v3.25.4
BORROWINGS - Summary of Bank Facility (Details)
€ in Millions, SFr in Millions, $ in Millions
Dec. 31, 2025
CHF (SFr)
Dec. 31, 2025
USD ($)
Dec. 31, 2024
CHF (SFr)
Dec. 31, 2024
USD ($)
Dec. 31, 2024
EUR (€)
Disclosure of detailed information about borrowings [line items]          
Borrowings SFr 4,337.2   SFr 4,676.8    
Undrawn borrowing facilities 485.7        
Principal amount          
Disclosure of detailed information about borrowings [line items]          
Borrowings 4,345.7   4,687.1    
Sunrise holding bank facility          
Disclosure of detailed information about borrowings [line items]          
Borrowings 1,540.5   2,231.2    
Undrawn borrowing facilities 485.7   662.0    
Sunrise holding bank facility | Principal amount          
Disclosure of detailed information about borrowings [line items]          
Borrowings SFr 1,547.2   SFr 2,239.0    
AAA          
Disclosure of detailed information about borrowings [line items]          
Borrowings, adjustment to interest rate basis 2.50% 2.50%      
Facility amount (in borrowing currency) | $   $ 1,950.0      
Borrowings SFr 1,540.5        
Undrawn borrowing facilities 0.0        
AAA | Principal amount          
Disclosure of detailed information about borrowings [line items]          
Borrowings SFr 1,547.2        
Revolving Facility B          
Disclosure of detailed information about borrowings [line items]          
Borrowings, adjustment to interest rate basis 2.00% 2.00% 2.50% 2.50% 2.50%
Facility amount (in borrowing currency) SFr 500.0       € 720.0
Borrowings 0.0   SFr 0.0    
Undrawn borrowing facilities 485.7   652.6    
Revolving Facility B | Principal amount          
Disclosure of detailed information about borrowings [line items]          
Borrowings SFr 0.0   SFr 0.0    
AT          
Disclosure of detailed information about borrowings [line items]          
Borrowings, adjustment to interest rate basis     2.40% 2.40% 2.40%
Facility amount (in borrowing currency) | $       $ 700.0  
Borrowings     SFr 633.8    
Undrawn borrowing facilities     0.0    
AT | Principal amount          
Disclosure of detailed information about borrowings [line items]          
Borrowings     SFr 635.4    
AU          
Disclosure of detailed information about borrowings [line items]          
Borrowings, adjustment to interest rate basis     2.50% 2.50% 2.50%
Facility amount (in borrowing currency) | €         € 400.0
Borrowings     SFr 374.7    
Undrawn borrowing facilities     0.0    
AU | Principal amount          
Disclosure of detailed information about borrowings [line items]          
Borrowings     SFr 375.8    
AX          
Disclosure of detailed information about borrowings [line items]          
Borrowings, adjustment to interest rate basis     3.00% 3.00% 3.00%
Facility amount (in borrowing currency) | $       $ 1,044.7  
Borrowings     SFr 944.0    
Undrawn borrowing facilities     0.0    
AX | Principal amount          
Disclosure of detailed information about borrowings [line items]          
Borrowings     SFr 948.3    
AY          
Disclosure of detailed information about borrowings [line items]          
Borrowings, adjustment to interest rate basis     3.00% 3.00% 3.00%
Facility amount (in borrowing currency) | €         € 297.6
Borrowings     SFr 278.8    
Undrawn borrowing facilities     0.0    
AY | Principal amount          
Disclosure of detailed information about borrowings [line items]          
Borrowings     SFr 279.6    
Revolving Facility A          
Disclosure of detailed information about borrowings [line items]          
Borrowings, adjustment to interest rate basis     2.50% 2.50% 2.50%
Facility amount (in borrowing currency) | €         € 10.0
Borrowings     SFr 0.0    
Undrawn borrowing facilities     9.4    
Revolving Facility A | Principal amount          
Disclosure of detailed information about borrowings [line items]          
Borrowings     SFr 0.0