Financial Instruments - Inception Gains And Losses (Details) - Impacts of the PPA Contract Amendments - CAD ($) $ in Millions	12 Months Ended
Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Changes in aggregate difference between fair value at initial recognition and transaction price yet to be recognised in profit or loss [abstract]
Unamortized net gain (loss) at beginning of year	$ 3	$ (213)	$ (131)
New inception loss	31	47	(37)
Change resulting from amended contract	0	190	0
Change in foreign exchange rates	(3)	6	(10)
Amortization recorded in net earnings during the year	(20)	(27)	(35)
Unamortized net gain (loss) at end of year	$ 11	$ 3	$ (213)

The aggregate difference between the fair value at initial recognition and the transaction price for financial instruments that is yet to be recognised in profit or loss. [Refer: Classes of financial instruments [domain]]

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The increase (decrease) in the aggregate difference between the fair value at initial recognition and the transaction price of financial instruments yet to be recognised in profit or loss. [Refer: Aggregate difference between fair value at initial recognition and transaction price yet to be recognised in profit or loss]

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The increase (decrease) in the aggregate difference between the fair value at initial recognition and the transaction price of financial instruments yet to be recognised in profit or loss resulting from amounts recognised in profit or loss. [Refer: Aggregate difference between fair value at initial recognition and transaction price yet to be recognised in profit or loss; Classes of financial instruments [domain]]

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The increase (decrease) in financial assets resulting from foreign exchange. [Refer: Financial assets]

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The increase (decrease) in the aggregate difference between the fair value at initial recognition and the transaction price of financial instruments yet to be recognised in profit or loss resulting from new transactions. [Refer: Aggregate difference between fair value at initial recognition and transaction price yet to be recognised in profit or loss; Classes of financial instruments [domain]]

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