v3.22.2.2
Securities - Summary of Allowance for Credit Losses - Securities at Amortized Cost (Detail) - Debt securities at amortized cost [member] - CAD ($)
$ in Millions
 12 Months Ended
Oct. 31, 2022
Oct. 31, 2021
Disclosure of credit risk exposure [line items]    
Balance at beginning of period $ 23 $ 29
Provision for credit losses    
Model changes   (4)
Purchases 11 9
Sales and maturities (1) (1)
Changes in risk, parameters and exposures (13) (8)
Exchange rate and other 2 (2)
Balance at end of period 22 23
Performing Stage one [member]    
Disclosure of credit risk exposure [line items]    
Balance at beginning of period 5 10
Provision for credit losses    
Model changes   (4)
Purchases 11 9
Sales and maturities (1) (1)
Changes in risk, parameters and exposures (7) (9)
Balance at end of period 8 5
Performing Stage two [member]    
Disclosure of credit risk exposure [line items]    
Balance at beginning of period 18 19
Provision for credit losses    
Changes in risk, parameters and exposures (6) 1
Exchange rate and other 2 (2)
Balance at end of period $ 14 $ 18