Long-Duration Insurance Contracts - Market Risk Benefits Rollforward (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Market Risk Benefit [Roll Forward]
Balance, beginning of period	$ (3.9)	$ 0.3
Balance, beginning of period, before effects of changes in the instrument-specific credit risk	(4.5)	0.0
Changes in market risk benefits	(2.9)	(4.5)
Balance, end of period	(7.4)	(4.5)
Effect of changes in the instrument-specific credit risk	0.6	0.6
Balance, end of period	(6.8)	(3.9)
Net amount at risk	$ 15.9	$ 20.5
Weighted-average attained age of contract holders	62 years	62 years