v3.26.1
Investments - Continuous Unrealized Loss (Details) - USD ($)
$ in Millions
Jun. 30, 2026
Dec. 31, 2025
U.S. Government and Government Agencies and Authorities    
Fixed Maturities:    
Fair Value $ 143.4 $ 3.1
Fair Value 359.2 380.3
Fair Value 502.6 383.4
Fixed Maturities:    
Unrealized Losses (1.5) 0.0
Unrealized Losses (83.8) (82.8)
Unrealized Losses (85.3) (82.8)
States and Political Subdivisions    
Fixed Maturities:    
Fair Value 121.0 86.2
Fair Value 1,027.7 1,063.3
Fair Value 1,148.7 1,149.5
Fixed Maturities:    
Unrealized Losses (2.2) (2.4)
Unrealized Losses (178.5) (183.3)
Unrealized Losses (180.7) (185.7)
Foreign Governments    
Fixed Maturities:    
Fair Value 1.7 1.0
Fair Value 0.5 0.5
Fair Value 2.2 1.5
Fixed Maturities:    
Unrealized Losses 0.0 0.0
Unrealized Losses (0.1) (0.1)
Unrealized Losses (0.1) (0.1)
Corporate Bonds and Notes    
Fixed Maturities:    
Fair Value 518.8 353.0
Fair Value 2,710.1 2,759.5
Fair Value 3,228.9 3,112.5
Fixed Maturities:    
Unrealized Losses (9.3) (5.4)
Unrealized Losses (455.3) (428.1)
Unrealized Losses (464.6) (433.5)
Redeemable Preferred Stocks    
Fixed Maturities:    
Fair Value 0.0 0.0
Fair Value 2.0 2.0
Fair Value 2.0 2.0
Fixed Maturities:    
Unrealized Losses 0.0 0.0
Unrealized Losses 0.0 0.0
Unrealized Losses 0.0 0.0
Collateralized Loan Obligations    
Fixed Maturities:    
Fair Value 309.7 238.2
Fair Value 55.6 61.7
Fair Value 365.3 299.9
Fixed Maturities:    
Unrealized Losses (2.7) (1.2)
Unrealized Losses (6.5) (6.6)
Unrealized Losses (9.2) (7.8)
Other Mortgage- and Asset-backed    
Fixed Maturities:    
Fair Value 43.4 24.7
Fair Value 230.9 249.5
Fair Value 274.3 274.2
Fixed Maturities:    
Unrealized Losses (1.1) (0.5)
Unrealized Losses (22.8) (22.7)
Unrealized Losses (23.9) (23.2)
Investments in Fixed Maturities    
Fixed Maturities:    
Fair Value 1,138.0 706.2
Fair Value 4,386.0 4,516.8
Fair Value 5,524.0 5,223.0
Fixed Maturities:    
Unrealized Losses (16.8) (9.5)
Unrealized Losses (747.0) (723.6)
Unrealized Losses $ (763.8) $ (733.1)