Employee benefit obligations - Schedule of Employee Benefit Expense (Details) - CHF (SFr) SFr in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2025 |
Dec. 31, 2024 |
Dec. 31, 2023 |
|
| Disclosure of defined benefit plans [abstract] | |||
| Current service cost | SFr (8.6) | SFr (5.3) | SFr (3.8) |
| Past service cost | 0.3 | 0.0 | 0.0 |
| Employee benefit expenses | SFr (8.3) | SFr (5.3) | SFr (3.8) |