Post-employment benefit plans - Disclosure of Contributions to Post-Employment Benefit Plans (Details) - CAD ($) $ in Millions |
12 Months Ended | |
|---|---|---|
Dec. 31, 2025 |
Dec. 31, 2024 |
|
| Disclosure of defined benefit plans [line items] | ||
| Contributions, defined benefit plan | $ (5) | $ (4) |
| Estimated of contributions expected to be paid to plan for next annual reporting period, defined contribution plan | 5 | |
| DB pension | ||
| Disclosure of defined benefit plans [line items] | ||
| Estimate of contributions expected to be paid to plan for next annual reporting period, defined benefit plan | 30 | |
| OPEBs | ||
| Disclosure of defined benefit plans [line items] | ||
| Estimate of contributions expected to be paid to plan for next annual reporting period, defined benefit plan | 60 | |
| Plan assets | DB pension | ||
| Disclosure of defined benefit plans [line items] | ||
| Contributions, defined benefit plan | (44) | (48) |
| Plan assets | OPEBs | ||
| Disclosure of defined benefit plans [line items] | ||
| Contributions, defined benefit plan | $ (59) | $ (61) |