Derivative Instruments - Impact on Balance Sheet (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Derivatives, Fair Value [Line Items]
Gross derivative receivables	$ 622,398	$ 526,239
Net derivative receivables	55,577	54,213
Gross derivative payables	598,219	501,888
Net derivative payables	47,790	41,769
Interest rate
Derivatives, Fair Value [Line Items]
Gross derivative receivables	375,933	268,704
Net derivative receivables	28,507	23,214
Gross derivative payables	338,713	242,782
Net derivative payables	10,223	7,784
Credit
Derivatives, Fair Value [Line Items]
Gross derivative receivables	15,717	20,095
Net derivative receivables	838	612
Gross derivative payables	17,062	20,276
Net derivative payables	2,159	1,667
Foreign exchange
Derivatives, Fair Value [Line Items]
Gross derivative receivables	163,132	167,685
Net derivative receivables	12,681	13,450
Gross derivative payables	165,742	165,217
Net derivative payables	15,016	12,785
Equity
Derivatives, Fair Value [Line Items]
Gross derivative receivables	46,378	49,285
Net derivative receivables	7,409	9,946
Gross derivative payables	50,891	51,195
Net derivative payables	10,603	10,161
Commodity
Derivatives, Fair Value [Line Items]
Gross derivative receivables	21,238	20,470
Net derivative receivables	6,142	6,991
Gross derivative payables	25,811	22,418
Net derivative payables	9,789	9,372
Not designated as hedges
Derivatives, Fair Value [Line Items]
Gross derivative receivables	620,526	524,531
Gross derivative payables	596,717	500,942
Not designated as hedges | Interest rate
Derivatives, Fair Value [Line Items]
Gross derivative receivables	375,082	267,871
Gross derivative payables	338,711	242,782
Not designated as hedges | Credit
Derivatives, Fair Value [Line Items]
Gross derivative receivables	15,717	20,095
Gross derivative payables	17,062	20,276
Not designated as hedges | Foreign exchange
Derivatives, Fair Value [Line Items]
Gross derivative receivables	162,364	167,057
Gross derivative payables	164,583	164,392
Not designated as hedges | Equity
Derivatives, Fair Value [Line Items]
Gross derivative receivables	46,378	49,285
Gross derivative payables	50,891	51,195
Not designated as hedges | Commodity
Derivatives, Fair Value [Line Items]
Gross derivative receivables	20,985	20,223
Gross derivative payables	25,470	22,297
Designated as hedges
Derivatives, Fair Value [Line Items]
Gross derivative receivables	1,872	1,708
Gross derivative payables	1,502	946
Designated as hedges | Interest rate
Derivatives, Fair Value [Line Items]
Gross derivative receivables	851	833
Gross derivative payables	2	0
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	768	628
Gross derivative payables	1,159	825
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	253	247
Gross derivative payables	$ 341	$ 121