Derivatives and Fair Value Measurements (Details 2) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Derivatives, Fair Value [Line Items]
Derivative Assets, Current	$ 346.0	$ 313.8
Derivative Assets, Noncurrent	257.8	240.7
Derivative Liabilities, Current	9.9	11.4
Derivative Liabilities, Noncurrent	6.8	19.5
Foreign Exchange Contract [Member] | Cash flow hedges [Member]
Derivatives, Fair Value [Line Items]
Derivative Assets, Current	284.8	270.4
Derivative Assets, Noncurrent	235.6	229.0
Derivative Liabilities, Current	1.7	4.3
Derivative Liabilities, Noncurrent	0.8	4.5
Commodity contracts [Member] | Cash flow hedges [Member]
Derivatives, Fair Value [Line Items]
Derivative Assets, Current	61.2	43.4
Derivative Assets, Noncurrent	22.2	11.7
Derivative Liabilities, Current	8.2	7.1
Derivative Liabilities, Noncurrent	$ 6.0	$ 15.0