v3.26.1
Investments - Schedule of Net Investment Income (Details) - USD ($)
$ in Millions
3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Debt and Equity Securities, FV-NI [Line Items]        
Investment expenses $ (4.8) $ (3.7) $ (10.8) $ (9.0)
Net investment income 65.5 68.2 131.9 139.4
Gross investment income        
Debt and Equity Securities, FV-NI [Line Items]        
Gross investment income 70.3 71.9 142.7 148.4
Debt securities, available for sale        
Debt and Equity Securities, FV-NI [Line Items]        
Gross investment income 60.2 61.6 124.9 122.9
Debt securities, trading        
Debt and Equity Securities, FV-NI [Line Items]        
Gross investment income 0.4 1.2 2.2 4.3
Short-term investments        
Debt and Equity Securities, FV-NI [Line Items]        
Gross investment income 0.2 (0.2) 0.5 1.0
Other long-term investments        
Debt and Equity Securities, FV-NI [Line Items]        
Gross investment income 3.5 2.8 3.8 4.4
Cash, cash equivalents and other        
Debt and Equity Securities, FV-NI [Line Items]        
Gross investment income $ 6.0 $ 6.5 $ 11.3 $ 15.8