Earnings (Loss) per Share - Calculation of Basic and Diluted EPS (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Calculation of basic earnings (loss) per share:
Net income (loss) applicable to common stock	$ 90.5	$ (608.6)
Weighted average common shares outstanding - basic (in shares)	155.7	115.7
Basic earnings (loss) per share (in dollars per share)	$ 0.58	$ (5.26)
Calculation of diluted earnings (loss) per share:
Net income (loss) applicable to common stock	$ 90.5	$ (608.6)
Convertible Notes	4.3	0.0
Diluted income (loss) applicable to common stock	$ 94.8	$ (608.6)
Weighted average common shares outstanding - diluted (in shares)	172.8	115.7
Diluted earnings (loss) per share (in dollars per share)	$ 0.55	$ (5.26)
Effective tax rate	18.50%	14.10%
Convertible Notes
Calculation of diluted earnings (loss) per share:
Effective tax rate	20.00%