Debt And Shareholders' Equity (Schedule Of Changes In Accumulated Other Comprehensive Income (Loss)) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Debt And Shareholders' Equity [Line Items]
Beginning balance			$ (592,084)	$ (461,296)
Net realized and unrealized holding losses, net of income tax expense/benefit			72,529	(90,109)
Reclassification for net losses included in earnings, net of income tax benefit	(191)	(405)	6,428	6,185
Noncredit-related impairment losses on securities not expected to be sold, net of income tax benefit			(16,006)	(26,318)
Accretion of securities with noncredit-related impairment losses not expected to be sold, net of income tax expense/benefit			724	131
Net unrealized losses, net of reclassification to earnings and income tax benefit			(6,329)	(17,427)
Other comprehensive income (loss)	41,409	(84,343)	57,346	(127,538)
Ending balance	(534,738)	(588,834)	(534,738)	(588,834)
Net realized and unrealized holding gains, income tax expense (benefit)			44,684	(55,668)
Reclassification for net losses included in earnings, income tax benefit			4,199	4,063
Noncredit-related impairment losses on securities not expected to be sold, income tax benefit			9,915	17,058
Accretion of securities with noncredit-related impairment losses not expected to be sold, income tax expense			472	77
Net unrealized losses, reclassification to earnings			10,871	30,840
Net unrealized losses, income tax benefit			4,153	11,115
Net Unrealized Gains (Losses) On investments And Other [Member]
Debt And Shareholders' Equity [Line Items]
Beginning balance			(546,763)	(456,264)
Net realized and unrealized holding losses, net of income tax expense/benefit			72,529	(90,109)
Reclassification for net losses included in earnings, net of income tax benefit			6,428	6,185
Noncredit-related impairment losses on securities not expected to be sold, net of income tax benefit			(16,006)	(26,318)
Accretion of securities with noncredit-related impairment losses not expected to be sold, net of income tax expense/benefit			724	131
Other comprehensive income (loss)			63,675	(110,111)
Ending balance	(483,088)	(566,375)	(483,088)	(566,375)
Net Unrealized Gains (Losses) On Derivative Instruments [Member]
Debt And Shareholders' Equity [Line Items]
Beginning balance			9,404	30,702
Net unrealized losses, net of reclassification to earnings and income tax benefit			(6,329)	(17,427)
Other comprehensive income (loss)			(6,329)	(17,427)
Ending balance	3,075	13,275	3,075	13,275
Pension And Post-Retirement [Member]
Debt And Shareholders' Equity [Line Items]
Beginning balance			(54,725)	(35,734)
Other comprehensive income (loss)			0	0
Ending balance	$ (54,725)	$ (35,734)	$ (54,725)	$ (35,734)