v3.25.2
Fair Value Measurements - Transfers (Details) - Recurring Fair Value Measurements - USD ($)
$ in Millions
3 Months Ended 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Fair Value Hierarchy Levels Transfers        
Transfers out of Level 3 into Level 2, net derivative assets (liabilities) $ 0.1      
Fixed maturities, trading        
Fair Value Hierarchy Levels Transfers        
Transfers out of Level 3 into Level 2     $ 4.8  
Available-for-sale | Fixed maturities        
Fair Value Hierarchy Levels Transfers        
Transfers out of Level 2 into Level 3 121.5 $ 90.5 121.5 $ 210.0
Transfers out of Level 3 into Level 2     24.8 111.6
Available-for-sale | States and political subdivisions        
Fair Value Hierarchy Levels Transfers        
Transfers out of Level 2 into Level 3   15.5   15.5
Available-for-sale | Corporate        
Fair Value Hierarchy Levels Transfers        
Transfers out of Level 2 into Level 3   19.4   58.9
Available-for-sale | Other debt obligations        
Fair Value Hierarchy Levels Transfers        
Transfers out of Level 2 into Level 3 $ 121.5 $ 55.6 121.5 135.6
Transfers out of Level 3 into Level 2     $ 24.8 $ 111.6