Acquisition and Discontinued Operations (Details 1) (Fair Value, Inputs, Level 3 [Member], USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012
Trust Loans [Member]
Quantitative Information about Level 3 Fair Value Measurements
Trust loans at fair value	$ 2,714
Trust loans, Valuation Techniques	Discounted cash flow
Trust Securities [Member]
Quantitative Information about Level 3 Fair Value Measurements
Trust securities at fair value	$ 2,512
Trust securities, Valuation Techniques	Discounted cash flow
Prepayment speed trust loan [Member]
Quantitative Information about Level 3 Fair Value Measurements
Percentage of significant unobservable input weighted-average	10.22%
Expected credit losses trust loan [Member]
Quantitative Information about Level 3 Fair Value Measurements
Percentage of significant unobservable input weighted-average	52.34%
Discount rate trust loan [Member]
Quantitative Information about Level 3 Fair Value Measurements
Percentage of significant unobservable input weighted-average	4.70%
Expected defaults trust loan [Member]
Quantitative Information about Level 3 Fair Value Measurements
Percentage of significant unobservable input weighted-average	18.58%
Discount rate trust securities [Member]
Quantitative Information about Level 3 Fair Value Measurements
Percentage of significant unobservable input weighted-average	4.10%
Minimum [Member] | Prepayment speed trust loan [Member]
Quantitative Information about Level 3 Fair Value Measurements
Percentage of significant unobservable input weighted-average	4.00%
Minimum [Member] | Expected credit losses trust loan [Member]
Quantitative Information about Level 3 Fair Value Measurements
Percentage of significant unobservable input weighted-average	2.00%
Minimum [Member] | Discount rate trust loan [Member]
Quantitative Information about Level 3 Fair Value Measurements
Percentage of significant unobservable input weighted-average	2.50%
Minimum [Member] | Expected defaults trust loan [Member]
Quantitative Information about Level 3 Fair Value Measurements
Percentage of significant unobservable input weighted-average	3.75%
Minimum [Member] | Discount rate trust securities [Member]
Quantitative Information about Level 3 Fair Value Measurements
Percentage of significant unobservable input weighted-average	1.80%
Maximum [Member] | Prepayment speed trust loan [Member]
Quantitative Information about Level 3 Fair Value Measurements
Percentage of significant unobservable input weighted-average	26.00%
Maximum [Member] | Expected credit losses trust loan [Member]
Quantitative Information about Level 3 Fair Value Measurements
Percentage of significant unobservable input weighted-average	80.00%
Maximum [Member] | Discount rate trust loan [Member]
Quantitative Information about Level 3 Fair Value Measurements
Percentage of significant unobservable input weighted-average	8.40%
Maximum [Member] | Expected defaults trust loan [Member]
Quantitative Information about Level 3 Fair Value Measurements
Percentage of significant unobservable input weighted-average	40.00%
Maximum [Member] | Discount rate trust securities [Member]
Quantitative Information about Level 3 Fair Value Measurements
Percentage of significant unobservable input weighted-average	7.20%