Derivative Instruments- Offsetting (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013		Dec. 31, 2012
Derivative [Line Items]
Asset derivatives fair value	$ 20,959	[1]	$ 27,602	[1]
Asset derivatives fair value, effect of master netting agreements	16,468	[2],[3]	22,311	[2],[3]
Asset derivatives fair value, fair value after effect of master netting agreements	4,491		5,291
Derivative Asset, Not Subject to Master Netting Arrangement	2,417		1,849
Securities Purchased under Agreements to Resell	9,176		6,718
Securities purchased under agreements to resell amount offset against collateral	120	[3],[4]	137	[3],[4]
Securities purchased under agreements to resell amount not offset against collateral	9,056		6,581
Fair value of financial and derivative asset	30,135		34,320
Fair value of financial and derivative asset amount offset against collateral	16,588	[3]	22,448	[3]
Fair value of financial and derivative asset amount not offset against collateral	13,547		11,872
Liability derivatives fair value	21,182	[1]	28,090	[1]
Liability derivatives fair value, effect of master netting agreements	14,975	[2],[5]	20,990	[2],[5]
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	6,207		7,100
DerivativeLiabilityNotSubjectToMasterNettingArrangement	2,774		1,083
Securities Sold under Agreements to Repurchase	8,933		7,153
SecuritiesSoldUnderAgreementsToRepurchaseAmountOffsetAgainstCollateral	120	[5],[6]	137	[5],[6]
SecuritiesSoldUnderAgreementsToRepurchaseAmountNotOffsetAgainstCollateralAbstract	8,813		7,016
FairValueOfFinancialandDerivativeLiability	30,115		35,243
FairValueOfFinancialandDerivativeLiabilityAmountOffsetAgainstCollateral	15,095	[5]	21,127	[5]
FairValueOfFinancialandDerivativeLiabilityAmountNotOffsetAgainstCollateral	15,020		14,116
DerivativesSubjectToNettingArrangments [Member]
Derivative [Line Items]
Asset derivatives fair value	18,542		25,753
Asset derivatives fair value, effect of master netting agreements	16,468	[3]	22,311	[3]
Asset derivatives fair value, fair value after effect of master netting agreements	2,074		3,442
Liability derivatives fair value	18,408		27,007
Liability derivatives fair value, effect of master netting agreements	14,975	[5]	20,990	[5]
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	3,433		6,017
Interest Rate Contract | DerivativesSubjectToNettingArrangments [Member]
Derivative [Line Items]
Asset derivatives fair value	15,483		22,234
Asset derivatives fair value, effect of master netting agreements	14,303	[3]	20,042	[3]
Asset derivatives fair value, fair value after effect of master netting agreements	1,180		2,192
Liability derivatives fair value	16,107		23,274
Liability derivatives fair value, effect of master netting agreements	13,271	[5]	19,069	[5]
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	2,836		4,205
Foreign Exchange Contract | DerivativesSubjectToNettingArrangments [Member]
Derivative [Line Items]
Asset derivatives fair value	2,687		3,255
Asset derivatives fair value, effect of master netting agreements	2,005	[3]	2,171	[3]
Asset derivatives fair value, fair value after effect of master netting agreements	682		1,084
Liability derivatives fair value	1,847		3,423
Liability derivatives fair value, effect of master netting agreements	1,544	[5]	1,823	[5]
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	303		1,600
Equity Contract | DerivativesSubjectToNettingArrangments [Member]
Derivative [Line Items]
Asset derivatives fair value	372		264
Asset derivatives fair value, effect of master netting agreements	160	[3]	98	[3]
Asset derivatives fair value, fair value after effect of master netting agreements	212		166
Liability derivatives fair value	454		310
Liability derivatives fair value, effect of master netting agreements	160	[5]	98	[5]
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	$ 294		$ 212

[1] Fair values are on a gross basis, before consideration of master netting agreements, as required by ASC 815.

[2] Master netting agreements are reported net of cash collateral received and paid of $1,631 million and $138 million, respectively, at Sept. 30, 2013, and $1,452 million and $131 million, respectively, at Dec. 31, 2012.

[3] Includes the effect of netting agreements and net cash collateral paid. The offset related to the over-the-counter derivatives was allocated to the various types of derivatives based on the net positions.

[4] Offsetting of reverse repurchase agreements relates to our involvement in the Fixed Income Clearing Corporation, where we settle government securities transactions on a net basis for payment and delivery through the Fedwire system.

[5] Includes the effect of netting agreements and net cash collateral received. The offset related to the over-the-counter derivatives was allocated to the various types of derivatives based on the net positions.

[6] Offsetting of repurchase agreements relates to our involvement in the Fixed Income Clearing Corporation, where we settle government securities transactions on a net basis for payment and delivery through the Fedwire system.