Fair value of financial instruments - Summary of Net Interest Income From Financial Instruments (Detail) - CAD ($) $ in Millions	12 Months Ended
	Oct. 31, 2022	Oct. 31, 2021
Disclosure of detailed information about financial instruments [line items]
Interest income	$ 40,771	$ 28,145
Interest expense	18,054	8,143
Net interest income	22,717	20,002
Interest and dividend income [member] \| Financial assets measured at fair value through profit or loss [member]
Disclosure of detailed information about financial instruments [line items]
Interest income	10,999	4,551
Interest and dividend income [member] \| Financial assets measured at fair value through other comprehensive income [member]
Disclosure of detailed information about financial instruments [line items]
Interest income	1,177	375
Interest and dividend income [member] \| Financial assets measured at amortized cost [member]
Disclosure of detailed information about financial instruments [line items]
Interest income	28,595	23,219
Interest expense [member] \| Financial liabilities measured at fair value through profit or loss [member]
Disclosure of detailed information about financial instruments [line items]
Interest expense	8,336	2,865
Interest expense [member] \| Financial liabilities measured at amortized cost [member]
Disclosure of detailed information about financial instruments [line items]
Interest expense	$ 9,718	$ 5,278