Derivative Financial Instruments (Weighted Average Rates Paid And Received For Interest Rate Swaps) (Details)	Dec. 31, 2011
Cash Flow Hedge Interest Rate Swaps [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Weighted-Average Interest Rate Received, Interest rate swaps	0.46%
Weighted-Average Interest Rate Paid, Interest rate swaps	1.85%
Non-Hedging Interest Rate Swaps [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Weighted-Average Interest Rate Received, Interest rate swaps	1.74%
Weighted-Average Interest Rate Paid, Interest rate swaps	1.65%