Financial Instruments and Risk Management (Derivatives Not Designated as Hedging Instruments Fair Values of Derivative Instruments) (Details) - Not designated as hedging instrument - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Derivatives, Fair Value [Line Items]
Asset Derivatives, Fair Value	$ 20.0	$ 1,859.0
Liability derivatives, fair value	9.3	1,855.8
Prepaid expenses and other current assets | Foreign currency forward contracts
Derivatives, Fair Value [Line Items]
Asset Derivatives, Fair Value	20.0	5.5
Prepaid expenses and other current assets | Purchased cash convertible note hedge
Derivatives, Fair Value [Line Items]
Asset Derivatives, Fair Value	0.0	1,853.5
Other current liabilities | Foreign currency forward contracts
Derivatives, Fair Value [Line Items]
Liability derivatives, fair value	9.3	2.3
Current portion of long-term debt | Cash conversion feature of Cash Convertible Notes
Derivatives, Fair Value [Line Items]
Liability derivatives, fair value	$ 0.0	$ 1,853.5