LONG-TERM INVESTMENTS - Narrative (Details) - CAD ($) $ in Millions			12 Months Ended
	Dec. 30, 2021	Jun. 06, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Mar. 18, 2021
Schedule of Equity Method Investments [Line Items]
Goodwill of investee			$ 2,500	$ 2,400
Amortizable assets of investee			730	657
Dividends received from equity investments			2,200	2,100	$ 2,200
Ownership interest (as a percent)						25.50%
Impairment of equity investments			111	2,351	0
Loss from equity method investment			$ (1,711)	(1,136)	$ (1,503)
Noverco Preferred Shares
Schedule of Equity Method Investments [Line Items]
Ownership interest (as a percent)		38.90%
Equity method investment cash subject to purchase price adjustments		$ 1,100
Proceeds from sale of equity method investments	$ 1,100
Equity method investment, realized gain (loss) on disposal	$ 303
PennEast Pipeline Company, LLC
Schedule of Equity Method Investments [Line Items]
Ownership interest (as a percent)			20.00%
Impairment of equity investments			$ 111
Equity investment			12	$ 116
Steckman Ridge, LP
Schedule of Equity Method Investments [Line Items]
Ownership interest (as a percent)				50.00%
Impairment of equity investments				$ 221
Equity investment			88	$ 90
Southeast Supply Header L.L.C.
Schedule of Equity Method Investments [Line Items]
Ownership interest (as a percent)				50.00%
Impairment of equity investments				$ 394
Equity investment			$ 82	84
DCP Midstream, LLC
Schedule of Equity Method Investments [Line Items]
Ownership interest (as a percent)			50.00%
Impairment of equity investments				1,700
Equity investment			$ 397	$ 331
Loss from equity method investment			$ 324
Gas Distribution and Storage | Common Shares | Noverco Preferred Shares
Schedule of Equity Method Investments [Line Items]
Ownership interest (as a percent)			38.90%	38.90%
Equity investment			$ 0	$ 156