CONDENSED CONSOLIDATING FINANCIAL INFORMATION - Statements of Cash Flow (Details) - CAD ($) $ in Millions	1 Months Ended	3 Months Ended
	Jan. 31, 2019	Mar. 31, 2019	Mar. 31, 2018
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by operating activities		$ 2,176	$ 3,194
Investing activities
Capital expenditures	$ (265)	(1,612)	(1,635)
Long-term investments and restricted long-term investments		(565)	(222)
Distributions from equity investments in excess of cumulative earnings		139	57
Additions to intangible assets		(26)	(258)
Affiliate loans, net		(84)	(10)
Contributions to subsidiaries		0	0
Return of share capital from subsidiaries		0
Advances to affiliates		0	0
Repayment of advances to affiliates		0	0
Net cash used in investing activities		(2,148)	(2,068)
Financing activities
Net change in short-term borrowings		(154)	(443)
Net change in commercial paper and credit facility draws		2,773	(465)
Debenture and term note issues, net of issue costs		1,195	2,061
Debenture and term note repayments		(1,789)	(996)
Debt extinguishment costs		0	(63)
Contributions from noncontrolling interests		3	8
Distributions to noncontrolling interests		(46)	(209)
Contributions from redeemable noncontrolling interests		0	20
Distributions to redeemable noncontrolling interests		0	(84)
Contributions from parents		0	0
Distributions to parents		0	0
Redemption of preferred shares held by subsidiary (Note 10)		(300)	0
Common shares issued		18	13
Preference share dividends		(90)	(87)
Common share dividends		(1,486)	(764)
Advances from affiliates		0	0
Repayment of advances from affiliates		0	0
Other		(25)	0
Net cash provided by/(used in) financing activities		99	(1,009)
Effect of translation of foreign denominated cash and cash equivalents and restricted cash		(7)	19
Net increase in cash and cash equivalents and restricted cash		120	136
Cash and cash equivalents and restricted cash at beginning of period	637	637	587
Cash and cash equivalents and restricted cash at end of period		757	723
Consolidation, Eliminations
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by operating activities		(789)	(367)
Investing activities
Capital expenditures		0	0
Long-term investments and restricted long-term investments		0	16
Distributions from equity investments in excess of cumulative earnings		(536)	(824)
Additions to intangible assets		0	0
Affiliate loans, net		0	0
Contributions to subsidiaries		2,331	151
Return of share capital from subsidiaries		(3,121)
Advances to affiliates		42,068	3,130
Repayment of advances to affiliates		(6,016)	(2,944)
Net cash used in investing activities		34,726	(471)
Financing activities
Net change in short-term borrowings		0	0
Net change in commercial paper and credit facility draws		0	0
Debenture and term note issues, net of issue costs		0	0
Debenture and term note repayments		0	0
Debt extinguishment costs			0
Contributions from noncontrolling interests		3	8
Distributions to noncontrolling interests		(46)	(209)
Contributions from redeemable noncontrolling interests			20
Distributions to redeemable noncontrolling interests			(84)
Contributions from parents		(2,331)	(151)
Distributions to parents		4,489	1,440
Redemption of preferred shares held by subsidiary (Note 10)		0
Common shares issued		0	0
Preference share dividends		0	0
Common share dividends		0	0
Advances from affiliates		(42,068)	(3,130)
Repayment of advances from affiliates		6,016	2,944
Other		0
Net cash provided by/(used in) financing activities		(33,937)	838
Effect of translation of foreign denominated cash and cash equivalents and restricted cash		0	0
Net increase in cash and cash equivalents and restricted cash		0	0
Cash and cash equivalents and restricted cash at beginning of period	0	0	0
Cash and cash equivalents and restricted cash at end of period		0	0
Parent Issuer and Guarantor | Reportable Legal Entities
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by operating activities		(415)	(135)
Investing activities
Capital expenditures		(24)	(5)
Long-term investments and restricted long-term investments		0	(16)
Distributions from equity investments in excess of cumulative earnings		0	336
Additions to intangible assets		(16)	(6)
Affiliate loans, net		0	0
Contributions to subsidiaries		(2,331)	(69)
Return of share capital from subsidiaries		3,121
Advances to affiliates		(19,908)	(401)
Repayment of advances to affiliates		3,996	0
Net cash used in investing activities		(15,162)	(161)
Financing activities
Net change in short-term borrowings		0	0
Net change in commercial paper and credit facility draws		2,312	(105)
Debenture and term note issues, net of issue costs		0	1,080
Debenture and term note repayments		(300)	0
Debt extinguishment costs			0
Contributions from noncontrolling interests		0	0
Distributions to noncontrolling interests		0	0
Contributions from redeemable noncontrolling interests			0
Distributions to redeemable noncontrolling interests			0
Contributions from parents		0	0
Distributions to parents		0	0
Redemption of preferred shares held by subsidiary (Note 10)		0
Common shares issued		18	13
Preference share dividends		(90)	(87)
Common share dividends		(1,513)	(764)
Advances from affiliates		15,150	209
Repayment of advances from affiliates		0	(43)
Other		0
Net cash provided by/(used in) financing activities		15,577	303
Effect of translation of foreign denominated cash and cash equivalents and restricted cash		0	0
Net increase in cash and cash equivalents and restricted cash		0	7
Cash and cash equivalents and restricted cash at beginning of period	9	9	2
Cash and cash equivalents and restricted cash at end of period		9	9
Subsidiary Non-Guarantors | Reportable Legal Entities
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by operating activities		4,566	3,224
Investing activities
Capital expenditures		(1,588)	(1,630)
Long-term investments and restricted long-term investments		(563)	(217)
Distributions from equity investments in excess of cumulative earnings		132	42
Additions to intangible assets		(10)	(252)
Affiliate loans, net		(84)	(10)
Contributions to subsidiaries		0	0
Return of share capital from subsidiaries		0
Advances to affiliates		(21,542)	(2,233)
Repayment of advances to affiliates		1,638	1,890
Net cash used in investing activities		(22,017)	(2,410)
Financing activities
Net change in short-term borrowings		(154)	(443)
Net change in commercial paper and credit facility draws		2,471	614
Debenture and term note issues, net of issue costs		1,195	981
Debenture and term note repayments		(300)	(996)
Debt extinguishment costs			(63)
Contributions from noncontrolling interests		0	0
Distributions to noncontrolling interests		0	0
Contributions from redeemable noncontrolling interests			0
Distributions to redeemable noncontrolling interests			0
Contributions from parents		2,331	151
Distributions to parents		(3,822)	(824)
Redemption of preferred shares held by subsidiary (Note 10)		(300)
Common shares issued		0	0
Preference share dividends		0	0
Common share dividends		27	0
Advances from affiliates		20,526	897
Repayment of advances from affiliates		(4,378)	(1,054)
Other		(14)
Net cash provided by/(used in) financing activities		17,582	(737)
Effect of translation of foreign denominated cash and cash equivalents and restricted cash		(7)	19
Net increase in cash and cash equivalents and restricted cash		124	96
Cash and cash equivalents and restricted cash at beginning of period	612	612	571
Cash and cash equivalents and restricted cash at end of period		736	667
Spectra Energy Partners L P | Subsidiary Issuer and Guarantor - SEP and EEP | Reportable Legal Entities
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by operating activities		232	803
Investing activities
Capital expenditures		0	0
Long-term investments and restricted long-term investments		(2)	(5)
Distributions from equity investments in excess of cumulative earnings		7	15
Additions to intangible assets		0	0
Affiliate loans, net		0	0
Contributions to subsidiaries		0	(77)
Return of share capital from subsidiaries		0
Advances to affiliates		0	0
Repayment of advances to affiliates		0	506
Net cash used in investing activities		5	439
Financing activities
Net change in short-term borrowings		0	0
Net change in commercial paper and credit facility draws		(2,010)	(756)
Debenture and term note issues, net of issue costs		0	0
Debenture and term note repayments		0	0
Debt extinguishment costs			0
Contributions from noncontrolling interests		0	0
Distributions to noncontrolling interests		0	0
Contributions from redeemable noncontrolling interests			0
Distributions to redeemable noncontrolling interests			0
Contributions from parents		0	0
Distributions to parents		(505)	(453)
Redemption of preferred shares held by subsidiary (Note 10)		0
Common shares issued		0	0
Preference share dividends		0	0
Common share dividends		0	0
Advances from affiliates		3,498	0
Repayment of advances from affiliates		(1,226)	0
Other		(5)
Net cash provided by/(used in) financing activities		(248)	(1,209)
Effect of translation of foreign denominated cash and cash equivalents and restricted cash		0	0
Net increase in cash and cash equivalents and restricted cash		(11)	33
Cash and cash equivalents and restricted cash at beginning of period	16	16	14
Cash and cash equivalents and restricted cash at end of period		5	47
Enbridge Energy Partners, L.P. | Subsidiary Issuer and Guarantor - SEP and EEP | Reportable Legal Entities
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by operating activities		(1,418)	(331)
Investing activities
Capital expenditures		0	0
Long-term investments and restricted long-term investments		0	0
Distributions from equity investments in excess of cumulative earnings		536	488
Additions to intangible assets		0	0
Affiliate loans, net		0	0
Contributions to subsidiaries		0	(5)
Return of share capital from subsidiaries		0
Advances to affiliates		(618)	(496)
Repayment of advances to affiliates		382	548
Net cash used in investing activities		300	535
Financing activities
Net change in short-term borrowings		0	0
Net change in commercial paper and credit facility draws		0	(218)
Debenture and term note issues, net of issue costs		0	0
Debenture and term note repayments		(1,189)	0
Debt extinguishment costs			0
Contributions from noncontrolling interests		0	0
Distributions to noncontrolling interests		0	0
Contributions from redeemable noncontrolling interests			0
Distributions to redeemable noncontrolling interests			0
Contributions from parents		0	0
Distributions to parents		(162)	(163)
Redemption of preferred shares held by subsidiary (Note 10)		0
Common shares issued		0	0
Preference share dividends		0	0
Common share dividends		0	0
Advances from affiliates		2,894	2,024
Repayment of advances from affiliates		(412)	(1,847)
Other		(6)
Net cash provided by/(used in) financing activities		1,125	(204)
Effect of translation of foreign denominated cash and cash equivalents and restricted cash		0	0
Net increase in cash and cash equivalents and restricted cash		7	0
Cash and cash equivalents and restricted cash at beginning of period	$ 0	0	0
Cash and cash equivalents and restricted cash at end of period		$ 7	$ 0