v3.26.1
Equity (Summary of Classes of Share Capital - Treasury Shares) (Details) - CAD ($)
shares in Thousands, $ in Millions
 3 Months Ended 6 Months Ended 9 Months Ended
Jul. 31, 2026
Jul. 31, 2025
Jul. 31, 2026
Jul. 31, 2026
Jul. 31, 2025
Disclosure of classes of share capital [line items]          
Balance at beginning of period       $ 127,827  
Purchase of shares, Amount $ (2,400)   $ (5,400)    
Balance at end of period $ 127,015 $ 125,394 $ 127,015 $ 127,015 $ 125,394
Common shares [member] | Treasury shares [member]          
Disclosure of classes of share capital [line items]          
Beginning balance, Number of shares 369 313   0 213
Purchase of shares, Number of shares 18,436 33,496   67,352 112,437
Sale of shares, Number of shares (18,691) (32,900)   (67,238) (111,741)
Ending balance, Number of shares 114 909 114 114 909
Balance at beginning of period $ (60) $ (26)   $ 0 $ (17)
Purchase of shares, Amount (2,949) (3,222)   (9,162) (9,606)
Sale of shares, Amount 2,990 3,156   9,143 9,531
Balance at end of period (19) (92) $ (19) (19) (92)
Preferred shares and other equity instruments [member]          
Disclosure of classes of share capital [line items]          
Balance at end of period $ 12,875 $ 10,788 $ 12,875 $ 12,875 $ 10,788
Preferred shares and other equity instruments [member] | Treasury shares [member]          
Disclosure of classes of share capital [line items]          
Beginning balance, Number of shares 25 141   29 163
Purchase of shares, Number of shares 1,671 705   2,240 4,147
Sale of shares, Number of shares (1,595) (779)   (2,168) (4,243)
Ending balance, Number of shares 101 67 101 101 67
Balance at beginning of period $ (14) $ (28)   $ (4) $ (18)
Purchase of shares, Amount (2,022) (73)   (2,537) (1,460)
Sale of shares, Amount 1,990 99   2,495 1,476
Balance at end of period $ (46) $ (2) $ (46) $ (46) $ (2)