Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Millions	Total	Series A Convertible Preferred Stock	Common Stock	Additional Paid-in Capital	Treasury Stock	(Accumulated Deficit) Retained Earnings	Accumulated Other Comprehensive (Loss) Income	Noncontrolling Interests
Beginning Balance at Dec. 31, 2016	$ 181.5	$ 0.0	$ 0.2	$ 2,422.0	$ (371.8)	$ (1,399.5)	$ (477.0)	$ 7.6
Net income (loss) attributable to common stockholders	(216.5)					(216.5)
Net income attributable to noncontrolling interests	4.8							4.8
Net (loss) income	(211.7)
Net unrealized gains on cash flow hedges	18.6						18.6
Postretirement plans and workers' compensation obligations	4.4						4.4
Foreign currency translation adjustment	5.5						5.5
Share-based compensation for equity-classified awards	1.9			1.9
Repurchase of employee common stock relinquished for tax withholding	(0.1)				(0.1)
Distributions to noncontrolling interests	(0.1)							(0.1)
Elimination of Predecessor equity	0.0		(0.2)	(2,423.9)	371.9	1,616.0	448.5	(12.3)
Ending Balance at Apr. 01, 2017	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
Issuance of Successor equity	3,131.9	1,305.4	0.7	1,774.9	0.0	0.0	0.0	50.9
Ending Balance at Apr. 02, 2017	3,131.9	1,305.4	0.7	1,774.9	0.0	0.0	0.0	50.9
Beginning Balance at Apr. 01, 2017	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
Net income (loss) attributable to common stockholders	498.6					678.1
Net income attributable to noncontrolling interests	15.2							15.2
Net (loss) income	693.3
Foreign currency translation adjustment	1.4						1.4
Warrant conversions	0.0		0.1	(0.1)
Series A Convertible Preferred Stock conversions	0.0	(748.2)	0.2	796.7		(48.7)
Series A Convertible Preferred Stock dividends	0.0	18.8		(3.0)		(15.8)
Share-based compensation for equity-classified awards	21.8			21.8
Common stock repurchases	(175.7)				(175.7)
Repurchase of employee common stock relinquished for tax withholding	(0.2)				(0.2)
Distributions to noncontrolling interests	(16.7)							(16.7)
Ending Balance at Dec. 31, 2017	3,655.8	576.0	1.0	2,590.3	(175.9)	613.6	1.4	49.4
Impact of adoption of Accounting Standards Update 2014-09	(22.5)					(22.5)
Net income (loss) attributable to common stockholders	544.4					646.9
Net income attributable to noncontrolling interests	16.9							16.9
Net (loss) income	663.8
Dividends declared ($0.485 per share)	(59.6)			(1.4)		61.0
Postretirement plans and workers' compensation obligations	44.6						44.6
Foreign currency translation adjustment	(5.9)						(5.9)
Series A Convertible Preferred Stock conversions	0.0	(576.0)	0.4	678.1		(102.5)
Share-based compensation for equity-classified awards	34.9			34.9
Common stock repurchases	(834.7)				(834.7)
Repurchase of employee common stock relinquished for tax withholding	(14.5)				(14.5)
Distributions to noncontrolling interests	(10.3)							(10.3)
Ending Balance at Dec. 31, 2018	3,451.6	0.0	1.4	3,304.7	(1,025.1)	1,074.5	40.1	56.0
Net income (loss) attributable to common stockholders	(211.3)					(211.3)
Net income attributable to noncontrolling interests	26.2							26.2
Net (loss) income	(185.1)
Dividends declared ($0.485 per share)	(258.1)			(8.1)		(266.2)
Postretirement plans and workers' compensation obligations	(8.7)						(8.7)
Foreign currency translation adjustment	0.2						0.2
Share-based compensation for equity-classified awards	38.3			38.3
Common stock repurchases	(329.9)				(329.9)
Repurchase of employee common stock relinquished for tax withholding	(12.3)				(12.3)
Distributions to noncontrolling interests	(23.5)							(23.5)
Ending Balance at Dec. 31, 2019	$ 2,672.5	$ 0.0	$ 1.4	$ 3,351.1	$ (1,367.3)	$ 597.0	$ 31.6	$ 58.7