Debt And Shareholders' Equity (Schedule Of Changes In Accumulated Other Comprehensive Income (Loss)) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Debt And Shareholders' Equity [Line Items]
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Tax			$ 43,595	$ 43,986
Interest income expense, net, after tax	104,490	55,385	180,680	143,709
Income Tax Expense (Benefit)	69,972	43,091	126,093	103,725
Interest Income (Expense), Net	416,283	430,657	832,748	848,772
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net	0	4,217	27	14,334
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax			83,190	65,209
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax			(27,926)	6,392
Beginning balance			(192,101)	(446,157)
Other comprehensive income (loss)	8,625	32,347	55,264	71,601
Ending balance	(136,837)	(374,556)	(136,837)	(374,556)
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax			638	(959)
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Tax			0	0
Other Comprehensive Income (Loss), Tax			44,233	43,027
Accumulated Net Unrealized Investment Gain (Loss) [Member]
Debt And Shareholders' Equity [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax			81,671	65,212
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax			(27,368)	7,818
Beginning balance			(167,032)	(397,616)
Other comprehensive income (loss)			54,303	73,030
Ending balance	(112,729)	(324,586)	(112,729)	(324,586)
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]
Debt And Shareholders' Equity [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax			1,519	(3)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax			(558)	(1,426)
Beginning balance			(217)	1,794
Other comprehensive income (loss)			961	(1,429)
Ending balance	744	365	744	365
Accumulated Defined Benefit Plans Adjustment [Member]
Debt And Shareholders' Equity [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax			0	0
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax			0	0
Beginning balance			(24,852)	(50,335)
Other comprehensive income (loss)			0	0
Ending balance	(24,852)	(50,335)	(24,852)	(50,335)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Unrealized Investment Gain (Loss) [Member]
Debt And Shareholders' Equity [Line Items]
Gain (Loss) on Investments, Excluding Other than Temporary Impairments	5,026	(1,153)	35,940	2,146
Interest income expense, net, after tax	0	(2,549)	(17)	(8,548)
Income Tax Expense (Benefit)	0	(1,668)	(10)	(5,384)
Other than temporary impairment losses investments accretion of noncreidt portion held to maturity securities, after tax	2,831	(3,647)	27,368	(7,818)
Other than temporary impairment losses investments accretion of noncredit portion held to maturity securities, tax	189	251	385	386
Other than Temporary Impairment Losses, Investments, Accretion of Noncredit Portion, Held-to-maturity Securities, before Tax	(462)	(637)	(944)	(981)
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net	0	(4,217)	(27)	(13,932)
Interest Rate Contract [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]
Debt And Shareholders' Equity [Line Items]
Interest income expense, net, after tax	348	469	558	1,426
Income Tax Expense (Benefit)	229	308	370	956
Interest Income (Expense), Net	577	777	928	2,382
Fixed income securities gain loss [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Unrealized Investment Gain (Loss) [Member]
Debt And Shareholders' Equity [Line Items]
Interest income expense, net, after tax	3,104	(712)	27,944	1,325
Income Tax Expense (Benefit)	$ 1,922	$ (441)	$ 7,996	$ 821