Investment Income And Gains And Losses (Significant Inputs Used In Schedule Of Measurement Of Credit Loss Component Recognized In Earnings For Each Significant Class Of ABS) (Details)	9 Months Ended
	Sep. 30, 2011		Sep. 30, 2010
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Expected size of losses, Weighted average	64.58%	[1],[2]	44.90%	[1],[2]
Current subordination levels, Weighted average	0.00%	[1],[3]	5.18%	[1],[3]
Prepayment speed (annual CPR), Weighted average	15.62	[1],[3]	9.08	[1],[3]
Minimum Range [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Expected size of losses, Range	1.59%	[4],[5]	0.21%	[4],[5]
Current subordination levels, Range	0.00%	[3],[5]	0.00%	[3],[5]
Prepayment speed (annual CPR), Range	0.00	[3],[5]	0.00	[3],[5]
Maximum Range [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Expected size of losses, Range	100.00%	[4],[5]	100.00%	[4],[5]
Current subordination levels, Range	29.46%	[3],[5]	42.16%	[3],[5]
Prepayment speed (annual CPR), Range	100.00	[3],[5]	38.13	[3],[5]

[1] Calculated by weighting the relevant input/assumption for each individual security by the outstanding notional of the security

[2] Represents future expected credit losses on impaired assets expressed as a percentage of total outstanding balance.

[3]

[4] Represents future expected credit losses on impaired assets expressed as a percentage of total outstanding balance.

[5] Represents the range of inputs/assumptions based upon the individual securities within each category.