Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period		$ 19.1	$ 20.7	$ 23.0
Charged to costs and expenses		2.3	(1.3)	(0.2)
Deductions	[1]	0.0	(0.3)	(2.1)
Balance at end of period		21.4	19.1	20.7
Deferred Tax Asset Valuation Allowance [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period		18.7	20.1	22.1
Charged to costs and expenses		2.5	(1.3)	(0.3)
Deductions	[1]	(0.3)	(0.1)	(1.7)
Balance at end of period		20.9	18.7	20.1
Allowance for Doubtful Accounts Receivable [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period		0.4	0.6	0.9
Charged to costs and expenses		(0.2)	0.0	0.1
Deductions	[1]	0.3	(0.2)	(0.4)
Balance at end of period		$ 0.5	$ 0.4	$ 0.6

[1] Includes accounts receivable written off, the write-off or write-down of valuation allowances, and translation adjustments.