v3.22.2.2
Income taxes - Significant Components of Deferred Tax Assets and Liabilities (Detail) - CAD ($)
$ in Millions
 12 Months Ended
Oct. 31, 2022
Oct. 31, 2021
Oct. 31, 2020
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Net deferred asset (liability) at beginning of period $ 1,937 $ 2,527  
Change through equity (278) (740)  
Change through profit or loss (381) 204  
Exchange rate differences 83 (49)  
Acquisitions/ disposals (331)    
Other components of deferred tax expense (income) 3 (5)  
Net deferred asset (liability) at ending of period 1,033 1,937  
Deferred tax assets and liabilities [abstract]      
Deferred tax assets 1,472 2,011 $ 2,579
Deferred tax liabilities (439) (74) $ (52)
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 (19) (68)  
Change through equity (2) 45  
Change through profit or loss   (1)  
Exchange rate differences 5 5  
Net deferred asset (liability) at ending of period (16) (19)  
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 974 1,362  
Change through profit or loss 2 (372)  
Exchange rate differences 11 (16)  
Net deferred asset (liability) at ending of period 987 974  
Deferred compensation [member]      
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Net deferred asset (liability) at beginning of period 1,614 1,269  
Change through equity (10) 17  
Change through profit or loss (211) 396  
Exchange rate differences 101 (68)  
Acquisitions/ disposals 10    
Net deferred asset (liability) at ending of period 1,504 1,614  
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 11 9  
Change through profit or loss 1 2  
Net deferred asset (liability) at ending of period 12 11  
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 242 204  
Change through profit or loss 67 40  
Exchange rate differences 2 (2)  
Acquisitions/ disposals 8    
Other components of deferred tax expense (income) 3    
Net deferred asset (liability) at ending of period 322 242  
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 110 (104)  
Change through equity (1) 6  
Change through profit or loss (126) 205  
Exchange rate differences 23 3  
Net deferred asset (liability) at ending of period 6 110  
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 (836) (784)  
Change through profit or loss 4 (82)  
Exchange rate differences (57) 30  
Acquisitions/ disposals (345)    
Net deferred asset (liability) at ending of period (1,234) (836)  
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 (163) 592  
Change through equity (287) (796)  
Change through profit or loss 19 45  
Exchange rate differences 4 (4)  
Acquisitions/ disposals (8)    
Net deferred asset (liability) at ending of period (435) (163)  
Other [member]      
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]      
Net deferred asset (liability) at beginning of period 4 47  
Change through equity 22 (12)  
Change through profit or loss (137) (29)  
Exchange rate differences (6) 3  
Acquisitions/ disposals 4    
Other components of deferred tax expense (income)   (5)  
Net deferred asset (liability) at ending of period $ (113) $ 4