Investment Securities - Disclosure of Carrying Value of Banks Investment Securities Per Measurement Category (Detail) - CAD ($) $ in Millions	Apr. 30, 2026	Jan. 31, 2026	Oct. 31, 2025
Disclosure of financial assets [line items]
Investment securities	$ 149,806	$ 142,399	$ 149,948
Debt Investments [member] \| Financial assets measured at fair value through other comprehensive income, category [member]
Disclosure of financial assets [line items]
Investment securities	125,491	117,567	123,732
Debt Investments [member] \| Financial assets at amortised cost, category [member]
Disclosure of financial assets [line items]
Investment securities	21,988	22,452	23,722
Debt Investments [member] \| Financial assets at fair value through profit or loss, category [member]
Disclosure of financial assets [line items]
Investment securities	2	23	23
Equity securities [member] \| Investments in equity instruments designated at fair value through other comprehensive income [member]
Disclosure of financial assets [line items]
Investment securities	313	377	398
Equity securities [member] \| Financial assets at fair value through profit or loss, category [member]
Disclosure of financial assets [line items]
Investment securities	$ 2,012	$ 1,980	$ 2,073