EMPLOYEE BENEFIT OBLIGAITONS - Pension Costs Resulting From Defined Benefit Plans (Details) - CHF (SFr) SFr in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2025 |
Dec. 31, 2024 |
Dec. 31, 2023 |
|
| Employee Benefit Obligations [Abstract] | |||
| Current service costs excluding interest costs | SFr 21.0 | SFr 19.5 | SFr 16.9 |
| Net interest costs on defined benefit obligation and service costs | 0.2 | 0.4 | 0.3 |
| Past service costs/(income) | 0.1 | (2.1) | (13.5) |
| Administration costs | 0.9 | 1.7 | 0.6 |
| Termination benefits | 0.8 | 0.2 | 0.2 |
| Total | SFr 23.0 | SFr 19.7 | SFr 4.5 |