Post-employment benefit plans - Components of Post-Employment Benefit Plans Financing Cost (Details) - CAD ($) $ in Millions |
12 Months Ended | |
|---|---|---|
Dec. 31, 2025 |
Dec. 31, 2024 |
|
| Disclosure of net defined benefit liability (asset) [line items] | ||
| Total net return on post-employment benefit plans | $ 102 | $ 66 |
| DB pension | ||
| Disclosure of net defined benefit liability (asset) [line items] | ||
| Total net return on post-employment benefit plans | 133 | 99 |
| OPEBs | ||
| Disclosure of net defined benefit liability (asset) [line items] | ||
| Total net return on post-employment benefit plans | $ (31) | $ (33) |