Earnings Per Share - Computation of Weighted Average Shares Outstanding (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Earnings Per Share [Abstract]
Net income from continuing operations attributable to common stockholders	$ 82.3	$ 8.4
Basic weighted average common shares outstanding (in shares)	247.2	250.3
Denominator adjustments for diluted EPS:
Number of shares issuable upon conversion of Series A Preferred Stock (in shares)	0.0	1.2
Number of stock options and RSUs (in shares)	1.4	0.5
Denominator adjustments for diluted EPS (in shares)	1.4	1.7
Diluted weighted average common shares outstanding (in shares)	248.6	252.0
Earnings per share from continuing operations attributable to common stockholders:
Basic (in dollars per share)	$ 0.33	$ 0.03
Diluted (in dollars per share)	$ 0.33	$ 0.03