v3.26.1
Property, plant and equipment - Narrative (Details) - CHF (SFr)
SFr in Millions
6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Dec. 31, 2025
Disclosure of detailed information about property, plant and equipment [line items]      
Additions SFr 46.5 SFr 25.5  
Non-cash additions of property, plant and equipment 4.6 0.0  
Other      
Disclosure of detailed information about property, plant and equipment [line items]      
Additions 1.7 SFr 8.6  
Other, fixed assets not yet in use SFr 7.8   SFr 7.9