Investment Securities (Rollforward Of Total Amount Of Credit-Related OTTI) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Investment [Line Items]
Balance of credit-related OTTI at beginning of period	$ (104,551)	$ (185,885)
Credit-related OTTI previously recognized when there is no intent to sell and no requirement to sell before recovery of amortized cost basis	0	(27)
Reductions for securities sold during the period	1,313	12,919
Balance of credit-related OTTI at end of period	(103,238)	(172,993)
Transfer of Securities from HTM to AFS	0	0
Held-to-maturity Securities [Member]
Investment [Line Items]
Balance of credit-related OTTI at beginning of period	(9,079)	(9,052)
Credit-related OTTI previously recognized when there is no intent to sell and no requirement to sell before recovery of amortized cost basis	0	(27)
Reductions for securities sold during the period	0	0
Balance of credit-related OTTI at end of period	0	(9,079)
Transfer of Securities from HTM to AFS	9,079	0
Available-for-sale Securities [Member]
Investment [Line Items]
Balance of credit-related OTTI at beginning of period	(95,472)	(176,833)
Credit-related OTTI previously recognized when there is no intent to sell and no requirement to sell before recovery of amortized cost basis	0	0
Reductions for securities sold during the period	1,313	12,919
Balance of credit-related OTTI at end of period	(103,238)	(163,914)
Transfer of Securities from HTM to AFS	$ (9,079)	$ 0