Other Comprehensive Income (Loss) (Schedule Of Other Comprehensive Income (Loss)) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Net change in unrealized gain on securities available for sale, Pre Tax Amount	$ (5,482)	$ 36,931	$ 135,297
Net change in unrealized gain on securities available for sale, Tax (Expense) Benefit	3,001	(14,590)	(47,296)
Net change in unrealized gain on securities available for sale, After Tax Amount	(2,481)	22,341	81,146
Net change in non-credit related other than temporary impairment on securities, Pre Tax Amount	882	(4,238)	(10,538)
Net change in non-credit related other than temporary impairment on securities, Tax (Expense) Benefit	(136)	1,690	3,683
Net change in non-credit related other than temporary impairment on securities, After Tax Amount	746	(2,548)	(6,855)
Net unrealized gain on securities available for sale, Pre Tax Amount	(4,600)	32,693	124,759
Net unrealized gain on securities available for sale, Tax (Expense) Benefit	2,865	(12,900)	(43,613)
Net unrealized gain on securities available for sale, After Tax Amount	(1,735)	19,793	81,146
Net unrealized loss on derivative instruments, Pre Tax Amount	(36,964)	(4,876)	2,149
Net unrealized loss on derivative instruments, Tax (Expense) Benefit	13,969	2,108	(752)
Net unrealized loss on derivative instruments, After Tax Amount	(22,995)	(2,768)	1,397
Amortization of unrealized loss on securities transferred to held to maturity, Pre Tax Amount	260	509	398
Amortization of unrealized loss on securities transferred to held to maturity, Tax (Expense) Benefit	(87)	(178)	(139)
Amortization of unrealized loss on securities transferred to held to maturity, After Tax Amount	173	331	259
Net actuarial loss and prior service costs for pension and other postretirement benefits, Pre Tax Amount	34,672	(4,117)	9,463
Net actuarial gain/loss and prior service costs for pension and other postretirement benefits, Tax (Expense) Benefit	12,734	1,441	(3,313)
Net actuarial gain/loss and prior service costs for pension and other postretirement benefits, After Tax Amount	(21,938)	(2,676)	6,150
Total other comprehensive income (loss), Pre Tax Amount	(75,976)	24,209	136,769
Total other comprehensive income (loss), Tax (Expense) Benefit	29,481	(9,529)	(47,817)
Total comprehensive income (loss), net of taxes	104,883	86,938	12,065
Total other comprehensive income	(46,495)	14,680	88,952
Available For Sale [Member]
Net change in unrealized gain on securities available for sale, After Tax Amount			$ 88,001