INTANGIBLE ASSETS (Details) - CAD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
INTANGIBLE ASSETS
Cost	$ 5,552	$ 5,726
Accumulated Amortization	(2,015)	(1,708)
Net	$ 3,537	$ 4,018
Software
INTANGIBLE ASSETS
Weighted Average Amortization Rate	12.00%	10.90%
Cost	$ 1,921	$ 2,019
Accumulated Amortization	(1,090)	(1,042)
Net	$ 831	$ 977
Power purchase agreements
INTANGIBLE ASSETS
Weighted Average Amortization Rate	4.30%	4.20%
Cost	$ 58	$ 64
Accumulated Amortization	(24)	(23)
Net	$ 34	$ 41
Project agreement
INTANGIBLE ASSETS
Weighted Average Amortization Rate	4.00%	4.00%
Cost	$ 158	$ 163
Accumulated Amortization	(41)	(36)
Net	$ 117	$ 127
Customer relationships
INTANGIBLE ASSETS
Weighted Average Amortization Rate	8.60%	8.60%
Cost	$ 2,636	$ 2,701
Accumulated Amortization	(675)	(459)
Net	$ 1,961	$ 2,242
Other intangible assets
INTANGIBLE ASSETS
Weighted Average Amortization Rate	8.20%	5.90%
Cost	$ 603	$ 621
Accumulated Amortization	(185)	(148)
Net	$ 418	$ 473
Under development
INTANGIBLE ASSETS
Weighted Average Amortization Rate	0.00%	0.00%
Cost	$ 176	$ 158
Accumulated Amortization	0	0
Net	$ 176	$ 158