Derivative Instruments (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Aggregate notional amount	$ 1,302.3	$ 742.6
Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Aggregate notional amount	365.2	273.3
Foreign Exchange Contract | Other current assets | Designated as Hedging Instrument
Summary of derivatives designated as hedging instruments
Asset derivatives	69.5	0.6
Foreign Exchange Contract | Other current assets | Not Designated as Hedging Instrument [Member]
Summary of derivatives designated as hedging instruments
Asset derivatives	1.3	3.2
Foreign Exchange Contract | Investments and other assets | Designated as Hedging Instrument
Summary of derivatives designated as hedging instruments
Asset derivatives	1.9
Foreign Exchange Contract | Accrued expenses and other | Designated as Hedging Instrument
Summary of derivatives designated as hedging instruments
Liability derivatives	0	23.4
Foreign Exchange Contract | Accrued expenses and other | Not Designated as Hedging Instrument [Member]
Summary of derivatives designated as hedging instruments
Liability derivatives	5.4	0.1
Foreign Exchange Contract | Other long-term liabilities | Designated as Hedging Instrument
Summary of derivatives designated as hedging instruments
Liability derivatives	0
Euro | Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Aggregate notional amount	1,174.6	636.3
Canadian dollar | Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Aggregate notional amount	56.7	34.0
British pound sterling | Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Aggregate notional amount	34.5	72.3
Australian dollar | Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Aggregate notional amount	19.9	0
Japanese yen | Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Aggregate notional amount	$ 16.6	$ 0