v3.25.2
Investments - Reconciliation of Net Unrealized Investment Gains (Losses) (Details) - USD ($)
$ in Millions
3 Months Ended 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Net unrealized investment gains (losses) on fixed maturity securities, net of tax        
Beginning of period     $ 1,287.5  
End of period $ 1,360.3 $ 1,208.8 1,360.3 $ 1,208.8
Net unrealized investment gains (losses) on securities        
Net unrealized investment gains (losses) on fixed maturity securities, net of tax        
Beginning of period (314.5) (348.0) (357.4) (328.3)
End of period (309.9) (370.4) (309.9) (370.4)
Net unrealized investment gains (losses) on securities | Fixed maturity securities        
Net unrealized investment gains (losses) on fixed maturity securities, net of tax        
Beginning of period (314.5) (348.0) (357.4) (328.3)
Change in net unrealized investment gains (losses) on fixed maturity securities 1.4 (24.1) 44.4 (44.6)
Reclassification of net investment losses on fixed maturity securities to net income 3.2 1.7 3.1 2.5
End of period $ (309.9) $ (370.4) $ (309.9) $ (370.4)