Variable Interest Entities - Loan Delinquencies and Net Charge-offs (Details 7) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Information about delinquencies, net charge-offs, and components of off-balance sheet securitized financial assets [Abstract]
Total assets held by securitization VIEs	$ 295,800,000,000	$ 340,000,000,000
Prime [Member]
Information about delinquencies, net charge-offs, and components of off-balance sheet securitized financial assets [Abstract]
Total assets held by securitization VIEs	107,200,000,000	129,900,000,000
Subprime [Member]
Information about delinquencies, net charge-offs, and components of off-balance sheet securitized financial assets [Abstract]
Total assets held by securitization VIEs	34,500,000,000	39,400,000,000
Option Arms
Information about delinquencies, net charge-offs, and components of off-balance sheet securitized financial assets [Abstract]
Total assets held by securitization VIEs	26,300,000,000	31,400,000,000
Commercial Mortgage Backed Securities [Member]
Information about delinquencies, net charge-offs, and components of off-balance sheet securitized financial assets [Abstract]
Total assets held by securitization VIEs	127,800,000,000	139,300,000,000
Securitized loans [Member]
Information about delinquencies, net charge-offs, and components of off-balance sheet securitized financial assets [Abstract]
90 days past due	37,512,000,000	53,413,000,000
Liquidation Losses	13,396,000,000	11,744,000,000
Securitized loans in which the firm has no continuing involvement	72,000,000,000	74,400,000,000
Securitized loans [Member] | Prime [Member]
Information about delinquencies, net charge-offs, and components of off-balance sheet securitized financial assets [Abstract]
90 days past due	16,270,000,000	24,285,000,000
Liquidation Losses	6,850,000,000	5,650,000,000
Securitized loans [Member] | Subprime [Member]
Information about delinquencies, net charge-offs, and components of off-balance sheet securitized financial assets [Abstract]
90 days past due	10,570,000,000	14,293,000,000
Liquidation Losses	3,013,000,000	3,086,000,000
Securitized loans [Member] | Option Arms
Information about delinquencies, net charge-offs, and components of off-balance sheet securitized financial assets [Abstract]
90 days past due	6,595,000,000	9,999,000,000
Liquidation Losses	2,268,000,000	1,907,000,000
Securitized loans [Member] | Commercial Mortgage Backed Securities [Member]
Information about delinquencies, net charge-offs, and components of off-balance sheet securitized financial assets [Abstract]
90 days past due	4,077,000,000	4,836,000,000
Liquidation Losses	1,265,000,000	1,101,000,000
Variable Interest Entity, Not Primary Beneficiary [Member]
Information about delinquencies, net charge-offs, and components of off-balance sheet securitized financial assets [Abstract]
Credit exposure / loans securitized	219,765,000,000	261,170,000,000
Variable Interest Entity, Not Primary Beneficiary [Member] | Prime [Member]
Information about delinquencies, net charge-offs, and components of off-balance sheet securitized financial assets [Abstract]
Credit exposure / loans securitized	80,572,000,000	101,004,000,000
Variable Interest Entity, Not Primary Beneficiary [Member] | Subprime [Member]
Information about delinquencies, net charge-offs, and components of off-balance sheet securitized financial assets [Abstract]
Credit exposure / loans securitized	31,264,000,000	35,755,000,000
Variable Interest Entity, Not Primary Beneficiary [Member] | Option Arms
Information about delinquencies, net charge-offs, and components of off-balance sheet securitized financial assets [Abstract]
Credit exposure / loans securitized	26,095,000,000	31,075,000,000
Variable Interest Entity, Not Primary Beneficiary [Member] | Commercial Mortgage Backed Securities [Member]
Information about delinquencies, net charge-offs, and components of off-balance sheet securitized financial assets [Abstract]
Credit exposure / loans securitized	81,834,000,000	93,336,000,000
Variable Interest Entity, Primary Beneficiary [Member]
Information about delinquencies, net charge-offs, and components of off-balance sheet securitized financial assets [Abstract]
Assets held in consolidated securitization VIEs	4,000,000,000	4,400,000,000
Variable Interest Entity, Primary Beneficiary [Member] | Prime [Member]
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	2,700,000,000
Variable Interest Entity, Primary Beneficiary [Member] | Subprime [Member]
Information about delinquencies, net charge-offs, and components of off-balance sheet securitized financial assets [Abstract]
Assets held in consolidated securitization VIEs	1,300,000,000	1,400,000,000
Variable Interest Entity, Primary Beneficiary [Member] | 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	300,000,000
Variable Interest Entity, Primary Beneficiary [Member] | Commercial Mortgage Backed Securities [Member]
Information about delinquencies, net charge-offs, and components of off-balance sheet securitized financial assets [Abstract]
Assets held in consolidated securitization VIEs	$ 0	$ 0