Financial Instruments, Risk Management and Fair Value Measurements - Derivatives Fair Value Balance Sheet Presentation (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Gross amounts offset in the consolidated balance sheet	$ 0.0	$ 0.0
Gross amount of derivatives, net derivative assets/(liabilities)	6.1	4.4
Net derivative assets (liabilities)	6.1	4.4
Prepaid and Other Current Assets
Derivatives, Fair Value [Line Items]
Gross amount of derivatives, assets	10.7	8.2
Gross amounts offset in the consolidated balance sheet	(2.9)	(1.5)
Net amounts, assets	7.8	6.7
Accured and Other Liabilities
Derivatives, Fair Value [Line Items]
Gross amounts offset in the consolidated balance sheet	2.9	1.5
Gross amount of derivatives, liabilities	(4.6)	(3.8)
Net amounts, liabilities	(1.7)	(2.3)
Foreign exchange contracts | Prepaid and Other Current Assets
Derivatives, Fair Value [Line Items]
Gross amount of derivatives, assets	10.7	8.2
Gross amounts offset in the consolidated balance sheet	(2.9)	(1.5)
Net amounts, assets	7.8	6.7
Foreign exchange contracts | Accured and Other Liabilities
Derivatives, Fair Value [Line Items]
Gross amounts offset in the consolidated balance sheet	2.9	1.5
Gross amount of derivatives, liabilities	(4.6)	(3.8)
Net amounts, liabilities	(1.7)	(2.3)
Designated as Cash Flow Hedges | Cash Flow Hedging
Derivatives, Fair Value [Line Items]
Gross amount of derivatives, net derivative assets/(liabilities)	4.4	3.4
Designated as Cash Flow Hedges | Cash Flow Hedging | Prepaid and Other Current Assets
Derivatives, Fair Value [Line Items]
Gross amount of derivatives, assets	9.0	7.0
Designated as Cash Flow Hedges | Cash Flow Hedging | Accured and Other Liabilities
Derivatives, Fair Value [Line Items]
Gross amount of derivatives, liabilities	(4.6)	(3.6)
Designated as Cash Flow Hedges | Cash Flow Hedging | Foreign exchange contracts | Prepaid and Other Current Assets
Derivatives, Fair Value [Line Items]
Gross amount of derivatives, assets	9.0	7.0
Designated as Cash Flow Hedges | Cash Flow Hedging | Foreign exchange contracts | Accured and Other Liabilities
Derivatives, Fair Value [Line Items]
Gross amount of derivatives, liabilities	(4.6)	(3.6)
Not Designated as Hedging Instruments
Derivatives, Fair Value [Line Items]
Gross amount of derivatives, net derivative assets/(liabilities)	1.7	1.0
Not Designated as Hedging Instruments | Prepaid and Other Current Assets
Derivatives, Fair Value [Line Items]
Gross amount of derivatives, assets	1.7	1.2
Not Designated as Hedging Instruments | Accured and Other Liabilities
Derivatives, Fair Value [Line Items]
Gross amount of derivatives, liabilities	0.0	(0.2)
Not Designated as Hedging Instruments | Foreign exchange contracts | Prepaid and Other Current Assets
Derivatives, Fair Value [Line Items]
Gross amount of derivatives, assets	1.7	1.2
Not Designated as Hedging Instruments | Foreign exchange contracts | Accured and Other Liabilities
Derivatives, Fair Value [Line Items]
Gross amount of derivatives, liabilities	$ 0.0	$ (0.2)