Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Statement of Comprehensive Income [Abstract]
Net income	$ 214.3	$ 202.1
Other comprehensive loss, net of tax:
Unrealized loss on securities, net of tax	(1.7)	(0.7)
Other comprehensive loss	(1.7)	(0.7)
Comprehensive income	$ 212.6	$ 201.4