RISK MANAGEMENT AND FINANCIAL INSTRUMENTS - Effects on Earnings and Comprehensive Income (Details) - CAD ($) $ in Millions	12 Months Ended
Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
The Effect of Derivative Instruments on the Statements of Earnings and Comprehensive Income
Amount of unrealized gain/(loss) recognized in OCI	$ 45	$ 282	$ 1,062
Amount of (income)/loss reclassified from AOCI to earnings	$ 83	28	203
Period to hedge exposures to the variability of cash flows for all forecasted transactions (in years)	2 years
Cash flow hedges
The Effect of Derivative Instruments on the Statements of Earnings and Comprehensive Income
Loss from AOCI expected to be reclassified	$ 0
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	53	0	13
Foreign exchange 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	3
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	(42)	15	(35)
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	31	28	186
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	67	201	1,151
Commodity contracts
The Effect of Derivative Instruments on the Statements of Earnings and Comprehensive Income
Amount of (income)/loss reclassified from AOCI to earnings	(1)	0	0
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	19	68	(53)
Other contracts
The Effect of Derivative Instruments on the Statements of Earnings and Comprehensive Income
Amount of (income)/loss reclassified from AOCI to earnings	0	0	4
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	$ 1	$ (2)	$ (4)

The estimated net amount of existing gains or losses on cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months.

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Amount, before tax and reclassification, of gain (loss) from derivative instrument designated and qualifying cash flow hedge included in assessment of hedge effectiveness.

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