Derivative Instruments - Derivatives Netting (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Gross and Net Derivative Receivables by Contract and Settlement Type:
Gross derivative receivables	$ 607,720	$ 510,314
Amounts netted on the Consolidated balance sheets	(566,821)	(472,026)
Net derivative receivables	40,899	38,288
Derivative receivables where an appropriate legal opinion has not been either sought or obtained	14,678	15,925
Total derivative receivables recognized on the Consolidated balance sheets, Gross derivative receivables	622,398	526,239
Total derivative receivables recognized on the Consolidated balance sheets, Net derivative receivables	55,577	54,213
Collateral not nettable on the Consolidated balance sheets	(13,224)	(13,046)
Net amounts	42,353	41,167
Gross and Net Derivative Payables by Contract and Settlement Type:
Gross derivative payables	584,635	485,036
Amounts netted on the Consolidated balance sheets	(550,429)	(460,119)
Net derivative payables	34,206	24,917
Derivative payables where an appropriate legal opinion has not been either sought or obtained	13,584	16,852
Total derivative payables recognized on the Consolidated balance sheets, Gross derivative payables	598,219	501,888
Total derivative payables recognized on the Consolidated balance sheets, Net derivative payables	47,790	41,769
Collateral not nettable on the Consolidated balance sheets	(9,236)	(4,449)
Net amounts	38,554	37,320
Net cash collateral receivables	78,800	55,200
Net cash collateral payables	62,400	43,300
Interest rate contracts
Gross and Net Derivative Receivables by Contract and Settlement Type:
Gross derivative receivables	371,090	264,953
Amounts netted on the Consolidated balance sheets	(347,426)	(245,490)
Net derivative receivables	23,664	19,463
Total derivative receivables recognized on the Consolidated balance sheets, Gross derivative receivables	375,933	268,704
Total derivative receivables recognized on the Consolidated balance sheets, Net derivative receivables	28,507	23,214
Gross and Net Derivative Payables by Contract and Settlement Type:
Gross derivative payables	337,314	240,777
Amounts netted on the Consolidated balance sheets	(328,490)	(234,998)
Net derivative payables	8,824	5,779
Total derivative payables recognized on the Consolidated balance sheets, Gross derivative payables	338,713	242,782
Total derivative payables recognized on the Consolidated balance sheets, Net derivative payables	10,223	7,784
Interest rate contracts | Over-the-counter (“OTC”)
Gross and Net Derivative Receivables by Contract and Settlement Type:
Gross derivative receivables	356,075	258,227
Amounts netted on the Consolidated balance sheets	(332,566)	(239,498)
Net derivative receivables	23,509	18,729
Gross and Net Derivative Payables by Contract and Settlement Type:
Gross derivative payables	321,553	233,404
Amounts netted on the Consolidated balance sheets	(313,017)	(228,369)
Net derivative payables	8,536	5,035
Interest rate contracts | OTC–cleared
Gross and Net Derivative Receivables by Contract and Settlement Type:
Gross derivative receivables	14,438	6,404
Amounts netted on the Consolidated balance sheets	(14,343)	(5,856)
Net derivative receivables	95	548
Gross and Net Derivative Payables by Contract and Settlement Type:
Gross derivative payables	15,176	7,163
Amounts netted on the Consolidated balance sheets	(14,960)	(6,494)
Net derivative payables	216	669
Interest rate contracts | Exchange-traded
Gross and Net Derivative Receivables by Contract and Settlement Type:
Gross derivative receivables	577	322
Amounts netted on the Consolidated balance sheets	(517)	(136)
Net derivative receivables	60	186
Gross and Net Derivative Payables by Contract and Settlement Type:
Gross derivative payables	585	210
Amounts netted on the Consolidated balance sheets	(513)	(135)
Net derivative payables	72	75
Net credit derivatives
Gross and Net Derivative Receivables by Contract and Settlement Type:
Gross derivative receivables	15,489	19,915
Amounts netted on the Consolidated balance sheets	(14,879)	(19,483)
Net derivative receivables	610	432
Total derivative receivables recognized on the Consolidated balance sheets, Gross derivative receivables	15,717	20,095
Total derivative receivables recognized on the Consolidated balance sheets, Net derivative receivables	838	612
Gross and Net Derivative Payables by Contract and Settlement Type:
Gross derivative payables	16,927	20,128
Amounts netted on the Consolidated balance sheets	(14,903)	(18,609)
Net derivative payables	2,024	1,519
Total derivative payables recognized on the Consolidated balance sheets, Gross derivative payables	17,062	20,276
Total derivative payables recognized on the Consolidated balance sheets, Net derivative payables	2,159	1,667
Net credit derivatives | Over-the-counter (“OTC”)
Gross and Net Derivative Receivables by Contract and Settlement Type:
Gross derivative receivables	11,168	12,648
Amounts netted on the Consolidated balance sheets	(10,682)	(12,261)
Net derivative receivables	486	387
Gross and Net Derivative Payables by Contract and Settlement Type:
Gross derivative payables	13,130	13,412
Amounts netted on the Consolidated balance sheets	(11,254)	(11,895)
Net derivative payables	1,876	1,517
Net credit derivatives | OTC–cleared
Gross and Net Derivative Receivables by Contract and Settlement Type:
Gross derivative receivables	4,321	7,267
Amounts netted on the Consolidated balance sheets	(4,197)	(7,222)
Net derivative receivables	124	45
Gross and Net Derivative Payables by Contract and Settlement Type:
Gross derivative payables	3,797	6,716
Amounts netted on the Consolidated balance sheets	(3,649)	(6,714)
Net derivative payables	148	2
Foreign exchange contracts
Gross and Net Derivative Receivables by Contract and Settlement Type:
Gross derivative receivables	160,377	164,129
Amounts netted on the Consolidated balance sheets	(150,451)	(154,235)
Net derivative receivables	9,926	9,894
Total derivative receivables recognized on the Consolidated balance sheets, Gross derivative receivables	163,132	167,685
Total derivative receivables recognized on the Consolidated balance sheets, Net derivative receivables	12,681	13,450
Gross and Net Derivative Payables by Contract and Settlement Type:
Gross derivative payables	162,540	161,220
Amounts netted on the Consolidated balance sheets	(150,726)	(152,432)
Net derivative payables	11,814	8,788
Total derivative payables recognized on the Consolidated balance sheets, Gross derivative payables	165,742	165,217
Total derivative payables recognized on the Consolidated balance sheets, Net derivative payables	15,016	12,785
Foreign exchange contracts | Over-the-counter (“OTC”)
Gross and Net Derivative Receivables by Contract and Settlement Type:
Gross derivative receivables	160,181	163,862
Amounts netted on the Consolidated balance sheets	(150,271)	(153,988)
Net derivative receivables	9,910	9,874
Gross and Net Derivative Payables by Contract and Settlement Type:
Gross derivative payables	162,336	160,930
Amounts netted on the Consolidated balance sheets	(150,537)	(152,161)
Net derivative payables	11,799	8,769
Foreign exchange contracts | OTC–cleared
Gross and Net Derivative Receivables by Contract and Settlement Type:
Gross derivative receivables	176	235
Amounts netted on the Consolidated balance sheets	(174)	(226)
Net derivative receivables	2	9
Gross and Net Derivative Payables by Contract and Settlement Type:
Gross derivative payables	190	274
Amounts netted on the Consolidated balance sheets	(185)	(268)
Net derivative payables	5	6
Foreign exchange contracts | Exchange-traded
Gross and Net Derivative Receivables by Contract and Settlement Type:
Gross derivative receivables	20	32
Amounts netted on the Consolidated balance sheets	(6)	(21)
Net derivative receivables	14	11
Gross and Net Derivative Payables by Contract and Settlement Type:
Gross derivative payables	14	16
Amounts netted on the Consolidated balance sheets	(4)	(3)
Net derivative payables	10	13
Equity contracts
Gross and Net Derivative Receivables by Contract and Settlement Type:
Gross derivative receivables	43,873	45,054
Amounts netted on the Consolidated balance sheets	(38,969)	(39,339)
Net derivative receivables	4,904	5,715
Total derivative receivables recognized on the Consolidated balance sheets, Gross derivative receivables	46,378	49,285
Total derivative receivables recognized on the Consolidated balance sheets, Net derivative receivables	7,409	9,946
Gross and Net Derivative Payables by Contract and Settlement Type:
Gross derivative payables	47,375	45,722
Amounts netted on the Consolidated balance sheets	(40,288)	(41,034)
Net derivative payables	7,087	4,688
Total derivative payables recognized on the Consolidated balance sheets, Gross derivative payables	50,891	51,195
Total derivative payables recognized on the Consolidated balance sheets, Net derivative payables	10,603	10,161
Equity contracts | Over-the-counter (“OTC”)
Gross and Net Derivative Receivables by Contract and Settlement Type:
Gross derivative receivables	22,195	26,178
Amounts netted on the Consolidated balance sheets	(20,281)	(23,879)
Net derivative receivables	1,914	2,299
Gross and Net Derivative Payables by Contract and Settlement Type:
Gross derivative payables	27,010	29,437
Amounts netted on the Consolidated balance sheets	(21,600)	(25,544)
Net derivative payables	5,410	3,893
Equity contracts | Exchange-traded
Gross and Net Derivative Receivables by Contract and Settlement Type:
Gross derivative receivables	21,678	18,876
Amounts netted on the Consolidated balance sheets	(18,688)	(15,460)
Net derivative receivables	2,990	3,416
Gross and Net Derivative Payables by Contract and Settlement Type:
Gross derivative payables	20,365	16,285
Amounts netted on the Consolidated balance sheets	(18,688)	(15,490)
Net derivative payables	1,677	795
Commodity contracts
Gross and Net Derivative Receivables by Contract and Settlement Type:
Gross derivative receivables	16,891	16,263
Amounts netted on the Consolidated balance sheets	(15,096)	(13,479)
Net derivative receivables	1,795	2,784
Total derivative receivables recognized on the Consolidated balance sheets, Gross derivative receivables	21,238	20,470
Total derivative receivables recognized on the Consolidated balance sheets, Net derivative receivables	6,142	6,991
Gross and Net Derivative Payables by Contract and Settlement Type:
Gross derivative payables	20,479	17,189
Amounts netted on the Consolidated balance sheets	(16,022)	(13,046)
Net derivative payables	4,457	4,143
Total derivative payables recognized on the Consolidated balance sheets, Gross derivative payables	25,811	22,418
Total derivative payables recognized on the Consolidated balance sheets, Net derivative payables	9,789	9,372
Commodity contracts | Over-the-counter (“OTC”)
Gross and Net Derivative Receivables by Contract and Settlement Type:
Gross derivative receivables	7,714	7,448
Amounts netted on the Consolidated balance sheets	(5,954)	(5,261)
Net derivative receivables	1,760	2,187
Gross and Net Derivative Payables by Contract and Settlement Type:
Gross derivative payables	10,450	8,930
Amounts netted on the Consolidated balance sheets	(6,874)	(4,838)
Net derivative payables	3,576	4,092
Commodity contracts | OTC–cleared
Gross and Net Derivative Receivables by Contract and Settlement Type:
Gross derivative receivables	26	0
Amounts netted on the Consolidated balance sheets	(25)	0
Net derivative receivables	1	0
Gross and Net Derivative Payables by Contract and Settlement Type:
Gross derivative payables	25	0
Amounts netted on the Consolidated balance sheets	(25)	0
Net derivative payables	0	0
Commodity contracts | Exchange-traded
Gross and Net Derivative Receivables by Contract and Settlement Type:
Gross derivative receivables	9,151	8,815
Amounts netted on the Consolidated balance sheets	(9,117)	(8,218)
Net derivative receivables	34	597
Gross and Net Derivative Payables by Contract and Settlement Type:
Gross derivative payables	10,004	8,259
Amounts netted on the Consolidated balance sheets	(9,123)	(8,208)
Net derivative payables	$ 881	$ 51