Other Comprehensive (Loss) Income (Schedule Of Comprehensive Income) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Other Comprehensive (Loss) Income [Abstract]
Net gains arising during the period, Before Tax	$ 2,438	$ 20,376	$ 70,869
Net gains arising during the period, Tax Effect	(925)	(7,739)	(23,518)
Net gains arising during the period, After Tax	1,513	12,637	47,351
Less reclassification adjustment for losses included in net income, Before Tax	3,067	1,967	460
Less reclassification adjustment for losses included in net income, Tax Effect	(1,287)	(825)	(193)
Less reclassification adjustment for gains included in net income	(19,674)	(7,330)	(5,003)
Net change, Unrealized gains and losses on securities available for sale, Before Tax	(29,630)	8,778	62,864
Net change, Unrealized gains and losses on securities available for sale, Tax Effect	11,469	(3,471)	(20,516)
Net change, Unrealized gains and losses on securities available for sale, After Tax	(18,161)	5,307	42,348
Net change in non-credit impairment losses on securities, Before Tax	(42,531)	5,301	(4,111)
Net change in non-credit impairment losses on securities, Tax Effect	15,875	(1,973)	1,337
Net change in non-credit impairment losses on securities, After Tax	(26,656)	3,328	(2,774)
Less reclassification adjustment for credit impairment losses included in net income, Before Tax	18,570	4,381	1,530
Less reclassification adjustment for credit impairment losses included in net income, Tax Effect	(6,937)	(1,640)	2,237
Less reclassification adjustment for credit impairment losses included in net income, After Tax	11,633	2,741	3,767
Net change, Non-credit impairment losses on securities, Before Tax	(23,961)	9,682	(2,581)
Net change, Non-credit impairment losses on securities, Tax Effect	8,938	(3,613)	3,574
Total	(15,023)	6,069	993
Net (losses) gains on hedge transactions arising during the period, Before Tax	(24,393)	1,493	3,475
Net (losses) gains on hedge transactions arising during the period, Tax Effect	10,236	(627)	(1,458)
Net (losses) gains on hedge transactions arising during the period, After Tax	(14,157)	866	2,017
Less reclassification adjustment for gains included in net income, Before Tax	(32,068)	(11,598)	(8,005)
Less reclassification adjustment for gains included in net income, Tax Effect	12,394	4,268	3,002
Less reclassification adjustment for gains included in net income, After Tax	1,780	1,142	267
Net change, Unrealized gains and losses on derivatives, Before Tax	(21,326)	3,460	3,935
Net change, Unrealized gains and losses on derivatives, Tax Effect	8,949	(1,452)	(1,651)
Total	(12,377)	2,008	2,284
Pension benefit adjustment, Before Tax	(19,219)	1,225	7,052
Pension benefit adjustment, Tax Effect	8,058	(512)	(2,957)
Pension benefit adjustment, After Tax	(11,161)	713	4,095
Total other comprehensive income, Before Tax	(94,136)	23,145	71,270
Total other comprehensive income, Tax Effect	37,414	(9,048)	(21,550)
Total other comprehensive income, net of tax	$ (56,722)	$ 14,097	$ 49,720