RISK MANAGEMENT AND FINANCIAL INSTRUMENTS - Schedule of Foreign Exchange Derivative Instruments that are Designated and Qualify as Fair Value Hedges (Details) - CAD ($) $ in Millions	3 Months Ended
Mar. 31, 2025	Mar. 31, 2024
RISK MANAGEMENT AND FINANCIAL INSTRUMENTS
Realized gain on derivative	$ 99	$ (22)
Interest rate contracts \| Fair value hedges
RISK MANAGEMENT AND FINANCIAL INSTRUMENTS
Unrealized loss on derivative	(42)	(63)
Unrealized gain on hedged item	50	74
Realized gain on derivative	61	59
Realized loss on hedged item	$ (74)	$ (79)

Amount of gain (loss) from the increase (decrease) in fair value of derivative and nonderivative instruments designated as fair value hedging instruments recognized in the income statement.

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Amount of the increase (decrease) in fair value of the hedged item in a fair value hedge recognized in the income statement.

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Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Gain (loss) incurred in hedging activities.

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