Derivative Instruments And Hedging Activities (Narrative) (Details) (USD $)	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012 Total Return Swap [Member]	Dec. 31, 2011 Total Return Swap [Member]	Jul. 28, 2010 Interest Rate Swaps [Member] Total Return Swap [Member]
Derivative [Line Items]
Reclassification included in OCI	$ 10,900,000	$ 30,800,000
Derivative Liability, Fair Value, Gross Liability	96,400,000
Fair values of derivative assets reduced (increased) by net credit valuation adjustments	5,200,000	5,400,000
Fair values of derivative liabilities reduced (increased) by net credit valuation adjustments	100,000	(300,000)
Derivative liability, fair value, amount offset against collateral	1,500,000	300,000
Estimated amounts in AOCI to be reclassified to interest income	5,000,000
Notional amount of bank and insurance trust preferred CDOs					1,160,000,000
Fair value of the TRS derivative liability			5,000,000	5,400,000
Expected net quarterly costs			5,400,000
Cash collateral pledged for derivative liabilities	104,600,000
Additional collateral that would be required to be pledge if credit rating was downgraded by one notch	$ 1,000,000