v3.26.1
Significant capital and funding transactions - Additional Information (Detail)
$ / shares in Units, $ / shares in Units, shares in Thousands, $ in Millions, $ in Millions
 3 Months Ended 6 Months Ended
Apr. 29, 2026
CAD ($)
Jan. 30, 2026
USD ($)
$ / shares
Jan. 27, 2026
USD ($)
Jan. 24, 2026
$ / shares
shares
Dec. 08, 2025
$ / shares
shares
Nov. 24, 2025
$ / shares
shares
Apr. 30, 2026
CAD ($)
Apr. 30, 2026
CAD ($)
Apr. 30, 2025
CAD ($)
Disclosure Of Significant Capital And Funding Transactions [Line Items]                  
Issue of preferred shares and other equity instruments             $ 0 $ 1,351 $ 1,386
Repayments of subordinated liabilities               $ 2,035 $ 1,500
Subordinated debentures [member]                  
Disclosure Of Significant Capital And Funding Transactions [Line Items]                  
Proceeds from issuance of subordinated debentures $ 1,750                
Borrowings, maturity May 5, 2036                
Borrowings interest rate 4.14%                
Earliest par value redemption date May 05, 2031                
Borrowings, interest rate basis Daily Compounded Canadian Overnight Repo Rate Average plus 1.23%                
Borrowings, adjustment to interest rate basis 1.23%                
January 27, 2026 [member] | Subordinated debentures [member]                  
Disclosure Of Significant Capital And Funding Transactions [Line Items]                  
Borrowings interest rate     4.65%            
Repayments of subordinated liabilities     $ 1,500            
Limited Recourse Capital Notes Series Eight [Member]                  
Disclosure Of Significant Capital And Funding Transactions [Line Items]                  
Equity instrument conversion floor price | $ / shares   $ 5              
Debt instrument variable interest rate spread   2.45%              
Debt instrument fixed interest rate   6.50%              
Issue of preferred shares and other equity instruments   $ 1,000              
Limited Recourse Capital Notes Series Eight [Member] | Fixed interest rate [member]                  
Disclosure Of Significant Capital And Funding Transactions [Line Items]                  
Borrowings, maturity   May 24, 2033              
Limited Recourse Capital Notes Series Eight [Member] | U S Treasury Rate [Member]                  
Disclosure Of Significant Capital And Funding Transactions [Line Items]                  
Borrowings, maturity   May 24, 2086              
Series CA Preferred Shares [Member]                  
Disclosure Of Significant Capital And Funding Transactions [Line Items]                  
Preferred shares issued price per share | $ / shares   $ 1,000              
Proceeds from issuing shares   $ 1,000              
Limited Recourse Capital Notes Series Two [Member]                  
Disclosure Of Significant Capital And Funding Transactions [Line Items]                  
Percentage of principal amount       100.00%          
Number of shares redeemed during period | shares       1,250,000          
Series BR Non Cumulative Five Year Fixed Rate Reset First Preferred Shares [Member]                  
Disclosure Of Significant Capital And Funding Transactions [Line Items]                  
Redemption price per share | $ / shares       $ 1,000          
Number of shares redeemed during period | shares       1,250          
Series BF On Non Cumulative Reset Five Year Rate First Preference Shares [Member]                  
Disclosure Of Significant Capital And Funding Transactions [Line Items]                  
Redemption price per share | $ / shares           $ 25      
Number of shares redeemed during period | shares           12,000      
Series BI Non Cumulative Fixed Rate First Preferred Shares [Member]                  
Disclosure Of Significant Capital And Funding Transactions [Line Items]                  
Redemption price per share | $ / shares         $ 25        
Number of shares redeemed during period | shares         6,000        
Series BH Non Cumulative Fixed Rate First Preferred Shares [Member]                  
Disclosure Of Significant Capital And Funding Transactions [Line Items]                  
Number of shares redeemed during period | shares         6,000