financial instruments - Fair values Non-derivative (Details) - CAD ($) $ in Millions |
Jun. 30, 2026 |
Dec. 31, 2025 |
|---|---|---|
| financial instruments | ||
| Long-term debt, excluding leases | $ 27,256 | $ 27,225 |
| Carrying value | ||
| financial instruments | ||
| Long-term debt, excluding leases | 27,256 | 27,225 |
| Fair value | ||
| financial instruments | ||
| Long-term debt, excluding leases | $ 27,412 | $ 27,507 |