Consolidated Investment Entities (Details 3) (Consolidated Investment Entities, USD $) In Millions, unless otherwise specified	9 Months Ended	12 Months Ended
	Sep. 30, 2013	Dec. 31, 2012
Summary of the significant unobservable inputs
Debt	$ 4,459	$ 4,450
Other assets
Summary of the significant unobservable inputs
Other assets	$ 1,591	$ 1,214
Other assets | Minimum | Discounted cash flow/market comparables
Summary of the significant unobservable inputs
Equivalent yield (as a percent)	3.50%	4.10%
Expected rental value (per square foot)	5	4
Other assets | Maximum | Discounted cash flow/market comparables
Summary of the significant unobservable inputs
Equivalent yield (as a percent)	12.50%	12.90%
Expected rental value (per square foot)	308	309
Other assets | Weighted Average | Discounted cash flow/market comparables
Summary of the significant unobservable inputs
Equivalent yield (as a percent)	7.60%	7.20%
Expected rental value (per square foot)	29	32
Debt | Minimum | Discounted cash flow valuation technique
Summary of the significant unobservable inputs
Annual default rate (as a percent)	2.50%	2.50%
Discount rate (as a percent)	1.50%	1.60%
Constant prepayment rate (as a percent)	5.00%	5.00%
Loss recovery (as a percent)	36.40%	36.40%
Debt | Maximum | Discounted cash flow valuation technique
Summary of the significant unobservable inputs
Annual default rate (as a percent)	2.50%	4.50%
Discount rate (as a percent)	9.30%	30.00%
Constant prepayment rate (as a percent)	10.00%	10.00%
Loss recovery (as a percent)	63.60%	63.60%
Debt | Weighted Average | Discounted cash flow valuation technique
Summary of the significant unobservable inputs
Annual default rate (as a percent)	2.50%	2.50%
Discount rate (as a percent)	2.80%	2.90%
Constant prepayment rate (as a percent)	9.70%	9.60%
Loss recovery (as a percent)	62.50%	62.00%