v3.26.1
Property and Casualty Insurance Reserves - Reserve Activity (Details) - USD ($)
$ in Millions
6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Incurred Losses and LAE related to:    
Incurred Losses and LAE Related to Prior Years   $ 14.4
Property, Liability and Casualty Insurance Product Line    
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]    
Gross of Reinsurance at Beginning of Year $ 2,910.8 2,611.9
Less: Reinsurance Recoverables at Beginning of Year 25.6 24.3
Property and Casualty Insurance Reserves, Net of Reinsurance at Beginning of Year 2,885.2 2,587.6
Incurred Losses and LAE related to:    
Incurred Losses and LAE Related to Current Year 1,491.4 1,440.4
Incurred Losses and LAE Related to Prior Years 15.9 14.4
Total Incurred Losses and LAE 1,507.3 1,454.8
Paid Losses and LAE related to:    
Paid Losses and LAE Related to Current Year 511.3 535.1
Paid Losses and LAE Related to Prior Years 838.5 866.8
Total Paid Losses and LAE 1,349.8 1,401.9
Property and Casualty Insurance Reserves, Net of Reinsurance at End of Period 3,042.7 2,640.5
Plus: Reinsurance Recoverables at End of Period 22.4 24.2
Property and Casualty Insurance Reserves, Gross of Reinsurance at End of Period $ 3,065.1 $ 2,664.7