Employee Future Benefits - Defined Contribution Plan (Narrative) (Details) - CAD ($) $ in Millions |
12 Months Ended | |
|---|---|---|
Dec. 31, 2023 |
Dec. 31, 2022 |
|
| Defined Benefit Plan Disclosure [Line Items] | ||
| Defined contribution plan cost recognized | $ 53 | $ 47 |
| Defined Benefit Pension Plans | ||
| Defined Benefit Plan Disclosure [Line Items] | ||
| Expected contributions for next fiscal year | 47 | |
| OPEB Plans | ||
| Defined Benefit Plan Disclosure [Line Items] | ||
| Expected contributions for next fiscal year | $ 17 | |