Financial Instruments and Risk Management (Derivatives Not Designated as Hedging Instruments Fair Values of Derivative Instruments) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Derivatives, Fair Value [Line Items]
Asset Derivatives, Fair Value	$ 62.2	$ 64.7
Liability derivatives, fair value	15.3	19.8
Not designated as hedging instrument
Derivatives, Fair Value [Line Items]
Asset Derivatives, Fair Value	14.0	20.0
Liability derivatives, fair value	15.3	9.3
Not designated as hedging instrument | Prepaid expenses and other current assets | Foreign currency forward contracts
Derivatives, Fair Value [Line Items]
Asset Derivatives, Fair Value	14.0	20.0
Not designated as hedging instrument | Other current liabilities | Foreign currency forward contracts
Derivatives, Fair Value [Line Items]
Liability derivatives, fair value	$ 15.3	$ 9.3