COMMITMENTS - Summary of Commitments Under Leases, Outsourcing and Other Agreements Due (Details) $ in Millions |
Dec. 31, 2025
CAD ($)
|
|---|---|
| Commitments and Contingencies Disclosure [Abstract] | |
| Outsourcing and other agreements, Year 1 | $ 48 |
| Outsourcing and other agreements, Year 2 | 47 |
| Outsourcing and other agreements, Year 3 | 33 |
| Outsourcing and other agreements, Year 4 | 1 |
| Outsourcing and other agreements, Year 5 | 1 |
| Outsourcing and other agreements, Thereafter | $ 17 |