LEASES - Narrative (Details) - CAD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Lessee, Lease, Description [Line Items]
Operating lease, expense	$ 132	$ 131	$ 118
Operating lease, payments	$ 128	$ 129	$ 123
Minimum
Lessee, Lease, Description [Line Items]
Remaining lease term	2 months
Lessor, operating lease, remaining lease term	3 months
Maximum
Lessee, Lease, Description [Line Items]
Remaining lease term	41 years
Lessor, operating lease, remaining lease term	27 years