Fair Value Disclosure (Financial Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Details) (Fair Value, Measurements, Recurring [Member], USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	$ 0	$ 0
Equity securities	15.2	16.0
Total Assets	15.2	16.0
Derivative liabilities	0	0
Total liabilities	0	0
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	10.7	36.5
Equity securities	0	0
Total Assets	10.7	36.5
Derivative liabilities	36.2	16.2
Total liabilities	36.2	16.2
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Equity securities	0	0
Total Assets	0	0
Derivative liabilities	0	0
Total liabilities	0	0
Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	10.7	36.5
Equity securities	15.2	16.0
Total Assets	25.9	52.5
Derivative liabilities	36.2	16.2
Total liabilities	$ 36.2	$ 16.2