Consolidated Statements Of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Statement of Comprehensive Income [Abstract]
Net income	$ 958.3	$ 421.0	$ 656.1
Other comprehensive income (Loss), net of tax [Abstract]
Unrealized gain (loss) on securities, net of tax	(1.4)	0.8	1.1
Other comprehensive income (loss)	(1.4)	0.8	1.1
Comprehensive income	$ 956.9	$ 421.8	$ 657.2