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, 2020	Mar. 31, 2019
Calculation of basic EPS:
Net income (loss) applicable to common stock	$ (608.6)	$ 41.0
Weighted average common shares outstanding (in shares)	115.7	116.3
Basic earnings (loss) (in dollars per share)	$ (5.26)	$ 0.35
Calculation of diluted EPS using two class method:
Net income (loss) applicable to common stock	$ (608.6)	$ 41.0
Diluted weighted average common shares outstanding (in shares)	115.7	118.6
Diluted earnings (loss) (in dollars per share)	$ (5.26)	$ 0.35