VARIABLE INTEREST ENTITIES - CONSOLIDATED VARIABLE INTEREST ENTITIES (Narrative) (Details)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
EECI
Schedule of Equity Method Investments [Line Items]
Ownership interest in subsidiary (as a percent)	100.00%
EIPLP | Alliance Pipeline
Schedule of Equity Method Investments [Line Items]
Ownership interest of equity method investment (as a percent)	50.00%
Enbridge Management Services Inc.
Schedule of Equity Method Investments [Line Items]
Ownership interest in subsidiary (as a percent)	100.00%
Direct common interest (as a percent)	53.10%
EEP
Schedule of Equity Method Investments [Line Items]
Economic interest (as a percent)	34.60%	35.30%
Enbridge Income Fund
Schedule of Equity Method Investments [Line Items]
Economic interest (as a percent)	82.50%	86.90%
Direct common interest (as a percent)	29.40%	43.20%
EIPLP
Schedule of Equity Method Investments [Line Items]
Economic interest (as a percent)	73.50%	79.10%
DakTex
Schedule of Equity Method Investments [Line Items]
Ownership interest in subsidiary (as a percent)	75.00%
DakTex | EEP
Schedule of Equity Method Investments [Line Items]
Ownership interest in subsidiary (as a percent)	25.00%
Bakken Pipeline System
Schedule of Equity Method Investments [Line Items]
Ownership interest of equity method investment (as a percent)	27.60%
SEP
Schedule of Equity Method Investments [Line Items]
Direct common interest (as a percent)	75.00%
Other Limited Partnerships
Schedule of Equity Method Investments [Line Items]
Direct common interest (as a percent)	100.00%