v3.25.4
Investments - Aging of Unrealized Losses on Investments in Fixed Maturities (Details) - USD ($)
$ in Millions
Dec. 31, 2025
Dec. 31, 2024
United States Government and Government Agencies and Authorities    
Fair Value    
Less Than 12 Months $ 3.1 $ 41.7
12 Months or Longer 380.3 383.6
Total 383.4 425.3
Unrealized Losses    
Less Than 12 Months 0.0 (0.5)
12 Months or Longer (82.8) (101.9)
Total (82.8) (102.4)
States and Political Subdivisions    
Fair Value    
Less Than 12 Months 86.2 242.7
12 Months or Longer 1,063.3 933.4
Total 1,149.5 1,176.1
Unrealized Losses    
Less Than 12 Months (2.4) (10.3)
12 Months or Longer (183.3) (215.1)
Total (185.7) (225.4)
Foreign Governments    
Fair Value    
Less Than 12 Months 1.0 0.0
12 Months or Longer 0.5 1.4
Total 1.5 1.4
Unrealized Losses    
Less Than 12 Months 0.0 0.0
12 Months or Longer (0.1) (0.2)
Total (0.1) (0.2)
Bonds and Notes    
Fair Value    
Less Than 12 Months 353.0 674.3
12 Months or Longer 2,759.5 2,605.7
Total 3,112.5 3,280.0
Unrealized Losses    
Less Than 12 Months (5.4) (40.9)
12 Months or Longer (428.1) (477.9)
Total (433.5) (518.8)
Redeemable Preferred Stocks    
Fair Value    
Less Than 12 Months 0.0 2.0
12 Months or Longer 2.0 6.6
Total 2.0 8.6
Unrealized Losses    
Less Than 12 Months 0.0 0.0
12 Months or Longer 0.0 (1.0)
Total 0.0 (1.0)
Collateralized Loan Obligations    
Fair Value    
Less Than 12 Months 238.2 34.2
12 Months or Longer 61.7 89.5
Total 299.9 123.7
Unrealized Losses    
Less Than 12 Months (1.2) (0.1)
12 Months or Longer (6.6) (7.1)
Total (7.8) (7.2)
Other Mortgage- and Asset-backed    
Fair Value    
Less Than 12 Months 24.7 12.0
12 Months or Longer 249.5 261.7
Total 274.2 273.7
Unrealized Losses    
Less Than 12 Months (0.5) (0.1)
12 Months or Longer (22.7) (34.4)
Total (23.2) (34.5)
Investments in Fixed Maturities    
Fair Value    
Less Than 12 Months 706.2 1,006.9
12 Months or Longer 4,516.8 4,281.9
Total 5,223.0 5,288.8
Unrealized Losses    
Less Than 12 Months (9.5) (51.9)
12 Months or Longer (723.6) (837.6)
Total $ (733.1) $ (889.5)