Derivative Instruments - Impact on Balance Sheet (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Derivatives, Fair Value [Line Items]
Gross derivative receivables	$ 516,475	$ 526,239
Net derivative receivables	50,333	54,213
Gross derivative payables	490,219	501,888
Net derivative payables	39,003	41,769
Interest rate
Derivatives, Fair Value [Line Items]
Gross derivative receivables	292,267	268,704
Net derivative receivables	22,758	23,214
Gross derivative payables	262,370	242,782
Net derivative payables	7,722	7,784
Credit
Derivatives, Fair Value [Line Items]
Gross derivative receivables	15,920	20,095
Net derivative receivables	724	612
Gross derivative payables	17,039	20,276
Net derivative payables	1,983	1,667
Foreign exchange
Derivatives, Fair Value [Line Items]
Gross derivative receivables	149,995	167,685
Net derivative receivables	11,871	13,450
Gross derivative payables	148,032	165,217
Net derivative payables	11,398	12,785
Equity
Derivatives, Fair Value [Line Items]
Gross derivative receivables	43,264	49,285
Net derivative receivables	9,322	9,946
Gross derivative payables	45,645	51,195
Net derivative payables	11,029	10,161
Commodity
Derivatives, Fair Value [Line Items]
Gross derivative receivables	15,029	20,470
Net derivative receivables	5,658	6,991
Gross derivative payables	17,133	22,418
Net derivative payables	6,871	9,372
Not designated as hedges
Derivatives, Fair Value [Line Items]
Gross derivative receivables	515,047	524,531
Gross derivative payables	488,965	500,942
Not designated as hedges | Interest rate
Derivatives, Fair Value [Line Items]
Gross derivative receivables	291,442	267,871
Gross derivative payables	262,369	242,782
Not designated as hedges | Credit
Derivatives, Fair Value [Line Items]
Gross derivative receivables	15,920	20,095
Gross derivative payables	17,039	20,276
Not designated as hedges | Foreign exchange
Derivatives, Fair Value [Line Items]
Gross derivative receivables	149,517	167,057
Gross derivative payables	146,994	164,392
Not designated as hedges | Equity
Derivatives, Fair Value [Line Items]
Gross derivative receivables	43,264	49,285
Gross derivative payables	45,645	51,195
Not designated as hedges | Commodity
Derivatives, Fair Value [Line Items]
Gross derivative receivables	14,904	20,223
Gross derivative payables	16,918	22,297
Designated as hedges
Derivatives, Fair Value [Line Items]
Gross derivative receivables	1,428	1,708
Gross derivative payables	1,254	946
Designated as hedges | Interest rate
Derivatives, Fair Value [Line Items]
Gross derivative receivables	825	833
Gross derivative payables	1	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	478	628
Gross derivative payables	1,038	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	125	247
Gross derivative payables	$ 215	$ 121