v3.25.4
Business Segments - Segment Revenues (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Segment Reporting Information [Line Items]      
Earned Premiums [1] $ 4,396.3 $ 4,215.9 $ 4,529.4
Net Investment Income 405.0 407.5 419.7
Other (Loss) Income (2.0) 10.5 10.1
Total Revenues 4,789.7 4,638.6 4,944.2
Change in Fair Value of Equity and Convertible Securities (4.3) (2.7) 4.7
Life Insurance      
Segment Reporting Information [Line Items]      
Earned Premiums (8.7) (7.2) (19.1)
Operating Segments      
Segment Reporting Information [Line Items]      
Earned Premiums 4,319.1 3,970.3 4,020.1
Total Revenues 4,729.0 4,337.7 4,388.4
Operating Segments | Specialty Property & Casualty Insurance      
Segment Reporting Information [Line Items]      
Earned Premiums 3,925.7 3,576.4 3,632.5
Net Investment Income 211.2 189.6 168.3
Other (Loss) Income 8.9 6.1 6.1
Total Revenues 4,145.8 3,772.1 3,806.9
Operating Segments | Life Insurance      
Segment Reporting Information [Line Items]      
Earned Premiums 393.4 393.9 387.6
Net Investment Income 188.2 170.6 193.4
Other (Loss) Income 1.6 1.1 0.5
Total Revenues 583.2 565.6 581.5
Non-Core Operations      
Segment Reporting Information [Line Items]      
Earned Premiums 77.2 245.6 509.3
Total Revenues 84.9 282.4 558.4
Net Realized Investment Gains (Losses), Impairment Losses, and Other (19.9) 21.2 (7.3)
Change in Fair Value of Equity and Convertible Securities $ (4.3) $ (2.7) $ 4.7
[1]
1 Includes a remeasurement loss related to the deferred profit liability within the Life Insurance business of $8.7 million for the year ended December 31, 2025, a remeasurement loss of $7.2 million for the year ended December 31, 2024, and a remeasurement loss of $19.1 million for the year ended December 31, 2023.