Variable Interest Entities - Loan Delinquencies and Net Charge-offs (Details 7) (USD $)	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Information about delinquencies, net charge-offs, and components of off-balance sheet securitized financial assets [Abstract]
Total assets held by securitization VIEs	$ 290,200,000,000		$ 295,800,000,000
Prime
Information about delinquencies, net charge-offs, and components of off-balance sheet securitized financial assets [Abstract]
Total assets held by securitization VIEs	101,700,000,000		107,200,000,000
Subprime
Information about delinquencies, net charge-offs, and components of off-balance sheet securitized financial assets [Abstract]
Total assets held by securitization VIEs	34,600,000,000		34,500,000,000
Option Arms
Information about delinquencies, net charge-offs, and components of off-balance sheet securitized financial assets [Abstract]
Total assets held by securitization VIEs	25,300,000,000		26,300,000,000
Commercial mortgage
Information about delinquencies, net charge-offs, and components of off-balance sheet securitized financial assets [Abstract]
Total assets held by securitization VIEs	128,600,000,000		127,800,000,000
Securitized loans
Information about delinquencies, net charge-offs, and components of off-balance sheet securitized financial assets [Abstract]
90 days past due	35,683,000,000		37,512,000,000
Liquidation Losses	2,578,000,000	3,345,000,000
Securitized loans in which the firm has no continuing involvement	73,200,000,000		72,000,000,000
Securitized loans | Prime
Information about delinquencies, net charge-offs, and components of off-balance sheet securitized financial assets [Abstract]
90 days past due	14,923,000,000		16,270,000,000
Liquidation Losses	1,238,000,000	1,699,000,000
Securitized loans | Subprime
Information about delinquencies, net charge-offs, and components of off-balance sheet securitized financial assets [Abstract]
90 days past due	10,341,000,000		10,570,000,000
Liquidation Losses	783,000,000	801,000,000
Securitized loans | Option Arms
Information about delinquencies, net charge-offs, and components of off-balance sheet securitized financial assets [Abstract]
90 days past due	6,028,000,000		6,595,000,000
Liquidation Losses	411,000,000	616,000,000
Securitized loans | Commercial mortgage
Information about delinquencies, net charge-offs, and components of off-balance sheet securitized financial assets [Abstract]
90 days past due	4,391,000,000		4,077,000,000
Liquidation Losses	146,000,000	229,000,000
Variable Interest Entity, Not Primary Beneficiary
Information about delinquencies, net charge-offs, and components of off-balance sheet securitized financial assets [Abstract]
Credit exposure / loans securitized	213,786,000,000		219,800,000,000
Variable Interest Entity, Not Primary Beneficiary | Prime
Information about delinquencies, net charge-offs, and components of off-balance sheet securitized financial assets [Abstract]
Credit exposure / loans securitized	76,311,000,000		80,600,000,000
Variable Interest Entity, Not Primary Beneficiary | Subprime
Information about delinquencies, net charge-offs, and components of off-balance sheet securitized financial assets [Abstract]
Credit exposure / loans securitized	31,407,000,000		31,300,000,000
Variable Interest Entity, Not Primary Beneficiary | Option Arms
Information about delinquencies, net charge-offs, and components of off-balance sheet securitized financial assets [Abstract]
Credit exposure / loans securitized	25,125,000,000		26,100,000,000
Variable Interest Entity, Not Primary Beneficiary | Commercial mortgage
Information about delinquencies, net charge-offs, and components of off-balance sheet securitized financial assets [Abstract]
Credit exposure / loans securitized	80,943,000,000		81,800,000,000
Variable Interest Entity, Primary Beneficiary
Information about delinquencies, net charge-offs, and components of off-balance sheet securitized financial assets [Abstract]
Assets held in consolidated securitization VIEs	3,200,000,000		4,000,000,000
Variable Interest Entity, Primary Beneficiary | Prime
Information about delinquencies, net charge-offs, and components of off-balance sheet securitized financial assets [Abstract]
Assets held in consolidated securitization VIEs	1,900,000,000		2,500,000,000
Variable Interest Entity, Primary Beneficiary | Subprime
Information about delinquencies, net charge-offs, and components of off-balance sheet securitized financial assets [Abstract]
Assets held in consolidated securitization VIEs	1,100,000,000		1,300,000,000
Variable Interest Entity, Primary Beneficiary | Option Arms
Information about delinquencies, net charge-offs, and components of off-balance sheet securitized financial assets [Abstract]
Assets held in consolidated securitization VIEs	200,000,000		200,000,000
Variable Interest Entity, Primary Beneficiary | Commercial mortgage
Information about delinquencies, net charge-offs, and components of off-balance sheet securitized financial assets [Abstract]
Assets held in consolidated securitization VIEs	$ 0		$ 0