Investment Securities - Disclosure of Carrying Value of Banks Investment Securities Per Measurement Category (Detail) - CAD ($) $ in Millions	Apr. 30, 2022	Jan. 31, 2022	Oct. 31, 2021
Disclosure of financial assets [line items]
Investment securities	$ 100,487	$ 81,699	$ 75,199
Debt Investments [member] | Financial assets measured at fair value through other comprehensive income, category [member]
Disclosure of financial assets [line items]
Investment securities	78,343	59,249	52,611
Debt Investments [member] | Financial assets at amortised cost, category [member]
Disclosure of financial assets [line items]
Investment securities	16,699	17,576	18,157
Debt Investments [member] | Financial assets at fair value through profit or loss, category [member]
Disclosure of financial assets [line items]
Investment securities	72	31	30
Equity securities [member] | Investments in equity instruments designated at fair value through other comprehensive income [member]
Disclosure of financial assets [line items]
Investment securities	3,797	3,542	3,178
Equity securities [member] | Financial assets at fair value through profit or loss, category [member]
Disclosure of financial assets [line items]
Investment securities	$ 1,576	$ 1,301	$ 1,223