Borrowed Funds (Schedule Of Callable Securities Sold Under Agreements To Repurchase) (Details) (USD $)	12 Months Ended
	Dec. 31, 2011
Borrowed Funds [Line Items]
Floating Rate, Rate index, 8% minus 3 month LIBOR	8.00%
No. of agreements	27
Amount	$ 1,400,000,000
Weighted average rate	4.14%
Fixed-To-Floating 150.0 Million With 3 Agreements At 3.75% [Member] | Fixed-To-Floating [Member]
Borrowed Funds [Line Items]
Maximum rate	3.75%
Minimum rate	0.00%
No. of agreements	3
Amount	150,000,000
Weighted average rate	3.75%
Final maturity	2014
Fixed-To-Floating 200.0 [Member] | Fixed-To-Floating [Member]
Borrowed Funds [Line Items]
Maximum rate	3.50%
Minimum rate	0.00%
No. of agreements	4
Amount	200,000,000
Weighted average rate	3.50%
Final maturity	2014
Fixed-To-Floating 150.0 Million With 3 Agreements At 3.5% [Member] | Fixed-To-Floating [Member]
Borrowed Funds [Line Items]
Maximum rate	3.50%
Minimum rate	0.00%
No. of agreements	3
Amount	150,000,000
Weighted average rate	3.50%
Final maturity	2015
Fixed-To-Floating 50.0 With 1 Agreement At 3.25% [Member] | Fixed-To-Floating [Member]
Borrowed Funds [Line Items]
Maximum rate	3.25%
Minimum rate	0.00%
No. of agreements	1
Amount	50,000,000
Weighted average rate	3.25%
Final maturity	2015
Floating-To-Fixed 550.0 [Member] | Floating-To-Fixed [Member]
Borrowed Funds [Line Items]
No. of agreements	10
Amount	550,000,000
Weighted average rate	4.54%
Final maturity	2014
Floating-To-Fixed 200.0 [Member] | Floating-To-Fixed [Member]
Borrowed Funds [Line Items]
No. of agreements	4
Amount	200,000,000
Weighted average rate	5.00%
Final maturity	2017
2014 [Member] | Fixed-To-Floating 50.0 With 1 Agreement At 3.53% [Member] | Fixed-To-Floating [Member]
Borrowed Funds [Line Items]
Maximum rate	3.53%
Minimum rate	0.00%
No. of agreements	1
Amount	50,000,000
Weighted average rate	3.53%
Final maturity	2014
2015 [Member] | Fixed-To-Floating 50.0 With 1 Agreement At 3.53% [Member] | Fixed-To-Floating [Member]
Borrowed Funds [Line Items]
Maximum rate	3.53%
Minimum rate	0.00%
No. of agreements	1
Amount	$ 50,000,000
Weighted average rate	3.53%
Final maturity	2015