Derivative Instruments - Impact on Balance Sheet (Details 1a) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Impact of derivatives on the Consolidated Balance Sheets [Abstract]
Fair value related to derivative receivables	$ 1,662,380	$ 1,884,499
Carrying value of derivative trading assets	74,983	92,477
Fair value related to derivative payables	1,639,558	1,837,256
Carrying value of derivative trading liabilities	70,656	74,977
Interest Rate Contract [Member]
Impact of derivatives on the Consolidated Balance Sheets [Abstract]
Fair value related to derivative receivables	1,329,248	1,441,521
Carrying value of derivative trading assets	39,205	46,369
Fair value related to derivative payables	1,287,614	1,399,817
Carrying value of derivative trading liabilities	24,906	28,010
Credit derivatives
Impact of derivatives on the Consolidated Balance Sheets [Abstract]
Fair value related to derivative receivables	100,310	169,650
Carrying value of derivative trading assets	1,735	6,684
Fair value related to derivative payables	100,027	165,121
Carrying value of derivative trading liabilities	2,504	5,610
Foreign exchange
Impact of derivatives on the Consolidated Balance Sheets [Abstract]
Fair value related to derivative receivables	148,259	168,163
Carrying value of derivative trading assets	14,142	17,890
Fair value related to derivative payables	161,642	166,008
Carrying value of derivative trading liabilities	18,601	17,435
Equity
Impact of derivatives on the Consolidated Balance Sheets [Abstract]
Fair value related to derivative receivables	40,938	47,736
Carrying value of derivative trading assets	9,266	6,793
Fair value related to derivative payables	42,810	46,366
Carrying value of derivative trading liabilities	11,819	9,655
Commodity
Impact of derivatives on the Consolidated Balance Sheets [Abstract]
Fair value related to derivative receivables	43,625	57,429
Carrying value of derivative trading assets	10,635	14,741
Fair value related to derivative payables	47,465	59,944
Carrying value of derivative trading liabilities	12,826	14,267
Not Designated as Hedging Instrument [Member]
Impact of derivatives on the Consolidated Balance Sheets [Abstract]
Fair value related to derivative receivables	1,654,153	1,868,677
Fair value related to derivative payables	1,633,661	1,833,301
Not Designated as Hedging Instrument [Member] | Interest Rate Contract [Member]
Impact of derivatives on the Consolidated Balance Sheets [Abstract]
Fair value related to derivative receivables	1,323,184	1,433,900
Fair value related to derivative payables	1,284,494	1,397,625
Not Designated as Hedging Instrument [Member] | Credit derivatives
Impact of derivatives on the Consolidated Balance Sheets [Abstract]
Fair value related to derivative receivables	100,310	169,650
Fair value related to derivative payables	100,027	165,121
Not Designated as Hedging Instrument [Member] | Foreign exchange
Impact of derivatives on the Consolidated Balance Sheets [Abstract]
Fair value related to derivative receivables	146,682	163,497
Fair value related to derivative payables	159,509	165,353
Not Designated as Hedging Instrument [Member] | Equity
Impact of derivatives on the Consolidated Balance Sheets [Abstract]
Fair value related to derivative receivables	40,938	47,736
Fair value related to derivative payables	42,810	46,366
Not Designated as Hedging Instrument [Member] | Commodity
Impact of derivatives on the Consolidated Balance Sheets [Abstract]
Fair value related to derivative receivables	43,039	53,894
Fair value related to derivative payables	46,821	58,836
Designated as Hedging Instrument [Member]
Impact of derivatives on the Consolidated Balance Sheets [Abstract]
Fair value related to derivative receivables	8,227	15,822
Fair value related to derivative payables	5,897	3,955
Designated as Hedging Instrument [Member] | Interest Rate Contract [Member]
Impact of derivatives on the Consolidated Balance Sheets [Abstract]
Fair value related to derivative receivables	6,064	7,621
Fair value related to derivative payables	3,120	2,192
Designated as Hedging Instrument [Member] | Credit derivatives
Impact of derivatives on the Consolidated Balance Sheets [Abstract]
Fair value related to derivative receivables	0	0
Fair value related to derivative payables	0	0
Designated as Hedging Instrument [Member] | Foreign exchange
Impact of derivatives on the Consolidated Balance Sheets [Abstract]
Fair value related to derivative receivables	1,577	4,666
Fair value related to derivative payables	2,133	655
Designated as Hedging Instrument [Member] | Equity
Impact of derivatives on the Consolidated Balance Sheets [Abstract]
Fair value related to derivative receivables	0	0
Fair value related to derivative payables	0	0
Designated as Hedging Instrument [Member] | Commodity
Impact of derivatives on the Consolidated Balance Sheets [Abstract]
Fair value related to derivative receivables	586	3,535
Fair value related to derivative payables	644	1,108
Designated as Hedging Instrument [Member] | Foreign currency-denominated debt [Member]
Derivatives Excluded From Trading Assets and Trading Liabilities [Abstract]
Foreign currency-denominated debt		$ 11