Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 202.1	$ (83.8)
Other comprehensive loss, net of tax:
Unrealized loss on securities, net of tax	(0.7)	(0.1)
Other comprehensive loss	(0.7)	(0.1)
Comprehensive income (loss)	$ 201.4	$ (83.9)