Long-Duration Insurance Contracts - Separate Account Liability Rollforward (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024
Separate Account, Liability [Roll Forward]
Balance, beginning of year	$ 3,708.8
Balance, end of period	4,157.4	$ 3,708.8
Variable Account Annuities
Separate Account, Liability [Roll Forward]
Balance, beginning of year	3,708.8	3,294.1
Deposits	293.8	266.2
Withdrawals	(316.4)	(290.3)
Net transfers	(27.5)	(21.1)
Fees and charges	(57.2)	(53.3)
Market appreciation (depreciation)	555.9	513.2
Other	0.0	0.0
Balance, end of period	$ 4,157.4	$ 3,708.8