Fair Value (Schedule Of Fair Value Of Predominantly Bank Trust Preferred CDOs) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012
Financing Receivable, Recorded Investment [Line Items]
Fair value of predominantly bank trust preferred CDOs	773,119
Percentage of total fair value by vintage	100.00%
AAA [Member]
Financing Receivable, Recorded Investment [Line Items]
Percentage of total fair value	75.20%
A [Member]
Financing Receivable, Recorded Investment [Line Items]
Percentage of total fair value	24.50%
BBB [Member]
Financing Receivable, Recorded Investment [Line Items]
Percentage of total fair value	0.30%
2001 [Member]
Financing Receivable, Recorded Investment [Line Items]
Fair value of predominantly bank trust preferred CDOs	55,426
Percentage of total fair value by vintage	7.20%
2001 [Member] | AAA [Member]
Financing Receivable, Recorded Investment [Line Items]
Percentage of total fair value	6.00%
2001 [Member] | A [Member]
Financing Receivable, Recorded Investment [Line Items]
Percentage of total fair value	1.10%
2001 [Member] | BBB [Member]
Financing Receivable, Recorded Investment [Line Items]
Percentage of total fair value	0.10%
2002 [Member]
Financing Receivable, Recorded Investment [Line Items]
Fair value of predominantly bank trust preferred CDOs	236,179
Percentage of total fair value by vintage	30.60%
2002 [Member] | AAA [Member]
Financing Receivable, Recorded Investment [Line Items]
Percentage of total fair value	28.10%
2002 [Member] | A [Member]
Financing Receivable, Recorded Investment [Line Items]
Percentage of total fair value	2.50%
2003 [Member]
Financing Receivable, Recorded Investment [Line Items]
Fair value of predominantly bank trust preferred CDOs	272,312
Percentage of total fair value by vintage	35.20%
2003 [Member] | AAA [Member]
Financing Receivable, Recorded Investment [Line Items]
Percentage of total fair value	25.50%
2003 [Member] | A [Member]
Financing Receivable, Recorded Investment [Line Items]
Percentage of total fair value	9.70%
2004 [Member]
Financing Receivable, Recorded Investment [Line Items]
Fair value of predominantly bank trust preferred CDOs	123,861
Percentage of total fair value by vintage	16.00%
2004 [Member] | AAA [Member]
Financing Receivable, Recorded Investment [Line Items]
Percentage of total fair value	7.50%
2004 [Member] | A [Member]
Financing Receivable, Recorded Investment [Line Items]
Percentage of total fair value	8.50%
2005 [Member]
Financing Receivable, Recorded Investment [Line Items]
Fair value of predominantly bank trust preferred CDOs	11,793
Percentage of total fair value by vintage	1.50%
2005 [Member] | AAA [Member]
Financing Receivable, Recorded Investment [Line Items]
Percentage of total fair value	0.90%
2005 [Member] | A [Member]
Financing Receivable, Recorded Investment [Line Items]
Percentage of total fair value	0.60%
2006 [Member]
Financing Receivable, Recorded Investment [Line Items]
Fair value of predominantly bank trust preferred CDOs	39,566
Percentage of total fair value by vintage	5.10%
2006 [Member] | AAA [Member]
Financing Receivable, Recorded Investment [Line Items]
Percentage of total fair value	2.80%
2006 [Member] | A [Member]
Financing Receivable, Recorded Investment [Line Items]
Percentage of total fair value	2.10%
2006 [Member] | BBB [Member]
Financing Receivable, Recorded Investment [Line Items]
Percentage of total fair value	0.20%
2007 [Member]
Financing Receivable, Recorded Investment [Line Items]
Fair value of predominantly bank trust preferred CDOs	33,982
Percentage of total fair value by vintage	4.40%
2007 [Member] | AAA [Member]
Financing Receivable, Recorded Investment [Line Items]
Percentage of total fair value	4.40%