STOCK-BASED COMPENSATION - Summary of Stock-based Compensation Expense (Details) - CAD ($) $ in Millions |
12 Months Ended | |
|---|---|---|
Dec. 31, 2025 |
Dec. 31, 2024 |
|
| Disclosure of terms and conditions of share-based payment arrangement [line items] | ||
| Total stock-based compensation expense | $ 98 | $ 54 |
| Stock options | ||
| Disclosure of terms and conditions of share-based payment arrangement [line items] | ||
| Total stock-based compensation expense | 37 | (58) |
| Restricted share units | ||
| Disclosure of terms and conditions of share-based payment arrangement [line items] | ||
| Total stock-based compensation expense | 68 | 20 |
| Deferred share units | ||
| Disclosure of terms and conditions of share-based payment arrangement [line items] | ||
| Total stock-based compensation expense | 15 | (10) |
| Equity derivative effect, net of interest receipt | ||
| Disclosure of terms and conditions of share-based payment arrangement [line items] | ||
| Total stock-based compensation expense | $ (22) | $ 102 |