Derivative Instruments - Derivatives Netting (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Gross and Net Derivative Receivables by Contract and Settlement Type:
Gross derivative receivables	$ 502,152	$ 510,314
Amounts netted on the Consolidated balance sheets	(466,142)	(472,026)
Net derivative receivables	36,010	38,288
Derivative receivables where an appropriate legal opinion has not been either sought or obtained	14,323	15,925
Total derivative receivables recognized on the Consolidated balance sheets, Gross derivative receivables	516,475	526,239
Total derivative receivables recognized on the Consolidated balance sheets, Net derivative receivables	50,333	54,213
Collateral not nettable on the Consolidated balance sheets	(11,929)	(13,046)
Net amounts	38,404	41,167
Gross and Net Derivative Payables by Contract and Settlement Type:
Gross derivative payables	475,775	485,036
Amounts netted on the Consolidated balance sheets	(451,216)	(460,119)
Net derivative payables	24,559	24,917
Derivative payables where an appropriate legal opinion has not been either sought or obtained	14,444	16,852
Total derivative payables recognized on the Consolidated balance sheets, Gross derivative payables	490,219	501,888
Total derivative payables recognized on the Consolidated balance sheets, Net derivative payables	39,003	41,769
Collateral not nettable on the Consolidated balance sheets	(4,993)	(4,449)
Net amounts	34,010	37,320
Net cash collateral receivables	59,500	55,200
Net cash collateral payables	44,600	43,300
Interest rate contracts
Gross and Net Derivative Receivables by Contract and Settlement Type:
Gross derivative receivables	288,345	264,953
Amounts netted on the Consolidated balance sheets	(269,509)	(245,490)
Net derivative receivables	18,836	19,463
Total derivative receivables recognized on the Consolidated balance sheets, Gross derivative receivables	292,267	268,704
Total derivative receivables recognized on the Consolidated balance sheets, Net derivative receivables	22,758	23,214
Gross and Net Derivative Payables by Contract and Settlement Type:
Gross derivative payables	260,805	240,777
Amounts netted on the Consolidated balance sheets	(254,648)	(234,998)
Net derivative payables	6,157	5,779
Total derivative payables recognized on the Consolidated balance sheets, Gross derivative payables	262,370	242,782
Total derivative payables recognized on the Consolidated balance sheets, Net derivative payables	7,722	7,784
Interest rate contracts | Over-the-counter (“OTC”)
Gross and Net Derivative Receivables by Contract and Settlement Type:
Gross derivative receivables	279,231	258,227
Amounts netted on the Consolidated balance sheets	(260,493)	(239,498)
Net derivative receivables	18,738	18,729
Gross and Net Derivative Payables by Contract and Settlement Type:
Gross derivative payables	250,582	233,404
Amounts netted on the Consolidated balance sheets	(245,040)	(228,369)
Net derivative payables	5,542	5,035
Interest rate contracts | OTC–cleared
Gross and Net Derivative Receivables by Contract and Settlement Type:
Gross derivative receivables	8,794	6,404
Amounts netted on the Consolidated balance sheets	(8,732)	(5,856)
Net derivative receivables	62	548
Gross and Net Derivative Payables by Contract and Settlement Type:
Gross derivative payables	9,873	7,163
Amounts netted on the Consolidated balance sheets	(9,290)	(6,494)
Net derivative payables	583	669
Interest rate contracts | Exchange-traded
Gross and Net Derivative Receivables by Contract and Settlement Type:
Gross derivative receivables	320	322
Amounts netted on the Consolidated balance sheets	(284)	(136)
Net derivative receivables	36	186
Gross and Net Derivative Payables by Contract and Settlement Type:
Gross derivative payables	350	210
Amounts netted on the Consolidated balance sheets	(318)	(135)
Net derivative payables	32	75
Net credit derivatives
Gross and Net Derivative Receivables by Contract and Settlement Type:
Gross derivative receivables	15,764	19,915
Amounts netted on the Consolidated balance sheets	(15,196)	(19,483)
Net derivative receivables	568	432
Total derivative receivables recognized on the Consolidated balance sheets, Gross derivative receivables	15,920	20,095
Total derivative receivables recognized on the Consolidated balance sheets, Net derivative receivables	724	612
Gross and Net Derivative Payables by Contract and Settlement Type:
Gross derivative payables	16,868	20,128
Amounts netted on the Consolidated balance sheets	(15,056)	(18,609)
Net derivative payables	1,812	1,519
Total derivative payables recognized on the Consolidated balance sheets, Gross derivative payables	17,039	20,276
Total derivative payables recognized on the Consolidated balance sheets, Net derivative payables	1,983	1,667
Net credit derivatives | Over-the-counter (“OTC”)
Gross and Net Derivative Receivables by Contract and Settlement Type:
Gross derivative receivables	12,231	12,648
Amounts netted on the Consolidated balance sheets	(11,713)	(12,261)
Net derivative receivables	518	387
Gross and Net Derivative Payables by Contract and Settlement Type:
Gross derivative payables	13,617	13,412
Amounts netted on the Consolidated balance sheets	(11,863)	(11,895)
Net derivative payables	1,754	1,517
Net credit derivatives | OTC–cleared
Gross and Net Derivative Receivables by Contract and Settlement Type:
Gross derivative receivables	3,533	7,267
Amounts netted on the Consolidated balance sheets	(3,483)	(7,222)
Net derivative receivables	50	45
Gross and Net Derivative Payables by Contract and Settlement Type:
Gross derivative payables	3,251	6,716
Amounts netted on the Consolidated balance sheets	(3,193)	(6,714)
Net derivative payables	58	2
Foreign exchange contracts
Gross and Net Derivative Receivables by Contract and Settlement Type:
Gross derivative receivables	147,587	164,129
Amounts netted on the Consolidated balance sheets	(138,124)	(154,235)
Net derivative receivables	9,463	9,894
Total derivative receivables recognized on the Consolidated balance sheets, Gross derivative receivables	149,995	167,685
Total derivative receivables recognized on the Consolidated balance sheets, Net derivative receivables	11,871	13,450
Gross and Net Derivative Payables by Contract and Settlement Type:
Gross derivative payables	145,329	161,220
Amounts netted on the Consolidated balance sheets	(136,634)	(152,432)
Net derivative payables	8,695	8,788
Total derivative payables recognized on the Consolidated balance sheets, Gross derivative payables	148,032	165,217
Total derivative payables recognized on the Consolidated balance sheets, Net derivative payables	11,398	12,785
Foreign exchange contracts | Over-the-counter (“OTC”)
Gross and Net Derivative Receivables by Contract and Settlement Type:
Gross derivative receivables	147,288	163,862
Amounts netted on the Consolidated balance sheets	(137,858)	(153,988)
Net derivative receivables	9,430	9,874
Gross and Net Derivative Payables by Contract and Settlement Type:
Gross derivative payables	145,047	160,930
Amounts netted on the Consolidated balance sheets	(136,368)	(152,161)
Net derivative payables	8,679	8,769
Foreign exchange contracts | OTC–cleared
Gross and Net Derivative Receivables by Contract and Settlement Type:
Gross derivative receivables	275	235
Amounts netted on the Consolidated balance sheets	(262)	(226)
Net derivative receivables	13	9
Gross and Net Derivative Payables by Contract and Settlement Type:
Gross derivative payables	275	274
Amounts netted on the Consolidated balance sheets	(262)	(268)
Net derivative payables	13	6
Foreign exchange contracts | Exchange-traded
Gross and Net Derivative Receivables by Contract and Settlement Type:
Gross derivative receivables	24	32
Amounts netted on the Consolidated balance sheets	(4)	(21)
Net derivative receivables	20	11
Gross and Net Derivative Payables by Contract and Settlement Type:
Gross derivative payables	7	16
Amounts netted on the Consolidated balance sheets	(4)	(3)
Net derivative payables	3	13
Equity contracts
Gross and Net Derivative Receivables by Contract and Settlement Type:
Gross derivative receivables	39,445	45,054
Amounts netted on the Consolidated balance sheets	(33,942)	(39,339)
Net derivative receivables	5,503	5,715
Total derivative receivables recognized on the Consolidated balance sheets, Gross derivative receivables	43,264	49,285
Total derivative receivables recognized on the Consolidated balance sheets, Net derivative receivables	9,322	9,946
Gross and Net Derivative Payables by Contract and Settlement Type:
Gross derivative payables	40,667	45,722
Amounts netted on the Consolidated balance sheets	(34,616)	(41,034)
Net derivative payables	6,051	4,688
Total derivative payables recognized on the Consolidated balance sheets, Gross derivative payables	45,645	51,195
Total derivative payables recognized on the Consolidated balance sheets, Net derivative payables	11,029	10,161
Equity contracts | Over-the-counter (“OTC”)
Gross and Net Derivative Receivables by Contract and Settlement Type:
Gross derivative receivables	22,945	26,178
Amounts netted on the Consolidated balance sheets	(20,477)	(23,879)
Net derivative receivables	2,468	2,299
Gross and Net Derivative Payables by Contract and Settlement Type:
Gross derivative payables	25,939	29,437
Amounts netted on the Consolidated balance sheets	(21,157)	(25,544)
Net derivative payables	4,782	3,893
Equity contracts | Exchange-traded
Gross and Net Derivative Receivables by Contract and Settlement Type:
Gross derivative receivables	16,500	18,876
Amounts netted on the Consolidated balance sheets	(13,465)	(15,460)
Net derivative receivables	3,035	3,416
Gross and Net Derivative Payables by Contract and Settlement Type:
Gross derivative payables	14,728	16,285
Amounts netted on the Consolidated balance sheets	(13,459)	(15,490)
Net derivative payables	1,269	795
Commodity contracts
Gross and Net Derivative Receivables by Contract and Settlement Type:
Gross derivative receivables	11,011	16,263
Amounts netted on the Consolidated balance sheets	(9,371)	(13,479)
Net derivative receivables	1,640	2,784
Total derivative receivables recognized on the Consolidated balance sheets, Gross derivative receivables	15,029	20,470
Total derivative receivables recognized on the Consolidated balance sheets, Net derivative receivables	5,658	6,991
Gross and Net Derivative Payables by Contract and Settlement Type:
Gross derivative payables	12,106	17,189
Amounts netted on the Consolidated balance sheets	(10,262)	(13,046)
Net derivative payables	1,844	4,143
Total derivative payables recognized on the Consolidated balance sheets, Gross derivative payables	17,133	22,418
Total derivative payables recognized on the Consolidated balance sheets, Net derivative payables	6,871	9,372
Commodity contracts | Over-the-counter (“OTC”)
Gross and Net Derivative Receivables by Contract and Settlement Type:
Gross derivative receivables	4,892	7,448
Amounts netted on the Consolidated balance sheets	(3,372)	(5,261)
Net derivative receivables	1,520	2,187
Gross and Net Derivative Payables by Contract and Settlement Type:
Gross derivative payables	5,811	8,930
Amounts netted on the Consolidated balance sheets	(4,291)	(4,838)
Net derivative payables	1,520	4,092
Commodity contracts | OTC–cleared
Gross and Net Derivative Receivables by Contract and Settlement Type:
Gross derivative receivables	13	0
Amounts netted on the Consolidated balance sheets	(11)	0
Net derivative receivables	2	0
Gross and Net Derivative Payables by Contract and Settlement Type:
Gross derivative payables	11	0
Amounts netted on the Consolidated balance sheets	(11)	0
Net derivative payables	0	0
Commodity contracts | Exchange-traded
Gross and Net Derivative Receivables by Contract and Settlement Type:
Gross derivative receivables	6,106	8,815
Amounts netted on the Consolidated balance sheets	(5,988)	(8,218)
Net derivative receivables	118	597
Gross and Net Derivative Payables by Contract and Settlement Type:
Gross derivative payables	6,284	8,259
Amounts netted on the Consolidated balance sheets	(5,960)	(8,208)
Net derivative payables	$ 324	$ 51