CONDENSED CONSOLIDATING FINANCIAL INFORMATION - Condensed Consolidating Statements of Cash Flows (Details) - CAD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by operating activities	$ 9,398	$ 10,502	$ 6,658
Capital expenditures	(5,492)	(6,806)	(8,287)
Long-term investments and restricted long-term investments	(1,159)	(1,312)	(3,586)
Distributions from equity investments in excess of cumulative earnings	417	1,277	125
Additions to intangible assets	(200)	(540)	(789)
Cash acquired in Merger Transaction	0	0	682
Affiliate loans, net	(314)	(76)	(22)
Proceeds from dispositions	2,110	4,452	628
Contributions to subsidiaries	0	0	0
Return of share capital from subsidiaries	0	0	0
Advances to affiliates	0	0	0
Repayment of advances to affiliates	0	0	0
Other	(20)	(12)	212
Net cash used in investing activities	(4,658)	(3,017)	(11,037)
Net change in short-term borrowings	(127)	(420)	721
Net change in commercial paper and credit facility draws	825	(2,256)	(1,249)
Debenture and term note issues, net of issue costs	6,176	3,537	9,483
Debenture and term note repayments	(4,668)	(4,445)	(5,054)
Purchase of interest in consolidated subsidiary	0	0	(227)
Sale of noncontrolling interest in subsidiary	0	1,289	0
Contributions from noncontrolling interests	12	24	832
Distributions to noncontrolling interests	(254)	(857)	(919)
Contributions from redeemable noncontrolling interests	0	70	1,178
Distributions to redeemable noncontrolling interests	0	(325)	(247)
Contributions from parents	0	0	0
Distributions to parents	0	0	0
Sponsored Vehicle buy-in cash payment	0	(64)	0
Preference shares issued	0	0	489
Redemption of preferred shares	(300)	(210)	0
Common shares issued	18	21	1,549
Preference share dividends	(383)	(364)	(330)
Common share dividends	(5,973)	(3,480)	(2,750)
Advances from affiliates	0	0	0
Repayment of advances from affiliates	0	0	0
Other	(71)	(23)	0
Net cash (used in)/provided by financing activities	(4,745)	(7,503)	3,476
Effect of translation of foreign denominated cash and cash equivalents and restricted cash	44	68	(72)
Net increase/(decrease) in cash and cash equivalents and restricted cash	39	50	(975)
Cash and cash equivalents and restricted cash at beginning of year	637	587	1,562
Cash and cash equivalents and restricted cash at end of year	676	637	587
Eliminations and Other
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by operating activities	(3,834)	(4,389)	(3,276)
Capital expenditures	0	0	0
Long-term investments and restricted long-term investments	0	78	202
Distributions from equity investments in excess of cumulative earnings	(1,196)	(1,269)	(957)
Additions to intangible assets	0	0	0
Cash acquired in Merger Transaction			0
Affiliate loans, net	0		0
Proceeds from dispositions	0	0	(2,217)
Contributions to subsidiaries	4,771	9,878	6,922
Return of share capital from subsidiaries	(5,281)	(3,753)	(3,724)
Advances to affiliates	114,462	14,251	12,094
Repayment of advances to affiliates	(40,301)	(15,573)	(9,522)
Other	0	0	0
Net cash used in investing activities	72,455	3,612	2,798
Net change in short-term borrowings	0	0	0
Net change in commercial paper and credit facility draws	0	0	0
Debenture and term note issues, net of issue costs	0	0	0
Debenture and term note repayments	0	0	0
Purchase of interest in consolidated subsidiary			2,217
Sale of noncontrolling interest in subsidiary		1,289
Contributions from noncontrolling interests	12	24	832
Distributions to noncontrolling interests	(254)	(857)	(919)
Contributions from redeemable noncontrolling interests	0	70	615
Distributions to redeemable noncontrolling interests	0	(325)	(247)
Contributions from parents	(4,771)	(9,230)	(6,922)
Distributions to parents	10,553	9,132	8,869
Sponsored Vehicle buy-in cash payment		0
Preference shares issued			0
Redemption of preferred shares	0	0	0
Common shares issued	0	(648)	(1,873)
Preference share dividends	0	0	478
Common share dividends	0	0	0
Advances from affiliates	(114,462)	(14,251)	(12,094)
Repayment of advances from affiliates	40,301	15,573	9,522
Other	0	0
Net cash (used in)/provided by financing activities	(68,621)	777	478
Effect of translation of foreign denominated cash and cash equivalents and restricted cash	0	0	0
Net increase/(decrease) in cash and cash equivalents and restricted cash	0	0	0
Cash and cash equivalents and restricted cash at beginning of year	0	0	0
Cash and cash equivalents and restricted cash at end of year	0	0	0
Parent Issuer and Guarantor | Parent and Subsidiaries
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by operating activities	2,246	1,696	620
Capital expenditures	(75)	(28)	(21)
Long-term investments and restricted long-term investments	(26)	(81)	(202)
Distributions from equity investments in excess of cumulative earnings	0	287	36
Additions to intangible assets	(68)	(43)	(47)
Cash acquired in Merger Transaction			0
Affiliate loans, net	0		0
Proceeds from dispositions	0	1,790	0
Contributions to subsidiaries	(4,759)	(8,131)	(4,866)
Return of share capital from subsidiaries	5,281	3,753	2,192
Advances to affiliates	(50,897)	(6,863)	(7,145)
Repayment of advances to affiliates	15,808	9,427	4,506
Other	0	0	0
Net cash used in investing activities	(34,736)	111	(5,547)
Net change in short-term borrowings	0	0	0
Net change in commercial paper and credit facility draws	3,158	(734)	(1,845)
Debenture and term note issues, net of issue costs	3,621	2,554	8,177
Debenture and term note repayments	(1,450)	0	(1,711)
Purchase of interest in consolidated subsidiary			0
Sale of noncontrolling interest in subsidiary		0
Contributions from noncontrolling interests	0	0	0
Distributions to noncontrolling interests	0	0	0
Contributions from redeemable noncontrolling interests	0	0	563
Distributions to redeemable noncontrolling interests	0	0	0
Contributions from parents	0	0	0
Distributions to parents	0	0	0
Sponsored Vehicle buy-in cash payment		(64)
Preference shares issued			489
Redemption of preferred shares	0	0	0
Common shares issued	18	21	1,549
Preference share dividends	(383)	(364)	(330)
Common share dividends	(5,973)	(3,480)	(2,336)
Advances from affiliates	46,860	710	407
Repayment of advances from affiliates	(13,361)	(443)	(40)
Other	0	0
Net cash (used in)/provided by financing activities	32,490	(1,800)	4,923
Effect of translation of foreign denominated cash and cash equivalents and restricted cash	0	0	0
Net increase/(decrease) in cash and cash equivalents and restricted cash	0	7	(4)
Cash and cash equivalents and restricted cash at beginning of year	9	2	6
Cash and cash equivalents and restricted cash at end of year	9	9	2
Subsidiary Non-Guarantors | Parent and Subsidiaries
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by operating activities	9,675	11,683	9,654
Capital expenditures	(5,417)	(6,778)	(8,266)
Long-term investments and restricted long-term investments	(1,122)	(1,297)	(3,535)
Distributions from equity investments in excess of cumulative earnings	393	1,232	103
Additions to intangible assets	(132)	(497)	(742)
Cash acquired in Merger Transaction			682
Affiliate loans, net	(314)	(76)	(22)
Proceeds from dispositions	2,110	2,662	1,103
Contributions to subsidiaries	0	(1,655)	0
Return of share capital from subsidiaries	0	0	0
Advances to affiliates	(60,787)	(5,685)	(3,020)
Repayment of advances to affiliates	22,136	4,124	2,887
Other	(20)	(12)	212
Net cash used in investing activities	(43,153)	(7,982)	(10,598)
Net change in short-term borrowings	(127)	(420)	721
Net change in commercial paper and credit facility draws	695	449	(1,053)
Debenture and term note issues, net of issue costs	2,555	983	787
Debenture and term note repayments	(704)	(3,288)	(2,810)
Purchase of interest in consolidated subsidiary			(1,969)
Sale of noncontrolling interest in subsidiary		0
Contributions from noncontrolling interests	0	0	0
Distributions to noncontrolling interests	0	0	0
Contributions from redeemable noncontrolling interests	0	0	0
Distributions to redeemable noncontrolling interests	0	0	0
Contributions from parents	4,771	8,223	6,922
Distributions to parents	(8,888)	(6,564)	(6,093)
Sponsored Vehicle buy-in cash payment		0
Preference shares issued			0
Redemption of preferred shares	(300)	(210)	1,613
Common shares issued	0	0	0
Preference share dividends	0	0	0
Common share dividends	0	0	(414)
Advances from affiliates	53,675	8,566	9,074
Repayment of advances from affiliates	(18,165)	(11,449)	(6,635)
Other	(60)	(18)
Net cash (used in)/provided by financing activities	33,452	(3,728)	143
Effect of translation of foreign denominated cash and cash equivalents and restricted cash	44	68	(70)
Net increase/(decrease) in cash and cash equivalents and restricted cash	18	41	(871)
Cash and cash equivalents and restricted cash at beginning of year	612	571	1,442
Cash and cash equivalents and restricted cash at end of year	630	612	571
Spectra Energy Partners, LP | Subsidiary Issuer and Guarantor | Parent and Subsidiaries
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by operating activities	1,676	1,751	355
Capital expenditures	0	0	0
Long-term investments and restricted long-term investments	(11)	(12)	(51)
Distributions from equity investments in excess of cumulative earnings	24	45	22
Additions to intangible assets	0	0	0
Cash acquired in Merger Transaction			0
Affiliate loans, net	0		0
Proceeds from dispositions	0	0	0
Contributions to subsidiaries	0	(79)	0
Return of share capital from subsidiaries	0	0	0
Advances to affiliates	0	0	(519)
Repayment of advances to affiliates	0	518	0
Other	0	0	0
Net cash used in investing activities	13	472	(548)
Net change in short-term borrowings	0	0	0
Net change in commercial paper and credit facility draws	(2,011)	(962)	1,965
Debenture and term note issues, net of issue costs	0	0	519
Debenture and term note repayments	0	(648)	(533)
Purchase of interest in consolidated subsidiary			0
Sale of noncontrolling interest in subsidiary		0
Contributions from noncontrolling interests	0	0	0
Distributions to noncontrolling interests	0	0	0
Contributions from redeemable noncontrolling interests	0	0	0
Distributions to redeemable noncontrolling interests	0	0	0
Contributions from parents	0	0	0
Distributions to parents	(1,014)	(1,902)	(1,987)
Sponsored Vehicle buy-in cash payment		0
Preference shares issued			0
Redemption of preferred shares	0	0	0
Common shares issued	0	648	227
Preference share dividends	0	0	0
Common share dividends	0	0	0
Advances from affiliates	5,678	1,474	0
Repayment of advances from affiliates	(4,321)	(826)	0
Other	(4)	(5)
Net cash (used in)/provided by financing activities	(1,672)	(2,221)	191
Effect of translation of foreign denominated cash and cash equivalents and restricted cash	0	0	0
Net increase/(decrease) in cash and cash equivalents and restricted cash	17	2	(2)
Cash and cash equivalents and restricted cash at beginning of year	16	14	16
Cash and cash equivalents and restricted cash at end of year	33	16	14
Enbridge Energy Partners, L.P. | Subsidiary Issuer and Guarantor | Parent and Subsidiaries
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by operating activities	(365)	(239)	(695)
Capital expenditures	0	0	0
Long-term investments and restricted long-term investments	0	0	0
Distributions from equity investments in excess of cumulative earnings	1,196	982	921
Additions to intangible assets	0	0	0
Cash acquired in Merger Transaction			0
Affiliate loans, net	0		0
Proceeds from dispositions	0	0	1,742
Contributions to subsidiaries	(12)	(13)	(2,056)
Return of share capital from subsidiaries	0	0	1,532
Advances to affiliates	(2,778)	(1,703)	(1,410)
Repayment of advances to affiliates	2,357	1,504	2,129
Other	0	0	0
Net cash used in investing activities	763	770	2,858
Net change in short-term borrowings	0	0	0
Net change in commercial paper and credit facility draws	(1,017)	(1,009)	(316)
Debenture and term note issues, net of issue costs	0	0	0
Debenture and term note repayments	(2,514)	(509)	0
Purchase of interest in consolidated subsidiary			(475)
Sale of noncontrolling interest in subsidiary		0
Contributions from noncontrolling interests	0	0	0
Distributions to noncontrolling interests	0	0	0
Contributions from redeemable noncontrolling interests	0	0	0
Distributions to redeemable noncontrolling interests	0	0	0
Contributions from parents	0	1,007	0
Distributions to parents	(651)	(666)	(789)
Sponsored Vehicle buy-in cash payment		0
Preference shares issued			0
Redemption of preferred shares	0	0	(1,613)
Common shares issued	0	0	1,646
Preference share dividends	0	0	(478)
Common share dividends	0	0	0
Advances from affiliates	8,249	3,501	2,613
Repayment of advances from affiliates	(4,454)	(2,855)	(2,847)
Other	(7)	0
Net cash (used in)/provided by financing activities	(394)	(531)	(2,259)
Effect of translation of foreign denominated cash and cash equivalents and restricted cash	0	0	(2)
Net increase/(decrease) in cash and cash equivalents and restricted cash	4	0	(98)
Cash and cash equivalents and restricted cash at beginning of year	0	0	98
Cash and cash equivalents and restricted cash at end of year	$ 4	$ 0	$ 0