Condensed Consolidated Financial Statements, Impacts of Adopting ASC 606 (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Condensed Consolidated Statements of Operations [Abstract]
Revenues		$ 689.3	$ 649.6	$ 1,977.1	$ 1,710.4
Cost of sales		426.9	395.7	1,233.6	1,066.0
Provision (benefit) for income taxes		22.6	4.4	63.2	(41.2)
Net income (loss)		72.2	$ 28.0	174.9	$ (125.1)
Assets [Abstract]
Inventories		550.1		550.1		$ 494.5
Other current assets		63.4		63.4		39.5
Liabilities and Stockholders' Equity [Abstract]
Accrued liabilities		258.9		258.9		271.2
Accumulated deficit		(403.2)		(403.2)		$ (577.8)
Adjustments [Member] | ASC 606 [Member]
Condensed Consolidated Statements of Operations [Abstract]
Revenues		(8.7)		(18.1)
Cost of sales		(5.4)		(11.2)
Provision (benefit) for income taxes		(0.8)		(1.8)
Net income (loss)		(2.5)		(5.1)
Assets [Abstract]
Inventories		11.2		11.2
Other current assets	[1]	(11.2)		(11.2)
Liabilities and Stockholders' Equity [Abstract]
Accrued liabilities		5.1		5.1
Accumulated deficit		(5.1)		(5.1)
Balance Without Adoption of ASC 606 [Member] | ASC 606 [Member]
Condensed Consolidated Statements of Operations [Abstract]
Revenues		680.6		1,959.0
Cost of sales		421.5		1,222.4
Provision (benefit) for income taxes		21.8		61.4
Net income (loss)		69.7		169.8
Assets [Abstract]
Inventories		561.3		561.3
Other current assets		52.2		52.2
Liabilities and Stockholders' Equity [Abstract]
Accrued liabilities		264.0		264.0
Accumulated deficit		$ (408.3)		$ (408.3)

[1] Adjustment represents "Contract asset." See Note 12 "Revenue from Contracts with Customers" for an explanation of the Contract assets account included in "Other current assets" in the Condensed Consolidated Balance Sheets.