RESTRUCTURING, INTEGRATION AND ACQUISITION COSTS - Analysis (Details) - CAD ($) $ in Millions |
12 Months Ended | |
|---|---|---|
Mar. 31, 2026 |
Mar. 31, 2025 |
|
| Restructuring, Integration and Acquisition costs [Abstract] | ||
| Impairment of non-financial assets – net | $ 58.9 | $ 5.2 |
| Severances and other employee related costs | 13.2 | 33.9 |
| Integration and acquisition costs | 0.0 | 11.5 |
| Other costs | 12.3 | 5.9 |
| Restructuring, integration and acquisition costs | $ 84.4 | $ 56.5 |