Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Statement of Comprehensive Income [Abstract]
Net income	$ 147.1	$ 116.4	$ 221.9	$ 163.1
Other comprehensive income (loss), net of tax:
Change in unrealized gains (losses) on debt securities	19.0	(5.8)	111.3	(56.4)
Change in foreign currency translation adjustment	34.9	(3.8)	38.8	(18.3)
Change in pension benefit adjustment	0.3	0.4	0.7	0.8
Total other comprehensive income (loss), net of tax	54.2	(9.2)	150.8	(73.9)
Comprehensive income	201.3	107.2	372.7	89.2
Less: Comprehensive income attributable to noncontrolling interests	1.0	0.4	1.6	0.4
Comprehensive income attributable to the Company	$ 200.3	$ 106.8	$ 371.1	$ 88.8