XML 177 R148.htm IDEA: XBRL DOCUMENT v3.22.4
Employee Future Benefits - Summary of Disaggregation of Defined Benefit Obligation (Detail) - CAD ($)
$ in Millions
Dec. 31, 2022
Dec. 31, 2021
Pension defined benefit plans [member]    
Disclosure of defined benefit plans [Line Items]    
Disaggregation of defined benefit obligation $ 3,794 $ 4,560
Retiree welfare plans [Member]    
Disclosure of defined benefit plans [Line Items]    
Disaggregation of defined benefit obligation 466 584
U.S. plans [Member] | Pension defined benefit plans [member]    
Disclosure of defined benefit plans [Line Items]    
Disaggregation of defined benefit obligation 2,515 2,908
U.S. plans [Member] | Pension defined benefit plans [member] | Active [member]    
Disclosure of defined benefit plans [Line Items]    
Disaggregation of defined benefit obligation 509 537
U.S. plans [Member] | Pension defined benefit plans [member] | Inactive and retired members [Member]    
Disclosure of defined benefit plans [Line Items]    
Disaggregation of defined benefit obligation 2,006 2,371
U.S. plans [Member] | Retiree welfare plans [Member]    
Disclosure of defined benefit plans [Line Items]    
Disaggregation of defined benefit obligation 355 433
U.S. plans [Member] | Retiree welfare plans [Member] | Active [member]    
Disclosure of defined benefit plans [Line Items]    
Disaggregation of defined benefit obligation 11 17
U.S. plans [Member] | Retiree welfare plans [Member] | Inactive and retired members [Member]    
Disclosure of defined benefit plans [Line Items]    
Disaggregation of defined benefit obligation 344 416
Canadian plans [Member] | Pension defined benefit plans [member]    
Disclosure of defined benefit plans [Line Items]    
Disaggregation of defined benefit obligation 1,279 1,652
Canadian plans [Member] | Pension defined benefit plans [member] | Active [member]    
Disclosure of defined benefit plans [Line Items]    
Disaggregation of defined benefit obligation 125 184
Canadian plans [Member] | Pension defined benefit plans [member] | Inactive and retired members [Member]    
Disclosure of defined benefit plans [Line Items]    
Disaggregation of defined benefit obligation 1,154 1,468
Canadian plans [Member] | Retiree welfare plans [Member]    
Disclosure of defined benefit plans [Line Items]    
Disaggregation of defined benefit obligation 111 151
Canadian plans [Member] | Retiree welfare plans [Member] | Active [member]    
Disclosure of defined benefit plans [Line Items]    
Disaggregation of defined benefit obligation 0  
Canadian plans [Member] | Retiree welfare plans [Member] | Inactive and retired members [Member]    
Disclosure of defined benefit plans [Line Items]    
Disaggregation of defined benefit obligation $ 111 $ 151