Variable Interest Entities - Credit Related Note, Asset Swap Vehicle VIEs (Details 2b) (USD $)	Mar. 31, 2012	Dec. 31, 2011
Variable Interest Entity, Not Primary Beneficiary [Member]
Exposure to nonconsolidated credit-linked note and asset swap VIEs [Abstract]
Exposure to non-consolidated VIEs	$ 3,300,000,000	$ 4,300,000,000
Par value of collateral held by VIEs	23,400,000,000	25,400,000,000
Variable Interest Entity, Not Primary Beneficiary [Member] | Net derivative receivables [Member]
Exposure to nonconsolidated credit-linked note and asset swap VIEs [Abstract]
Exposure to non-consolidated VIEs	3,200,000,000	4,300,000,000
Variable Interest Entity, Not Primary Beneficiary [Member] | Trading assets
Exposure to nonconsolidated credit-linked note and asset swap VIEs [Abstract]
Exposure to non-consolidated VIEs	100,000,000	0
Variable Interest Entity, Not Primary Beneficiary [Member] | Credit linked notes [Member]
Exposure to nonconsolidated credit-linked note and asset swap VIEs [Abstract]
Exposure to non-consolidated VIEs	2,700,000,000	3,700,000,000
Par value of collateral held by VIEs	15,000,000,000	16,800,000,000
Variable Interest Entity, Not Primary Beneficiary [Member] | Credit linked notes [Member] | Net derivative receivables [Member]
Exposure to nonconsolidated credit-linked note and asset swap VIEs [Abstract]
Exposure to non-consolidated VIEs	2,600,000,000	3,700,000,000
Variable Interest Entity, Not Primary Beneficiary [Member] | Credit linked notes [Member] | Trading assets
Exposure to nonconsolidated credit-linked note and asset swap VIEs [Abstract]
Exposure to non-consolidated VIEs	100,000,000	0
Variable Interest Entity, Not Primary Beneficiary [Member] | Static structure [Member]
Exposure to nonconsolidated credit-linked note and asset swap VIEs [Abstract]
Exposure to non-consolidated VIEs	600,000,000	1,000,000,000
Par value of collateral held by VIEs	7,600,000,000	9,100,000,000
Variable Interest Entity, Not Primary Beneficiary [Member] | Static structure [Member] | Net derivative receivables [Member]
Exposure to nonconsolidated credit-linked note and asset swap VIEs [Abstract]
Exposure to non-consolidated VIEs	600,000,000	1,000,000,000
Variable Interest Entity, Not Primary Beneficiary [Member] | Static structure [Member] | Trading assets
Exposure to nonconsolidated credit-linked note and asset swap VIEs [Abstract]
Exposure to non-consolidated VIEs	0	0
Variable Interest Entity, Not Primary Beneficiary [Member] | Managed structure [Member]
Exposure to nonconsolidated credit-linked note and asset swap VIEs [Abstract]
Exposure to non-consolidated VIEs	2,100,000,000	2,700,000,000
Par value of collateral held by VIEs	7,400,000,000	7,700,000,000
Variable Interest Entity, Not Primary Beneficiary [Member] | Managed structure [Member] | Net derivative receivables [Member]
Exposure to nonconsolidated credit-linked note and asset swap VIEs [Abstract]
Exposure to non-consolidated VIEs	2,000,000,000	2,700,000,000
Variable Interest Entity, Not Primary Beneficiary [Member] | Managed structure [Member] | Trading assets
Exposure to nonconsolidated credit-linked note and asset swap VIEs [Abstract]
Exposure to non-consolidated VIEs	100,000,000	0
Variable Interest Entity, Not Primary Beneficiary [Member] | Asset Swap VIEs [Member]
Exposure to nonconsolidated credit-linked note and asset swap VIEs [Abstract]
Exposure to non-consolidated VIEs	600,000,000	600,000,000
Par value of collateral held by VIEs	8,400,000,000	8,600,000,000
Variable Interest Entity, Not Primary Beneficiary [Member] | Asset Swap VIEs [Member] | Net derivative receivables [Member]
Exposure to nonconsolidated credit-linked note and asset swap VIEs [Abstract]
Exposure to non-consolidated VIEs	600,000,000	600,000,000
Variable Interest Entity, Not Primary Beneficiary [Member] | Asset Swap VIEs [Member] | Trading assets
Exposure to nonconsolidated credit-linked note and asset swap VIEs [Abstract]
Exposure to non-consolidated VIEs	0	0
Variable Interest Entity, Primary Beneficiary [Member] | Credit linked notes [Member]
Exposure to nonconsolidated credit-linked note and asset swap VIEs [Abstract]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	$ 400,000,000	$ 231,000,000