v3.26.1
Investments - Schedule of Continuous Loss Position (Details)
$ in Millions
Jun. 30, 2026
USD ($)
security
Dec. 31, 2025
USD ($)
security
Debt Securities, Available-for-Sale [Line Items]    
Fair value $ 818.5 $ 136.2
Gross unrealized losses (4.7) (0.5)
Gross unrealized losses $ (0.2) $ (0.1)
Number of securities | security 499 215
U.S. Treasuries    
Debt Securities, Available-for-Sale [Line Items]    
Fair value $ 378.5 $ 50.1
Gross unrealized losses (1.3) (0.1)
Gross unrealized losses $ 0.0 $ (0.1)
Number of securities | security 84 49
Non-U.S. government    
Debt Securities, Available-for-Sale [Line Items]    
Fair value $ 5.7 $ 5.3
Gross unrealized losses (0.1) 0.0
Gross unrealized losses $ 0.0 $ 0.0
Number of securities | security 4 3
Corporate bonds    
Debt Securities, Available-for-Sale [Line Items]    
Fair value $ 344.0 $ 53.3
Gross unrealized losses (2.8) (0.3)
Gross unrealized losses $ (0.1) $ 0.0
Number of securities | security 344 132
Residential mortgage-backed    
Debt Securities, Available-for-Sale [Line Items]    
Fair value $ 14.2 $ 2.2
Gross unrealized losses (0.1) 0.0
Gross unrealized losses $ 0.0 $ 0.0
Number of securities | security 5 1
Commercial mortgage-backed    
Debt Securities, Available-for-Sale [Line Items]    
Fair value $ 2.3  
Gross unrealized losses 0.0  
Gross unrealized losses $ 0.0  
Number of securities | security 5  
Other asset-backed securities    
Debt Securities, Available-for-Sale [Line Items]    
Fair value $ 73.8 $ 25.3
Gross unrealized losses (0.4) (0.1)
Gross unrealized losses $ (0.1) $ 0.0
Number of securities | security 57 30