Financial Instruments - Net (Gain) Loss from Risk Management Activities (Details) - CAD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2025 |
Dec. 31, 2024 |
Dec. 31, 2023 |
|
| Financial Instruments [Abstract] | |||
| Net realized risk management (gain) loss | $ (89) | $ 168 | $ (14) |
| Net unrealized risk management loss (gain) | 71 | 9 | 12 |
| Gains (loss) on change in fair value of derivatives | $ (18) | $ 177 | $ (2) |