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
	Mar. 31, 2025	Mar. 31, 2024
The Effect of Derivative Instruments on the Statements of Earnings and Comprehensive Income
Amount of unrealized gain/(loss) recognized in OCI	$ (40)	$ 136
Amount of loss reclassified from AOCI to earnings	20	19
Foreign exchange contracts
The Effect of Derivative Instruments on the Statements of Earnings and Comprehensive Income
Amount of loss reclassified from AOCI to earnings	12	19
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	(6)	(15)
Interest rate contracts
The Effect of Derivative Instruments on the Statements of Earnings and Comprehensive Income
Amount of loss reclassified from AOCI to earnings	8	0
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	(35)	138
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	1	12
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	$ 1