Financial Instruments Schedule of Fair Values of Derivative Instruments (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Derivative Asset, Fair Value, Gross Asset	$ 9.3	$ 21.5
Derivative Liability, Fair Value, Gross Liability	22.2	2.6
Designated Hedges [Member]
Derivative Asset, Fair Value, Gross Asset	3.1	1.9
Derivative Liability, Fair Value, Gross Liability	0.3	1.7
Undesignated Hedges [Member]
Derivative Asset, Fair Value, Gross Asset	6.2	19.6
Derivative Liability, Fair Value, Gross Liability	21.9	0.9
Fair Value, Inputs, Level 2 [Member]
Derivative Asset, Fair Value, Gross Asset	9.3	21.5
Derivative Liability, Fair Value, Gross Liability	$ 22.2	$ 2.6