RISK MANAGEMENT AND FINANCIAL INSTRUMENTS - Schedule of Effects on Cash Flow Hedges and Fair Value Hedges on Consolidated Earnings and Comprehensive Income (Details) - CAD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
The Effect of Derivative Instruments on the Statements of Earnings and Comprehensive Income
Amount of unrealized gain/(loss) recognized in OCI	$ 36	$ 2	$ (4)	$ 138
Amount of (income)/loss reclassified from AOCI to earnings	(6)	23	14	42
Foreign exchange contracts
The Effect of Derivative Instruments on the Statements of Earnings and Comprehensive Income
Amount of (income)/loss reclassified from AOCI to earnings	(15)	12	(3)	31
Foreign exchange contracts | Fair value hedges
The Effect of Derivative Instruments on the Statements of Earnings and Comprehensive Income
Amount of unrealized gain/(loss) recognized in OCI	18	(11)	12	(26)
Interest rate contracts
The Effect of Derivative Instruments on the Statements of Earnings and Comprehensive Income
Amount of (income)/loss reclassified from AOCI to earnings	9	12	17	12
Interest rate contracts | Cash flow hedges
The Effect of Derivative Instruments on the Statements of Earnings and Comprehensive Income
Amount of unrealized gain/(loss) recognized in OCI	21	10	(14)	148
Commodity contracts
The Effect of Derivative Instruments on the Statements of Earnings and Comprehensive Income
Amount of (income)/loss reclassified from AOCI to earnings	0	(1)	0	(1)
Commodity contracts | Cash flow hedges
The Effect of Derivative Instruments on the Statements of Earnings and Comprehensive Income
Amount of unrealized gain/(loss) recognized in OCI	(3)	3	(2)	15
Other contracts | Cash flow hedges
The Effect of Derivative Instruments on the Statements of Earnings and Comprehensive Income
Amount of unrealized gain/(loss) recognized in OCI	$ 0	$ 0	$ 0	$ 1