DEBT - Schedule of Long-Term Debt Repayments (Details) CAD in Millions, $ in Millions		1 Months Ended												2 Months Ended	3 Months Ended	7 Months Ended			12 Months Ended
	Jul. 13, 2017 USD ($)	Dec. 31, 2017 CAD	Nov. 30, 2017 CAD	Sep. 30, 2017 CAD	Jul. 31, 2017 CAD	Jun. 30, 2017 CAD	Apr. 30, 2017 CAD	Mar. 31, 2017 CAD	Dec. 31, 2016 CAD	Nov. 30, 2016 CAD	Oct. 31, 2016 CAD	Aug. 31, 2016 CAD	May 31, 2016 CAD	Sep. 08, 2017 USD ($)	Sep. 30, 2017 CAD	Dec. 31, 2017 CAD	Nov. 30, 2017 CAD	Dec. 31, 2016 CAD	Dec. 31, 2017 CAD	Dec. 31, 2017 USD ($)
8.00% senior notes due 2019
Debt Instrument [Line Items]
Aggregate principal amount tendered and redeemed | $														$ 500
Enbridge Energy Partners, L.P. | 5.88% senior notes
Debt Instrument [Line Items]
Principal Amount									CAD 300
Interest rate		5.88%														5.88%			5.88%	5.88%
Enbridge Gas Distribution Inc. | 1.85% medium-term notes
Debt Instrument [Line Items]
Principal Amount							CAD 0
Interest rate		1.85%														1.85%			1.85%	1.85%
Enbridge Gas Distribution Inc. | 5.16% medium-term notes
Debt Instrument [Line Items]
Principal Amount		CAD 0
Interest rate		5.16%														5.16%			5.16%	5.16%
Enbridge Income Fund | Floating rate note
Debt Instrument [Line Items]
Principal Amount										CAD 0
Enbridge Income Fund | 5.00% medium-term notes
Debt Instrument [Line Items]
Principal Amount						CAD 0
Interest rate		5.00%														5.00%			5.00%	5.00%
Enbridge Income Fund | 2.92% medium-term notes
Debt Instrument [Line Items]
Principal Amount		CAD 0
Interest rate		2.92%														2.92%			2.92%	2.92%
Enbridge Pipelines (Southern Lights) L.L.C. | 3.98% medium-term note due June 2040
Debt Instrument [Line Items]
Principal Amount																CAD 37		CAD 30
Interest rate		3.98%														3.98%			3.98%	3.98%
Enbridge Southern Lights LP | 4.01% medium-term note due June 2040
Debt Instrument [Line Items]
Principal Amount						0												CAD 0
Interest rate		4.01%														4.01%			4.01%	4.01%
Spectra Energy Capitals, LLC
Debt Instrument [Line Items]
Loss on debt extinguishment																			CAD 50	$ 38
Spectra Energy Capitals, LLC | 8.00% senior notes due 2019
Debt Instrument [Line Items]
Principal Amount														$ 581	CAD 500
Interest rate		8.00%												8.00%		8.00%			8.00%	8.00%
Spectra Energy Capitals, LLC | Senior notes carrying interest ranging from 3.3% to 7.5% due 2018 to 2038
Debt Instrument [Line Items]
Principal Amount	$ 761				CAD 761
Repayments of related party debt | $	$ 857
Spectra Energy Partners, LP | 6.00% senior notes
Debt Instrument [Line Items]
Principal Amount				CAD 400
Interest rate		6.00%														6.00%			6.00%	6.00%
Spectra Energy Partners, LP | 7.39% subordinated secured notes
Debt Instrument [Line Items]
Principal Amount																CAD 12
Interest rate		7.39%														7.39%			7.39%	7.39%
Union Gas Limited | 9.70% debentures
Debt Instrument [Line Items]
Principal Amount			CAD 0
Interest rate		9.70%														9.70%			9.70%	9.70%
Westcoast Energy Inc. | 6.90% senior secured notes
Debt Instrument [Line Items]
Principal Amount																	CAD 0
Interest rate		6.90%														6.90%			6.90%	6.90%
Westcoast Energy Inc. | 4.34% senior secured notes
Debt Instrument [Line Items]
Principal Amount																	CAD 0
Interest rate		4.34%														4.34%			4.34%	4.34%
Enbridge Inc. | Floating rate note
Debt Instrument [Line Items]
Principal Amount						CAD 500		CAD 0			CAD 350
Enbridge Inc. | 5.60% medium-term notes
Debt Instrument [Line Items]
Principal Amount							CAD 400
Interest rate		5.60%														5.60%			5.60%	5.60%
Enbridge Inc. | 5.17% medium-term notes
Debt Instrument [Line Items]
Principal Amount													CAD 0
Interest rate		5.17%														5.17%			5.17%	5.17%
Enbridge Inc. | 5.00% medium-term notes
Debt Instrument [Line Items]
Principal Amount												CAD 0
Interest rate		5.00%														5.00%			5.00%	5.00%
Minimum | Spectra Energy Capitals, LLC | Senior notes carrying interest ranging from 3.3% to 7.5% due 2018 to 2038
Debt Instrument [Line Items]
Interest rate	3.30%	3.30%														3.30%			3.30%	3.30%
Debt maturity (term)	1 year
Maximum
Debt Instrument [Line Items]
Interest rate	7.50%	7.50%														7.50%			7.50%	7.50%
Maximum | Spectra Energy Capitals, LLC | Senior notes carrying interest ranging from 3.3% to 7.5% due 2018 to 2038
Debt Instrument [Line Items]
Debt maturity (term)	21 years