CONDENSED CONSOLIDATED STATEMENTS OF EQUITY (Unaudited) Statement - USD ($) shares in Millions, $ in Millions	Total	Common Stock, Value [Member]	Treasury Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Other Comprehensive Income (Loss) [Member]
Stockholders' Equity	$ 2,750.9	$ 2.4	$ (45.6)	$ 1,431.9	$ 1,376.5	$ (14.3)
Common Stock, Shares		239.8
Treasury Stock, Shares			(3.1)
Stockholders' Equity	2,636.1	$ 2.4	$ (51.8)	1,440.2	1,259.8	(14.5)
Net income (loss)	(116.7)				(116.7)
Share-based compensation, Shares		2.2
Share-based compensation	2.1	$ 0.0	$ 6.2	8.3	0.0	0.0
Shares Paid for Tax Withholding for Share Based Compensation			(0.8)
Change in pension and postretirement liability, net of tax	(0.2)					(0.2)
Stockholders' Equity at Mar. 31, 2019	2,636.1	2.4	$ (51.8)	1,440.2	1,259.8	(14.5)
Stockholders' Equity	2,636.1	$ 2.4	$ (51.8)	1,440.2	1,259.8	(14.5)
Common Stock, Shares		242.0
Treasury Stock, Shares			(3.9)
Stockholders' Equity	$ 2,660.6	$ 2.4	$ (55.4)	1,456.5	1,269.6	(12.5)
Common Stock, Shares		242.1
Treasury Stock, Shares	(4.4)		(4.4)
Stockholders' Equity	$ 3,026.0	$ 2.5	$ (56.2)	1,459.9	1,632.2	(12.4)
Net income (loss)	367.4				367.4
Cash dividends paid, $0.02 per share	(4.8)				(4.8)
Share-based compensation, Shares		4.9
Share-based compensation	2.7	$ 0.1	$ (0.8)	3.4	0.0	0.0
Shares Paid for Tax Withholding for Share Based Compensation			(0.4)
Change in pension and postretirement liability, net of tax	0.1					0.1
Stockholders' Equity at Mar. 31, 2020	3,026.0	2.5	$ (56.2)	1,459.9	1,632.2	(12.4)
Stockholders' Equity	$ 3,026.0	$ 2.5	$ (56.2)	$ 1,459.9	$ 1,632.2	$ (12.4)
Common Stock, Shares		247.0
Treasury Stock, Shares	(4.8)		(4.8)