Derivative Instruments - Impact on Balance Sheet (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Gross derivative receivables	$ 526,239	$ 559,553
Net derivative receivables	54,213	56,523
Gross derivative payables	501,888	530,806
Net derivative payables	41,769	37,777
Interest rate
Derivatives, Fair Value [Line Items]
Gross derivative receivables	268,704	315,992
Net derivative receivables	23,214	24,673
Gross derivative payables	242,782	284,436
Net derivative payables	7,784	7,129
Credit
Derivatives, Fair Value [Line Items]
Gross derivative receivables	20,095	23,205
Net derivative receivables	612	869
Gross derivative payables	20,276	23,252
Net derivative payables	1,667	1,299
Foreign exchange
Derivatives, Fair Value [Line Items]
Gross derivative receivables	167,685	160,231
Net derivative receivables	13,450	16,151
Gross derivative payables	165,217	155,822
Net derivative payables	12,785	12,473
Equity
Derivatives, Fair Value [Line Items]
Gross derivative receivables	49,285	40,040
Net derivative receivables	9,946	7,882
Gross derivative payables	51,195	45,395
Net derivative payables	10,161	9,192
Commodity
Derivatives, Fair Value [Line Items]
Gross derivative receivables	20,470	20,085
Net derivative receivables	6,991	6,948
Gross derivative payables	22,418	21,901
Net derivative payables	9,372	7,684
Not designated as hedges
Derivatives, Fair Value [Line Items]
Gross derivative receivables	524,531	558,013
Gross derivative payables	500,942	529,179
Not designated as hedges | Interest rate
Derivatives, Fair Value [Line Items]
Gross derivative receivables	267,871	314,962
Gross derivative payables	242,782	284,433
Not designated as hedges | Credit
Derivatives, Fair Value [Line Items]
Gross derivative receivables	20,095	23,205
Gross derivative payables	20,276	23,252
Not designated as hedges | Foreign exchange
Derivatives, Fair Value [Line Items]
Gross derivative receivables	167,057	159,740
Gross derivative payables	164,392	154,601
Not designated as hedges | Equity
Derivatives, Fair Value [Line Items]
Gross derivative receivables	49,285	40,040
Gross derivative payables	51,195	45,395
Not designated as hedges | Commodity
Derivatives, Fair Value [Line Items]
Gross derivative receivables	20,223	20,066
Gross derivative payables	22,297	21,498
Designated as hedges
Derivatives, Fair Value [Line Items]
Gross derivative receivables	1,708	1,540
Gross derivative payables	946	1,627
Designated as hedges | Interest rate
Derivatives, Fair Value [Line Items]
Gross derivative receivables	833	1,030
Gross derivative payables	0	3
Designated as hedges | Credit
Derivatives, Fair Value [Line Items]
Gross derivative receivables	0	0
Gross derivative payables	0	0
Designated as hedges | Foreign exchange
Derivatives, Fair Value [Line Items]
Gross derivative receivables	628	491
Gross derivative payables	825	1,221
Designated as hedges | Equity
Derivatives, Fair Value [Line Items]
Gross derivative receivables	0	0
Gross derivative payables	0	0
Designated as hedges | Commodity
Derivatives, Fair Value [Line Items]
Gross derivative receivables	247	19
Gross derivative payables	$ 121	$ 403