Short- Duration Insurance Contracts - Narrative (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Property & Casualty
Segment Reporting [Line Items]
Favorable (unfavorable) development of total reserves for claims occurring in prior years	$ 8.0	$ 3.0	$ 19.6	$ 13.8
Group Benefits
Segment Reporting [Line Items]
Favorable (unfavorable) development of total reserves for claims occurring in prior years	$ (1.0)	$ 2.6	$ 3.3	$ 5.2

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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+ Details