Derivative Instruments- Offsetting (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013		Dec. 31, 2012
Derivative [Line Items]
Asset derivatives fair value	$ 25,691	[1]	$ 27,602	[1]
Asset derivatives fair value, effect of master netting agreements	20,279	[2],[3]	22,311	[2],[3]
Asset derivatives fair value, fair value after effect of master netting agreements	5,412		5,291
Derivative Asset, Not Subject to Master Netting Arrangement	1,757		1,849
Securities Purchased under Agreements to Resell	1,085		1,477
Securities purchased under agreements to resell amount offset against collateral	269	[2],[4]	137	[2],[4]
Securities purchased under agreements to resell amount not offset against collateral	816		1,340
Fair value of financial and derivative asset	26,776		29,079
Fair value of financial and derivative asset amount offset against collateral	20,548	[2]	22,448	[2]
Fair value of financial and derivative asset amount not offset against collateral	6,228		6,631
Liability derivatives fair value	25,304	[1]	28,090	[1]
Derivative Liability, Fair Value, Amount Offset Against Collateral	18,742	[3],[5]	20,990	[3],[5]
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	6,562		7,100
DerivativeLiabilityNotSubjectToMasterNettingArrangement	496		1,083
Securities Sold under Agreements to Repurchase	2,308		2,443
SecuritiesSoldUnderAgreementsToRepurchaseAmountOffsetAgainstCollateral	269	[5],[6]	137	[5],[6]
SecuritiesSoldUnderAgreementsToRepurchaseAmountNotOffsetAgainstCollateralAbstract	2,039		2,306
FairValueOfFinancialandDerivativeLiability	27,612		30,533
FairValueOfFinancialandDerivativeLiabilityAmountOffsetAgainstCollateral	19,011	[5]	21,127	[5]
FairValueOfFinancialandDerivativeLiabilityAmountNotOffsetAgainstCollateral	8,601		9,406
DerivativesSubjectToNettingArrangments [Member]
Derivative [Line Items]
Asset derivatives fair value	23,934		25,753
Asset derivatives fair value, effect of master netting agreements	20,279	[2]	22,311	[2]
Asset derivatives fair value, fair value after effect of master netting agreements	3,655		3,442
Liability derivatives fair value	24,808		27,007
Derivative Liability, Fair Value, Amount Offset Against Collateral	18,742	[5]	20,990	[5]
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	6,066		6,017
Interest Rate Contract | DerivativesSubjectToNettingArrangments [Member]
Derivative [Line Items]
Asset derivatives fair value	19,366		22,234
Asset derivatives fair value, effect of master netting agreements	17,877	[2]	20,042	[2]
Asset derivatives fair value, fair value after effect of master netting agreements	1,489		2,192
Liability derivatives fair value	20,313		23,274
Derivative Liability, Fair Value, Amount Offset Against Collateral	16,666	[5]	19,069	[5]
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	3,647		4,205
Foreign Exchange Contract | DerivativesSubjectToNettingArrangments [Member]
Derivative [Line Items]
Asset derivatives fair value	4,248		3,255
Asset derivatives fair value, effect of master netting agreements	2,239	[2]	2,171	[2]
Asset derivatives fair value, fair value after effect of master netting agreements	2,009		1,084
Liability derivatives fair value	4,115		3,423
Derivative Liability, Fair Value, Amount Offset Against Collateral	1,913	[5]	1,823	[5]
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	2,202		1,600
Equity Contract | DerivativesSubjectToNettingArrangments [Member]
Derivative [Line Items]
Asset derivatives fair value	320		264
Asset derivatives fair value, effect of master netting agreements	163	[2]	98	[2]
Asset derivatives fair value, fair value after effect of master netting agreements	157		166
Liability derivatives fair value	380		310
Derivative Liability, Fair Value, Amount Offset Against Collateral	163	[5]	98	[5]
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	$ 217		$ 212

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

[2] 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.

[3] Master netting agreements are reported net of cash collateral received and paid of $1,709 million and $172 million, respectively, at March 31, 2013, and $1,452 million and $131 million, respectively, at Dec. 31, 2012.

[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.