v3.26.3
Investments - Schedule of Net Investment Income (Details) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Debt and Equity Securities, FV-NI [Line Items]        
Investment expenses $ (4.1) $ (4.9) $ (14.9) $ (13.9)
Net investment income 65.9 66.5 197.8 205.9
Gross investment income        
Debt and Equity Securities, FV-NI [Line Items]        
Gross investment income 70.0 71.4 212.7 219.8
Debt securities, available for sale        
Debt and Equity Securities, FV-NI [Line Items]        
Gross investment income 65.1 63.2 190.0 186.1
Debt securities, trading        
Debt and Equity Securities, FV-NI [Line Items]        
Gross investment income 0.8 2.0 3.0 6.3
Short-term investments        
Debt and Equity Securities, FV-NI [Line Items]        
Gross investment income 0.1 0.4 0.6 1.4
Other long-term investments        
Debt and Equity Securities, FV-NI [Line Items]        
Gross investment income 0.2 0.4 4.0 4.8
Cash, cash equivalents and other        
Debt and Equity Securities, FV-NI [Line Items]        
Gross investment income $ 3.8 $ 5.4 $ 15.1 $ 21.2