v3.25.4
BORROWINGS - Third-Party Debt (Details) - CHF (SFr)
SFr in Millions
Dec. 31, 2025
Dec. 31, 2024
Disclosure of detailed information about borrowings [line items]    
Undrawn borrowing facilities SFr 485.7  
Borrowings SFr 4,337.2 SFr 4,676.8
Weighted average    
Disclosure of detailed information about borrowings [line items]    
Interest rate 4.85%  
Principal amount    
Disclosure of detailed information about borrowings [line items]    
Borrowings SFr 4,345.7 4,687.1
Deferred Financing Costs, Discounts And Premiums, Net    
Disclosure of detailed information about borrowings [line items]    
Borrowings SFr (8.5) SFr (10.3)
Deferred Financing Costs, Discounts And Premiums, Net | Weighted average    
Disclosure of detailed information about borrowings [line items]    
Interest rate 2.80% 3.00%
Sunrise holding bank facility    
Disclosure of detailed information about borrowings [line items]    
Undrawn borrowing facilities SFr 485.7 SFr 662.0
Borrowings SFr 1,540.5 2,231.2
Sunrise holding bank facility | Weighted average    
Disclosure of detailed information about borrowings [line items]    
Interest rate 6.07%  
Sunrise holding bank facility | Principal amount    
Disclosure of detailed information about borrowings [line items]    
Borrowings SFr 1,547.2 2,239.0
Sunrise holding SPE notes    
Disclosure of detailed information about borrowings [line items]    
Borrowings SFr 2,141.3 1,467.2
Sunrise holding SPE notes | Weighted average    
Disclosure of detailed information about borrowings [line items]    
Interest rate 4.60%  
Sunrise holding SPE notes | Principal amount    
Disclosure of detailed information about borrowings [line items]    
Borrowings SFr 2,143.3 1,468.8
Sunrise holding senior note    
Disclosure of detailed information about borrowings [line items]    
Borrowings SFr 267.8 628.0
Sunrise holding senior note | Weighted average    
Disclosure of detailed information about borrowings [line items]    
Interest rate 3.88%  
Sunrise holding senior note | Principal amount    
Disclosure of detailed information about borrowings [line items]    
Borrowings SFr 268.0 629.3
Vendor financing | Weighted average    
Disclosure of detailed information about borrowings [line items]    
Interest rate 1.96%  
Vendor financing | Principal amount    
Disclosure of detailed information about borrowings [line items]    
Borrowings SFr 387.2 SFr 350.0