v3.22.4
Income Taxes - Additional Information (Detail) - CAD ($)
$ in Millions
 1 Months Ended 3 Months Ended
Apr. 30, 2022
Jan. 31, 2023
Oct. 31, 2022
Jan. 31, 2022
Nov. 30, 2021
Disclosure Of Income Taxes [Line Items]          
Additional income tax by denying the tax deductibility   $ 1,602      
Income tax expense   $ 738 $ 284 $ 531  
Canada Recovery Dividend Tax On Banks And Life Insurance Groups [Member]          
Disclosure Of Income Taxes [Line Items]          
One time Canada Recovery Dividend tax (CRD) rate 15.00%        
Minimum taxable income used as a basis for one time Canada Recovery Dividend Tax $ 1,000        
Minimum taxable income on prospective increase in tax $ 100        
Percentage of prospective increase in tax rate 1.50% 1.50%      
One time Canada recovery dividend tax payment term 5 years        
Income tax expense   $ 35      
Income tax based on present value of recovery dividend   510      
Recovery dividend   555      
Discount on recovery dividend   $ 45      
Period of accretion of discount on recovery dividend   4 years      
2017 Taxation Year [Member]          
Disclosure Of Income Taxes [Line Items]          
Additional income tax by denying the tax deductibility   $ 182      
Foreign Exchange Capital Loss Reassessment [member]          
Disclosure Of Income Taxes [Line Items]          
Income tax reassessment exposure of additional tax and interest         $ 300
Income tax reassessment unrecognized capital tax loss carryforwards         $ 600