Fair Values - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Assets at fair value
Derivative and other contracts	$ 37,432	$ 37,313
Investment securities	142,596	145,566
Total trading assets	367,633	367,074
Investment securities—AFS	87,313	88,113
Securities purchased under agreements to resell	0	7
Liabilities at fair value
Deposits	6,429	6,472
Derivative and other contracts	32,010	35,275
Securities sold under agreements to repurchase	827	1,020
Other secured financings	11,077	9,899
Borrowings	95,104	93,900
State and municipal securities
Assets at fair value
Investment securities—AFS	492	1,173
Recurring
Assets at fair value
Netting	(39,842)	(42,915)
Liabilities at fair value
Netting	(42,871)	(42,757)
Borrowings	95,104	93,900
Recurring | Interest rate
Liabilities at fair value
Borrowings	30,553	31,055
Recurring | Credit
Liabilities at fair value
Borrowings	2,384	2,400
Recurring | Foreign exchange
Liabilities at fair value
Borrowings	1,601	1,574
Recurring | Equity
Liabilities at fair value
Borrowings	47,086	46,073
Recurring | Commodity and other
Liabilities at fair value
Borrowings	13,480	12,798
Recurring | Loans and lending commitments
Assets at fair value
Trading assets	9,925	8,188
Recurring | Total
Assets at fair value
Derivative and other contracts	37,432	37,313
Netting	(275,463)	(289,137)
Investment securities	2,898	2,566
Physical commodities	1,322	736
Total trading assets	362,294	361,550
Investment securities—AFS	87,313	88,113
Securities purchased under agreements to resell		7
Total assets at fair value	449,607	449,670
Liabilities at fair value
Deposits	6,429	6,472
Trading liabilities	152,843	151,512
Derivative and other contracts	32,010	35,275
Netting	(278,492)	(288,979)
Securities sold under agreements to repurchase	827	1,020
Other secured financings	11,077	9,899
Borrowings	95,104	93,900
Total liabilities at fair value	266,280	262,803
Recurring | Total | Interest rate
Assets at fair value
Derivative and other contracts	136,867	148,207
Liabilities at fair value
Derivative and other contracts	127,445	138,840
Recurring | Total | Credit
Assets at fair value
Derivative and other contracts	10,451	10,637
Liabilities at fair value
Derivative and other contracts	10,897	11,092
Recurring | Total | Foreign exchange
Assets at fair value
Derivative and other contracts	72,352	93,250
Liabilities at fair value
Derivative and other contracts	66,922	90,361
Recurring | Total | Equity
Assets at fair value
Derivative and other contracts	76,460	58,075
Liabilities at fair value
Derivative and other contracts	90,829	68,894
Recurring | Total | Commodity and other
Assets at fair value
Derivative and other contracts	16,765	16,281
Liabilities at fair value
Derivative and other contracts	14,409	15,067
Recurring | Total | U.S. Treasury and agency securities
Liabilities at fair value
Trading liabilities	24,504	27,724
Recurring | Total | Other sovereign government obligations
Liabilities at fair value
Trading liabilities	34,051	30,790
Recurring | Total | Corporate and other debt
Liabilities at fair value
Trading liabilities	12,693	10,569
Recurring | Total | Corporate equities
Liabilities at fair value
Trading liabilities	49,585	47,154
Recurring | Total | U.S. Treasury and agency securities
Assets at fair value
Trading assets	108,910	110,200
Recurring | Total | Other sovereign government obligations
Assets at fair value
Trading assets	38,905	32,620
Recurring | Total | State and municipal securities
Assets at fair value
Trading assets	2,029	2,182
Recurring | Total | MABS
Assets at fair value
Trading assets	2,146	2,029
Recurring | Total | Loans and lending commitments
Assets at fair value
Trading assets	9,925	8,188
Recurring | Total | Corporate and other debt
Assets at fair value
Trading assets	39,346	37,816
Recurring | Total | Corporate equities
Assets at fair value
Equity securities	119,381	127,900
Recurring | Level 1
Assets at fair value
Derivative and other contracts	1,395	3,430
Netting	(4,301)	(7,643)
Investment securities	1,049	781
Physical commodities	0	0
Total trading assets	212,785	210,022
Investment securities—AFS	58,224	57,405
Securities purchased under agreements to resell		0
Total assets at fair value	271,009	267,427
Liabilities at fair value
Deposits	0	0
Trading liabilities	105,712	105,852
Derivative and other contracts	1,522	4,506
Netting	(4,301)	(7,643)
Securities sold under agreements to repurchase	0	0
Other secured financings	0	0
Borrowings	0	0
Total liabilities at fair value	105,712	105,852
Recurring | Level 1 | Interest rate
Assets at fair value
Derivative and other contracts	2,067	7,284
Liabilities at fair value
Derivative and other contracts	1,823	8,000
Recurring | Level 1 | Credit
Assets at fair value
Derivative and other contracts	1	0
Liabilities at fair value
Derivative and other contracts	0	0
Recurring | Level 1 | Foreign exchange
Assets at fair value
Derivative and other contracts	34	12
Liabilities at fair value
Derivative and other contracts	151	96
Recurring | Level 1 | Equity
Assets at fair value
Derivative and other contracts	1,831	2,169
Liabilities at fair value
Derivative and other contracts	1,975	2,411
Recurring | Level 1 | Commodity and other
Assets at fair value
Derivative and other contracts	1,763	1,608
Liabilities at fair value
Derivative and other contracts	1,874	1,642
Recurring | Level 1 | U.S. Treasury and agency securities
Liabilities at fair value
Trading liabilities	24,479	27,708
Recurring | Level 1 | Other sovereign government obligations
Liabilities at fair value
Trading liabilities	30,427	26,829
Recurring | Level 1 | Corporate and other debt
Liabilities at fair value
Trading liabilities	0	0
Recurring | Level 1 | Corporate equities
Liabilities at fair value
Trading liabilities	49,284	46,809
Recurring | Level 1 | U.S. Treasury and agency securities
Assets at fair value
Trading assets	64,272	56,459
Recurring | Level 1 | Other sovereign government obligations
Assets at fair value
Trading assets	27,671	22,580
Recurring | Level 1 | State and municipal securities
Assets at fair value
Trading assets	0	0
Recurring | Level 1 | MABS
Assets at fair value
Trading assets	0	0
Recurring | Level 1 | Loans and lending commitments
Assets at fair value
Trading assets	0	0
Recurring | Level 1 | Corporate and other debt
Assets at fair value
Trading assets	0	0
Recurring | Level 1 | Corporate equities
Assets at fair value
Equity securities	118,398	126,772
Recurring | Level 2
Assets at fair value
Derivative and other contracts	71,899	73,285
Netting	(230,318)	(237,497)
Investment securities	879	836
Physical commodities	1,322	736
Total trading assets	179,573	185,116
Investment securities—AFS	29,089	30,708
Securities purchased under agreements to resell		7
Total assets at fair value	208,662	215,831
Liabilities at fair value
Deposits	6,378	6,439
Trading liabilities	86,365	84,690
Derivative and other contracts	69,795	69,859
Netting	(230,318)	(237,497)
Securities sold under agreements to repurchase	367	571
Other secured financings	11,003	9,807
Borrowings	93,077	92,022
Total liabilities at fair value	197,190	193,529
Recurring | Level 2 | Interest rate
Assets at fair value
Derivative and other contracts	133,957	140,139
Liabilities at fair value
Derivative and other contracts	124,827	129,983
Recurring | Level 2 | Credit
Assets at fair value
Derivative and other contracts	10,049	10,244
Liabilities at fair value
Derivative and other contracts	10,623	10,795
Recurring | Level 2 | Foreign exchange
Assets at fair value
Derivative and other contracts	72,069	93,218
Liabilities at fair value
Derivative and other contracts	66,542	89,880
Recurring | Level 2 | Equity
Assets at fair value
Derivative and other contracts	74,034	55,319
Liabilities at fair value
Derivative and other contracts	87,270	64,794
Recurring | Level 2 | Commodity and other
Assets at fair value
Derivative and other contracts	12,108	11,862
Liabilities at fair value
Derivative and other contracts	10,851	11,904
Recurring | Level 2 | U.S. Treasury and agency securities
Liabilities at fair value
Trading liabilities	25	16
Recurring | Level 2 | Other sovereign government obligations
Liabilities at fair value
Trading liabilities	3,624	3,955
Recurring | Level 2 | Corporate and other debt
Liabilities at fair value
Trading liabilities	12,654	10,560
Recurring | Level 2 | Corporate equities
Liabilities at fair value
Trading liabilities	267	300
Recurring | Level 2 | U.S. Treasury and agency securities
Assets at fair value
Trading assets	44,638	53,741
Recurring | Level 2 | Other sovereign government obligations
Assets at fair value
Trading assets	11,170	9,946
Recurring | Level 2 | State and municipal securities
Assets at fair value
Trading assets	1,927	2,148
Recurring | Level 2 | MABS
Assets at fair value
Trading assets	1,689	1,540
Recurring | Level 2 | Loans and lending commitments
Assets at fair value
Trading assets	8,030	6,122
Recurring | Level 2 | Corporate and other debt
Assets at fair value
Trading assets	37,304	35,833
Recurring | Level 2 | Corporate equities
Assets at fair value
Equity securities	715	929
Recurring | Level 3
Assets at fair value
Equity securities	268	199
Derivative and other contracts	3,980	3,513
Netting	(1,002)	(1,082)
Investment securities	970	949
Physical commodities	0	0
Total trading assets	9,778	9,327
Investment securities—AFS	0	0
Securities purchased under agreements to resell		0
Total assets at fair value	9,778	9,327
Liabilities at fair value
Deposits	51	33
Trading liabilities	3,637	3,727
Derivative and other contracts	3,564	3,667
Netting	(1,002)	(1,082)
Securities sold under agreements to repurchase	460	449
Other secured financings	74	92
Borrowings	2,027	1,878
Total liabilities at fair value	6,249	6,179
Recurring | Level 3 | Interest rate
Assets at fair value
Derivative and other contracts	843	784
Liabilities at fair value
Derivative and other contracts	795	857
Recurring | Level 3 | Credit
Assets at fair value
Derivative and other contracts	401	393
Liabilities at fair value
Derivative and other contracts	274	297
Recurring | Level 3 | Foreign exchange
Assets at fair value
Derivative and other contracts	249	20
Liabilities at fair value
Derivative and other contracts	229	385
Recurring | Level 3 | Equity
Assets at fair value
Derivative and other contracts	595	587
Liabilities at fair value
Derivative and other contracts	1,584	1,689
Recurring | Level 3 | Commodity and other
Assets at fair value
Derivative and other contracts	2,894	2,811
Liabilities at fair value
Derivative and other contracts	1,684	1,521
Recurring | Level 3 | U.S. Treasury and agency securities
Liabilities at fair value
Trading liabilities	0	0
Recurring | Level 3 | Other sovereign government obligations
Liabilities at fair value
Trading liabilities	0	6
Recurring | Level 3 | Corporate and other debt
Liabilities at fair value
Trading liabilities	39	9
Recurring | Level 3 | Corporate equities
Liabilities at fair value
Trading liabilities	34	45
Recurring | Level 3 | U.S. Treasury and agency securities
Assets at fair value
Trading assets	0	0
Recurring | Level 3 | Other sovereign government obligations
Assets at fair value
Trading assets	64	94
Recurring | Level 3 | State and municipal securities
Assets at fair value
Trading assets	102	34
Recurring | Level 3 | MABS
Assets at fair value
Trading assets	457	489
Recurring | Level 3 | Loans and lending commitments
Assets at fair value
Trading assets	1,895	2,066
Recurring | Level 3 | Corporate and other debt
Assets at fair value
Trading assets	2,042	1,983
Recurring | Level 3 | Corporate equities
Assets at fair value
Equity securities	$ 268	$ 199