Derivative Financial Instruments - Fair Value of Derivatives and Balance Offsetting (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014		Dec. 31, 2013
Derivatives, Fair Value [Line Items]
Derivative assets	$ 72,532		$ 80,055
Derivative liabilities	71,546		78,080
Less: Gross amounts of payable subject to enforceable master netting agreements	63,522	[1],[2]	68,616	[1],[2]
Less: Gross amounts of receivable subject to enforceable master netting agreements	63,522	[1],[2]	68,616	[1],[2]
Less: Gross amounts of cash collateral received subject to enforceable master netting agreements(5)(6)	3,128	[1],[3]	3,870	[1],[3]
Less: Gross amounts of cash collateral posted subject to enforceable master netting agreements(5)(6)	2,277	[1],[3]	2,116	[1],[3]
Net amounts of derivative assets presented in the balance sheet	5,882		7,569
Net amounts of derivative liabilities presented in the balance sheet	5,747		7,348
Less: Gross amounts of financial instrument collateral received subject to enforceable master netting agreements but not offset in the consolidated balance sheet	1,247		1,641
Less: Gross amounts of financial instrument collateral posted subject to enforceable master netting agreements but not offset in the consolidated balance sheet	2,160		3,094
Net amounts of derivative assets	4,635		5,928
Net amounts of derivative liabilities	3,587		4,254
Trading Assets [Member]
Derivatives, Fair Value [Line Items]
Less: Gross amounts of cash collateral received subject to enforceable master netting agreements(5)(6)	3,128		3,870
Trading Liabilities [Member]
Derivatives, Fair Value [Line Items]
Less: Gross amounts of cash collateral posted subject to enforceable master netting agreements(5)(6)	2,277		2,116
Designated as Hedging Instrument [Member] | Other assets [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	100	[4]	310	[4]
Designated as Hedging Instrument [Member] | Interest taxes and other liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities	515	[4]	277	[4]
Interest rate contracts [Member] | Not Designated as Hedging Instrument [Member] | Trading Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	52,364	[5]	55,397	[5]
Interest rate contracts [Member] | Not Designated as Hedging Instrument [Member] | Trading Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities	53,118	[5]	55,951	[5]
Foreign exchange contracts [Member] | Not Designated as Hedging Instrument [Member] | Trading Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	12,774	[5]	15,429	[5]
Foreign exchange contracts [Member] | Not Designated as Hedging Instrument [Member] | Trading Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities	11,586	[5]	14,581	[5]
Precious metals contracts [Member] | Not Designated as Hedging Instrument [Member] | Trading Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	646	[5]	1,583	[5]
Precious metals contracts [Member] | Not Designated as Hedging Instrument [Member] | Trading Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities	775	[5]	821	[5]
Credit contracts [Member] | Not Designated as Hedging Instrument [Member] | Trading Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	3,799	[5]	4,655	[5]
Credit contracts [Member] | Not Designated as Hedging Instrument [Member] | Trading Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities	3,909	[5]	4,708	[5]
Fair Value Hedging [Member] | Interest rate contracts [Member] | Designated as Hedging Instrument [Member] | Other assets [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	80	[4]	278	[4]
Fair Value Hedging [Member] | Interest rate contracts [Member] | Designated as Hedging Instrument [Member] | Interest taxes and other liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities	386	[4]	212	[4]
Cash Flow Hedging [Member] | Interest rate contracts [Member] | Designated as Hedging Instrument [Member] | Other assets [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	19	[4]	32	[4]
Cash Flow Hedging [Member] | Interest rate contracts [Member] | Designated as Hedging Instrument [Member] | Interest taxes and other liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities	111	[4]	62	[4]
Cash Flow Hedging [Member] | Foreign exchange contracts [Member] | Designated as Hedging Instrument [Member] | Other assets [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	1	[4]	0	[4]
Cash Flow Hedging [Member] | Foreign exchange contracts [Member] | Designated as Hedging Instrument [Member] | Interest taxes and other liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities	18	[4]	3	[4]
OTC Cleared [Member] | Interest rate contracts [Member] | Not Designated as Hedging Instrument [Member] | Trading Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	21,454	[5],[6]	24,218	[5],[6]
OTC Cleared [Member] | Interest rate contracts [Member] | Not Designated as Hedging Instrument [Member] | Trading Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities	22,595	[5],[6]	25,468	[5],[6]
OTC Cleared [Member] | Credit contracts [Member] | Not Designated as Hedging Instrument [Member] | Trading Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	516	[5],[6]	576	[5],[6]
OTC Cleared [Member] | Credit contracts [Member] | Not Designated as Hedging Instrument [Member] | Trading Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities	540	[5],[6]	604	[5],[6]
OTC Cleared [Member] | Fair Value Hedging [Member] | Interest rate contracts [Member] | Designated as Hedging Instrument [Member] | Other assets [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	20	[4],[6]	75	[4],[6]
OTC Cleared [Member] | Fair Value Hedging [Member] | Interest rate contracts [Member] | Designated as Hedging Instrument [Member] | Interest taxes and other liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities	132	[4],[6]	20	[4],[6]
OTC Cleared [Member] | Cash Flow Hedging [Member] | Interest rate contracts [Member] | Designated as Hedging Instrument [Member] | Other assets [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	14	[4],[6]	16	[4],[6]
OTC Cleared [Member] | Cash Flow Hedging [Member] | Interest rate contracts [Member] | Designated as Hedging Instrument [Member] | Interest taxes and other liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities	0	[4],[6]	0	[4],[6]
Bilateral OTC [Member] | Interest rate contracts [Member] | Not Designated as Hedging Instrument [Member] | Other assets [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	604	[4],[6]	470	[4],[6]
Bilateral OTC [Member] | Interest rate contracts [Member] | Not Designated as Hedging Instrument [Member] | Interest taxes and other liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities	74	[4],[6]	91	[4],[6]
Bilateral OTC [Member] | Interest rate contracts [Member] | Not Designated as Hedging Instrument [Member] | Trading Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	30,814	[5],[6]	31,097	[5],[6]
Bilateral OTC [Member] | Interest rate contracts [Member] | Not Designated as Hedging Instrument [Member] | Trading Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities	30,486	[5],[6]	30,451	[5],[6]
Bilateral OTC [Member] | Foreign exchange contracts [Member] | Not Designated as Hedging Instrument [Member] | Other assets [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	1	[4],[6]	0	[4],[6]
Bilateral OTC [Member] | Foreign exchange contracts [Member] | Not Designated as Hedging Instrument [Member] | Interest taxes and other liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities	18	[4],[6]	44	[4],[6]
Bilateral OTC [Member] | Foreign exchange contracts [Member] | Not Designated as Hedging Instrument [Member] | Trading Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	12,745	[5],[6]	15,422	[5],[6]
Bilateral OTC [Member] | Foreign exchange contracts [Member] | Not Designated as Hedging Instrument [Member] | Trading Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities	11,586	[5],[6]	14,565	[5],[6]
Bilateral OTC [Member] | Equity contracts [Member] | Not Designated as Hedging Instrument [Member] | Other assets [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	806	[4],[6]	789	[4],[6]
Bilateral OTC [Member] | Equity contracts [Member] | Not Designated as Hedging Instrument [Member] | Interest taxes and other liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities	102	[4],[6]	148	[4],[6]
Bilateral OTC [Member] | Equity contracts [Member] | Not Designated as Hedging Instrument [Member] | Trading Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	1,421	[5],[6]	1,413	[5],[6]
Bilateral OTC [Member] | Equity contracts [Member] | Not Designated as Hedging Instrument [Member] | Trading Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities	1,418	[5],[6]	1,412	[5],[6]
Bilateral OTC [Member] | Precious metals contracts [Member] | Not Designated as Hedging Instrument [Member] | Other assets [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	0	[4],[6]	0	[4],[6]
Bilateral OTC [Member] | Precious metals contracts [Member] | Not Designated as Hedging Instrument [Member] | Interest taxes and other liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities	19	[4],[6]	36	[4],[6]
Bilateral OTC [Member] | Precious metals contracts [Member] | Not Designated as Hedging Instrument [Member] | Trading Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	643	[5],[6]	1,402	[5],[6]
Bilateral OTC [Member] | Precious metals contracts [Member] | Not Designated as Hedging Instrument [Member] | Trading Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities	637	[5],[6]	815	[5],[6]
Bilateral OTC [Member] | Credit contracts [Member] | Not Designated as Hedging Instrument [Member] | Other assets [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	17	[4],[6]	9	[4],[6]
Bilateral OTC [Member] | Credit contracts [Member] | Not Designated as Hedging Instrument [Member] | Interest taxes and other liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities	12	[4],[6]	11	[4],[6]
Bilateral OTC [Member] | Credit contracts [Member] | Not Designated as Hedging Instrument [Member] | Trading Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	3,283	[5],[6]	4,079	[5],[6]
Bilateral OTC [Member] | Credit contracts [Member] | Not Designated as Hedging Instrument [Member] | Trading Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities	3,369	[5],[6]	4,104	[5],[6]
Bilateral OTC [Member] | Fair Value Hedging [Member] | Interest rate contracts [Member] | Designated as Hedging Instrument [Member] | Other assets [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	60	[4],[6]	203	[4],[6]
Bilateral OTC [Member] | Fair Value Hedging [Member] | Interest rate contracts [Member] | Designated as Hedging Instrument [Member] | Interest taxes and other liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities	254	[4],[6]	192	[4],[6]
Bilateral OTC [Member] | Cash Flow Hedging [Member] | Interest rate contracts [Member] | Designated as Hedging Instrument [Member] | Other assets [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	5	[4],[6]	16	[4],[6]
Bilateral OTC [Member] | Cash Flow Hedging [Member] | Interest rate contracts [Member] | Designated as Hedging Instrument [Member] | Interest taxes and other liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities	111	[4],[6]	62	[4],[6]
Bilateral OTC [Member] | Cash Flow Hedging [Member] | Foreign exchange contracts [Member] | Designated as Hedging Instrument [Member] | Other assets [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	1	[4],[6]	0	[4],[6]
Bilateral OTC [Member] | Cash Flow Hedging [Member] | Foreign exchange contracts [Member] | Designated as Hedging Instrument [Member] | Interest taxes and other liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities	18	[4],[6]	3	[4],[6]
Exchange Traded [Member] | Interest rate contracts [Member] | Not Designated as Hedging Instrument [Member] | Trading Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	96	[5],[6]	82	[5],[6]
Exchange Traded [Member] | Interest rate contracts [Member] | Not Designated as Hedging Instrument [Member] | Trading Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities	37	[5],[6]	32	[5],[6]
Exchange Traded [Member] | Foreign exchange contracts [Member] | Not Designated as Hedging Instrument [Member] | Trading Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	29	[5],[6]	7	[5],[6]
Exchange Traded [Member] | Foreign exchange contracts [Member] | Not Designated as Hedging Instrument [Member] | Trading Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities	0	[5],[6]	16	[5],[6]
Exchange Traded [Member] | Precious metals contracts [Member] | Not Designated as Hedging Instrument [Member] | Trading Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	3	[5],[6]	181	[5],[6]
Exchange Traded [Member] | Precious metals contracts [Member] | Not Designated as Hedging Instrument [Member] | Trading Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities	$ 138	[5],[6]	$ 6	[5],[6]

[1] Netting is performed at a counterparty level in cases where enforceable master netting and credit support agreements are in place, regardless of the type of derivative instrument. Therefore, we have not attempted to allocate netting to the different types of derivative instruments shown in the table above.

[2] Represents the netting of derivative receivable and payable balances for the same counterparty under enforceable netting agreements.

[3] Represents the netting of cash collateral posted and received by counterparty under enforceable credit support agreements.

[4] Derivative assets/liabilities related to cash flow hedges, fair value hedges and derivative instruments held for purposes other than for trading are recorded in other assets / interest, taxes and other liabilities on the consolidated balance sheet.

[5] Trading related derivative assets/liabilities are recorded in trading assets/trading liabilities on the consolidated balance sheet.

[6] Over-the-counter (OTC) derivatives include derivatives executed and settled bilaterally with counterparties without the use of an organized exchange or central clearing house. The credit risk associated with bilateral OTC derivatives is managed through master netting agreements and obtaining collateral. OTC-cleared derivatives are executed bilaterally in the OTC market but then novated to a central clearing counterparty, whereby the central clearing counterparty becomes the counterparty to both of the original counterparties. Exchange traded derivatives are executed directly on an organized exchange that provides pre-trade price transparency. Credit risk is minimized for OTC-cleared derivatives and exchange traded derivatives through daily margining required by central clearing counterparties.