Debt And Shareholders' Equity (Schedule Of Changes In Accumulated Other Comprehensive Income (Loss)) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2012 Net Unrealized Gains (Losses) On investments And Other [Member]	Mar. 31, 2011 Net Unrealized Gains (Losses) On investments And Other [Member]	Mar. 31, 2012 Net Unrealized Gains (Losses) On Derivative Instruments [Member]	Mar. 31, 2011 Net Unrealized Gains (Losses) On Derivative Instruments [Member]	Mar. 31, 2012 Pension And Post-Retirement [Member]	Dec. 31, 2011 Pension And Post-Retirement [Member]	Mar. 31, 2011 Pension And Post-Retirement [Member]	Dec. 31, 2010 Pension And Post-Retirement [Member]
Debt And Shareholders' Equity [Line Items]
Beginning balance	$ (592,084)	$ (461,296)	$ (546,763)	$ (456,264)	$ 9,404	$ 30,702	$ (54,725)	$ (54,725)	$ (35,734)	$ (35,734)
Net realized and unrealized holding losses, net of income tax benefit (expense)	22,614	(31,788)	22,614	(31,788)
Reclassification for net losses included in earnings, net of income tax benefit	5,798	1,954	5,798	1,954
Noncredit-related impairment losses on securities not expected to be sold, net of income tax benefit of $3,085	(4,980)		(4,980)
Accretion of securities with noncredit-related impairment losses not expected to be sold, net of income tax expense	165	26	165	26
Net unrealized losses, net of reclassification to earnings and income tax benefit	(3,080)	(8,059)			(3,080)	(8,059)
Other comprehensive loss	20,517	(37,867)	23,597	(29,808)	(3,080)	(8,059)
Ending balance	(571,567)	(499,163)	(523,166)	(486,072)	6,324	22,643	(54,725)	(54,725)	(35,734)	(35,734)
Net realized and unrealized holding losses, income tax benefit	13,967	19,677
Reclassification for net losses included in earnings, income tax benefit	3,691	1,210
Noncredit-related impairment losses on securities not expected to be sold, income tax benefit	3,085
Accretion of securities with noncredit-related impairment losses not expected to be sold, income tax expense	102	16
Net unrealized losses, reclassification to earnings	5,294	13,237
Net unrealized losses, income tax benefit	$ 2,004	$ 5,156