Variable Interest Entities - Resecuritizations, Multi-seller Conduits (Details 1) (USD $)	3 Months Ended			9 Months Ended
	Sep. 30, 2011		Sep. 30, 2010	Sep. 30, 2011		Sep. 30, 2010	Dec. 31, 2010
Variable Interest Entity [Line Items]
Securities transferred to agency resecuritization VIEs	$ 2,800,000,000		$ 13,500,000,000	$ 20,100,000,000		$ 27,800,000,000
Securities transferred to private-label re-securitization VIEs	189,000,000		138,000,000	381,000,000		1,200,000,000
Assets	2,289,240,000,000	[1]		2,289,240,000,000	[1]		2,117,605,000,000	[1]
Unfunded Portion of Commitments to Multi-Seller Conduits	973,093,000,000		954,082,000,000	973,093,000,000		954,082,000,000	958,709,000,000
Nonconsolidated Private-Label Re-securitizations [Member]
Variable Interest Entity [Line Items]
Assets	3,300,000,000			3,300,000,000			3,600,000,000
Residential Mortgage Backed Securities [Member] | Mortgage Securitization Entities Member | Re securitizations [Member] | Private label Resecuritizations [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	435,000,000			435,000,000			477,000,000
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities	190,000,000			190,000,000			230,000,000
Mortgage Securitization Entities Member | Re securitizations [Member]
Variable Interest Entity [Line Items]
Senior and subordinated interest in nonconsolidated agency re-securitization entities	3,600,000,000			3,600,000,000			3,500,000,000
Mortgage Securitization Entities Member | Re securitizations [Member] | Private label Resecuritizations [Member]
Variable Interest Entity [Line Items]
Senior and subordinated interest in nonconsolidated agency re-securitization entities	15,000,000			15,000,000			46,000,000
Commercial Mortgage Backed Securities [Member] | Firm Administered Multi Seller Conduits Member
Variable Interest Entity [Line Items]
Unfunded Portion of Commitments to Multi-Seller Conduits	11,200,000,000			11,200,000,000			10,000,000,000
Firm Administered Multi Seller Conduits Member
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	22,300,000,000			22,300,000,000			21,700,000,000
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities	$ 19,900,000,000			$ 19,900,000,000			$ 21,600,000,000

[1] The following table presents information on assets and liabilities related to VIEs that are consolidated by the Firm at September 30, 2011, and December 31, 2010. The difference between total VIE assets and liabilities represents the Firm’s interests in those entities, which were eliminated in consolidation.