Derivative Instruments - Derivatives Netting (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Gross and Net Derivative Receivables by Contract and Settlement Type:
Gross derivative receivables	$ 510,314	$ 544,296
Amounts netted on the Consolidated balance sheets	(472,026)	(503,030)
Net derivative receivables	38,288	41,266
Derivative receivables where an appropriate legal opinion has not been either sought or obtained	15,925	15,257
Total derivative receivables recognized on the Consolidated balance sheets, Gross derivate receivables	526,239	559,553
Total derivative receivables recognized on the Consolidated balance sheets, Net derivative receivables	54,213	56,523
Collateral not nettable on the Consolidated balance sheets, Net derivative receivables	(13,046)	(13,363)
Net amounts, Net derivative receivables	41,167	43,160
Net cash collateral payables	55,200	55,500
Gross and Net Derivative Payables by Contract and Settlement Type:
Gross derivative payables	485,036	516,185
Amounts netted on the Consolidated balance sheets	(460,119)	(493,029)
Net derivative payables	24,917	23,156
Derivative payables where an appropriate legal opinion has not been either sought or obtained	16,852	14,621
Total derivative payables recognized on the Consolidated balance sheets, Gross derivative payables	501,888	530,806
Total derivative payables recognized on the Consolidated balance sheets, Net derivative payables	41,769	37,777
Collateral not nettable on the Consolidated balance sheets, Net derivative payables	(4,449)	(4,180)
Net amounts, Net derivative payables	37,320	33,597
Netted cash collateral receivables	43,300	45,500
Interest rate contracts
Gross and Net Derivative Receivables by Contract and Settlement Type:
Gross derivative receivables	264,953	312,285
Amounts netted on the Consolidated balance sheets	(245,490)	(291,319)
Net derivative receivables	19,463	20,966
Total derivative receivables recognized on the Consolidated balance sheets, Gross derivate receivables	268,704	315,992
Total derivative receivables recognized on the Consolidated balance sheets, Net derivative receivables	23,214	24,673
Gross and Net Derivative Payables by Contract and Settlement Type:
Gross derivative payables	240,777	283,091
Amounts netted on the Consolidated balance sheets	(234,998)	(277,306)
Net derivative payables	5,779	5,785
Total derivative payables recognized on the Consolidated balance sheets, Gross derivative payables	242,782	284,436
Total derivative payables recognized on the Consolidated balance sheets, Net derivative payables	7,784	7,129
Interest rate contracts | OTC
Gross and Net Derivative Receivables by Contract and Settlement Type:
Gross derivative receivables	258,227	305,569
Amounts netted on the Consolidated balance sheets	(239,498)	(284,917)
Net derivative receivables	18,729	20,652
Gross and Net Derivative Payables by Contract and Settlement Type:
Gross derivative payables	233,404	276,960
Amounts netted on the Consolidated balance sheets	(228,369)	(271,294)
Net derivative payables	5,035	5,666
Interest rate contracts | OTC–cleared
Gross and Net Derivative Receivables by Contract and Settlement Type:
Gross derivative receivables	6,404	6,531
Amounts netted on the Consolidated balance sheets	(5,856)	(6,318)
Net derivative receivables	548	213
Gross and Net Derivative Payables by Contract and Settlement Type:
Gross derivative payables	7,163	6,004
Amounts netted on the Consolidated balance sheets	(6,494)	(5,928)
Net derivative payables	669	76
Interest rate contracts | Exchange-traded
Gross and Net Derivative Receivables by Contract and Settlement Type:
Gross derivative receivables	322	185
Amounts netted on the Consolidated balance sheets	(136)	(84)
Net derivative receivables	186	101
Gross and Net Derivative Payables by Contract and Settlement Type:
Gross derivative payables	210	127
Amounts netted on the Consolidated balance sheets	(135)	(84)
Net derivative payables	75	43
Credit contracts
Gross and Net Derivative Receivables by Contract and Settlement Type:
Gross derivative receivables	19,915	22,615
Amounts netted on the Consolidated balance sheets	(19,483)	(22,335)
Net derivative receivables	432	280
Total derivative receivables recognized on the Consolidated balance sheets, Gross derivate receivables	20,095	23,205
Total derivative receivables recognized on the Consolidated balance sheets, Net derivative receivables	612	869
Gross and Net Derivative Payables by Contract and Settlement Type:
Gross derivative payables	20,128	22,995
Amounts netted on the Consolidated balance sheets	(18,609)	(21,954)
Net derivative payables	1,519	1,041
Total derivative payables recognized on the Consolidated balance sheets, Gross derivative payables	20,276	23,252
Total derivative payables recognized on the Consolidated balance sheets, Net derivative payables	1,667	1,299
Credit contracts | OTC
Gross and Net Derivative Receivables by Contract and Settlement Type:
Gross derivative receivables	12,648	15,390
Amounts netted on the Consolidated balance sheets	(12,261)	(15,165)
Net derivative receivables	387	225
Gross and Net Derivative Payables by Contract and Settlement Type:
Gross derivative payables	13,412	16,194
Amounts netted on the Consolidated balance sheets	(11,895)	(15,170)
Net derivative payables	1,517	1,024
Credit contracts | OTC–cleared
Gross and Net Derivative Receivables by Contract and Settlement Type:
Gross derivative receivables	7,267	7,225
Amounts netted on the Consolidated balance sheets	(7,222)	(7,170)
Net derivative receivables	45	55
Gross and Net Derivative Payables by Contract and Settlement Type:
Gross derivative payables	6,716	6,801
Amounts netted on the Consolidated balance sheets	(6,714)	(6,784)
Net derivative payables	2	17
Foreign exchange contracts
Gross and Net Derivative Receivables by Contract and Settlement Type:
Gross derivative receivables	164,129	157,126
Amounts netted on the Consolidated balance sheets	(154,235)	(144,081)
Net derivative receivables	9,894	13,045
Total derivative receivables recognized on the Consolidated balance sheets, Gross derivate receivables	167,685	160,231
Total derivative receivables recognized on the Consolidated balance sheets, Net derivative receivables	13,450	16,151
Gross and Net Derivative Payables by Contract and Settlement Type:
Gross derivative payables	161,220	152,619
Amounts netted on the Consolidated balance sheets	(152,432)	(143,349)
Net derivative payables	8,788	9,270
Total derivative payables recognized on the Consolidated balance sheets, Gross derivative payables	165,217	155,822
Total derivative payables recognized on the Consolidated balance sheets, Net derivative payables	12,785	12,473
Foreign exchange contracts | OTC
Gross and Net Derivative Receivables by Contract and Settlement Type:
Gross derivative receivables	163,862	155,289
Amounts netted on the Consolidated balance sheets	(153,988)	(142,420)
Net derivative receivables	9,874	12,869
Gross and Net Derivative Payables by Contract and Settlement Type:
Gross derivative payables	160,930	150,966
Amounts netted on the Consolidated balance sheets	(152,161)	(141,789)
Net derivative payables	8,769	9,177
Foreign exchange contracts | OTC–cleared
Gross and Net Derivative Receivables by Contract and Settlement Type:
Gross derivative receivables	235	1,696
Amounts netted on the Consolidated balance sheets	(226)	(1,654)
Net derivative receivables	9	42
Gross and Net Derivative Payables by Contract and Settlement Type:
Gross derivative payables	274	1,555
Amounts netted on the Consolidated balance sheets	(268)	(1,553)
Net derivative payables	6	2
Foreign exchange contracts | Exchange-traded
Gross and Net Derivative Receivables by Contract and Settlement Type:
Gross derivative receivables	32	141
Amounts netted on the Consolidated balance sheets	(21)	(7)
Net derivative receivables	11	134
Gross and Net Derivative Payables by Contract and Settlement Type:
Gross derivative payables	16	98
Amounts netted on the Consolidated balance sheets	(3)	(7)
Net derivative payables	13	91
Equity contracts
Gross and Net Derivative Receivables by Contract and Settlement Type:
Gross derivative receivables	45,054	36,212
Amounts netted on the Consolidated balance sheets	(39,339)	(32,158)
Net derivative receivables	5,715	4,054
Total derivative receivables recognized on the Consolidated balance sheets, Gross derivate receivables	49,285	40,040
Total derivative receivables recognized on the Consolidated balance sheets, Net derivative receivables	9,946	7,882
Gross and Net Derivative Payables by Contract and Settlement Type:
Gross derivative payables	45,722	40,913
Amounts netted on the Consolidated balance sheets	(41,034)	(36,203)
Net derivative payables	4,688	4,710
Total derivative payables recognized on the Consolidated balance sheets, Gross derivative payables	51,195	45,395
Total derivative payables recognized on the Consolidated balance sheets, Net derivative payables	10,161	9,192
Equity contracts | OTC
Gross and Net Derivative Receivables by Contract and Settlement Type:
Gross derivative receivables	26,178	22,024
Amounts netted on the Consolidated balance sheets	(23,879)	(19,917)
Net derivative receivables	2,299	2,107
Gross and Net Derivative Payables by Contract and Settlement Type:
Gross derivative payables	29,437	28,193
Amounts netted on the Consolidated balance sheets	(25,544)	(23,969)
Net derivative payables	3,893	4,224
Equity contracts | Exchange-traded
Gross and Net Derivative Receivables by Contract and Settlement Type:
Gross derivative receivables	18,876	14,188
Amounts netted on the Consolidated balance sheets	(15,460)	(12,241)
Net derivative receivables	3,416	1,947
Gross and Net Derivative Payables by Contract and Settlement Type:
Gross derivative payables	16,285	12,720
Amounts netted on the Consolidated balance sheets	(15,490)	(12,234)
Net derivative payables	795	486
Commodity contracts
Gross and Net Derivative Receivables by Contract and Settlement Type:
Gross derivative receivables	16,263	16,058
Amounts netted on the Consolidated balance sheets	(13,479)	(13,137)
Net derivative receivables	2,784	2,921
Total derivative receivables recognized on the Consolidated balance sheets, Gross derivate receivables	20,470	20,085
Total derivative receivables recognized on the Consolidated balance sheets, Net derivative receivables	6,991	6,948
Gross and Net Derivative Payables by Contract and Settlement Type:
Gross derivative payables	17,189	16,567
Amounts netted on the Consolidated balance sheets	(13,046)	(14,217)
Net derivative payables	4,143	2,350
Total derivative payables recognized on the Consolidated balance sheets, Gross derivative payables	22,418	21,901
Total derivative payables recognized on the Consolidated balance sheets, Net derivative payables	9,372	7,684
Commodity contracts | OTC
Gross and Net Derivative Receivables by Contract and Settlement Type:
Gross derivative receivables	7,448	7,204
Amounts netted on the Consolidated balance sheets	(5,261)	(4,436)
Net derivative receivables	2,187	2,768
Gross and Net Derivative Payables by Contract and Settlement Type:
Gross derivative payables	8,930	7,697
Amounts netted on the Consolidated balance sheets	(4,838)	(5,508)
Net derivative payables	4,092	2,189
Commodity contracts | Exchange-traded
Gross and Net Derivative Receivables by Contract and Settlement Type:
Gross derivative receivables	8,815	8,854
Amounts netted on the Consolidated balance sheets	(8,218)	(8,701)
Net derivative receivables	597	153
Gross and Net Derivative Payables by Contract and Settlement Type:
Gross derivative payables	8,259	8,870
Amounts netted on the Consolidated balance sheets	(8,208)	(8,709)
Net derivative payables	$ 51	$ 161