v3.22.4
Pensions and Other Postretirement Benefits (Curtailment Event) (Details) - CAD ($)
$ in Millions
12 Months Ended
Oct. 31, 2021
Dec. 31, 2022
Dec. 31, 2021
Dec. 31, 2020
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]        
Increase in discount rate   2.11% 0.60%  
Pension Plan [Member]        
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]        
Decrease in projected benefit obligation for curtailment   $ 0 $ 52  
Actuarial gain   $ 3,548 $ 1,206  
Discount rate   5.26% 3.15% 2.55%
Actual return on plan assets   $ (2,888) $ 1,605  
Expected return on plan assets   $ 1,132 $ 1,076 $ 1,095
Pension Plan [Member] | Funded [Member]        
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]        
Decrease in projected benefit obligation for curtailment $ 52      
Actuarial gain 1,915      
Actuarial gain for increase in discount rate $ 1,808      
Increase in discount rate 0.84%      
Discount rate 3.39%     2.55%
Actuarial gain for increase in plan assets $ 107      
Actual return on plan assets 982      
Expected return on plan assets 875      
Increase in net periodic benefit cost 25      
Decrease in service cost 9      
Increase in other cost $ 16