Financial Instruments - Balance Sheet (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Foreign currency contracts | Prepayments and other current assets
Derivatives, Fair Value [Line Items]
Derivative assets	$ 2.2	$ 3.4
Foreign currency contracts | Accounts payable and accrued expenses
Derivatives, Fair Value [Line Items]
Derivative liabilities	4.7	7.4
Net investment hedge contracts | Other non-current assets
Derivatives, Fair Value [Line Items]
Derivative assets	0	0
Net investment hedge contracts | Other non-current liabilities
Derivatives, Fair Value [Line Items]
Derivative liabilities	$ 23.7	$ 24.3