v3.26.1
Business Segments - Segment Expenses (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Segment Reporting [Line Items]        
Incurred Losses and LAE Related to Prior Years       $ 14.4
Income Tax Expense $ (1.0) $ 17.7 $ (4.5) 40.5
Operating Segments        
Segment Reporting [Line Items]        
Operating Expenses 1,069.9 1,117.0 2,144.8 2,164.7
Operating Segments | Specialty Property & Casualty Insurance        
Segment Reporting [Line Items]        
Total Incurred Losses and LAE 748.0 749.4 1,495.7 1,436.2
Policy Acquisition Costs 122.5 140.1 245.4 272.4
Business Unit Operating Costs 29.1 40.7 67.1 78.4
Corporate Overhead Costs 32.7 34.0 68.0 69.1
Total Insurance Expenses 184.3 214.8 380.5 419.9
Income Tax Expense 3.5 19.9 2.7 44.1
Operating Expenses 935.8 984.1 1,878.9 1,900.2
Operating Segments | Specialty Property & Casualty Insurance | Non-catastrophe Losses        
Segment Reporting [Line Items]        
Incurred Losses and LAE Related to Current Year 732.7 730.1 1,475.5 1,412.4
Incurred Losses and LAE Related to Prior Years 9.1 13.6 12.3 14.1
Operating Segments | Specialty Property & Casualty Insurance | Catastrophe Losses        
Segment Reporting [Line Items]        
Incurred Losses and LAE Related to Current Year 6.1 5.3 7.4 9.1
Incurred Losses and LAE Related to Prior Years 0.1 0.4 0.5 0.6
Operating Segments | Life Insurance        
Segment Reporting [Line Items]        
Policy Acquisition Costs 34.0 35.2 63.3 64.9
Business Unit Operating Costs 24.9 24.0 51.2 51.5
Corporate Overhead Costs 8.4 8.5 17.4 17.7
Total Insurance Expenses 67.3 67.7 131.9 134.1
Income Tax Expense 3.3 1.7 6.5 4.7
Policyholders’ Benefits and Incurred Losses and LAE 63.5 63.5 127.5 125.7
Operating Expenses $ 134.1 $ 132.9 $ 265.9 $ 264.5