Deferred Acquisition Costs and Other Actuarial Balances - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Long-duration and short-duration insurance
Deferred Acquisition Costs
Amortization of deferred acquisition costs	$ 103.1	$ 103.4	$ 303.6	$ 300.6

Amount of amortization expense (reversal of expense) for deferred policy acquisition costs.

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+ Details