Fair Value Measurements Fair Value Measurements, Liabilities (Details) (USD $) In Millions	Sep. 30, 2011	Dec. 31, 2010
Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items]
Fair Value, Liabilities Measured on Recurring Basis, Derivative Financial Instruments, Liabilities	$ 10.2	$ 11.6
Fair Value Liabilities Measured On Recurring Basis Total Liabilities	10.2	11.6
Fair Value, Inputs, Level 1 [Member]
Fair Value, Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items]
Fair Value, Liabilities Measured on Recurring Basis, Derivative Financial Instruments, Liabilities	9.6	6.1
Fair Value Liabilities Measured On Recurring Basis Total Liabilities	9.6	6.1
Fair Value, Inputs, Level 2 [Member]
Fair Value, Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items]
Fair Value, Liabilities Measured on Recurring Basis, Derivative Financial Instruments, Liabilities	0.6	5.5
Fair Value Liabilities Measured On Recurring Basis Total Liabilities	0.6	5.5
Fair Value, Inputs, Level 3 [Member]
Fair Value, Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items]
Fair Value, Liabilities Measured on Recurring Basis, Derivative Financial Instruments, Liabilities	0	0
Fair Value Liabilities Measured On Recurring Basis Total Liabilities	$ 0	$ 0