Investment Securities (Rollforward Of Total Amount Of Credit-Related OTTI) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Investment [Line Items]
Balance of credit-related OTTI at beginning of period	$ (172,993)	$ (418,160)	$ (185,885)	$ (408,043)
Credit-related OTTI not previously recognized	0	0	0	(403)
Credit-related OTTI previously recognized when there is no intent to sell and no requirement to sell before recovery of amortized cost basis	0	(4,217)	(27)	(13,931)
Subtotal of amounts recognized in earnings	0	(4,217)	(27)	(14,334)
Reductions for securities sold during the period	0	1,848	12,919	1,848
Balance of credit-related OTTI at end of period	(172,993)	(420,529)	(172,993)	(420,529)
Held-to-maturity Securities [Member]
Investment [Line Items]
Balance of credit-related OTTI at beginning of period	(9,079)	(13,952)	(9,052)	(13,549)
Credit-related OTTI not previously recognized	0	0	0	(403)
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	(27)	0
Subtotal of amounts recognized in earnings	0	0	(27)	(403)
Reductions for securities sold during the period	0	0	0	0
Balance of credit-related OTTI at end of period	(9,079)	(13,952)	(9,079)	(13,952)
Available-for-sale Securities [Member]
Investment [Line Items]
Balance of credit-related OTTI at beginning of period	(163,914)	(404,208)	(176,833)	(394,494)
Credit-related OTTI not previously recognized	0	0	0	0
Credit-related OTTI previously recognized when there is no intent to sell and no requirement to sell before recovery of amortized cost basis	0	(4,217)	0	(13,931)
Subtotal of amounts recognized in earnings	0	(4,217)	0	(13,931)
Reductions for securities sold during the period	0	1,848	12,919	1,848
Balance of credit-related OTTI at end of period	$ (163,914)	$ (406,577)	$ (163,914)	$ (406,577)