Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Statement of Comprehensive Income [Abstract]
Net income	$ 46.7	$ 46.0
Other comprehensive income (loss), net of tax:
Unrealized (losses) gains on debt securities	(50.6)	110.1
Foreign currency translation adjustment	(14.5)	2.6
Pension benefit adjustment	0.4	0.3
Total other comprehensive income, net of tax	(64.7)	113.0
Comprehensive (loss) income	(18.0)	159.0
Less: Comprehensive income attributable to noncontrolling interests	0.0	0.1
Comprehensive (loss) income attributable to the Company	$ (18.0)	$ 158.9