Variable Interest Entities - Resecuritizations, Multi-seller Conduits (Details 1) (USD $)	3 Months Ended
	Mar. 31, 2012		Mar. 31, 2011		Dec. 31, 2011
Variable Interest Entity [Line Items]
Securities transferred to agency resecuritization VIEs	$ 2,900,000,000		$ 8,800,000,000
Securities transferred to private-label re-securitization VIEs	241,000,000		192,000,000
Assets	2,320,164,000,000	[1]	2,198,161,000,000	[1]	2,265,792,000,000	[1]
Unfunded Portion of Commitments to Multi-Seller Conduits	997,503,000,000		985,934,000,000		975,662,000,000
Mortgage Securitization Entities | Re securitizations [Member]
Variable Interest Entity [Line Items]
Senior and subordinated interest in nonconsolidated agency re-securitization entities	2,800,000,000				3,600,000,000
Mortgage Securitization Entities | Re securitizations [Member] | Private label Resecuritizations [Member]
Variable Interest Entity [Line Items]
Senior and subordinated interest in nonconsolidated agency re-securitization entities	7,000,000				14,000,000
Mortgage Securitization Entities | Re securitizations [Member] | Residential mortgage [Member] | Private label Resecuritizations [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	152,000,000				348,000,000
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities	4,000,000				139,000,000
Multi-seller conduits
Variable Interest Entity [Line Items]
Commercial paper issued by consolidated Variable Interest Entities eliminated in Consolidation	9,800,000,000				11,300,000,000
Multi-seller conduits | Commercial Mortgage Backed Securities [Member]
Variable Interest Entity [Line Items]
Unfunded Portion of Commitments to Multi-Seller Conduits	12,100,000,000				10,800,000,000
Nonconsolidated Private-Label Re-securitizations [Member]
Variable Interest Entity [Line Items]
Assets	$ 3,700,000,000				$ 3,300,000,000

[1] (a)The following table presents information on assets and liabilities related to VIEs that are consolidated by the Firm at March 31, 2012, and December 31, 2011. The difference between total VIE assets and liabilities represents the Firm’s interests in those entities, which were eliminated in consolidation.