Fair Value Measurement - Summary of Financial Instruments Carried On Consolidated Balance Sheet at Fair Value (Parenthetical) (Detail) - At fair value [member] - CAD ($) $ in Millions	Oct. 31, 2025	Oct. 31, 2024
Disclosures Of Fair Value Hierarchy Of Financial Assets And Financial Liabilities [Line items]
Deposits designated at FVTPL	$ 43,723	$ 39,008
Derivative instrument liabilities	313	521
Other liabilities designated at FVTPL	8	19
Other financial liabilities measured at fair value	$ 220	$ 158