v3.22.2.2
Employee benefits - Pension and other post-employment benefits - Additional Information (Detail) - CAD ($)
shares in Millions, $ in Millions
 12 Months Ended
Oct. 31, 2022
Oct. 31, 2021
Disclosure of employee benefits [line items]    
Plan assets, fair value of our debt securities $ 48 $ 29
Dividends received on our common shares held in plan assets $ 4 $ 4
Common shares [member]    
Disclosure of employee benefits [line items]    
Number of our common shares included in plan assets 0.7 1.0
Plan assets, fair value of our common shares $ 89 $ 128
Defined benefit pension plans [member] | Canada [member]    
Disclosure of employee benefits [line items]    
Remeasurement gains (losses) recorded in OCI 798 2,819
Defined benefit pension plans [member] | Foreign countries [member]    
Disclosure of employee benefits [line items]    
Remeasurement gains (losses) recorded in OCI 15 48
Defined benefit and contribution pension plans [member]    
Disclosure of employee benefits [line items]    
Contributions to pension plans (defined benefit and defined contribution plans) and other post-employment benefit plans 427 456
Estimated contributions to pension plans and other post-employment benefit plans 341  
Defined benefit and contribution pension plans [member] | Canada [member]    
Disclosure of employee benefits [line items]    
Service costs for pension plans 305 356
Net interest expense (income) for pension plans (83) 7
Defined benefit and contribution pension plans [member] | Foreign countries [member]    
Disclosure of employee benefits [line items]    
Service costs for pension plans 2 3
Net interest expense (income) for pension plans 1 0
Other post employment benefit plan [member]    
Disclosure of employee benefits [line items]    
Contributions to pension plans (defined benefit and defined contribution plans) and other post-employment benefit plans 79 $ 75
Estimated contributions to pension plans and other post-employment benefit plans $ 84