Foreign Exchange (Gain) Loss, Net - Schedule of Foreign Exchange Gain Loss Net (Detail) - CAD ($) $ in Millions	12 Months Ended
Dec. 31, 2024	Dec. 31, 2023
Disclosure Of Effect Of Changes In Foreign Exchange Rates Gain Loss [Line Items]
Unrealized Foreign Exchange (Gain) Loss	$ 550	$ (210)
Realized Foreign Exchange (Gain) Loss	(88)	143
Total	462	(67)
U.S. Dollar Debt Issued From Canada
Disclosure Of Effect Of Changes In Foreign Exchange Rates Gain Loss [Line Items]
Unrealized Foreign Exchange (Gain) Loss	442	(231)
Other
Disclosure Of Effect Of Changes In Foreign Exchange Rates Gain Loss [Line Items]
Unrealized Foreign Exchange (Gain) Loss	$ 108	$ 21

The amount of exchange differences recognised in profit or loss that arise from foreign currency transactions, excluding those arising on financial instruments measured at fair value through profit or loss in accordance with IFRS 9. [Refer: At fair value [member]; Classes of financial instruments [domain]]

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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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