v3.24.3
Income taxes - Significant Components of Deferred Tax Assets and Liabilities (Detail) - CAD ($)
$ in Millions
 12 Months Ended
Oct. 31, 2024
Oct. 31, 2023
Oct. 31, 2022
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Net deferred asset (liability) at beginning of period $ 2,690 $ 1,681  
Change through equity (22) (263)  
Change through profit or loss 1,501 1,254  
Exchange rate differences (4) 37  
Acquisitions/ disposals (379) (19)  
Net deferred asset (liability) at ending of period 3,786 2,690  
Deferred tax assets and liabilities [abstract]      
Deferred tax assets 4,328 3,116 $ 2,120
Deferred tax liabilities (542) (426) $ (439)
Financial Instruments Classified As Fair Value Through Other Comprehensive Income Category [member]      
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Net deferred asset (liability) at beginning of period (321) (16)  
Change through equity 164 (330)  
Change through profit or loss (1)    
Exchange rate differences   25  
Net deferred asset (liability) at ending of period (158) (321)  
Allowance for credit losses [member]      
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Net deferred asset (liability) at beginning of period 1,174 987  
Change through equity 4    
Change through profit or loss 217 185  
Exchange rate differences (1) 2  
Net deferred asset (liability) at ending of period 1,394 1,174  
Deferred compensation [member]      
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Net deferred asset (liability) at beginning of period 1,522 1,504  
Change through equity 12 (2)  
Change through profit or loss 614 (2)  
Exchange rate differences 19 22  
Net deferred asset (liability) at ending of period 2,167 1,522  
Business realignment charges [member]      
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Net deferred asset (liability) at beginning of period 23 12  
Change through profit or loss 16 11  
Acquisitions/ disposals 4    
Net deferred asset (liability) at ending of period 43 23  
Tax loss and tax credit carryforwards [member]      
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Net deferred asset (liability) at beginning of period 261 322  
Change through profit or loss 71 (57)  
Exchange rate differences (1) 1  
Acquisitions/ disposals   (5)  
Net deferred asset (liability) at ending of period 331 261  
Deferred (income) expense [member]      
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Net deferred asset (liability) at beginning of period 651 6  
Change through equity 4 (3)  
Change through profit or loss 641 661  
Exchange rate differences 2 (11)  
Acquisitions/ disposals 20 (2)  
Net deferred asset (liability) at ending of period 1,318 651  
Premises and equipment and intangibles [member]      
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Net deferred asset (liability) at beginning of period (967) (1,234)  
Change through profit or loss 136 302  
Exchange rate differences (22) (27)  
Acquisitions/ disposals (623) (8)  
Net deferred asset (liability) at ending of period (1,476) (967)  
Pension and post employment related [member]      
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Net deferred asset (liability) at beginning of period (333) (435)  
Change through equity (206) 68  
Change through profit or loss 20 37  
Exchange rate differences (1) 1  
Acquisitions/ disposals 57 (4)  
Net deferred asset (liability) at ending of period (463) (333)  
Other [member]      
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Net deferred asset (liability) at beginning of period 680 535  
Change through equity   4  
Change through profit or loss (213) 117  
Exchange rate differences   24  
Acquisitions/ disposals 163    
Net deferred asset (liability) at ending of period $ 630 $ 680