v3.26.3
Fair Value Measurements - Transfers (Details) - Recurring Fair Value Measurements - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
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 $ 78.2   $ 163.4 121.5
Transfers out of Level 3 into Level 2 31.9 $ 94.2 149.6 119.0
Available-for-sale | Corporate        
Fair Value Hierarchy Levels Transfers        
Transfers out of Level 2 into Level 3 76.0   76.0  
Available-for-sale | Commercial mortgage-backed securities        
Fair Value Hierarchy Levels Transfers        
Transfers out of Level 2 into Level 3 2.2   2.2  
Available-for-sale | States and political subdivisions        
Fair Value Hierarchy Levels Transfers        
Transfers out of Level 2 into Level 3     32.6  
Transfers out of Level 3 into Level 2 $ 31.9   31.9  
Available-for-sale | Other debt obligations        
Fair Value Hierarchy Levels Transfers        
Transfers out of Level 2 into Level 3     52.6 121.5
Transfers out of Level 3 into Level 2   $ 94.2 $ 117.7 $ 119.0