Condensed Consolidating Financial Information Condensed Consolidating Statement of Cash Flows (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2016	Dec. 31, 2015	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
CASH FLOWS FROM OPERATING ACTIVITIES
Net Income	$ 281		$ 243	$ 812	$ 648
Adjustments, Noncash Items, to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract]
Depreciation and amortization				599	584
(Earnings) loss from equity investments	(51)		(48)	(100)	117
Equity in earnings of consolidated subsidiaries	0		0	0	0
Distributions from equity investments				88	145
Other				200	329
Net cash provided by (used in) operating activities				1,599	1,823
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures				(2,407)	(1,817)
Investments in and loans to unconsolidated affiliates				(181)	(91)
Purchase of intangible, net				(80)	0
Disposition				204	0
Purchases of held-to-maturity securities				(479)	(463)
Proceeds from sales and maturities of held-to-maturity securities				475	457
Purchases of available-for-sale securities				(565)	0
Proceeds from sales and maturities of available-for-sale securities				559	1
Distributions from equity investments				45	441
Distribution to equity investment				(148)	0
Advances from (to) affiliates				0	0
Other changes in restricted funds				(19)	(24)
Other				1	(7)
Net cash provided by (used in) investing activities				(2,595)	(1,503)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt				382	1,332
Payments for the redemption of long-term debt				(619)	(153)
Net increase (decrease) in commercial paper				502	(984)
Distributions to noncontrolling interests				(176)	(140)
Contributions from noncontrolling interests				437	164
Proceeds from the issuances of Spectra Energy common stock				878	0
Proceeds from the issuances of Spectra Energy Partners, LP common units				473	351
Proceeds from the issuance of Westcoast Energy Inc. preferred stock				229	0
Dividends paid on common stock				(842)	(747)
Distributions and advances from (to) affiliates				0	0
Other				(20)	(14)
Net cash provided by (used in) financing activities				1,244	(191)
Effect of exchange rate changes on cash				3	(6)
Net increase in cash and cash equivalents				251	123
Cash and cash equivalents at beginning of period		$ 338		213	215
Cash and cash equivalents at end of period	464	213	338	464	338
Eliminations
CASH FLOWS FROM OPERATING ACTIVITIES
Net Income	(465)		(477)	(1,489)	(1,235)
Adjustments, Noncash Items, to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract]
Depreciation and amortization				0	0
(Earnings) loss from equity investments	0		0	0	0
Equity in earnings of consolidated subsidiaries	465		477	1,489	1,235
Distributions from equity investments				0	0
Other				0	0
Net cash provided by (used in) operating activities				0	0
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures				0	0
Investments in and loans to unconsolidated affiliates				0	0
Purchase of intangible, net				0
Disposition				0
Purchases of held-to-maturity securities				0	0
Proceeds from sales and maturities of held-to-maturity securities				0	0
Purchases of available-for-sale securities				0
Proceeds from sales and maturities of available-for-sale securities				0	0
Distributions from equity investments				0	0
Distribution to equity investment				0
Advances from (to) affiliates				(139)	20
Other changes in restricted funds				0	0
Other				0	0
Net cash provided by (used in) investing activities				(139)	20
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt				0	0
Payments for the redemption of long-term debt				0	0
Net increase (decrease) in commercial paper				0	0
Distributions to noncontrolling interests				0	0
Contributions from noncontrolling interests				0	0
Proceeds from the issuances of Spectra Energy common stock				0
Proceeds from the issuances of Spectra Energy Partners, LP common units				0	0
Proceeds from the issuance of Westcoast Energy Inc. preferred stock				0
Dividends paid on common stock				0	0
Distributions and advances from (to) affiliates				139	(20)
Other				0	0
Net cash provided by (used in) financing activities				139	(20)
Effect of exchange rate changes on cash				0	0
Net increase in cash and cash equivalents				0	0
Cash and cash equivalents at beginning of period		0		0	0
Cash and cash equivalents at end of period	0	0	0	0	0
Spectra Energy Corp
CASH FLOWS FROM OPERATING ACTIVITIES
Net Income	195		174	578	459
Adjustments, Noncash Items, to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract]
Depreciation and amortization				0	0
(Earnings) loss from equity investments	0		0	0	0
Equity in earnings of consolidated subsidiaries	(193)		(170)	(564)	(445)
Distributions from equity investments				0	0
Other				(9)	44
Net cash provided by (used in) operating activities				5	58
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures				0	0
Investments in and loans to unconsolidated affiliates				0	0
Purchase of intangible, net				0
Disposition				0
Purchases of held-to-maturity securities				0	0
Proceeds from sales and maturities of held-to-maturity securities				0	0
Purchases of available-for-sale securities				0
Proceeds from sales and maturities of available-for-sale securities				0	0
Distributions from equity investments				0	0
Distribution to equity investment				0
Advances from (to) affiliates				(57)	(82)
Other changes in restricted funds				0	0
Other				0	0
Net cash provided by (used in) investing activities				(57)	(82)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt				0	0
Payments for the redemption of long-term debt				0	0
Net increase (decrease) in commercial paper				0	0
Distributions to noncontrolling interests				0	0
Contributions from noncontrolling interests				0	0
Proceeds from the issuances of Spectra Energy common stock				878
Proceeds from the issuances of Spectra Energy Partners, LP common units				0	0
Proceeds from the issuance of Westcoast Energy Inc. preferred stock				0
Dividends paid on common stock				(842)	(747)
Distributions and advances from (to) affiliates				14	774
Other				2	(3)
Net cash provided by (used in) financing activities				52	24
Effect of exchange rate changes on cash				0	0
Net increase in cash and cash equivalents				0	0
Cash and cash equivalents at beginning of period		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	193		170	564	445
Adjustments, Noncash Items, to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract]
Depreciation and amortization				0	0
(Earnings) loss from equity investments	0		0	0	0
Equity in earnings of consolidated subsidiaries	(272)		(307)	(925)	(790)
Distributions from equity investments				0	0
Other				194	109
Net cash provided by (used in) operating activities				(167)	(236)
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures				0	0
Investments in and loans to unconsolidated affiliates				0	0
Purchase of intangible, net				0
Disposition				0
Purchases of held-to-maturity securities				0	0
Proceeds from sales and maturities of held-to-maturity securities				0	0
Purchases of available-for-sale securities				0
Proceeds from sales and maturities of available-for-sale securities				0	0
Distributions from equity investments				0	0
Distribution to equity investment				0
Advances from (to) affiliates				196	62
Other changes in restricted funds				0	0
Other				0	0
Net cash provided by (used in) investing activities				196	62
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt				0	0
Payments for the redemption of long-term debt				0	0
Net increase (decrease) in commercial paper				(21)	170
Distributions to noncontrolling interests				0	0
Contributions from noncontrolling interests				0	0
Proceeds from the issuances of Spectra Energy common stock				0
Proceeds from the issuances of Spectra Energy Partners, LP common units				0	0
Proceeds from the issuance of Westcoast Energy Inc. preferred stock				0
Dividends paid on common stock				0	0
Distributions and advances from (to) affiliates				(8)	4
Other				0	0
Net cash provided by (used in) financing activities				(29)	174
Effect of exchange rate changes on cash				0	0
Net increase in cash and cash equivalents				0	0
Cash and cash equivalents at beginning of period		1		1	1
Cash and cash equivalents at end of period	1	1	1	1	1
Non-Guarantor Subsidiaries
CASH FLOWS FROM OPERATING ACTIVITIES
Net Income	358		376	1,159	979
Adjustments, Noncash Items, to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract]
Depreciation and amortization				599	584
(Earnings) loss from equity investments	(51)		(48)	(100)	117
Equity in earnings of consolidated subsidiaries	0		0	0	0
Distributions from equity investments				88	145
Other				15	176
Net cash provided by (used in) operating activities				1,761	2,001
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures				(2,407)	(1,817)
Investments in and loans to unconsolidated affiliates				(181)	(91)
Purchase of intangible, net				(80)
Disposition				204
Purchases of held-to-maturity securities				(479)	(463)
Proceeds from sales and maturities of held-to-maturity securities				475	457
Purchases of available-for-sale securities				(565)
Proceeds from sales and maturities of available-for-sale securities				559	1
Distributions from equity investments				45	441
Distribution to equity investment				(148)
Advances from (to) affiliates				0	0
Other changes in restricted funds				(19)	(24)
Other				1	(7)
Net cash provided by (used in) investing activities				(2,595)	(1,503)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from the issuance of long-term debt				382	1,332
Payments for the redemption of long-term debt				(619)	(153)
Net increase (decrease) in commercial paper				523	(1,154)
Distributions to noncontrolling interests				(176)	(140)
Contributions from noncontrolling interests				437	164
Proceeds from the issuances of Spectra Energy common stock				0
Proceeds from the issuances of Spectra Energy Partners, LP common units				473	351
Proceeds from the issuance of Westcoast Energy Inc. preferred stock				229
Dividends paid on common stock				0	0
Distributions and advances from (to) affiliates				(145)	(758)
Other				(22)	(11)
Net cash provided by (used in) financing activities				1,082	(369)
Effect of exchange rate changes on cash				3	(6)
Net increase in cash and cash equivalents				251	123
Cash and cash equivalents at beginning of period		337		212	214
Cash and cash equivalents at end of period	$ 463	$ 212	$ 337	$ 463	$ 337