XML 181 R154.htm IDEA: XBRL DOCUMENT v3.20.4
Pension Plans and Other Post-Retirement Benefits - Schedule of Sensitivity Analysis (Details)
$ in Millions
Dec. 31, 2020
CAD ($)
Interest/discount rate sensitivity  
Disclosure of sensitivity analysis for actuarial assumptions [line items]  
Percentage of reasonably possible decrease in actuarial assumption 1.00%
Percentage of reasonably possible increase in actuarial assumption 1.00%
Percentage of reasonably possible decrease in actuarial assumption 1.00%
Rate of compensation increase assumption  
Disclosure of sensitivity analysis for actuarial assumptions [line items]  
Percentage of reasonably possible decrease in actuarial assumption 1.00%
Percentage of reasonably possible increase in actuarial assumption 1.00%
Percentage of reasonably possible decrease in actuarial assumption 1.00%
Health care trend rate assumption  
Disclosure of sensitivity analysis for actuarial assumptions [line items]  
Percentage of reasonably possible decrease in actuarial assumption 1.00%
Percentage of reasonably possible increase in actuarial assumption 1.00%
Percentage of reasonably possible decrease in actuarial assumption 1.00%
Mortality rates  
Disclosure of sensitivity analysis for actuarial assumptions [line items]  
Percentage of reasonably possible decrease in actuarial assumption 10.00%
Percentage of reasonably possible decrease in actuarial assumption 10.00%
Pension | Interest/discount rate sensitivity  
Disclosure of sensitivity analysis for actuarial assumptions [line items]  
Increase (decrease) in defined benefit obligation due to reasonably possible decrease in actuarial assumption $ 754
Increase (decrease) in defined benefit obligation due to reasonably possible increase in actuarial assumption (586)
Pension | Rate of compensation increase assumption  
Disclosure of sensitivity analysis for actuarial assumptions [line items]  
Increase (decrease) in defined benefit obligation due to reasonably possible decrease in actuarial assumption (82)
Increase (decrease) in defined benefit obligation due to reasonably possible increase in actuarial assumption 86
Pension | Mortality rates  
Disclosure of sensitivity analysis for actuarial assumptions [line items]  
Increase (decrease) in defined benefit obligation due to reasonably possible decrease in actuarial assumption 98
Other post-retirement | Interest/discount rate sensitivity  
Disclosure of sensitivity analysis for actuarial assumptions [line items]  
Increase (decrease) in defined benefit obligation due to reasonably possible decrease in actuarial assumption 34
Increase (decrease) in defined benefit obligation due to reasonably possible increase in actuarial assumption (29)
Other post-retirement | Health care trend rate assumption  
Disclosure of sensitivity analysis for actuarial assumptions [line items]  
Increase (decrease) in defined benefit obligation due to reasonably possible decrease in actuarial assumption (13)
Increase (decrease) in defined benefit obligation due to reasonably possible increase in actuarial assumption 15
Other post-retirement | Mortality rates  
Disclosure of sensitivity analysis for actuarial assumptions [line items]  
Increase (decrease) in defined benefit obligation due to reasonably possible decrease in actuarial assumption $ 6