Investment Securities (Rollforward Of Total Amount Of Credit-Related OTTI) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Investment [Line Items]
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Additions, Additional Credit Losses		$ 0		$ (27)
Balance of credit-related OTTI at beginning of period	$ 0	(172,993)	$ 104,551	185,885
Reductions for securities sold during the period	0	44,929	104,551	57,848
Balance of credit-related OTTI at end of period	0	(128,064)	0	(128,064)
Transfer of Securities from HTM to AFS	0		0
Held-to-maturity Securities [Member]
Investment [Line Items]
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Additions, Additional Credit Losses		0		(27)
Balance of credit-related OTTI at beginning of period	0	(9,079)	9,079	9,052
Reductions for securities sold during the period	0	0	0	0
Balance of credit-related OTTI at end of period	0	(9,079)	0	(9,079)
Transfer of Securities from HTM to AFS	0		9,079
Available-for-sale Securities [Member]
Investment [Line Items]
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Additions, Additional Credit Losses		0		0
Balance of credit-related OTTI at beginning of period	0	(163,914)	95,472	176,833
Reductions for securities sold during the period	0	44,929	104,551	57,848
Balance of credit-related OTTI at end of period	0	$ (118,985)	0	$ (118,985)
Transfer of Securities from HTM to AFS	$ 0		$ (9,079)