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, 2015	Mar. 31, 2014
Debt And Shareholders' Equity [Line Items]
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Tax	$ 6,957	$ 40,396
Interest income expense, net, after tax	75,279	76,190
Income Tax Expense (Benefit)	51,176	56,121
Interest Income (Expense), Net	417,346	416,471
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net	0	27
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	13,613	71,386
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	(481)	(24,747)
Beginning balance	(128,041)	(192,101)
Other comprehensive income (loss)	13,132	46,639
Ending balance	(114,909)	(145,462)
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax	1,088	(1,683)
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Tax	0	0
Other Comprehensive Income (Loss), Tax	8,045	38,713
Accumulated Net Unrealized Investment Gain (Loss) [Member]
Debt And Shareholders' Equity [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	11,424	73,907
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	148	(24,537)
Beginning balance	(91,921)	(168,805)
Other comprehensive income (loss)	11,572	49,370
Ending balance	(80,349)	(119,435)
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	2,189	(2,521)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	(629)	(210)
Beginning balance	2,226	1,556
Other comprehensive income (loss)	1,560	(2,731)
Ending balance	3,786	(1,175)
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	(38,346)	(24,852)
Other comprehensive income (loss)	0	0
Ending balance	(38,346)	(24,852)
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	(239)	30,914
Interest income expense, net, after tax	0	(17)
Income Tax Expense (Benefit)	0	(10)
Other than temporary impairment losses investments accretion of noncreidt portion held to maturity securities, after tax	(148)	24,537
Other than temporary impairment losses investments accretion of noncredit portion held to maturity securities, tax	0	196
Other than Temporary Impairment Losses, Investments, Accretion of Noncredit Portion, Held-to-maturity Securities, before Tax	0	(482)
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net	0	(27)
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	629	210
Income Tax Expense (Benefit)	387	141
Interest Income (Expense), Net	1,016	351
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	(148)	24,840
Income Tax Expense (Benefit)	$ (91)	$ 6,074