v3.22.2.2
Nature and extent of risks arising from financial instruments - Summary of Credit Exposure Associated With on-and Off-balance Sheet Financial Instruments (Parenthetical) (Detail) - Credit risk [member] - On balance sheet risk [member]
 12 Months Ended
Oct. 31, 2022
Oct. 31, 2021
On balance sheet assets other than derivatives [member]    
Disclosure of nature and extent of risks arising from financial instruments [line items]    
Concentration risk threshold percentage 20.00% 20.00%
Number of companies above threshold percentage No industry accounts for more than 20% (October 31, 2021 – 20%) of total on-balance sheet credit instruments  
On balance sheet assets other than derivatives [member] | Banking [member]    
Disclosure of nature and extent of risks arising from financial instruments [line items]    
Concentration risk threshold percentage 26.00% 24.00%
On balance sheet assets other than derivatives [member] | Government [member]    
Disclosure of nature and extent of risks arising from financial instruments [line items]    
Concentration risk threshold percentage 32.00% 37.00%
On balance sheet assets other than derivatives [member] | Ontario Canada [member]    
Disclosure of nature and extent of risks arising from financial instruments [line items]    
Maximum exposure to credit risk 56.00% 56.00%
On balance sheet assets other than derivatives [member] | Prairies Canada [member]    
Disclosure of nature and extent of risks arising from financial instruments [line items]    
Maximum exposure to credit risk 15.00% 16.00%
On balance sheet assets other than derivatives [member] | British Columbia and the Territories [member]    
Disclosure of nature and extent of risks arising from financial instruments [line items]    
Maximum exposure to credit risk 15.00% 14.00%
On balance sheet assets other than derivatives [member] | Quebec [member]    
Disclosure of nature and extent of risks arising from financial instruments [line items]    
Maximum exposure to credit risk 10.00% 10.00%
Committed and uncommitted [member] | Retail [member]    
Disclosure of nature and extent of risks arising from financial instruments [line items]    
Maximum exposure to credit risk 45.00% 45.00%
Committed and uncommitted [member] | Wholesale [member]    
Disclosure of nature and extent of risks arising from financial instruments [line items]    
Maximum exposure to credit risk 55.00% 55.00%
Committed and uncommitted [member] | Wholesale [member] | Bank financial services [member]    
Disclosure of nature and extent of risks arising from financial instruments [line items]    
Maximum exposure to credit risk 15.00% 13.00%
Committed and uncommitted [member] | Wholesale [member] | Utilities [member]    
Disclosure of nature and extent of risks arising from financial instruments [line items]    
Maximum exposure to credit risk 12.00% 10.00%
Committed and uncommitted [member] | Wholesale [member] | Real estate and related [member]    
Disclosure of nature and extent of risks arising from financial instruments [line items]    
Maximum exposure to credit risk 11.00% 10.00%
Committed and uncommitted [member] | Wholesale [member] | Other Services [Member]    
Disclosure of nature and extent of risks arising from financial instruments [line items]    
Maximum exposure to credit risk 7.00% 8.00%
Committed and uncommitted [member] | Wholesale [member] | Oil and gas [Member]    
Disclosure of nature and extent of risks arising from financial instruments [line items]    
Maximum exposure to credit risk 6.00% 6.00%