Financial Instruments - Balance Sheet (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Foreign currency contracts [Member] | Prepayments and other current assets
Derivatives, Fair Value [Line Items]
Derivative assets	$ 5.7	$ 2.6
Foreign currency contracts [Member] | Other non-current assets
Derivatives, Fair Value [Line Items]
Derivative assets	0.2	0.1
Foreign currency contracts [Member] | Accounts payable and accrued expenses
Derivatives, Fair Value [Line Items]
Derivative liabilities	9.8	2.4
Foreign currency contracts [Member] | Other non-current liabilities
Derivatives, Fair Value [Line Items]
Derivative liabilities	0	0.5
Net investment hedge contracts [Member] | Other non-current assets
Derivatives, Fair Value [Line Items]
Derivative assets	0	0
Net investment hedge contracts [Member] | Other non-current liabilities
Derivatives, Fair Value [Line Items]
Derivative liabilities	$ 58.1	$ 85.0