Long-Duration Insurance Contracts - Deferred Policy Acquisition Costs, Reconciliation to Balance Sheet (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Deferred Policy Acquisition Cost [Line Items]
Deferred policy acquisition costs	$ 358.2	$ 347.2
Whole Life
Deferred Policy Acquisition Cost [Line Items]
Deferred policy acquisition costs	24.9	23.8	$ 22.3	$ 20.9
Term Life
Deferred Policy Acquisition Cost [Line Items]
Deferred policy acquisition costs	35.5	34.2	32.6	30.0
Experience life
Deferred Policy Acquisition Cost [Line Items]
Deferred policy acquisition costs	5.2	5.5	5.7	5.8
Limited-Pay Whole Life
Deferred Policy Acquisition Cost [Line Items]
Deferred policy acquisition costs	8.3	8.0	7.4	6.7
Indexed Universal Life
Deferred Policy Acquisition Cost [Line Items]
Deferred policy acquisition costs	22.8	19.2	16.8	15.4
Supplemental health
Deferred Policy Acquisition Cost [Line Items]
Deferred policy acquisition costs	13.7	10.6	8.2	6.2
Total Annuities
Deferred Policy Acquisition Cost [Line Items]
Deferred policy acquisition costs	207.7	211.4	$ 214.0	$ 221.1
Reconciling items
Deferred Policy Acquisition Cost [Line Items]
Deferred policy acquisition costs	$ 40.1	$ 34.5