INTANGIBLE ASSETS (Details) - CAD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
INTANGIBLE ASSETS
Cost	$ 5,535	$ 3,653
Accumulated Amortization	(1,527)	(1,573)
Net	4,008	2,080
Amortization expenses
Amortization expense for intangible assets	$ 348	$ 294	$ 296
Software
INTANGIBLE ASSETS
Weighted Average Amortization Rate (as a percent)	8.50%	10.50%
Cost	$ 2,532	$ 2,043
Accumulated Amortization	(215)	(1,299)
Net	$ 2,317	$ 744
Power purchase agreements
INTANGIBLE ASSETS
Weighted Average Amortization Rate (as a percent)	4.50%	4.50%
Cost	$ 63	$ 63
Accumulated Amortization	(21)	(18)
Net	$ 42	$ 45
Project agreement
INTANGIBLE ASSETS
Weighted Average Amortization Rate (as a percent)	4.00%	4.00%
Cost	$ 152	$ 153
Accumulated Amortization	(27)	(21)
Net	$ 125	$ 132
Customer relationships
INTANGIBLE ASSETS
Weighted Average Amortization Rate (as a percent)	12.00%	5.00%
Cost	$ 2,067	$ 724
Accumulated Amortization	(1,148)	(139)
Net	$ 919	$ 585
Other intangible assets
INTANGIBLE ASSETS
Weighted Average Amortization Rate (as a percent)	3.90%	2.70%
Cost	$ 475	$ 456
Accumulated Amortization	(116)	(96)
Net	$ 359	$ 360
Under development
INTANGIBLE ASSETS
Weighted Average Amortization Rate (as a percent)	0.00%	0.00%
Cost	$ 246	$ 214
Accumulated Amortization	0	0
Net	$ 246	$ 214