Short-Duration Insurance Contracts - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024
Segment Reporting Information [Line Items]
Automobile liability coverage percent reserves	72.00%
Annual percentage payout as a percent of property & casualty incurred losses	95.00%
Potential variability of property and casualty loss reserves	1.00%
Probability of other possible outcomes possible impact on net income	$ 2.9
Sensitivity analysis, hypothetical change in loss ratio, percent	1.00%
Sensitivity analysis, hypothetical change in loss ratio, amount	$ 0.8
Property & Casualty
Segment Reporting Information [Line Items]
Net favorable (unfavorable) development of total reserves for claims occurring in prior years	18.8	$ 11.8
Favorable development of prior years auto reserves	7.0
Favorable loss trends for accidents in prior years	11.8	29.5
Offsetting recognition of loss reserves for legacy commercial lines		17.7
Group benefits
Segment Reporting Information [Line Items]
Net favorable (unfavorable) development of total reserves for claims occurring in prior years	$ 5.0	$ 14.5