Consolidated Investment Entities (Details 3) (Consolidated Investment Entities, USD $)				12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012 Other assets	Dec. 31, 2012 Other assets Maximum Discounted cash flow/market comparables	Dec. 31, 2012 Other assets Minimum Discounted cash flow/market comparables	Dec. 31, 2012 Other assets Weighted Average Discounted cash flow/market comparables	Dec. 31, 2012 Debt Maximum Discounted cash flow valuation technique	Dec. 31, 2012 Debt Minimum Discounted cash flow valuation technique	Dec. 31, 2012 Debt Weighted Average Discounted cash flow valuation technique
Summary of the significant unobservable inputs
Other assets			$ 1,214,000,000
Debt	4,450,000,000	4,712,000,000	4,450,000,000
Equivalent yield (as a percent)				12.90%	4.10%	7.20%
Expected rental value (per square foot)				$ 309	$ 4	$ 32
Annual default rate (as a percent)							4.50%	2.50%	2.50%
Discount rate (as a percent)							30.00%	1.60%	1.80%
Constant prepayment rate (as a percent)							10.00%	5.00%	9.60%
Loss recovery (as a percent)							63.60%	36.40%	62.00%