Fair Values - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Assets at fair value
Derivative and other contracts	$ 38,605	$ 37,313
Investment securities	145,198	145,566
Total trading assets	357,043	367,074
Investment securities—AFS	91,238	88,113
Securities purchased under agreements to resell	0	7
Liabilities at fair value
Deposits	6,792	6,472
Derivative and other contracts	32,363	35,275
Securities sold under agreements to repurchase	1,012	1,020
Other secured financings	13,123	9,899
Borrowings	97,055	93,900
State and municipal securities
Assets at fair value
Investment securities—AFS	760	1,173
Recurring
Assets at fair value
Netting	(40,627)	(42,915)
Liabilities at fair value
Netting	(45,877)	(42,757)
Borrowings	97,055	93,900
Recurring | Interest rate
Liabilities at fair value
Borrowings	31,490	31,055
Recurring | Credit
Liabilities at fair value
Borrowings	2,388	2,400
Recurring | Foreign exchange
Liabilities at fair value
Borrowings	1,528	1,574
Recurring | Equity
Liabilities at fair value
Borrowings	48,186	46,073
Recurring | Commodity and other
Liabilities at fair value
Borrowings	13,463	12,798
Recurring | Loans and lending commitments
Assets at fair value
Trading assets	9,449	8,188
Recurring | Total
Assets at fair value
Derivative and other contracts	38,605	37,313
Netting	(278,255)	(289,137)
Investment securities	2,722	2,566
Physical commodities	575	736
Total trading assets	351,371	361,550
Investment securities—AFS	91,238	88,113
Securities purchased under agreements to resell		7
Total assets at fair value	442,609	449,670
Liabilities at fair value
Deposits	6,792	6,472
Trading liabilities	155,017	151,512
Derivative and other contracts	32,363	35,275
Netting	(283,505)	(288,979)
Securities sold under agreements to repurchase	1,012	1,020
Other secured financings	13,123	9,899
Borrowings	97,055	93,900
Total liabilities at fair value	272,999	262,803
Recurring | Total | Interest rate
Assets at fair value
Derivative and other contracts	136,078	148,207
Liabilities at fair value
Derivative and other contracts	126,391	138,840
Recurring | Total | Credit
Assets at fair value
Derivative and other contracts	9,190	10,637
Liabilities at fair value
Derivative and other contracts	9,590	11,092
Recurring | Total | Foreign exchange
Assets at fair value
Derivative and other contracts	79,159	93,250
Liabilities at fair value
Derivative and other contracts	73,477	90,361
Recurring | Total | Equity
Assets at fair value
Derivative and other contracts	76,221	58,075
Liabilities at fair value
Derivative and other contracts	92,001	68,894
Recurring | Total | Commodity and other
Assets at fair value
Derivative and other contracts	16,212	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	22,476	27,724
Recurring | Total | Other sovereign government obligations
Liabilities at fair value
Trading liabilities	29,435	30,790
Recurring | Total | Corporate and other debt
Liabilities at fair value
Trading liabilities	12,485	10,569
Recurring | Total | Corporate equities
Liabilities at fair value
Trading liabilities	58,258	47,154
Recurring | Total | U.S. Treasury and agency securities
Assets at fair value
Trading assets	106,548	110,200
Recurring | Total | Other sovereign government obligations
Assets at fair value
Trading assets	42,945	32,620
Recurring | Total | State and municipal securities
Assets at fair value
Trading assets	2,712	2,182
Recurring | Total | MABS
Assets at fair value
Trading assets	2,229	2,029
Recurring | Total | Loans and lending commitments
Assets at fair value
Trading assets	9,449	8,188
Recurring | Total | Corporate and other debt
Assets at fair value
Trading assets	38,814	37,816
Recurring | Total | Corporate equities
Assets at fair value
Equity securities	106,772	127,900
Recurring | Level 1
Assets at fair value
Derivative and other contracts	646	3,430
Netting	(4,816)	(7,643)
Investment securities	998	781
Physical commodities	0	0
Total trading assets	196,334	210,022
Investment securities—AFS	62,777	57,405
Securities purchased under agreements to resell		0
Total assets at fair value	259,111	267,427
Liabilities at fair value
Deposits	0	0
Trading liabilities	109,057	105,852
Derivative and other contracts	888	4,506
Netting	(4,816)	(7,643)
Securities sold under agreements to repurchase	0	0
Other secured financings	0	0
Borrowings	0	0
Total liabilities at fair value	109,057	105,852
Recurring | Level 1 | Interest rate
Assets at fair value
Derivative and other contracts	2,415	7,284
Liabilities at fair value
Derivative and other contracts	2,345	8,000
Recurring | Level 1 | Credit
Assets at fair value
Derivative and other contracts	0	0
Liabilities at fair value
Derivative and other contracts	0	0
Recurring | Level 1 | Foreign exchange
Assets at fair value
Derivative and other contracts	50	12
Liabilities at fair value
Derivative and other contracts	218	96
Recurring | Level 1 | Equity
Assets at fair value
Derivative and other contracts	1,080	2,169
Liabilities at fair value
Derivative and other contracts	1,180	2,411
Recurring | Level 1 | Commodity and other
Assets at fair value
Derivative and other contracts	1,917	1,608
Liabilities at fair value
Derivative and other contracts	1,961	1,642
Recurring | Level 1 | U.S. Treasury and agency securities
Liabilities at fair value
Trading liabilities	22,448	27,708
Recurring | Level 1 | Other sovereign government obligations
Liabilities at fair value
Trading liabilities	27,708	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	58,013	46,809
Recurring | Level 1 | U.S. Treasury and agency securities
Assets at fair value
Trading assets	55,809	56,459
Recurring | Level 1 | Other sovereign government obligations
Assets at fair value
Trading assets	33,634	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	105,247	126,772
Recurring | Level 2
Assets at fair value
Derivative and other contracts	75,081	73,285
Netting	(232,020)	(237,497)
Investment securities	881	836
Physical commodities	575	736
Total trading assets	186,501	185,116
Investment securities—AFS	28,461	30,708
Securities purchased under agreements to resell		7
Total assets at fair value	214,962	215,831
Liabilities at fair value
Deposits	6,758	6,439
Trading liabilities	88,706	84,690
Derivative and other contracts	74,263	69,859
Netting	(232,020)	(237,497)
Securities sold under agreements to repurchase	563	571
Other secured financings	13,032	9,807
Borrowings	95,079	92,022
Total liabilities at fair value	204,138	193,529
Recurring | Level 2 | Interest rate
Assets at fair value
Derivative and other contracts	133,091	140,139
Liabilities at fair value
Derivative and other contracts	123,736	129,983
Recurring | Level 2 | Credit
Assets at fair value
Derivative and other contracts	8,804	10,244
Liabilities at fair value
Derivative and other contracts	9,328	10,795
Recurring | Level 2 | Foreign exchange
Assets at fair value
Derivative and other contracts	79,109	93,218
Liabilities at fair value
Derivative and other contracts	73,141	89,880
Recurring | Level 2 | Equity
Assets at fair value
Derivative and other contracts	74,519	55,319
Liabilities at fair value
Derivative and other contracts	89,144	64,794
Recurring | Level 2 | Commodity and other
Assets at fair value
Derivative and other contracts	11,578	11,862
Liabilities at fair value
Derivative and other contracts	10,934	11,904
Recurring | Level 2 | U.S. Treasury and agency securities
Liabilities at fair value
Trading liabilities	28	16
Recurring | Level 2 | Other sovereign government obligations
Liabilities at fair value
Trading liabilities	1,725	3,955
Recurring | Level 2 | Corporate and other debt
Liabilities at fair value
Trading liabilities	12,473	10,560
Recurring | Level 2 | Corporate equities
Liabilities at fair value
Trading liabilities	217	300
Recurring | Level 2 | U.S. Treasury and agency securities
Assets at fair value
Trading assets	50,739	53,741
Recurring | Level 2 | Other sovereign government obligations
Assets at fair value
Trading assets	9,237	9,946
Recurring | Level 2 | State and municipal securities
Assets at fair value
Trading assets	2,712	2,148
Recurring | Level 2 | MABS
Assets at fair value
Trading assets	1,806	1,540
Recurring | Level 2 | Loans and lending commitments
Assets at fair value
Trading assets	7,273	6,122
Recurring | Level 2 | Corporate and other debt
Assets at fair value
Trading assets	36,889	35,833
Recurring | Level 2 | Corporate equities
Assets at fair value
Equity securities	1,308	929
Recurring | Level 3
Assets at fair value
Equity securities	217	199
Derivative and other contracts	3,505	3,513
Netting	(792)	(1,082)
Investment securities	843	949
Physical commodities	0	0
Total trading assets	9,163	9,327
Investment securities—AFS	0	0
Securities purchased under agreements to resell		0
Total assets at fair value	9,163	9,327
Liabilities at fair value
Deposits	34	33
Trading liabilities	3,131	3,727
Derivative and other contracts	3,089	3,667
Netting	(792)	(1,082)
Securities sold under agreements to repurchase	449	449
Other secured financings	91	92
Borrowings	1,976	1,878
Total liabilities at fair value	5,681	6,179
Recurring | Level 3 | Interest rate
Assets at fair value
Derivative and other contracts	572	784
Liabilities at fair value
Derivative and other contracts	310	857
Recurring | Level 3 | Credit
Assets at fair value
Derivative and other contracts	386	393
Liabilities at fair value
Derivative and other contracts	262	297
Recurring | Level 3 | Foreign exchange
Assets at fair value
Derivative and other contracts	0	20
Liabilities at fair value
Derivative and other contracts	118	385
Recurring | Level 3 | Equity
Assets at fair value
Derivative and other contracts	622	587
Liabilities at fair value
Derivative and other contracts	1,677	1,689
Recurring | Level 3 | Commodity and other
Assets at fair value
Derivative and other contracts	2,717	2,811
Liabilities at fair value
Derivative and other contracts	1,514	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	2	6
Recurring | Level 3 | Corporate and other debt
Liabilities at fair value
Trading liabilities	12	9
Recurring | Level 3 | Corporate equities
Liabilities at fair value
Trading liabilities	28	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	74	94
Recurring | Level 3 | State and municipal securities
Assets at fair value
Trading assets	0	34
Recurring | Level 3 | MABS
Assets at fair value
Trading assets	423	489
Recurring | Level 3 | Loans and lending commitments
Assets at fair value
Trading assets	2,176	2,066
Recurring | Level 3 | Corporate and other debt
Assets at fair value
Trading assets	1,925	1,983
Recurring | Level 3 | Corporate equities
Assets at fair value
Equity securities	$ 217	$ 199