v3.26.1
Equity - Summary of Classes of Preferred and Common Shares Outstanding (Details) - CAD ($)
$ / shares in Units, $ in Millions
 3 Months Ended 6 Months Ended 12 Months Ended
Nov. 12, 2025
Nov. 01, 2025
Apr. 30, 2026
Jan. 31, 2026
Apr. 30, 2025
Jan. 31, 2025
Apr. 30, 2026
Apr. 30, 2025
Oct. 31, 2025
Oct. 31, 2024
Aug. 25, 2024
Disclosure of classes of share capital [line items]                      
Amount     $ 85,617   $ 85,833   $ 85,617 $ 85,833 $ 88,100    
Common stock conversion price     $ 5.00       $ 5.00        
Burgundy Asset Management Ltd.                      
Disclosure of classes of share capital [line items]                      
Number of shares issued in an acquisition (in shares)   2,723,726                  
Value of shares issued in an acquisition   $ 481                  
Treasury shares                      
Disclosure of classes of share capital [line items]                      
Number of shares (in shares)     0       0   0    
4.800% Additional Tier 1 Capital Notes (AT1 Notes)                      
Disclosure of classes of share capital [line items]                      
Borrowings, interest rate                     4.80%
Borrowings, adjustment to interest rate basis                     6.709%
Preferred Shares and Other Equity Instruments                      
Disclosure of classes of share capital [line items]                      
Amount     $ 7,706 $ 7,706 7,787 $ 7,787 $ 7,706 7,787 $ 8,956 $ 8,087  
Preferred Shares – Classified as Equity                      
Disclosure of classes of share capital [line items]                      
Amount     $ 1,550       $ 1,550   $ 1,550    
Class B – Series 44                      
Disclosure of classes of share capital [line items]                      
Number of shares (in shares)     16,000,000       16,000,000   16,000,000    
Amount     $ 400       $ 400   $ 400    
Dividends declared per share (in canadian dollars per share)             $ 0.85   $ 1.70    
Class B – Series 50                      
Disclosure of classes of share capital [line items]                      
Number of shares (in shares)     500,000       500,000   500,000    
Amount     $ 500       $ 500   $ 500    
Dividends declared per share (in canadian dollars per share)             $ 36.87   $ 73.73    
Class B – Series 52                      
Disclosure of classes of share capital [line items]                      
Number of shares (in shares)     650,000       650,000   650,000    
Amount     $ 650       $ 650   $ 650    
Dividends declared per share (in canadian dollars per share)             $ 35.29   $ 70.57    
Other Equity Instruments                      
Disclosure of classes of share capital [line items]                      
Amount     6,156       $ 6,156   $ 7,406    
Other Equity Instruments | 4.800% Additional Tier 1 Capital Notes (AT1 Notes)                      
Disclosure of classes of share capital [line items]                      
Amount     $ 658       $ 658   658    
Borrowings, interest rate     4.80%       4.80%        
Other Equity Instruments | 4.300% Limited Recourse Capital Notes, Series 1 (LRCNs, Series 1)                      
Disclosure of classes of share capital [line items]                      
Amount     $ 0       $ 0   1,250    
Borrowings, interest rate     4.30%       4.30%        
Redemption amount $ 1,250                    
Compound instrument interest rate 4.30%                    
Other Equity Instruments | 5.625% Limited Recourse Capital Notes, Series 2 (LRCNs, Series 2)                      
Disclosure of classes of share capital [line items]                      
Amount     $ 750       $ 750   750    
Borrowings, interest rate     5.625%       5.625%        
Other Equity Instruments | 7.325% Limited Recourse Capital Notes, Series 3 (LRCNs, Series 3)                      
Disclosure of classes of share capital [line items]                      
Amount     $ 1,000       $ 1,000   1,000    
Borrowings, interest rate     7.325%       7.325%        
Other Equity Instruments | 7.700% Limited Recourse Capital Notes, Series 4 (LRCNs, Series 4)                      
Disclosure of classes of share capital [line items]                      
Amount     $ 1,356       $ 1,356   1,356    
Borrowings, interest rate     7.70%       7.70%        
Other Equity Instruments | 7.300% Limited Recourse Capital Notes, Series 5 (LRCNs, Series 5)                      
Disclosure of classes of share capital [line items]                      
Amount     $ 1,023       $ 1,023   1,023    
Borrowings, interest rate     7.30%       7.30%        
Other Equity Instruments | 6.875% Limited Recourse Capital Notes, Series 6 (LRCNs, Series 6)                      
Disclosure of classes of share capital [line items]                      
Amount     $ 1,369       $ 1,369   $ 1,369    
Borrowings, interest rate     6.875%       6.875%        
Class B - Series 48                      
Disclosure of classes of share capital [line items]                      
Preferred shares redeemed $ 1,250                    
Common Shares                      
Disclosure of classes of share capital [line items]                      
Number of shares (in shares)     700,416,619       700,416,619   708,905,679    
Amount     $ 23,537 $ 23,708 $ 23,730 $ 23,923 $ 23,537 $ 23,730 $ 23,359 $ 23,921  
Dividends declared per share (in canadian dollars per share)     $ 1.67 $ 1.67 $ 1.59   $ 3.34 $ 3.18 $ 6.44    
Common shares convertible from stock option plan (in shares)           5,699,134 5,676,320        
Number of share options exercisable in share-based payment arrangement (in shares)     2,528,025       2,528,025   2,245,942    
Value of shares issued in an acquisition     $ 0   $ 0   $ 481 $ 0      
Common Shares | Stock Option Plan                      
Disclosure of classes of share capital [line items]                      
Common shares issued under stock option plan (in shares)     178,305   211,309   787,214 685,719