Employee retirement benefits - Benefit Obligations (Detail) - CAD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2025 |
Dec. 31, 2024 |
Dec. 31, 2023 |
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| Pension benefits | |||
| Change in benefit obligation | |||
| Benefit obligation at January 1 | $ 8,131 | $ 8,154 | |
| Service cost | 186 | 186 | $ 162 |
| Interest cost | 369 | 365 | 373 |
| Actuarial loss (gain) | (247) | (88) | |
| Amendments and other | 19 | 0 | |
| Benefits paid | (502) | (486) | |
| Benefit obligation at December 31 | 7,956 | 8,131 | 8,154 |
| Accumulated benefit obligation at December 31 | 7,225 | 7,385 | |
| Other postretirement benefits | |||
| Change in benefit obligation | |||
| Benefit obligation at January 1 | 476 | 581 | |
| Service cost | 4 | 13 | 12 |
| Interest cost | 22 | 25 | 28 |
| Actuarial loss (gain) | (43) | (29) | |
| Amendments and other | 1 | (78) | |
| Benefits paid | 5 | (36) | |
| Benefit obligation at December 31 | $ 465 | $ 476 | $ 581 |
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- Definition Defined Benefit Plan, Benefit Obligation, Benefits Paid, Net No definition available.
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- Definition Amount of actuarial present value of benefits attributed to employee service rendered, excluding assumptions about future compensation level. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount of gain (loss) from change in actuarial assumptions which (increases) decreases benefit obligation of defined benefit plan. Assumptions include, but are not limited to, interest, mortality, employee turnover, salary, and temporary deviation from substantive plan. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount of actuarial present value of benefits attributed to service rendered by employee for defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. No definition available.
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- Definition Amount of cost recognized for passage of time related to defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Amount of increase (decrease) in benefit obligation of defined benefit plan from change, classified as other. No definition available.
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- Definition Amount of cost for actuarial present value of benefits attributed to service rendered by employee for defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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