v3.26.1
Share capital - Narrative (Details) - CHF (SFr)
SFr / shares in Units, SFr in Millions
Jun. 30, 2026
Dec. 31, 2025
Disclosure of classes of share capital [line items]    
Share capital SFr 34.1 SFr 34.1
Share capital, paid-in percentage 100.00%  
Class A    
Disclosure of classes of share capital [line items]    
Number of shares registered (in shares) 308,472,124  
Par value per share (in CHF per share) SFr 0.10  
Number of shares outstanding (in shares) 301,715,535 296,873,353
Class B    
Disclosure of classes of share capital [line items]    
Number of shares registered (in shares) 324,991,680  
Par value per share (in CHF per share) SFr 0.01  
Number of shares outstanding (in shares) 324,991,680 341,241,680