Variable Interest Entities - Loan Delinquencies and Net Charge-offs (Details 7) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 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	$ 283,800,000,000		$ 283,800,000,000		$ 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	96,400,000,000		96,400,000,000		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	33,700,000,000		33,700,000,000		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	24,500,000,000		24,500,000,000		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	129,200,000,000		129,200,000,000		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	29,091,000,000		29,091,000,000		37,512,000,000
Liquidation Losses	2,250,000,000	3,371,000,000	4,828,000,000	6,716,000,000
Securitized loans in which the firm has no continuing involvement	58,500,000,000		58,500,000,000		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	11,972,000,000		11,972,000,000		16,270,000,000
Liquidation Losses	1,007,000,000	2,125,000,000	2,245,000,000	3,824,000,000
Securitized loans | Subprime
Information about delinquencies, net charge-offs, and components of off-balance sheet securitized financial assets [Abstract]
90 days past due	8,915,000,000		8,915,000,000		10,570,000,000
Liquidation Losses	756,000,000	320,000,000	1,539,000,000	1,121,000,000
Securitized loans | Option ARMs
Information about delinquencies, net charge-offs, and components of off-balance sheet securitized financial assets [Abstract]
90 days past due	5,384,000,000		5,384,000,000		6,595,000,000
Liquidation Losses	303,000,000	634,000,000	714,000,000	1,250,000,000
Securitized loans | Commercial mortgage
Information about delinquencies, net charge-offs, and components of off-balance sheet securitized financial assets [Abstract]
90 days past due	2,820,000,000		2,820,000,000		4,077,000,000
Liquidation Losses	184,000,000	292,000,000	330,000,000	521,000,000
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	221,518,000,000		221,518,000,000		219,765,000,000
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	74,919,000,000		74,919,000,000		80,572,000,000
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	30,271,000,000		30,271,000,000		31,264,000,000
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	24,253,000,000		24,253,000,000		26,095,000,000
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	92,075,000,000		92,075,000,000		81,834,000,000
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	3,800,000,000		3,800,000,000		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	2,500,000,000		2,500,000,000		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		1,100,000,000		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		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		$ 0