 2,021
Westcoast | 3.12% medium-term notes due December 2022
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	3.12%
Debt instrument, maturity date, description	December 2,022
Westcoast | 3.43% medium-term notes due September 2024
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	3.43%
Debt instrument, maturity date, description	September 2,024
Westcoast | 8.85% debentures due July 2025
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	8.85%
Debt instrument, maturity date, description	July 2,025
Westcoast | 8.80% medium-term notes due November 2025
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	8.80%
Debt instrument, maturity date, description	November 2,025
Westcoast | 3.77% medium-term notes due December 2025
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	3.77%
Debt instrument, maturity date, description	December 2,025
Westcoast | 7.30% debentures due December 2026
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	7.30%
Debt instrument, maturity date, description	December 2,026
Westcoast | 6.75% medium-term notes due December 2027
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	6.75%
Debt instrument, maturity date, description	December 2,027
Westcoast | 7.15% medium-term notes due March 2031
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	7.15%
Debt instrument, maturity date, description	March 2,031
Westcoast | 4.79% medium-term notes due October 2041
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	4.79%
Debt instrument, maturity date, description	October 2,041
M&N Canada | M&N Canada 6.90% senior secured notes due 2015 to 2019
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	6.90%
Debt instrument, maturity date, description	2015 to 2019
M&N Canada | M&N Canada 4.34% senior secured notes due 2015 to 2019
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	4.34%
Debt instrument, maturity date, description	2015 to 2019
Union Gas | 11.50% debentures due August 2015
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	11.50%
Debt instrument, maturity date, description	August 2,015
Union Gas | 4.64% medium-term notes due June 2016
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	4.64%
Debt instrument, maturity date, description	June 2,016
Union Gas | 9.70% debentures due November 2017
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	9.70%
Debt instrument, maturity date, description	November 2,017
Union Gas | 5.35% medium-term notes due April 2018
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	5.35%
Debt instrument, maturity date, description	April 2,018
Union Gas | 8.75% debentures due August 2018
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	8.75%
Debt instrument, maturity date, description	August 2,018
Union Gas | 8.65% senior debentures due October 2018
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	8.65%
Debt instrument, maturity date, description	October 2,018
Union Gas | 2.76% medium-term notes due June 2021
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	2.76%
Debt instrument, maturity date, description	June 2,021
Union Gas | 4.85% medium-term notes due April 2022
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	4.85%
Debt instrument, maturity date, description	April 2,022
Union Gas | 3.79% medium-term notes due July 2023
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	3.79%
Debt instrument, maturity date, description	July 2,023
Union Gas | 3.19% medium-term notes due September 2025
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	3.19%
Debt instrument, maturity date, description	September 2,025
Union Gas | 8.65% debentures due November 2025
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	8.65%
Debt instrument, maturity date, description	November 2,025
Union Gas | 5.46% medium-term notes due September 2036
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	5.46%
Debt instrument, maturity date, description	September 2,036
Union Gas | 6.05% medium-term notes due September 2038
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	6.05%
Debt instrument, maturity date, description	September 2,038
Union Gas | 5.20% medium-term notes due July 2040
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	5.20%
Debt instrument, maturity date, description	July 2,040
Union Gas | 4.88% medium-term notes due June 2041
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	4.88%
Debt instrument, maturity date, description	June 2,041
Union Gas | 4.20% medium-term notes due June 2044
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	4.20%
Debt instrument, maturity date, description	June 2,044

Debt and Credit Facilities - An

Debt and Credit Facilities - Annual Maturities (Detail) - USD ($) $ in Millions		Dec. 31, 2015	Dec. 31, 2014
Debt Disclosure [Abstract]
2,016		$ 650
2,017		543
2,018		2,277
2,019		745
2,020		963
Thereafter		8,408
Total long-term debt, including current maturities	[1]	13,586
Commercial Paper	[2],[3]	1,112	$ 1,583
Capital Leases		$ 19	$ 24
[1]	Excludes commercial paper of $1,112 million. Includes capital leases of $19 million.
[2]	The weighted-average days to maturity was 12 days as of December 31, 2015 and 14 days as of December 31, 2014.
[3]	Weighted-average rate on outstanding commercial paper was 0.9% at December 31, 2015 and 0.6% at December 31, 2014.

Debt and Credit Facilities - Av

Debt and Credit Facilities - Available Credit Facilities and Restrictive Debt Covenants (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014
Line of Credit Facility [Line Items]
Total Credit Facilities Capacity		$ 3,650
Commercial Paper	[1],[2]	1,112	$ 1,583
Available Credit Facilities Capacity		2,538
Spectra Energy Capital, LLC
Line of Credit Facility [Line Items]
Commercial Paper		$ 481	$ 398
Spectra Energy Capital, LLC | Multi Year Syndicated
Line of Credit Facility [Line Items]
Expiration Date	[3]	2,019
Total Credit Facilities Capacity	[3]	$ 1,000
Commercial Paper	[3]	481
Available Credit Facilities Capacity	[3]	$ 519
Spectra Energy Partners, LP | Multi Year Syndicated
Line of Credit Facility [Line Items]
Expiration Date	[4]	2,019
Total Credit Facilities Capacity	[4]	$ 2,000
Commercial Paper	[4]	476
Available Credit Facilities Capacity	[4]	$ 1,524
Westcoast | Multi Year Syndicated
Line of Credit Facility [Line Items]
Expiration Date	[5]	2,019
Total Credit Facilities Capacity	[5]	$ 289
Commercial Paper	[5]	6
Available Credit Facilities Capacity	[5]	$ 283
Union Gas | Multi Year Syndicated
Line of Credit Facility [Line Items]
Expiration Date	[6]	2,019
Total Credit Facilities Capacity	[6]	$ 361
Commercial Paper	[6]	149
Available Credit Facilities Capacity	[6]	$ 212
[1]	The weighted-average days to maturity was 12 days as of December 31, 2015 and 14 days as of December 31, 2014.
[2]	Weighted-average rate on outstanding commercial paper was 0.9% at December 31, 2015 and 0.6% at December 31, 2014.
[3]	Revolving credit facility contains a covenant requiring the Spectra Energy consolidated debt-to-total capitalization ratio, as defined in the agreement, to not exceed 65%. Per the terms of the agreement, collateralized debt is excluded from the calculation of the ratio. This ratio was 59.6% at December 31, 2015.
[4]	Revolving credit facility contains a covenant that requires SEP to maintain a ratio of total Consolidated Indebtedness-to-Consolidated EBITDA, as defined in the agreement, of 5.0 to 1 or less. As of December 31, 2015, this ratio was 3.6 to 1.
[5]	U.S. dollar equivalent at December 31, 2015. The revolving credit facility is 400 million Canadian dollars and contains a covenant that requires the Westcoast non-consolidated debt-to-total capitalization ratio to not exceed 75%. The ratio was 35.4% at December 31, 2015.
[6]	U.S. dollar equivalent at December 31, 2015. The revolving credit facility is 500 million Canadian dollars and contains a covenant that requires the Union Gas debt-to-total capitalization ratio to not exceed 75% and a provision which requires Union Gas to repay all borrowings under the facility for a period of two days during the second quarter of each year. The ratio was 67.8% at December 31, 2015.

Debt and Credit Facilities -104

Debt and Credit Facilities - Available Credit Facilities and Restrictive Debt Covenants (Notes) (Detail) $ in Millions	Dec. 31, 2015USD ($)	Dec. 31, 2015CAD
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity | $	$ 3,650
Spectra Energy Capital, LLC | Covenant Requirement
Line of Credit Facility [Line Items]
Debt-to-total defined capitalization ratio	59.60%	59.60%
Spectra Energy Capital, LLC | Covenant Requirement | Maximum
Line of Credit Facility [Line Items]
Debt-to-total defined capitalization ratio	65.00%	65.00%
Spectra Energy Partners, LP | Covenant Requirement
Line of Credit Facility [Line Items]
Total consolidated indebtedness-consolidated EBITDA	5	5
Current total consolidated indebtedness-consolidated EBITDA	3.6	3.6
Westcoast | Covenant Requirement
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity		CAD 400,000,000
Non-consolidated debt to total capitalization ratio	35.40%	35.40%
Westcoast | Covenant Requirement | Maximum
Line of Credit Facility [Line Items]
Non-consolidated debt to total capitalization ratio	75.00%	75.00%
Union Gas | Covenant Requirement
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity		CAD 500,000,000
Non-consolidated debt to total capitalization ratio	67.80%	67.80%
Union Gas | Covenant Requirement | Maximum
Line of Credit Facility [Line Items]
Non-consolidated debt to total capitalization ratio	75.00%	75.00%

Debt and Credit Facilities - Ad

Debt and Credit Facilities - Additional Information (Detail) $ in Millions	Dec. 31, 2015USD ($)	Dec. 31, 2015CAD	Dec. 31, 2014USD ($)
Debt Instrument [Line Items]
Secured debt	$ 274
Line of credit facility, maximum borrowing capacity	3,650
Canadian Dollars Denominated
Debt Instrument [Line Items]
Long-term debt	4,681		$ 5,264
Floating Rate Debt
Debt Instrument [Line Items]
Long-term debt	$ 1,812		$ 2,283	[1],[2]
Debt, Weighted Average Interest Rate	1.15%	1.15%	0.80%
Spectra Energy Capital, LLC
Debt Instrument [Line Items]
Equity (net assets) restricted	$ 7,900
Spectra Energy Capital, LLC | Covenant Requirement
Debt Instrument [Line Items]
Debt-to-total defined capitalization ratio	59.60%	59.60%
Spectra Energy Capital, LLC | Covenant Requirement | Maximum
Debt Instrument [Line Items]
Debt-to-total defined capitalization ratio	65.00%	65.00%
Westcoast Energy Inc. | Covenant Requirement
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity | CAD		CAD 400,000,000
Union Gas Limited | Covenant Requirement
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity | CAD		CAD 500,000,000
[1]	The weighted-average days to maturity was 12 days as of December 31, 2015 and 14 days as of December 31, 2014.
[2]	Weighted-average rate on outstanding commercial paper was 0.9% at December 31, 2015 and 0.6% at December 31, 2014.

Preferred Stock of Subsidiar106

Preferred Stock of Subsidiaries (Details) shares in Millions, CAD in Millions, $ in Millions	Dec. 15, 2015USD ($)shares	Dec. 15, 2015CADshares	Dec. 31, 2015
Class of Stock [Line Items]
Percentage of redeemable preferred shares at the option of Westcoast and Union			78.00%
Westcoast Energy Inc.
Class of Stock [Line Items]
Stock Issued During Period, Shares, New Issues	4.6	4.6
Proceeds from Issuance of Redeemable Preferred Stock	$ 84	CAD 115

Fair Value Measurements - Asset

Fair Value Measurements - Assets and Liabilities Measured at Fair Value on Recurring Basis with Fair Value Hierarchy Levels (Detail) - Fair Value, Measurements, Recurring - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Assets	$ 246	$ 211
Corporate Debt Securities | Cash and Cash Equivalents
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Assets	137	85
Corporate Debt Securities | Current Assets - Other
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Assets	20	3
Corporate Debt Securities | Investments and Other Assets - Other
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Assets	11	20
Commodity Contract | Current Assets - Other
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Assets	36	57
Commodity Contract | Investments and Other Assets - Other
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Assets	5	21
Interest Rate Swap | Current Assets - Other
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Assets		2
Interest Rate Swap | Investments and Other Assets - Other
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Assets	37	22
Money Market Funds | Investments and Other Assets - Other
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Assets		1
Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Assets	0	1
Level 1 | Corporate Debt Securities | Cash and Cash Equivalents
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Assets	0	0
Level 1 | Corporate Debt Securities | Current Assets - Other
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Assets	0	0
Level 1 | Corporate Debt Securities | Investments and Other Assets - Other
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Assets	0	0
Level 1 | Commodity Contract | Current Assets - Other
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Assets	0	0
Level 1 | Commodity Contract | Investments and Other Assets - Other
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Assets	0	0
Level 1 | Interest Rate Swap | Current Assets - Other
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Assets		0
Level 1 | Interest Rate Swap | Investments and Other Assets - Other
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Assets	0	0
Level 1 | Money Market Funds | Investments and Other Assets - Other
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Assets		1
Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Assets	205	132
Level 2 | Corporate Debt Securities | Cash and Cash Equivalents
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Assets	137	85
Level 2 | Corporate Debt Securities | Current Assets - Other
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Assets	20	3
Level 2 | Corporate Debt Securities | Investments and Other Assets - Other
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Assets	11	20
Level 2 | Commodity Contract | Current Assets - Other
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Assets	0	0
Level 2 | Commodity Contract | Investments and Other Assets - Other
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Assets	0	0
Level 2 | Interest Rate Swap | Current Assets - Other
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Assets		2
Level 2 | Interest Rate Swap | Investments and Other Assets - Other
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Assets	37	22
Level 2 | Money Market Funds | Investments and Other Assets - Other
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Assets		0
Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Assets	41	78
Level 3 | Corporate Debt Securities | Cash and Cash Equivalents
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Assets	0	0
Level 3 | Corporate Debt Securities | Current Assets - Other
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Assets	0	0
Level 3 | Corporate Debt Securities | Investments and Other Assets - Other
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Assets	0	0
Level 3 | Commodity Contract | Current Assets - Other
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Assets	36	57
Level 3 | Commodity Contract | Investments and Other Assets - Other
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Assets	5	21
Level 3 | Interest Rate Swap | Current Assets - Other
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Assets		0
Level 3 | Interest Rate Swap | Investments and Other Assets - Other
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Assets	$ 0	0
Level 3 | Money Market Funds | Investments and Other Assets - Other
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Assets		$ 0

Fair Value Measurements - Chang

Fair Value Measurements - Changes in Level 3 Assets and Liabilities that are Measured at Fair Value on Recurring Basis using Significant Unobservable Inputs (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Derivative Financial Instruments, Liabilities
Total gains (losses):
Fair value, beginning of period		$ (3)
Gain (loss) included in other comprehensive income	$ (10)
Gain (loss) on purchases	3	0
Gain (loss) on settlements	(67)	$ (15)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Assets	(19)
Derivative Financial Instruments, Assets
Total gains (losses):
Fair value, beginning of period	$ 78
Gain (loss) included in earnings	43	91
Gain (loss) included in other comprehensive income		$ 5
Fair value, end of period	$ 41	(78)
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Assets		$ 56

Fair Value Measurements - Fair

Fair Value Measurements - Fair Value of Financial Instruments Recorded and Carried at Book Value (Detail) - USD ($) $ in Millions		Dec. 31, 2015	Dec. 31, 2014
Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes receivable, noncurrent	[1]	$ 71	$ 71
Long-term debt, including current maturities	[2]	13,567	13,060
Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes receivable, noncurrent	[1]	71	71
Long-term debt, including current maturities	[2]	$ 13,891	$ 14,446
[1]	Included within Investments in and Loans to Unconsolidated Affiliates.
[2]	Excludes capital leases, unamortized items and fair value hedge carrying value adjustments.

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details) gal in Millions	12 Months Ended
	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)gal	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Goodwill, Impairment Loss		$ 333,000,000	$ 0	$ 0
Assets, Fair Value Adjustment			$ 0
BC Pipeline and BC Field Services
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Goodwill, Impairment Loss		270,000,000
Empress
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Goodwill, Impairment Loss		$ 63,000,000
Commodity Contract
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative, Nonmonetary Notional Amount, Volume | gal		152
Scenario, Forecast | Commodity Contract
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing Asset at Fair Value, Description of Other Changes that Affect Balance	$ 0.10
Servicing Asset at Fair Value, Changes in Fair Value Resulting from Changes in Valuation Inputs or Changes in Assumptions	$ 15,000,000

Risk Management and Hedging 111

Risk Management and Hedging Activities - Derivative Portfolio Carrying Value (Detail) $ in Millions	Dec. 31, 2015USD ($)
Derivative Portfolio Carrying Value [Line Items]
Maturities in 2016	$ 36
Maturities in 2017	7
Maturities in 2018	12
Maturities in 2019 and Thereafter	23
Total Carrying Value	78
Designated as Hedging
Derivative Portfolio Carrying Value [Line Items]
Maturities in 2016	0
Maturities in 2017	2
Maturities in 2018	12
Maturities in 2019 and Thereafter	23
Total Carrying Value	37
Not designated as hedging
Derivative Portfolio Carrying Value [Line Items]
Maturities in 2016	36
Maturities in 2017	5
Maturities in 2018	0
Maturities in 2019 and Thereafter	0
Total Carrying Value	41
Interest Rate Swap | Designated as Hedging
Derivative Portfolio Carrying Value [Line Items]
Maturities in 2016	0
Maturities in 2017	2
Maturities in 2018	12
Maturities in 2019 and Thereafter	23
Total Carrying Value	37
Commodity Contract | Not designated as hedging
Derivative Portfolio Carrying Value [Line Items]
Maturities in 2016	36
Maturities in 2017	5
Maturities in 2018	0
Maturities in 2019 and Thereafter	0
Total Carrying Value	$ 41

Risk Management and Hedging 112

Risk Management and Hedging Activities - Derivative Assets And Liabilities Offsetting Information (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Commodity Contract
Derivative Assets And Liabilities with Netting or Rights of Offset Arrangements [Line Items]
Derivative Asset, Fair Value, Gross Asset	$ 104
Derivative Asset, Fair Value, Amount Offset Against Collateral	63
Net Amount, Assets	41
Derivative Liability, Fair Value, Gross Liability	63
Derivative Liability, Fair Value, Amount Offset Against Collateral	63
Net Amount, Liabilities	0
Interest Rate Swap
Derivative Assets And Liabilities with Netting or Rights of Offset Arrangements [Line Items]
Derivative Asset, Fair Value, Gross Asset	37	$ 24
Net Amount, Assets	37	24
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	$ 0	$ 0

Risk Management and Hedging 113

Risk Management and Hedging Activities - Commodity Derivative Impact on Consolidated Statements of Operations (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Sales of Natural Gas Liquids [Member]
Commodity Derivative Impact on Consolidated Statements of Income [Line Items]
Sales of natural gas liquids	$ 40	$ 93	$ 0

Risk Management and Hedging 114

Risk Management and Hedging Activities - Additional Information (Detail) gal in Millions	12 Months Ended
	Dec. 31, 2015USD ($)gal	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)
Commodity Contract
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount, Volume | gal	152
Pay Floating Receive Fixed Swaps
Derivative [Line Items]
Derivative, Notional Amount	$ 2,000,000,000
Sales of Natural Gas Liquids [Member]
Derivative [Line Items]
Gain (Loss) on Interest Rate Fair Value Hedge Ineffectiveness	$ 0	$ 0	$ 0

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Accrual for Environmental Loss Contingencies	$ 8	$ 10
Rental expense for operating leases included in Operating, Maintenance and Other on the Consolidated Statements of Operations	$ 47	$ 38

Commitments and Contingencie116

Commitments and Contingencies - Summary of Future Minimum Lease Payments Under Operating Leases (Detail) $ in Millions	Dec. 31, 2015USD ($)
Commitments and Contingencies Disclosure [Abstract]
2,016	$ 49
2,017	41
2,018	39
2,019	35
2,020	31
Thereafter	139
Total future minimum lease payments	$ 334

Guarantees and Indemnificati117

Guarantees and Indemnifications - Additional Information (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2015USD ($)
Duke Energy
Guarantor Obligations [Line Items]
Maximum potential amount of future payments required to make under performance guarantees	$ 406
Duke Energy | Guarantees Expire in 2028
Guarantor Obligations [Line Items]
Maximum potential amount of future payments required to make under performance guarantees	$ 201
Guarantee Year of Expiration	2,028
Fluor Enterprises
Guarantor Obligations [Line Items]
Equity Method Investment, Ownership Percentage	50.00%
Westcoast Energy Inc.
Guarantor Obligations [Line Items]
Percentage of ownership interests	100.00%

Effects of Changes in Noncon118

Effects of Changes in Noncontrolling Interests Ownership Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Abstract]
Net Income—Controlling Interests	$ (263)	$ 174	$ 18	$ 267	$ 316	$ 201	$ 146	$ 419	$ 196	$ 1,082	$ 1,038
Increase (decrease) in additional paid-in capital resulting from issuances/retirements of SEP units (a)									(105)	49	42
Total net income—controlling interests and changes in equity—controlling interests									$ 91	$ 1,131	$ 1,080

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum number of common stock awarded (in shares)	40,000,000
Tax benefit in income from continuing operations associated with recorded expense	$ 7	$ 7	$ 8
Recognized tax benefits from stock-based compensation cost in additional paid in capital	$ 1	3	5
Restricted, performance and phantom stock awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based awards granted percentage vested	100.00%
Stock-based awards vesting period	3 years
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based awards vesting period	3 years
Stock-based awards term	10 years
Total intrinsic value of options exercised	$ 1	6	21
Cash received from options exercised	$ 3	11	43
Performance awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based awards vesting period	3 years
Granted (in shares)	564,000
Share based compensation arrangement by share based payment award, fair value assumptions, yield, period	3 years
Total fair value of shares vested	$ 1	20	19
Future compensation cost related to stock awards expected to be recognized	$ 26
Performance awards | Single Subsidiary EBITDA
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested and outstanding performance awards granted containing EBITDA	12,900
Performance awards | Total shareholder return
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested and outstanding performance awards granted containing EBITDA	1,689,640
Performance awards | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected future compensation cost related to stock awards, weighted-average period of recognition	1 year
Phantom Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based awards vesting period	3 years
Granted (in shares)	395,000
Total fair value of shares vested	$ 13	$ 11	$ 14
Future compensation cost related to stock awards expected to be recognized	$ 12
Phantom Stock Awards | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected future compensation cost related to stock awards, weighted-average period of recognition	2 years
Equity-classified awards | Performance awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	564,300	557,100	356,600
Fair value of equity classified awards granted	$ 27	$ 26	$ 13
Equity-classified awards | Phantom Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	39,200	101,500	474,500
Fair value of equity classified awards granted	$ 1	$ 4	$ 14
Liability-classified award | Performance awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	0	0	343,700
Fair value of liability-classified awards granted			$ 13
Liability-classified award | Phantom Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	356,100	353,000
Fair value of equity classified awards granted	$ 13	$ 13

Stock-Based Compensation - Comp

Stock-Based Compensation - Components of Pre-Tax Stock Based Compensation Expense in Continuing Operations (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Pre tax stock based compensation	$ 29	$ 27	$ 46
Phantom stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Pre tax stock based compensation	11	14	13
Performance awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Pre tax stock based compensation	$ 18	$ 13	$ 33

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock Awards Activity (Detail) shares in Thousands	12 Months Ended
	Dec. 31, 2015$ / sharesshares
Performance Awards
Units
Outstanding at beginning of period (in shares) | shares	1,775
Granted (in shares) | shares	564
Vested (in shares) | shares	(2)
Forfeited (in shares) | shares	(635)
Outstanding at end of period (in shares) | shares	1,702
Awards expected to vest (in shares) | shares	1,608
Weighted Average Grant Date Fair Value
Outstanding at beginning of period (in usd per share) | $ / shares	$ 35
Granted (in usd per share) | $ / shares	48
Vested (in usd per share) | $ / shares	41
Forfeited (in usd per share) | $ / shares	22
Outstanding at end of period (in usd per share) | $ / shares	39
Awards expected to vest (in usd per share) | $ / shares	$ 39
Phantom Stock Awards
Units
Outstanding at beginning of period (in shares) | shares	1,281
Granted (in shares) | shares	395
Vested (in shares) | shares	(428)
Forfeited (in shares) | shares	(36)
Outstanding at end of period (in shares) | shares	1,212
Awards expected to vest (in shares) | shares	1,176
Weighted Average Grant Date Fair Value
Outstanding at beginning of period (in usd per share) | $ / shares	$ 33
Granted (in usd per share) | $ / shares	36
Vested (in usd per share) | $ / shares	31
Forfeited (in usd per share) | $ / shares	30
Outstanding at end of period (in usd per share) | $ / shares	28
Awards expected to vest (in usd per share) | $ / shares	$ 28

Stock-Based Compensation - Weig

Stock-Based Compensation - Weighted Average Assumptions for Performance Awards (Detail) - Performance Awards	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free rate of return	1.10%	0.70%	0.40%
Expected life	3 years	3 years	3 years
Expected volatility—Spectra Energy	18.00%	20.00%	21.00%
Expected volatility, Minimum-peer group	13.00%	14.00%	13.00%
Expected volatility, Maximum-peer group	27.00%	32.00%	33.00%
Market index (a)			0.16

Stock-Based Compensation - S123

Stock-Based Compensation - Stock Option Activity (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Options
Outstanding at beginning of period (in shares)	1,102
Exercised (in shares)	(134)
Forfeited or expired (in shares)	(10)
Outstanding at end of period (in shares)	958	1,102
Exercisable at end of period (in shares)	958
Weighted- Average Exercise Price
Outstanding at beginning of period (in usd per share)	$ 25
Exercised (in usd per share)	23
Forfeited or expired (in usd per share)	23
Outstanding at end of period (in usd per share)	26	$ 25
Exercisable at end of period (in usd per share)	$ 26
Weighted- Average Remaining Life
Outstanding at beginning of period	1 year 2 months 12 days	2 years
Outstanding at end of period	1 year 2 months 12 days	2 years
Exercisable at end of period	1 year 2 months 12 days
Aggregate Intrinsic Value
Outstanding at beginning of period	$ 12
Outstanding at end of period	0	$ 12
Exercisable at end of period	$ 0

Employee Benefit Plans - Additi

Employee Benefit Plans - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Money Market Funds Fair Value Disclosure	$ 18,000,000	$ 17,000,000
Canadian Postretirement Benefit Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Net Prior Service Cost (Credit), before Tax	(3,000,000)	(4,000,000)
Defined Benefit Plan, Benefit Obligation	107,000,000	133,000,000	$ 133,000,000
Defined Benefit Plan, Contributions by Employer	4,000,000	4,000,000
Defined Benefit Plans, Estimated Future Employer Contributions in Next Fiscal Year	4,000,000
Fair values of plan assets	0	0	0
U.S.
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Net Prior Service Cost (Credit), before Tax	0	0
Defined Benefit Plan, Benefit Obligation	166,000,000	172,000,000	184,000,000
Defined Benefit Plan, Contributions by Employer	12,000,000	14,000,000
Defined Benefit Plans, Estimated Future Employer Contributions in Next Fiscal Year	$ 0
Average Remaining Service Period Of Active Employees	14 years
Defined Benefit Plan Periods Of Changes In Fair Value Of Plan Asset Used To Determine Market Related Value	5 years
Fair values of plan assets	$ 88,000,000	92,000,000	87,000,000
U.S.
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Net Prior Service Cost (Credit), before Tax	0	0
Defined Benefit Plan, Future Amortization of Gain (Loss)	(7,000,000)
Defined Benefit Plan, Benefit Obligation	571,000,000	586,000,000	575,000,000
Defined Benefit Plan, Contributions by Employer	22,000,000	21,000,000	22,000,000
Defined Benefit Plans, Estimated Future Employer Contributions in Next Fiscal Year	$ 22,000,000
Average Remaining Service Period Of Active Employees	11 years
Defined Benefit Plan Periods Of Changes In Fair Value Of Plan Asset Used To Determine Market Related Value	5 years
Defined Benefit Plan, Accumulated Benefit Obligation	$ 549,000,000	567,000,000
Fair values of plan assets	532,000,000	551,000,000	531,000,000
Canada
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Net Prior Service Cost (Credit), before Tax	5,000,000	6,000,000
Defined Benefit Plan, Future Amortization of Gain (Loss)	(17,000,000)
Defined Benefit Plan, Benefit Obligation	1,034,000,000	1,202,000,000	1,131,000,000
Defined Benefit Plan, Contributions by Employer	22,000,000	36,000,000	80,000,000
Defined Benefit Plans, Estimated Future Employer Contributions in Next Fiscal Year	$ 16,000,000
Average Remaining Service Period Of Active Employees	11 years
Defined Benefit Plan Periods Of Changes In Fair Value Of Plan Asset Used To Determine Market Related Value	3 years
Defined Benefit Plan, Accumulated Benefit Obligation	$ 967,000,000	1,123,000,000
Fair values of plan assets	908,000,000	1,050,000,000	1,040,000,000
Defined Benefit Plan, Future Amortization of Prior Service Cost (Credit)	1,000,000
Canada
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Contribution Plan, Employer Discretionary Contribution Amount	8,000,000	9,000,000	9,000,000
Defined Contribution Plan Estimated Future Employer Contributions In Next Fiscal Year	8,000,000
Nonqualifed and Unfunded Pension Plans | U.S.
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Benefit Obligation	23,000,000	22,000,000
Nonqualifed and Unfunded Pension Plans | Canada
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Benefit Obligation	103,000,000	117,000,000
Plans with accumulated benefit obligations in excess of plan assets | U.S.
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Pension Plans with Accumulated Benefit Obligations in Excess of Plan Assets, Aggregate Projected Benefit Obligation	23,000,000
Defined Benefit Plan, Accumulated Benefit Obligation	20,000,000
Plans with accumulated benefit obligations in excess of plan assets | Canada
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Pension Plans with Accumulated Benefit Obligations in Excess of Plan Assets, Aggregate Projected Benefit Obligation	340,000,000
Defined Benefit Plan, Accumulated Benefit Obligation	316,000,000
Fair values of plan assets	215,000,000
Accumulated Other Comprehensive Income (Loss) | Canadian Postretirement Benefit Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Net Prior Service Cost (Credit), before Tax	1,000,000
Canada | Canadian Postretirement Benefit Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Contribution Plan, Cost Recognized	$ 13,000,000	13,000,000	13,000,000
Canada | U.S.
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Contribution Plan Contribution Rates As Percentage Of Employees Earnings	5.00%
UNITED STATES | U.S.
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Contribution Plan Contribution Rates As Percentage Of Employees Earnings	6.00%
Defined Contribution Plan, Cost Recognized	$ 15,000,000	$ 15,000,000	$ 14,000,000

Employee Benefit Plans - Change

Employee Benefit Plans - Change in Projected Benefit Obligation and Change in Fair Value of Plan Assets (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
U.S.
Change in Projected Benefit Obligation
Projected benefit obligation, beginning balance	$ 586	$ 575
Service cost	19	19
Interest cost	24	24	$ 21
Actuarial loss (gain)	(18)	13
Participant contributions	0	0
Benefits paid	(40)	(45)
Foreign currency translation effect	0	0
Projected benefit obligation, ending balance	571	586	575
Change in Fair Value of Plan Assets
Plan assets, beginning of period	551	531
Actual return on plan assets	(1)	44
Benefits paid	(40)	(45)
Employer contributions	22	21	22
Plan participants’ contributions	0	0
Expected non-investment expenses	0	0
Foreign currency translation effect	0	0
Plan assets, end of period	532	551	531
Net amount recognized	(39)	(35)
Accumulated Benefit Obligation	549	567
Defined Benefit Plan, Current Liabilities - Other	(2)	(2)
Defined Benefit Plan, Deferred Credits and Other Liabilities - Regulatory and Other	(37)	(33)
Defined Benefit Plan, Other Assets - Other	0	0
Defined Contribution Plan, Cost Recognized	(39)	(35)
Canada
Change in Projected Benefit Obligation
Projected benefit obligation, beginning balance	1,202	1,131
Service cost	28	25
Interest cost	43	52	50
Actuarial loss (gain)	(3)	143
Participant contributions	5	5
Benefits paid	(47)	(49)
Foreign currency translation effect	(194)	(105)
Projected benefit obligation, ending balance	1,034	1,202	1,131
Change in Fair Value of Plan Assets
Plan assets, beginning of period	1,050	1,040
Actual return on plan assets	52	115
Benefits paid	(47)	(49)
Employer contributions	22	36	80
Plan participants’ contributions	5	5
Expected non-investment expenses	(3)	(3)
Foreign currency translation effect	(171)	(94)
Plan assets, end of period	908	1,050	$ 1,040
Net amount recognized	(126)	(152)
Accumulated Benefit Obligation	967	1,123
Defined Benefit Plan, Current Liabilities - Other	(5)	(6)
Defined Benefit Plan, Deferred Credits and Other Liabilities - Regulatory and Other	(142)	(165)
Defined Benefit Plan, Other Assets - Other	21	19
Defined Contribution Plan, Cost Recognized	$ (126)	$ (152)

Employee Benefit Plans - Amount

Employee Benefit Plans - Amounts Recognized in Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
U.S.
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	$ 156	$ 141
Prior service cost	0	0
Total amount recognized in AOCI	156	141
Canada
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	330	345
Prior service cost	5	6
Total amount recognized in AOCI	$ 335	$ 351

Employee Benefit Plans - Compon

Employee Benefit Plans - Components of Net Periodic Pension Cost (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
U.S.
Net Periodic Pension Cost
Defined Benefit Plan, Other Costs	$ 19	$ 19	$ 19
Interest cost on projected benefit obligation	24	24	21
Expected return on plan assets	(42)	(39)	(33)
Amortization of prior service cost	0	0	0
Amortization of loss	10	13	20
Net periodic other post-retirement benefit cost	11	17	27
Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income
Current year actuarial loss (gain)	25	8	(69)
Amortization of actuarial loss	(10)	(13)	(20)
Amortization of prior service credit	0	0	0
Total recognized in other comprehensive income	15	(5)	(89)
Total Recognized in Net Periodic Pension Cost and Other Comprehensive Income	26	12	(62)
Canada
Net Periodic Pension Cost
Defined Benefit Plan, Other Costs	31	29	33
Interest cost on projected benefit obligation	43	52	50
Expected return on plan assets	(65)	(69)	(66)
Amortization of prior service cost	1	2	2
Amortization of loss	25	22	35
Net periodic other post-retirement benefit cost	35	36	54
Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income
Current year actuarial loss (gain)	10	93	(133)
Amortization of actuarial loss	(25)	(22)	(35)
Amortization of prior service credit	(1)	(2)	(2)
Total recognized in other comprehensive income	(16)	69	(170)
Total Recognized in Net Periodic Pension Cost and Other Comprehensive Income	$ 19	$ 105	$ (116)

Employee Benefit Plans - Assump

Employee Benefit Plans - Assumptions Used for Pension Benefits Accounting (Detail)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
U.S.
Benefit Obligations
Discount rate	4.58%	4.10%	4.31%
Salary increase	4.00%	4.00%	4.61%
Net Periodic Benefit Cost
Discount rate	4.10%	4.31%	3.55%
Salary increase	4.00%	4.61%	4.61%
Expected long-term rate of return on plan assets	8.00%	8.00%	7.40%
Canada
Benefit Obligations
Discount rate	4.03%	4.00%	4.81%
Salary increase	3.00%	3.25%	3.25%
Net Periodic Benefit Cost
Discount rate	4.00%	4.81%	4.15%
Salary increase	3.25%	3.25%	3.25%
Expected long-term rate of return on plan assets	7.40%	7.40%	7.10%

Employee Benefit Plans - Qualif

Employee Benefit Plans - Qualified Pension Plan Assets (Detail) - Qualified pension plans	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
U.S.
Defined Benefit Plan Disclosure [Line Items]
Target Allocation	100.00%
Plan Asset Allocations	100.00%	100.00%
U.S. | U.S. equity securities
Defined Benefit Plan Disclosure [Line Items]
Target Allocation	23.00%
Plan Asset Allocations	22.00%	31.00%
U.S. | Canadian equity securities
Defined Benefit Plan Disclosure [Line Items]
Target Allocation	0.00%
Plan Asset Allocations	0.00%	0.00%
U.S. | Other Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Target Allocation	10.00%
Plan Asset Allocations	10.00%	11.00%
U.S. | Fixed Income Securities
Defined Benefit Plan Disclosure [Line Items]
Target Allocation	57.00%
Plan Asset Allocations	57.00%	48.00%
U.S. | Other Investments
Defined Benefit Plan Disclosure [Line Items]
Target Allocation	10.00%
Plan Asset Allocations	11.00%	10.00%
Canada
Defined Benefit Plan Disclosure [Line Items]
Target Allocation	100.00%
Plan Asset Allocations	100.00%	100.00%
Canada | U.S. equity securities
Defined Benefit Plan Disclosure [Line Items]
Target Allocation	17.00%
Plan Asset Allocations	18.00%	17.00%
Canada | Canadian equity securities
Defined Benefit Plan Disclosure [Line Items]
Target Allocation	25.00%
Plan Asset Allocations	24.00%	25.00%
Canada | Other Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Target Allocation	13.00%
Plan Asset Allocations	13.00%	13.00%
Canada | Fixed Income Securities
Defined Benefit Plan Disclosure [Line Items]
Target Allocation	45.00%
Plan Asset Allocations	45.00%	45.00%
Canada | Other Investments
Defined Benefit Plan Disclosure [Line Items]
Target Allocation	0.00%
Plan Asset Allocations	0.00%	0.00%

Employee Benefit Plans - Fair V

Employee Benefit Plans - Fair Values of Pension Plan Assets Recorded at Each Fair Value Hierarchy Level (Detail) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
U.S.
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	$ 532	$ 551	$ 531
Canada
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	908	1,050	$ 1,040
Qualified pension plans | U.S. | Fair Value, Measurements, Recurring
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	532	551
Qualified pension plans | U.S. | Fair Value, Measurements, Recurring | Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	2	3
Qualified pension plans | U.S. | Fair Value, Measurements, Recurring | Fixed Income Securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	304	262
Qualified pension plans | U.S. | Fair Value, Measurements, Recurring | Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	171	233
Qualified pension plans | U.S. | Fair Value, Measurements, Recurring | Other
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	55	53
Qualified pension plans | U.S. | Fair Value, Measurements, Recurring | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	477	498
Qualified pension plans | U.S. | Fair Value, Measurements, Recurring | Level 1 | Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	2	3
Qualified pension plans | U.S. | Fair Value, Measurements, Recurring | Level 1 | Fixed Income Securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	304	262
Qualified pension plans | U.S. | Fair Value, Measurements, Recurring | Level 1 | Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	171	233
Qualified pension plans | U.S. | Fair Value, Measurements, Recurring | Level 1 | Other
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0	0
Qualified pension plans | U.S. | Fair Value, Measurements, Recurring | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0	0
Qualified pension plans | U.S. | Fair Value, Measurements, Recurring | Level 2 | Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0	0
Qualified pension plans | U.S. | Fair Value, Measurements, Recurring | Level 2 | Fixed Income Securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0	0
Qualified pension plans | U.S. | Fair Value, Measurements, Recurring | Level 2 | Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0	0
Qualified pension plans | U.S. | Fair Value, Measurements, Recurring | Level 2 | Other
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0	0
Qualified pension plans | U.S. | Fair Value, Measurements, Recurring | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	55	53
Qualified pension plans | U.S. | Fair Value, Measurements, Recurring | Level 3 | Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0	0
Qualified pension plans | U.S. | Fair Value, Measurements, Recurring | Level 3 | Fixed Income Securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0	0
Qualified pension plans | U.S. | Fair Value, Measurements, Recurring | Level 3 | Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0	0
Qualified pension plans | U.S. | Fair Value, Measurements, Recurring | Level 3 | Other
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	55	53
Qualified pension plans | Canada | Fair Value, Measurements, Recurring
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	908	1,050
Qualified pension plans | Canada | Fair Value, Measurements, Recurring | Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	3	3
Qualified pension plans | Canada | Fair Value, Measurements, Recurring | Fixed Income Securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	404	471
Qualified pension plans | Canada | Fair Value, Measurements, Recurring | Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	501	576
Qualified pension plans | Canada | Fair Value, Measurements, Recurring | Other
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0	0
Qualified pension plans | Canada | Fair Value, Measurements, Recurring | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	628	816
Qualified pension plans | Canada | Fair Value, Measurements, Recurring | Level 1 | Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	3	3
Qualified pension plans | Canada | Fair Value, Measurements, Recurring | Level 1 | Fixed Income Securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	404	471
Qualified pension plans | Canada | Fair Value, Measurements, Recurring | Level 1 | Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	221	342
Qualified pension plans | Canada | Fair Value, Measurements, Recurring | Level 1 | Other
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0	0
Qualified pension plans | Canada | Fair Value, Measurements, Recurring | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	280	234
Qualified pension plans | Canada | Fair Value, Measurements, Recurring | Level 2 | Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0	0
Qualified pension plans | Canada | Fair Value, Measurements, Recurring | Level 2 | Fixed Income Securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0	0
Qualified pension plans | Canada | Fair Value, Measurements, Recurring | Level 2 | Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	280	234
Qualified pension plans | Canada | Fair Value, Measurements, Recurring | Level 2 | Other
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0	0
Qualified pension plans | Canada | Fair Value, Measurements, Recurring | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0	0
Qualified pension plans | Canada | Fair Value, Measurements, Recurring | Level 3 | Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0	0
Qualified pension plans | Canada | Fair Value, Measurements, Recurring | Level 3 | Fixed Income Securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0	0
Qualified pension plans | Canada | Fair Value, Measurements, Recurring | Level 3 | Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0	0
Qualified pension plans | Canada | Fair Value, Measurements, Recurring | Level 3 | Other
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	$ 0	$ 0

Employee Benefit Plans - Cha131

Employee Benefit Plans - Changes in Level 3 Assets That are Measured at Fair Value on Recurring Basis (Detail) - U.S. - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning of period	$ 53	$ 49
Gain (loss) included in other comprehensive income	2	4
Fair value, end of period	$ 55	$ 53

Employee Benefit Plans - Expect

Employee Benefit Plans - Expected Benefit Payments (Detail) - Qualified pension plans $ in Millions	Dec. 31, 2015USD ($)
U.S.
Defined Benefit Plan Disclosure [Line Items]
2,016	$ 84
2,017	49
2,018	47
2,019	49
2,020	50
2021- 2025	233
Canada
Defined Benefit Plan Disclosure [Line Items]
2,016	44
2,017	47
2,018	49
2,019	51
2,020	54
2021- 2025	$ 297

Employee Benefit Plans - Other

Employee Benefit Plans - Other Post Retirement Benefit Plans Change in Projected Benefit Obligation and Fair Value of Plan Assets (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
U.S.
Change in Benefit Obligation
Projected benefit obligation, beginning balance		$ 172	$ 184
Service cost		1	1	$ 1
Interest cost		7	8	7
Plan participants' contributions		3	2
Actuarial loss (gain)		1	(7)
Prescription Drug Benefit, Effect of Subsidy on Net Periodic Postretirement Benefit Cost		2	2
Benefits paid		(20)	(18)
Foreign currency translation effect		0	0
Projected benefit obligation, ending balance		166	172	184
Change in Fair Value of Plan Assets
Plan assets, beginning of period		92	87
Actual return on plan assets		1	7
Benefits paid		(20)	(18)
Employer contributions		12	14
Plan participants’ contributions		3	2
Plan assets, end of period		88	92	87
Net amount recognized	[1]	(78)	(80)
Canadian Postretirement Benefit Plan
Change in Benefit Obligation
Projected benefit obligation, beginning balance		133	133
Service cost		4	4	5
Interest cost		5	6	6
Plan participants' contributions		0	0
Actuarial loss (gain)		(11)	7
Prescription Drug Benefit, Effect of Subsidy on Net Periodic Postretirement Benefit Cost		0	0
Benefits paid		(4)	(4)
Foreign currency translation effect		(20)	(13)
Projected benefit obligation, ending balance		107	133	133
Change in Fair Value of Plan Assets
Plan assets, beginning of period		0	0
Actual return on plan assets		0	0
Benefits paid		(4)	(4)
Employer contributions		4	4
Plan participants’ contributions		0	0
Plan assets, end of period		0	0	$ 0
Net amount recognized	[1]	$ (107)	$ (133)
[1]	Recognized primarily in Deferred Credits and Other Liabilities—Regulatory and Other in the Consolidated Balance Sheets.

Employee Benefit Plans - Oth134

Employee Benefit Plans - Other Post Retirement Benefit Plans Amounts Recognized in Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
U.S.
Defined Benefit Plan Disclosure [Line Items]
Prior service cost	$ 0	$ 0
Net actuarial loss	3	(4)
Total amount recognized in AOCI	3	(4)
Canadian Postretirement Benefit Plan
Defined Benefit Plan Disclosure [Line Items]
Prior service cost	(3)	(4)
Net actuarial loss	1	12
Total amount recognized in AOCI	$ (2)	$ 8

Employee Benefit Plans - Oth135

Employee Benefit Plans - Other Post Retirement Benefit Plans Components of Net Periodic Benefit Cost (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
U.S.
Other Post-Retirement Benefit Plans-Components of Net Periodic Benefit Cost
Service cost benefit earned	$ 1	$ 1	$ 1
Interest cost on accumulated post-retirement benefit obligation	7	8	7
Expected return on plan assets	(6)	(5)	(4)
Amortization of prior service credit	0	0	0
Amortization of loss	0	1	2
Net periodic other post-retirement benefit cost	2	5	6
Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income
Current year actuarial loss (gain)	7	(9)	(18)
Amortization of actuarial loss	0	(1)	(2)
Amortization of prior service credit	0	0	0
Total recognized in other comprehensive income	7	(10)	(20)
Total recognized in net periodic benefit cost and other comprehensive income	9	(5)	(14)
Canadian Postretirement Benefit Plan
Other Post-Retirement Benefit Plans-Components of Net Periodic Benefit Cost
Service cost benefit earned	4	4	5
Interest cost on accumulated post-retirement benefit obligation	5	6	6
Expected return on plan assets	0	0	0
Amortization of prior service credit	(1)	(1)	(1)
Amortization of loss	0	0	0
Net periodic other post-retirement benefit cost	8	9	10
Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income
Current year actuarial loss (gain)	(11)	6	(13)
Amortization of actuarial loss	0	0	0
Amortization of prior service credit	1	1	1
Total recognized in other comprehensive income	(10)	7	(12)
Total recognized in net periodic benefit cost and other comprehensive income	$ (2)	$ 16	$ (2)

Employee Benefit Plans - Oth136

Employee Benefit Plans - Other Post Retirement Benefits Plans Assumptions Used for Benefits Accounting (Detail)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
U.S.
Benefit Obligations
Discount rate	4.53%	4.08%	4.46%
Salary increase	4.00%	4.00%	4.61%
Net Periodic Benefit Cost
Discount rate	4.08%	4.46%	3.70%
Salary increase	4.00%	4.61%	4.61%
Expected return on plan assets	6.83%	6.98%	6.51%
Canadian Postretirement Benefit Plan
Benefit Obligations
Discount rate	4.03%	4.00%	4.83%
Salary increase	3.00%	3.25%	3.25%
Net Periodic Benefit Cost
Discount rate	4.00%	4.83%	4.20%
Salary increase	3.25%	3.25%	3.25%

Employee Benefit Plans - Assume

Employee Benefit Plans - Assumed Health Care Cost Trend Rates (Detail)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
U.S.
Defined Benefit Plan Disclosure [Line Items]
Health care cost trend rate assumed for next year	7.00%	7.00%
Rate to which the cost trend is assumed to decline	5.00%	5.00%
Year that the rate reaches the ultimate trend rate	2,020	2,019
Canadian Postretirement Benefit Plan
Defined Benefit Plan Disclosure [Line Items]
Health care cost trend rate assumed for next year	5.50%	6.00%
Rate to which the cost trend is assumed to decline	5.00%	5.00%
Year that the rate reaches the ultimate trend rate	2,017	2,017

Employee Benefit Plans - Sensit

Employee Benefit Plans - Sensitivity to Changes in Assumed Health Care Cost Trend Rates (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2015USD ($)
U.S.
Defined Benefit Plan Disclosure [Line Items]
Effect of 1% point increase on total service and interest costs	$ 0
Effect of 1% point increase on post-retirement benefit obligations	7
Effect of 1% point decrease on total service and interest costs	0
Effect of 1% point decrease on post-retirement benefit obligations	(6)
Canadian Postretirement Benefit Plan
Defined Benefit Plan Disclosure [Line Items]
Effect of 1% point increase on total service and interest costs	1
Effect of 1% point increase on post-retirement benefit obligations	5
Effect of 1% point decrease on total service and interest costs	(1)
Effect of 1% point decrease on post-retirement benefit obligations	$ (5)

Employee Benefit Plans - Oth139

Employee Benefit Plans - Other Post Retirement Plan Assets (Detail) - U.S. - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	$ 88	$ 92	$ 87
Plan asset allocations	100.00%	100.00%
Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Plan asset allocations	3.00%	0.00%
Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Plan asset allocations	45.00%	48.00%
Fixed Income Securities
Defined Benefit Plan Disclosure [Line Items]
Plan asset allocations	46.00%	47.00%
Other Assets
Defined Benefit Plan Disclosure [Line Items]
Plan asset allocations	6.00%	5.00%

Employee Benefit Plans - Fai140

Employee Benefit Plans - Fair Values of Other Post-Retirement Plan Assets Recorded at Each Hierarchy Level (Detail) - U.S. - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	$ 88	$ 92	$ 87
Fair Value, Measurements, Recurring | Veba Trust
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	41	46
Fair Value, Measurements, Recurring | Master Trust Fund
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	46	46
Fair Value, Measurements, Recurring | Cash and Cash Equivalents | Veba Trust
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	3
Fair Value, Measurements, Recurring | Cash and Cash Equivalents | Master Trust Fund
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0
Fair Value, Measurements, Recurring | Fixed Income Securities | Veba Trust
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	14	21
Fair Value, Measurements, Recurring | Fixed Income Securities | Master Trust Fund
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	26	22
Fair Value, Measurements, Recurring | Equity Securities | Veba Trust
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	24	25
Fair Value, Measurements, Recurring | Equity Securities | Master Trust Fund
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	15	20
Fair Value, Measurements, Recurring | Other Security Investments | Veba Trust
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0	0
Fair Value, Measurements, Recurring | Other Security Investments | Master Trust Fund
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	5	4
Level 1 | Fair Value, Measurements, Recurring | Veba Trust
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	3	0
Level 1 | Fair Value, Measurements, Recurring | Master Trust Fund
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	41	42
Level 1 | Fair Value, Measurements, Recurring | Cash and Cash Equivalents | Veba Trust
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	3
Level 1 | Fair Value, Measurements, Recurring | Cash and Cash Equivalents | Master Trust Fund
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0
Level 1 | Fair Value, Measurements, Recurring | Fixed Income Securities | Veba Trust
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0	0
Level 1 | Fair Value, Measurements, Recurring | Fixed Income Securities | Master Trust Fund
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	26	22
Level 1 | Fair Value, Measurements, Recurring | Equity Securities | Veba Trust
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0	0
Level 1 | Fair Value, Measurements, Recurring | Equity Securities | Master Trust Fund
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	15	20
Level 1 | Fair Value, Measurements, Recurring | Other Security Investments | Veba Trust
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0	0
Level 1 | Fair Value, Measurements, Recurring | Other Security Investments | Master Trust Fund
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0	0
Level 2 | Fair Value, Measurements, Recurring | Veba Trust
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	38	46
Level 2 | Fair Value, Measurements, Recurring | Master Trust Fund
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0	0
Level 2 | Fair Value, Measurements, Recurring | Cash and Cash Equivalents | Veba Trust
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0
Level 2 | Fair Value, Measurements, Recurring | Cash and Cash Equivalents | Master Trust Fund
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0
Level 2 | Fair Value, Measurements, Recurring | Fixed Income Securities | Veba Trust
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	14	21
Level 2 | Fair Value, Measurements, Recurring | Fixed Income Securities | Master Trust Fund
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0	0
Level 2 | Fair Value, Measurements, Recurring | Equity Securities | Veba Trust
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	24	25
Level 2 | Fair Value, Measurements, Recurring | Equity Securities | Master Trust Fund
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0	0
Level 2 | Fair Value, Measurements, Recurring | Other Security Investments | Veba Trust
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0	0
Level 2 | Fair Value, Measurements, Recurring | Other Security Investments | Master Trust Fund
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0	0
Level 3 | Fair Value, Measurements, Recurring | Veba Trust
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0	0
Level 3 | Fair Value, Measurements, Recurring | Master Trust Fund
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	5	4
Level 3 | Fair Value, Measurements, Recurring | Cash and Cash Equivalents | Veba Trust
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0
Level 3 | Fair Value, Measurements, Recurring | Cash and Cash Equivalents | Master Trust Fund
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0
Level 3 | Fair Value, Measurements, Recurring | Fixed Income Securities | Veba Trust
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0	0
Level 3 | Fair Value, Measurements, Recurring | Fixed Income Securities | Master Trust Fund
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0	0
Level 3 | Fair Value, Measurements, Recurring | Equity Securities | Veba Trust
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0	0
Level 3 | Fair Value, Measurements, Recurring | Equity Securities | Master Trust Fund
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0	0
Level 3 | Fair Value, Measurements, Recurring | Other Security Investments | Veba Trust
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0	0
Level 3 | Fair Value, Measurements, Recurring | Other Security Investments | Master Trust Fund
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	$ 5	$ 4

Employee Benefit Plans - Cha141

Employee Benefit Plans - Changes in Level 3 Assets That are Measured at Fair Value on Recurring Basis Using Significant Unobservable Inputs (Detail) - U.S. - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, beginning of period	$ 4	$ 4
Unrealized gain included in other comprehensive income	1	0
Fair value, end of period	$ 5	$ 4

Employee Benefit Plans - Benefi

Employee Benefit Plans - Benefit Payments and Subsidies Expected to be Paid (or Received) (Detail) $ in Millions	Dec. 31, 2015USD ($)
U.S.
Benefit payments
2,016	$ 16
2,017	15
2,018	15
2,019	15
2,020	14
2021- 2025	61
Medicare Part D subsidy receipts
2,016	(1)
2,017	(1)
2,018	(1)
2,019	(1)
2,020	(1)
2021 - 2025	(5)
Canadian Postretirement Benefit Plan
Benefit payments
2,016	4
2,017	4
2,018	4
2,019	4
2,020	5
2021- 2025	$ 26

Condensed Consolidating Stateme

Condensed Consolidating Statement of Operations (Detail) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Condensed Financial Statements, Captions [Line Items]
Total operating revenues	$ 1,316	$ 1,103	$ 1,192	$ 1,623	$ 1,600	$ 1,207	$ 1,253	$ 1,843	$ 5,234	$ 5,903	$ 5,518
Total operating expenses									3,801	3,979	3,852
Operating Income	97	389	406	541	565	382	338	639	1,433	1,924	1,666
Earnings (loss) from equity investments									(290)	361	445
Equity in earnings of consolidated subsidiaries									0	0	0
Other income and expenses, net									114	59	124
Interest expense									636	679	657
Earnings Before Income Taxes									621	1,665	1,578
Income tax expense (benefit)									161	382	419
Net income	(188)	243	80	325	374	254	188	467	460	1,283	1,159
Net income—noncontrolling interests									264	201	121
Net Income—Controlling Interests	$ (263)	$ 174	$ 18	$ 267	$ 316	$ 201	$ 146	$ 419	196	1,082	1,038
Spectra Energy Corp
Condensed Financial Statements, Captions [Line Items]
Total operating revenues									0	0	0
Total operating expenses									6	6	8
Operating Income									(6)	(6)	(8)
Earnings (loss) from equity investments									0	0	0
Equity in earnings of consolidated subsidiaries									161	1,054	1,015
Other income and expenses, net									0	(2)	1
Interest expense									0	0	0
Earnings Before Income Taxes									155	1,046	1,008
Income tax expense (benefit)									(41)	(36)	(30)
Net income									196	1,082	1,038
Net income—noncontrolling interests									0	0	0
Net Income—Controlling Interests									196	1,082	1,038
Spectra Energy Capital
Condensed Financial Statements, Captions [Line Items]
Total operating revenues									0	0	0
Total operating expenses									(4)	1	3
Operating Income									4	(1)	(3)
Earnings (loss) from equity investments									0	0	0	[1]
Equity in earnings of consolidated subsidiaries									573	1,651	1,649
Other income and expenses, net									1	9	15
Interest expense									244	253	216
Earnings Before Income Taxes									334	1,406	1,445
Income tax expense (benefit)									173	352	430
Net income									161	1,054	1,015	[1]
Net income—noncontrolling interests									0	0	0
Net Income—Controlling Interests									161	1,054	1,015
Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Total operating revenues									5,237	5,906	5,521
Total operating expenses									3,802	3,975	3,844
Operating Income									1,435	1,931	1,677
Earnings (loss) from equity investments									(290)	361	445	[1]
Equity in earnings of consolidated subsidiaries									0	0	0
Other income and expenses, net									113	52	108
Interest expense									392	426	441
Earnings Before Income Taxes									866	1,918	1,789
Income tax expense (benefit)									29	66	19
Net income									837	1,852	1,770	[1]
Net income—noncontrolling interests									264	201	121
Net Income—Controlling Interests									573	1,651	1,649
Eliminations
Condensed Financial Statements, Captions [Line Items]
Total operating revenues									(3)	(3)	(3)
Total operating expenses									(3)	(3)	(3)
Operating Income									0	0	0
Earnings (loss) from equity investments									0	0	0
Equity in earnings of consolidated subsidiaries									(734)	(2,705)	(2,664)
Other income and expenses, net									0	0	0
Interest expense									0	0	0
Earnings Before Income Taxes									(734)	(2,705)	(2,664)
Income tax expense (benefit)									0	0	0
Net income									(734)	(2,705)	(2,664)
Net income—noncontrolling interests									0	0	0
Net Income—Controlling Interests									$ (734)	$ (2,705)	$ (2,664)
[1]	Excludes the effects of $3,869 million of non-cash equitizations of advances receivable owed to Spectra Capital.

Condensed Consolidating Stat144

Condensed Consolidating Statements of Comprehensive Income (Detail) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Condensed Financial Statements, Captions [Line Items]
Net income	$ (188)	$ 243	$ 80	$ 325	$ 374	$ 254	$ 188	$ 467	$ 460	$ 1,283	$ 1,159
Other comprehensive income (loss)									(944)	(586)	(275)
Total Comprehensive Income (Loss), net of tax									(484)	697	884
Less: comprehensive income—noncontrolling interests									251	194	114
Comprehensive Income (Loss) — Controlling Interests									(735)	503	770
Spectra Energy Corp
Condensed Financial Statements, Captions [Line Items]
Net income									196	1,082	1,038
Other comprehensive income (loss)									(14)	9	69
Total Comprehensive Income (Loss), net of tax									182	1,091	1,107
Less: comprehensive income—noncontrolling interests									0	0	0
Comprehensive Income (Loss) — Controlling Interests									182	1,091	1,107
Spectra Energy Capital
Condensed Financial Statements, Captions [Line Items]
Net income									161	1,054	1,015	[1]
Other comprehensive income (loss)									1	1	2
Total Comprehensive Income (Loss), net of tax									162	1,055	1,017
Less: comprehensive income—noncontrolling interests									0	0	0
Comprehensive Income (Loss) — Controlling Interests									162	1,055	1,017
Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Net income									837	1,852	1,770	[1]
Other comprehensive income (loss)									(931)	(596)	(346)
Total Comprehensive Income (Loss), net of tax									(94)	1,256	1,424
Less: comprehensive income—noncontrolling interests									251	194	114
Comprehensive Income (Loss) — Controlling Interests									(345)	1,062	1,310
Eliminations
Condensed Financial Statements, Captions [Line Items]
Net income									(734)	(2,705)	(2,664)
Other comprehensive income (loss)									0	0	0
Total Comprehensive Income (Loss), net of tax									(734)	(2,705)	(2,664)
Less: comprehensive income—noncontrolling interests									0	0	0
Comprehensive Income (Loss) — Controlling Interests									$ (734)	$ (2,705)	$ (2,664)
[1]	Excludes the effects of $3,869 million of non-cash equitizations of advances receivable owed to Spectra Capital.

Condensed Consolidating Balance

Condensed Consolidating Balance Sheet (Detail) - USD ($) $ in Millions		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents		$ 213	$ 215	$ 201	$ 94
Receivables - consolidated subsidiaries		0	0
Receivables (net of allowance for doubtful accounts of $11 at December 31, 2015 and 2014)		806	1,336
Other current assets		629	781
Total current assets		1,648	2,332
Investments in and loans to unconsolidated affiliates		2,592	2,966
Investments in consolidated subsidiaries		0	0
Advances receivable - consolidated subsidiaries		0	0
Notes receivable - consolidated subsidiaries		0	0
Goodwill		4,154	4,714	4,810
Other assets		310	327
Net property, plant and equipment		22,918	22,307
Regulatory Assets and Deferred Debits		1,301	1,352
Total Assets		32,923	33,998	33,486
Accounts payable		511	458
Accounts payable - consolidated subsidiaries		0	0
Commercial paper	[1],[2]	1,112	1,583
Short-term borrowings - consolidated subsidiaries		0	0
Taxes accrued		78	91
Current maturities of long-term debt		652	327
Other current liabilities		1,039	1,350
Total current liabilities		3,392	3,809
Long-term debt		12,892	12,727
Advances payable - consolidated subsidiaries		0	0
Notes payable—consolidated subsidiaries		0
Deferred credits and other liabilities		6,768	6,806
Preferred stock of subsidiaries		339	258
Equity
Total controlling interests		6,526	8,160
Noncontrolling interests		3,006	2,238
Total equity		9,532	10,398	10,323	9,843
Total Liabilities and Equity		32,923	33,998
Spectra Energy Corp
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents		0	0	0	0
Receivables - consolidated subsidiaries		15	18
Receivables (net of allowance for doubtful accounts of $11 at December 31, 2015 and 2014)		2	2
Other current assets		25	71
Total current assets		42	91
Investments in and loans to unconsolidated affiliates		0	0
Investments in consolidated subsidiaries		13,919	14,531
Advances receivable - consolidated subsidiaries		0	0
Notes receivable - consolidated subsidiaries		0	0
Goodwill		0	0
Other assets		41	38
Net property, plant and equipment		0	0
Regulatory Assets and Deferred Debits		3	4
Total Assets		14,005	14,664
Accounts payable		2	3
Accounts payable - consolidated subsidiaries		4	0
Commercial paper		0	0
Short-term borrowings - consolidated subsidiaries		0	0
Taxes accrued		5	5
Current maturities of long-term debt		0	0
Other current liabilities		102	96
Total current liabilities		113	104
Long-term debt		0	0
Advances payable - consolidated subsidiaries		6,599	5,581
Notes payable—consolidated subsidiaries		0
Deferred credits and other liabilities		767	819
Preferred stock of subsidiaries		0	0
Equity
Total controlling interests		6,526	8,160
Noncontrolling interests		0	0
Total equity		6,526	8,160
Total Liabilities and Equity		14,005	14,664
Spectra Energy Capital, LLC
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents		1	1	12	3	[3]
Receivables - consolidated subsidiaries		6	0
Receivables (net of allowance for doubtful accounts of $11 at December 31, 2015 and 2014)		0	0
Other current assets		0	2
Total current assets		7	3
Investments in and loans to unconsolidated affiliates		0	0
Investments in consolidated subsidiaries		19,161	20,562
Advances receivable - consolidated subsidiaries		5,273	4,683
Notes receivable - consolidated subsidiaries		0	0
Goodwill		0	0
Other assets		27	22
Net property, plant and equipment		0	0
Regulatory Assets and Deferred Debits		3	5
Total Assets		24,471	25,275
Accounts payable		3	0
Accounts payable - consolidated subsidiaries		28	17
Commercial paper		481	398
Short-term borrowings - consolidated subsidiaries		387	398
Taxes accrued		0	0
Current maturities of long-term debt		0	0
Other current liabilities		48	54
Total current liabilities		947	867
Long-term debt		2,891	2,890
Advances payable - consolidated subsidiaries		0	0
Notes payable—consolidated subsidiaries		2,800	2,800
Deferred credits and other liabilities		3,914	4,187
Preferred stock of subsidiaries		0	0
Equity
Total controlling interests		13,919	14,531
Noncontrolling interests		0	0
Total equity		13,919	14,531
Total Liabilities and Equity		24,471	25,275
Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents		212	214	189	91	[3]
Receivables - consolidated subsidiaries		13	11
Notes receivable From Consolidated Subsidiaries current [Abstract]		387
Receivables (net of allowance for doubtful accounts of $11 at December 31, 2015 and 2014)		804	1,334
Other current assets		604	708
Total current assets		2,020	2,267
Investments in and loans to unconsolidated affiliates		2,592	2,966
Investments in consolidated subsidiaries		0	0
Advances receivable - consolidated subsidiaries		1,326	898
Notes receivable - consolidated subsidiaries		2,800	3,198
Goodwill		4,154	4,714
Other assets		242	267
Net property, plant and equipment		22,918	22,307
Regulatory Assets and Deferred Debits		1,295	1,343
Total Assets		37,347	37,960
Accounts payable		506	455
Accounts payable - consolidated subsidiaries		2	12
Commercial paper		631	1,185
Short-term borrowings - consolidated subsidiaries		0	0
Taxes accrued		73	86
Current maturities of long-term debt		652	327
Other current liabilities		889	1,200
Total current liabilities		2,753	3,265
Long-term debt		10,001	9,837
Advances payable - consolidated subsidiaries		0	0
Notes payable—consolidated subsidiaries		0
Deferred credits and other liabilities		2,087	1,800
Preferred stock of subsidiaries		339	258
Equity
Total controlling interests		19,161	20,562
Noncontrolling interests		3,006	2,238
Total equity		22,167	22,800
Total Liabilities and Equity		37,347	37,960
Eliminations
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents		0	0	$ 0	$ 0
Receivables - consolidated subsidiaries		(34)	(29)
Notes receivable From Consolidated Subsidiaries current [Abstract]		(387)
Receivables (net of allowance for doubtful accounts of $11 at December 31, 2015 and 2014)		0	0
Other current assets		0	0
Total current assets		(421)	(29)
Investments in and loans to unconsolidated affiliates		0	0
Investments in consolidated subsidiaries		(33,080)	(35,093)
Advances receivable - consolidated subsidiaries		(6,599)	(5,581)
Notes receivable - consolidated subsidiaries		(2,800)	(3,198)
Goodwill		0	0
Other assets		0	0
Net property, plant and equipment		0	0
Regulatory Assets and Deferred Debits		0	0
Total Assets		(42,900)	(43,901)
Accounts payable		0	0
Accounts payable - consolidated subsidiaries		(34)	(29)
Commercial paper		0	0
Short-term borrowings - consolidated subsidiaries		(387)	(398)
Taxes accrued		0	0
Current maturities of long-term debt		0	0
Other current liabilities		0	0
Total current liabilities		(421)	(427)
Long-term debt		0	0
Advances payable - consolidated subsidiaries		(6,599)	(5,581)
Notes payable—consolidated subsidiaries		(2,800)	(2,800)
Deferred credits and other liabilities		0	0
Preferred stock of subsidiaries		0	0
Equity
Total controlling interests		(33,080)	(35,093)
Noncontrolling interests		0	0
Total equity		(33,080)	(35,093)
Total Liabilities and Equity		$ (42,900)	$ (43,901)
[1]	The weighted-average days to maturity was 12 days as of December 31, 2015 and 14 days as of December 31, 2014.
[2]	Weighted-average rate on outstanding commercial paper was 0.9% at December 31, 2015 and 0.6% at December 31, 2014.
[3]	Excludes the effects of $3,869 million of non-cash equitizations of advances receivable owed to Spectra Capital.

Condensed Consolidating Stat146

Condensed Consolidating Statement of Cash Flows (Detail) - USD ($) $ in Millions		3 Months Ended								12 Months Ended
		Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
CASH FLOWS FROM OPERATING ACTIVITIES
Net income		$ (188)	$ 243	$ 80	$ 325	$ 374	$ 254	$ 188	$ 467	$ 460	$ 1,283	$ 1,159
Depreciation and amortization										778	809	787
Impairment charges										349	0	0
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
(Earnings) loss from equity investments										290	(361)	(445)
Equity in earnings of consolidated subsidiaries										0	0	0
Distributions from equity investments										161	380	324
Other										209	110	205
Net cash provided by operating activities										2,247	2,221	2,030
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures										(2,848)	(2,028)	(1,947)
Investments in and loans to unconsolidated affiliates										(124)	(259)	(312)
Acquisitions, net of cash acquired										0	0	(1,254)
Purchases of held-to-maturity securities										(668)	(790)	(985)
Proceeds from sales and maturities of held-to-maturity securities										695	815	1,023
Purchases of available-for-sale securities										(95)	(13)	(5,878)
Proceeds from sales and maturities of available-for-sale securities										87	7	6,024
Distributions from equity investments										451	266	87
Advances (to) from affiliates										0	0	0
Distribution to equity investment										(248)	0	(71)
Repayment of loan to equity investment										0	0	71
Other changes in restricted funds										(33)	(1)	2
Other										1	0	4
Net cash used in investing activities										(2,782)	(2,003)	(3,236)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt										1,585	1,028	4,372
Payments for the redemption of long-term debt										(285)	(1,184)	(2,139)
Net increase (decrease) in commercial paper										(439)	574	(206)
Net decrease in revolving credit facilities borrowings												0
Distributions to noncontrolling interests										(198)	(175)	(144)
Contributions from noncontrolling interests										248	145	23
Proceeds from the issuance of Spectra Energy Partners common units										546	327	214
Proceeds from the issuance of Westcoast Energy, Inc. preferred stock										84	0	0
Dividends paid on common stock										(996)	(925)	(821)
Distributions and advances from (to) affiliates										0	0	0
Other										(5)	11	17
Net cash provided by (used in) financing activities										540	(199)	1,316
Effect of exchange rate changes on cash										(7)	(5)	(3)
Net increase (decrease) in cash and cash equivalents										(2)	14	107
Cash and cash equivalents at beginning of period					215				201	215	201	94
Cash and cash equivalents at end of period		213				215				213	215	201
Spectra Energy Corp
CASH FLOWS FROM OPERATING ACTIVITIES
Net income										196	1,082	1,038
Depreciation and amortization										0	0	0
Impairment charges										0
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
(Earnings) loss from equity investments										0	0	0
Equity in earnings of consolidated subsidiaries										(161)	(1,054)	(1,015)
Distributions from equity investments										0	0	0
Other										187	14	(2)
Net cash provided by operating activities										222	42	21
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures										0	0	0
Investments in and loans to unconsolidated affiliates										0	0	0
Acquisitions, net of cash acquired												0
Purchases of held-to-maturity securities										0	0	0
Proceeds from sales and maturities of held-to-maturity securities										0	0	0
Purchases of available-for-sale securities										0	0	0
Proceeds from sales and maturities of available-for-sale securities										0	0	0
Distributions from equity investments										0	0	0
Advances (to) from affiliates										(240)	92	(75)
Distribution to equity investment										0		0
Repayment of loan to equity investment												0
Other changes in restricted funds										0	0	0
Other										0		0
Net cash used in investing activities										(240)	92	(75)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt										0	0	0
Payments for the redemption of long-term debt										0	0	0
Net increase (decrease) in commercial paper										0	0	0
Net decrease in revolving credit facilities borrowings												0
Distributions to noncontrolling interests										0	0	0
Contributions from noncontrolling interests										0	0
Proceeds from the issuance of Spectra Energy Partners common units										0	0	0
Proceeds from the issuance of Westcoast Energy, Inc. preferred stock										0
Proceeds from the issuance of Spectra Energy common stock												0
Dividends paid on common stock										(996)	(925)	(821)
Distributions and advances from (to) affiliates										1,018	777	847
Other										(4)	14	28
Net cash provided by (used in) financing activities										18	(134)	54
Effect of exchange rate changes on cash										0	0	0
Net increase (decrease) in cash and cash equivalents										0	0	0
Cash and cash equivalents at beginning of period					0				0	0	0	0
Cash and cash equivalents at end of period		0				0				0	0	0
Spectra Energy Capital, LLC
CASH FLOWS FROM OPERATING ACTIVITIES
Net income										161	1,054	1,015	[1]
Depreciation and amortization										0	0	0
Impairment charges										0
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
(Earnings) loss from equity investments										0	0	0	[1]
Equity in earnings of consolidated subsidiaries										(573)	(1,651)	(1,649)	[1]
Distributions from equity investments										0	0	0	[1]
Other										33	304	478	[1]
Net cash provided by operating activities										(379)	(293)	(156)	[1]
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures										0	0	0	[1]
Investments in and loans to unconsolidated affiliates										0	0	0	[1]
Acquisitions, net of cash acquired	[1]											0
Purchases of held-to-maturity securities										0	0	0	[1]
Proceeds from sales and maturities of held-to-maturity securities										0	0	0	[1]
Purchases of available-for-sale securities										0	0	0	[1]
Proceeds from sales and maturities of available-for-sale securities										0	0	0	[1]
Distributions from equity investments										0	0	0	[1]
Advances (to) from affiliates										296	495	(1,856)	[1]
Distribution to equity investment										0		0
Repayment of loan to equity investment												71
Other changes in restricted funds										0	0	0	[1]
Other										0		0	[1]
Net cash used in investing activities										296	495	(1,785)	[1]
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt										0	300	1,848	[1]
Payments for the redemption of long-term debt										0	(557)	(1,944)	[1]
Net increase (decrease) in commercial paper										83	54	(170)	[1]
Net decrease in revolving credit facilities borrowings	[1]											(497)
Distributions to noncontrolling interests										0	0	0	[1]
Contributions from noncontrolling interests										0	0
Proceeds from the issuance of Spectra Energy Partners common units										0	0	0	[1]
Proceeds from the issuance of Westcoast Energy, Inc. preferred stock										0
Proceeds from the issuance of Spectra Energy common stock	[1]											0
Dividends paid on common stock										0	0	0	[1]
Distributions and advances from (to) affiliates										0	(10)	2,718	[1]
Other										0	0	(5)	[1]
Net cash provided by (used in) financing activities										83	(213)	1,950	[1]
Effect of exchange rate changes on cash										0	0	0	[1]
Net increase (decrease) in cash and cash equivalents										0	(11)	9	[1]
Cash and cash equivalents at beginning of period					1				12	1	12	3	[1]
Cash and cash equivalents at end of period		1				1				1	1	12
Non-Guarantor Subsidiaries
CASH FLOWS FROM OPERATING ACTIVITIES
Net income										837	1,852	1,770	[1]
Depreciation and amortization										778	809	787
Impairment charges										349
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
(Earnings) loss from equity investments										290	(361)	(445)	[1]
Equity in earnings of consolidated subsidiaries										0	0	0	[1]
Distributions from equity investments										161	380	324	[1]
Other										(11)	(208)	(271)	[1]
Net cash provided by operating activities										2,404	2,472	2,165	[1]
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures										(2,848)	(2,028)	(1,947)	[1]
Investments in and loans to unconsolidated affiliates										(124)	(259)	(312)	[1]
Acquisitions, net of cash acquired	[1]											(1,254)
Purchases of held-to-maturity securities										(668)	(790)	(985)	[1]
Proceeds from sales and maturities of held-to-maturity securities										695	815	1,023	[1]
Purchases of available-for-sale securities										(95)	(13)	(5,878)	[1]
Proceeds from sales and maturities of available-for-sale securities										87	7	6,024	[1]
Distributions from equity investments										451	266	87	[1]
Advances (to) from affiliates										0	0	0	[1]
Distribution to equity investment										(248)		(71)
Repayment of loan to equity investment												0
Other changes in restricted funds										(33)	(1)	2	[1]
Other										1		4	[1]
Net cash used in investing activities										(2,782)	(2,003)	(3,307)	[1]
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt										1,585	728	2,524	[1]
Payments for the redemption of long-term debt										(285)	(627)	(195)	[1]
Net increase (decrease) in commercial paper										(522)	520	(36)	[1]
Net decrease in revolving credit facilities borrowings	[1]											0
Distributions to noncontrolling interests										(198)	(175)	(144)	[1]
Contributions from noncontrolling interests										248	145
Proceeds from the issuance of Spectra Energy Partners common units										546	327	214	[1]
Proceeds from the issuance of Westcoast Energy, Inc. preferred stock										84
Proceeds from the issuance of Spectra Energy common stock	[1]											23
Dividends paid on common stock										0	0	0	[1]
Distributions and advances from (to) affiliates										(1,074)	(1,354)	(1,137)	[1]
Other										(1)	(3)	(6)	[1]
Net cash provided by (used in) financing activities										383	(439)	1,243	[1]
Effect of exchange rate changes on cash										(7)	(5)	(3)	[1]
Net increase (decrease) in cash and cash equivalents										(2)	25	98	[1]
Cash and cash equivalents at beginning of period					214				189	214	189	91	[1]
Cash and cash equivalents at end of period		212				214				212	214	189
Eliminations
CASH FLOWS FROM OPERATING ACTIVITIES
Net income										(734)	(2,705)	(2,664)
Depreciation and amortization										0	0	0
Impairment charges										0
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
(Earnings) loss from equity investments										0	0	0
Equity in earnings of consolidated subsidiaries										734	2,705	2,664
Distributions from equity investments										0	0	0
Other										0	0	0
Net cash provided by operating activities										0	0	0
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures										0	0	0
Investments in and loans to unconsolidated affiliates										0	0	0
Acquisitions, net of cash acquired												0
Purchases of held-to-maturity securities										0	0	0
Proceeds from sales and maturities of held-to-maturity securities										0	0	0
Purchases of available-for-sale securities										0	0	0
Proceeds from sales and maturities of available-for-sale securities										0	0	0
Distributions from equity investments										0	0	0
Advances (to) from affiliates										(56)	(587)	1,931
Distribution to equity investment										0		0
Repayment of loan to equity investment												0
Other changes in restricted funds										0	0	0
Other										0		0
Net cash used in investing activities										(56)	(587)	1,931
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt										0	0	0
Payments for the redemption of long-term debt										0	0	0
Net increase (decrease) in commercial paper										0	0	0
Net decrease in revolving credit facilities borrowings												497
Distributions to noncontrolling interests										0	0	0
Contributions from noncontrolling interests										0	0
Proceeds from the issuance of Spectra Energy Partners common units										0	0	0
Proceeds from the issuance of Westcoast Energy, Inc. preferred stock										0
Proceeds from the issuance of Spectra Energy common stock												0
Dividends paid on common stock										0	0	0
Distributions and advances from (to) affiliates										56	587	(2,428)
Other										0	0	0
Net cash provided by (used in) financing activities										56	587	(1,931)
Effect of exchange rate changes on cash										0	0	0
Net increase (decrease) in cash and cash equivalents										0	0	0
Cash and cash equivalents at beginning of period					$ 0				$ 0	0	0	0
Cash and cash equivalents at end of period		$ 0				$ 0				$ 0	$ 0	$ 0
[1]	Excludes the effects of $3,869 million of non-cash equitizations of advances receivable owed to Spectra Capital.

Condensed Consolidating Stat147

Condensed Consolidating Statement of Cash Flows (Notes) (Detail) $ in Millions	Dec. 31, 2013USD ($)
Spectra Energy Capital, LLC
Condensed Financial Statements, Captions [Line Items]
Non-cash equitization of advances receivables owed to Spectra Capital	$ 3,869

Quarterly Financial Data (Un148

Quarterly Financial Data (Unaudited) (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended																12 Months Ended
	Dec. 31, 2015		Sep. 30, 2015		Jun. 30, 2015		Mar. 31, 2015		Dec. 31, 2014		Sep. 30, 2014		Jun. 30, 2014		Mar. 31, 2014		Dec. 31, 2015		Dec. 31, 2014		Dec. 31, 2013
Quarterly Financial Information Disclosure [Abstract]
Operating revenues	$ 1,316		$ 1,103		$ 1,192		$ 1,623		$ 1,600		$ 1,207		$ 1,253		$ 1,843		$ 5,234		$ 5,903		$ 5,518
Operating Income	97		389		406		541		565		382		338		639		1,433		1,924		1,666
Net income	(188)		243		80		325		374		254		188		467		460		1,283		1,159
Net Income—Controlling Interests	$ (263)		$ 174		$ 18		$ 267		$ 316		$ 201		$ 146		$ 419		$ 196		$ 1,082		$ 1,038
Earnings per share
Basic (in usd per share)	$ (0.39)	[1]	$ 0.26	[1]	$ 0.03	[1]	$ 0.40	[1]	$ 0.47	[1]	$ 0.30	[1]	$ 0.22	[1]	$ 0.63	[1]	$ 0.29	[1]	$ 1.61	[1]	$ 1.55
Diluted (in usd per share)	$ (0.39)	[1]	$ 0.26	[1]	$ 0.03	[1]	$ 0.40	[1]	$ 0.47	[1]	$ 0.30	[1]	$ 0.22	[1]	$ 0.62	[1]	$ 0.29	[1]	$ 1.61	[1]	$ 1.55
Goodwill [Line Items]
Goodwill, Impairment Loss																	$ 333		$ 0		$ 0
BC Pipeline and BC Field Services
Goodwill [Line Items]
Goodwill, Impairment Loss																	270
Empress
Goodwill [Line Items]
Goodwill, Impairment Loss																	63
Investment Income (Expense) | DCP Midstream, LLC
Goodwill [Line Items]
Goodwill Impairment Recorded by Equity Method Investment																	460
Other Asset Impairment Recorded by Equity Method Investment	$ 342
Goodwill, Impairment Loss, Net of Tax																	231
Western Canada Transmission & Processing
Goodwill [Line Items]
Goodwill, Impairment Loss																	333
Western Canada Transmission & Processing | BC Pipeline and BC Field Services
Goodwill [Line Items]
Goodwill, Impairment Loss																	270
Western Canada Transmission & Processing | Empress
Goodwill [Line Items]
Goodwill, Impairment Loss																	$ 63
[1]	Quarterly earnings-per-share amounts are stand-alone calculations and may not be additive to full-year amounts due to rounding.

Valuation and Qualifying Accoun

Valuation and Qualifying Accounts and Reserves (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period		$ 124	$ 174	$ 194
Additions Charged to Expense		43	35	28
Additions Charged to Other Accounts		24	0	0
Deductions	[1]	46	85	48
Balance at End of Period		145	124	174
Allowance for doubtful accounts
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period		11	10	13
Additions Charged to Expense		7	6	7
Additions Charged to Other Accounts		0	0	0
Deductions	[1]	7	5	10
Balance at End of Period		11	11	10
Other (b)
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	[2]	113	164	181
Additions Charged to Expense	[2]	36	29	21
Additions Charged to Other Accounts	[2]	24	0	0
Deductions	[1],[2]	39	80	38
Balance at End of Period	[2]	$ 134	$ 113	$ 164
[1]	Principally cash payments and reserve reversals.
[2]	Principally income tax, insurance-related, litigation and other reserves, included primarily in Deferred Credits and Other Liabilities—Regulatory and Other on the Consolidated Balance Sheets.