ASSET RETIREMENT OBLIGATIONS (Details) - CAD ($) $ in Millions |
12 Months Ended | |
|---|---|---|
Dec. 31, 2025 |
Dec. 31, 2024 |
|
| Asset Retirement Obligations [Line Items] | ||
| Long-term inflation assumption of current costs (as a percent) | 2.00% | |
| Decommissioning liability | $ 20 | $ 19 |
| Asset retirement obligations | 43 | 38 |
| Hydro One Remotes Operating Territory | ||
| Asset Retirement Obligations [Line Items] | ||
| Decommissioning liability | 1 | 2 |
| Asbestos Containing Materials | ||
| Asset Retirement Obligations [Line Items] | ||
| Increase (decrease) asset retirement obligation, | 3 | 0 |
| Asset retirement obligations | $ 22 | $ 18 |
| Minimum | ||
| Asset Retirement Obligations [Line Items] | ||
| Discounted future expenditures (as a percent) | 1.00% | 1.00% |
| Maximum | ||
| Asset Retirement Obligations [Line Items] | ||
| Discounted future expenditures (as a percent) | 3.00% | 3.00% |