Financial Instruments - Balance Sheet (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Foreign currency contracts [Member] | Prepayments and other current assets [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	$ 2.6	$ 2.7
Foreign currency contracts [Member] | Other non-current assets [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	0.1	0
Foreign currency contracts [Member] | Accounts payable and accrued expenses [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities	2.4	3.3
Foreign currency contracts [Member] | Other non-current liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities	0.5	3.1
Net investment hedge contracts [Member] | Other non-current assets [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	0	0
Net investment hedge contracts [Member] | Other non-current liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities	$ 85.0	$ 75.7