Short- Duration Insurance Contracts - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2026	Mar. 31, 2025
Property & Casualty
Segment Reporting Information [Line Items]
Favorable (unfavorable) development of total reserves for claims occurring in prior years	$ 5.0	$ 5.3
Group Benefits
Segment Reporting Information [Line Items]
Favorable (unfavorable) development of total reserves for claims occurring in prior years	$ 2.7	$ (0.4)

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