v3.26.1
Capital and financing transactions - Schedule of capital and financing transactions (Detail) - CAD ($)
$ in Millions
 1 Months Ended 3 Months Ended 6 Months Ended 10 Months Ended
Apr. 07, 2026
Apr. 30, 2026
Apr. 30, 2026
Apr. 30, 2025
Apr. 30, 2026
Apr. 30, 2025
Apr. 01, 2026
Disclosure of objectives, policies and processes for managing capital [line items]              
Beginning Balance     $ 89,022   $ 88,587 $ 84,076  
Issued in relation to share-based payments, net [1]         10 11  
Repurchased for cancellation under the Normal Course Issuer Bid (shares) 15,000,000 2,100,000 6,400,000       20,000,000
Repurchased for cancellation under the Normal Course Issuer Bid   $ (218) $ (655)       $ (1,846)
Ending Balance   $ 88,582 $ 88,582 $ 86,506 $ 88,582 $ 86,506  
Common shares [member]              
Disclosure of objectives, policies and processes for managing capital [line items]              
Outstanding at beginning of period     1,232,792,128 1,245,527,961 1,236,305,738 1,244,435,686  
Beginning Balance     $ 22,089 $ 22,136 $ 22,067 $ 22,054  
Issued in relation to share-based payments, net (shares)     378,695 21,402 1,741,732 1,113,677  
Issued in relation to share-based payments, net     $ 29 $ 2 $ 140 $ 84  
Repurchased for cancellation under the Normal Course Issuer Bid (shares)     (6,383,463)   (11,260,110)    
Repurchased for cancellation under the Normal Course Issuer Bid     $ (116)   $ (205)    
Outstanding at end of period   1,226,787,360 1,226,787,360 1,245,549,363 1,226,787,360 1,245,549,363  
Ending Balance   $ 22,002 $ 22,002 $ 22,138 $ 22,002 $ 22,138  
[1] Represents amounts on account of share-based payments (refer to Note 12).