Employee Future Benefits - Summary of Benefit Obligations and Fair Value (Narrative) (Details) - CAD ($) $ in Millions |
Dec. 31, 2023 |
Dec. 31, 2022 |
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| Defined Benefit Pension Plans | ||
| Defined Benefit Plan Disclosure [Line Items] | ||
| Projected benefit obligation | $ 1,940 | $ 978 |
| Plan with projected benefit obligation, fair value of plan assets | 1,681 | 790 |
| Accumulated benefit obligation | 268 | 833 |
| Plan with accumulated benefit obligation, fair value of plan assets | 130 | 790 |
| OPEB Plans | ||
| Defined Benefit Plan Disclosure [Line Items] | ||
| Accumulated benefit obligation | 320 | 310 |
| Plan with accumulated benefit obligation, fair value of plan assets | $ 36 | $ 31 |
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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- Definition Amount of plan asset for defined benefit pension plan with projected benefit obligation in excess of plan assets. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Amount of projected benefit obligation for defined benefit pension plan with projected benefit obligation in excess of plan assets. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Amount of accumulated benefit obligation for defined benefit plan with accumulated benefit obligation in excess of plan assets. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Amount of plan asset for defined benefit plan with accumulated benefit obligation in excess of plan assets. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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