Derivative financial instruments and hedging activities - Notional Amount of Derivatives by Term to Maturity (Absolute Amounts) (Detail) - CAD ($) $ in Millions	Oct. 31, 2022	Oct. 31, 2021
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	$ 7,776,875	$ 6,415,878
Derivative notional amount	26,479,660	23,344,503
Credit derivatives [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	1,000	1,000
Under 1 year [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	10,104,168	8,637,171
1 to 5 years [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	10,260,443	9,163,667
Over 5 years [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	6,115,049	5,543,665
Over-the-counter contracts [member] \| Interest rate contracts forward rate agreements [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	807,939	1,028,697
Over-the-counter contracts [member] \| Interest rate contracts swaps [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	16,710,150	14,763,913
Over-the-counter contracts [member] \| Interest rate contracts options purchased [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	829,368	764,494
Over-the-counter contracts [member] \| Interest rate contracts options written [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	848,263	784,205
Over-the-counter contracts [member] \| Foreign exchange contracts forward contracts [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	2,275,908	1,789,538
Over-the-counter contracts [member] \| Foreign exchange contracts cross currency swaps [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	237,946	213,148
Over-the-counter contracts [member] \| Foreign exchange contracts cross currency interest rate swaps [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	2,970,275	2,408,900
Over-the-counter contracts [member] \| Foreign exchange contracts options purchased [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	79,335	65,216
Over-the-counter contracts [member] \| Foreign exchange contracts options written [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	82,163	72,524
Over-the-counter contracts [member] \| Credit derivatives [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	43,515	42,911
Over-the-counter contracts [member] \| Other contracts [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	341,532	337,877
Over-the-counter contracts [member] \| Under 1 year [member] \| Interest rate contracts forward rate agreements [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	763,398	866,704
Over-the-counter contracts [member] \| Under 1 year [member] \| Interest rate contracts swaps [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	4,994,006	3,936,638
Over-the-counter contracts [member] \| Under 1 year [member] \| Interest rate contracts options purchased [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	100,504	266,798
Over-the-counter contracts [member] \| Under 1 year [member] \| Interest rate contracts options written [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	108,770	271,000
Over-the-counter contracts [member] \| Under 1 year [member] \| Foreign exchange contracts forward contracts [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	2,187,124	1,730,712
Over-the-counter contracts [member] \| Under 1 year [member] \| Foreign exchange contracts cross currency swaps [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	87,942	82,316
Over-the-counter contracts [member] \| Under 1 year [member] \| Foreign exchange contracts cross currency interest rate swaps [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	518,244	439,169
Over-the-counter contracts [member] \| Under 1 year [member] \| Foreign exchange contracts options purchased [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	58,075	46,060
Over-the-counter contracts [member] \| Under 1 year [member] \| Foreign exchange contracts options written [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	62,266	53,342
Over-the-counter contracts [member] \| Under 1 year [member] \| Credit derivatives [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	1,143	1,027
Over-the-counter contracts [member] \| Under 1 year [member] \| Other contracts [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	228,709	218,270
Over-the-counter contracts [member] \| 1 to 5 years [member] \| Interest rate contracts forward rate agreements [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	44,188	161,835
Over-the-counter contracts [member] \| 1 to 5 years [member] \| Interest rate contracts swaps [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	6,934,996	6,559,032
Over-the-counter contracts [member] \| 1 to 5 years [member] \| Interest rate contracts options purchased [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	577,780	312,149
Over-the-counter contracts [member] \| 1 to 5 years [member] \| Interest rate contracts options written [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	556,652	309,540
Over-the-counter contracts [member] \| 1 to 5 years [member] \| Foreign exchange contracts forward contracts [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	86,136	56,335
Over-the-counter contracts [member] \| 1 to 5 years [member] \| Foreign exchange contracts cross currency swaps [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	67,345	57,968
Over-the-counter contracts [member] \| 1 to 5 years [member] \| Foreign exchange contracts cross currency interest rate swaps [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	1,572,490	1,193,669
Over-the-counter contracts [member] \| 1 to 5 years [member] \| Foreign exchange contracts options purchased [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	18,061	16,097
Over-the-counter contracts [member] \| 1 to 5 years [member] \| Foreign exchange contracts options written [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	16,623	16,122
Over-the-counter contracts [member] \| 1 to 5 years [member] \| Credit derivatives [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	35,621	35,759
Over-the-counter contracts [member] \| 1 to 5 years [member] \| Other contracts [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	93,431	98,850
Over-the-counter contracts [member] \| Over 5 years [member] \| Interest rate contracts forward rate agreements [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	353	158
Over-the-counter contracts [member] \| Over 5 years [member] \| Interest rate contracts swaps [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	4,781,148	4,268,243
Over-the-counter contracts [member] \| Over 5 years [member] \| Interest rate contracts options purchased [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	151,084	185,547
Over-the-counter contracts [member] \| Over 5 years [member] \| Interest rate contracts options written [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	182,841	203,665
Over-the-counter contracts [member] \| Over 5 years [member] \| Foreign exchange contracts forward contracts [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	2,648	2,491
Over-the-counter contracts [member] \| Over 5 years [member] \| Foreign exchange contracts cross currency swaps [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	82,659	72,864
Over-the-counter contracts [member] \| Over 5 years [member] \| Foreign exchange contracts cross currency interest rate swaps [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	879,541	776,062
Over-the-counter contracts [member] \| Over 5 years [member] \| Foreign exchange contracts options purchased [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	3,199	3,059
Over-the-counter contracts [member] \| Over 5 years [member] \| Foreign exchange contracts options written [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	3,274	3,060
Over-the-counter contracts [member] \| Over 5 years [member] \| Credit derivatives [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	6,751	6,125
Over-the-counter contracts [member] \| Over 5 years [member] \| Other contracts [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	19,392	20,757
Exchange-traded contracts [member] \| Interest rate contracts options purchased [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	68,526	43,321
Exchange-traded contracts [member] \| Interest rate contracts options written [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	22,562	23,572
Exchange-traded contracts [member] \| Other contracts [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	630,344	476,649
Exchange-traded contracts [member] \| Interest rate contracts, Futures long positions [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	198,901	258,880
Exchange-traded contracts [member] \| Interest rate contracts, Futures short positions [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	332,769	270,529
Exchange-traded contracts [member] \| Foreign exchange contracts, Futures long positions [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	164	129
Exchange-traded contracts [member] \| Under 1 year [member] \| Interest rate contracts options purchased [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	56,353	28,071
Exchange-traded contracts [member] \| Under 1 year [member] \| Interest rate contracts options written [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	16,394	22,272
Exchange-traded contracts [member] \| Under 1 year [member] \| Other contracts [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	539,103	391,339
Exchange-traded contracts [member] \| Under 1 year [member] \| Interest rate contracts, Futures long positions [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	148,032	110,285
Exchange-traded contracts [member] \| Under 1 year [member] \| Interest rate contracts, Futures short positions [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	233,941	173,039
Exchange-traded contracts [member] \| Under 1 year [member] \| Foreign exchange contracts, Futures long positions [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	164	129
Exchange-traded contracts [member] \| 1 to 5 years [member] \| Interest rate contracts options purchased [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	12,173	15,250
Exchange-traded contracts [member] \| 1 to 5 years [member] \| Interest rate contracts options written [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	6,168	1,300
Exchange-traded contracts [member] \| 1 to 5 years [member] \| Other contracts [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	89,147	84,135
Exchange-traded contracts [member] \| 1 to 5 years [member] \| Interest rate contracts, Futures long positions [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	50,869	148,262
Exchange-traded contracts [member] \| 1 to 5 years [member] \| Interest rate contracts, Futures short positions [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	98,763	97,364
Exchange-traded contracts [member] \| Over 5 years [member] \| Other contracts [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	2,094	1,175
Exchange-traded contracts [member] \| Over 5 years [member] \| Interest rate contracts, Futures long positions [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount		333
Exchange-traded contracts [member] \| Over 5 years [member] \| Interest rate contracts, Futures short positions [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	65	126
Trading Derivatives [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	25,651,512	22,733,022
Trading Derivatives [member] \| Over-the-counter contracts [member] \| Interest rate contracts forward rate agreements [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	806,576	1,015,263
Trading Derivatives [member] \| Over-the-counter contracts [member] \| Interest rate contracts swaps [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	16,001,414	14,259,757
Trading Derivatives [member] \| Over-the-counter contracts [member] \| Interest rate contracts options purchased [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	829,368	764,494
Trading Derivatives [member] \| Over-the-counter contracts [member] \| Interest rate contracts options written [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	848,263	784,205
Trading Derivatives [member] \| Over-the-counter contracts [member] \| Foreign exchange contracts forward contracts [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	2,230,901	1,753,075
Trading Derivatives [member] \| Over-the-counter contracts [member] \| Foreign exchange contracts cross currency swaps [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	233,617	204,789
Trading Derivatives [member] \| Over-the-counter contracts [member] \| Foreign exchange contracts cross currency interest rate swaps [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	2,918,063	2,376,225
Trading Derivatives [member] \| Over-the-counter contracts [member] \| Foreign exchange contracts options purchased [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	79,335	65,216
Trading Derivatives [member] \| Over-the-counter contracts [member] \| Foreign exchange contracts options written [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	82,163	72,524
Trading Derivatives [member] \| Over-the-counter contracts [member] \| Credit derivatives [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	42,785	42,428
Trading Derivatives [member] \| Over-the-counter contracts [member] \| Other contracts [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	327,860	325,226
Trading Derivatives [member] \| Exchange-traded contracts [member] \| Interest rate contracts options purchased [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	68,526	43,321
Trading Derivatives [member] \| Exchange-traded contracts [member] \| Interest rate contracts options written [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	22,562	23,572
Trading Derivatives [member] \| Exchange-traded contracts [member] \| Other contracts [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	630,344	476,649
Trading Derivatives [member] \| Exchange-traded contracts [member] \| Interest rate contracts, Futures long positions [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	197,251	256,020
Trading Derivatives [member] \| Exchange-traded contracts [member] \| Interest rate contracts, Futures short positions [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	332,320	270,129
Trading Derivatives [member] \| Exchange-traded contracts [member] \| Foreign exchange contracts, Futures long positions [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	164	129
Other than trading [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	828,148	611,481
Other than trading [member] \| Over-the-counter contracts [member] \| Interest rate contracts forward rate agreements [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	1,363	13,434
Other than trading [member] \| Over-the-counter contracts [member] \| Interest rate contracts swaps [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	708,736	504,156
Other than trading [member] \| Over-the-counter contracts [member] \| Foreign exchange contracts forward contracts [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	45,007	36,463
Other than trading [member] \| Over-the-counter contracts [member] \| Foreign exchange contracts cross currency swaps [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	4,329	8,359
Other than trading [member] \| Over-the-counter contracts [member] \| Foreign exchange contracts cross currency interest rate swaps [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	52,212	32,675
Other than trading [member] \| Over-the-counter contracts [member] \| Credit derivatives [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	730	483
Other than trading [member] \| Over-the-counter contracts [member] \| Other contracts [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	13,672	12,651
Other than trading [member] \| Exchange-traded contracts [member] \| Interest rate contracts, Futures long positions [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	1,650	2,860
Other than trading [member] \| Exchange-traded contracts [member] \| Interest rate contracts, Futures short positions [member]
Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [line items]
Derivative notional amount	$ 449	$ 400

Derivative financial instruments and hedging activities - Notional Amount of Derivatives by Term to Maturity (Absolute Amounts) (Detail) - CAD ($)
$ in Millions