Fair Values - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Assets at fair value
Derivative and other contracts	$ 37,227	$ 37,313
Investments	152,722	145,566
Total trading assets	362,298	367,074
Investment securities—AFS	97,828	88,113
Securities purchased under agreements to resell	0	7
Liabilities at fair value
Deposits	7,327	6,472
Derivative and other contracts	32,619	35,275
Securities sold under agreements to repurchase	996	1,020
Other secured financings	14,127	9,899
Borrowings	107,547	93,900
State and municipal securities
Assets at fair value
Investment securities—AFS	1,611	1,173
Recurring
Assets at fair value
Netting	(39,608)	(42,915)
Liabilities at fair value
Netting	(42,619)	(42,757)
Borrowings	107,547	93,900
Recurring | Interest rate
Liabilities at fair value
Borrowings	35,239	31,055
Recurring | Credit
Liabilities at fair value
Borrowings	3,047	2,400
Recurring | Foreign exchange
Liabilities at fair value
Borrowings	1,660	1,574
Recurring | Equity
Liabilities at fair value
Borrowings	53,530	46,073
Recurring | Commodity and other
Liabilities at fair value
Borrowings	14,071	12,798
Recurring | Loans and lending commitments
Assets at fair value
Trading assets	8,886	8,188
Recurring | Total
Assets at fair value
Derivative and other contracts	37,227	37,313
Netting	(298,712)	(289,137)
Investments	2,702	2,566
Physical commodities	603	736
Total trading assets	356,554	361,550
Investment securities—AFS	97,828	88,113
Securities purchased under agreements to resell		7
Total assets at fair value	454,382	449,670
Liabilities at fair value
Deposits	7,327	6,472
Trading liabilities	152,238	151,512
Derivative and other contracts	32,619	35,275
Netting	(301,723)	(288,979)
Securities sold under agreements to repurchase	996	1,020
Other secured financings	14,127	9,899
Borrowings	107,547	93,900
Total liabilities at fair value	282,235	262,803
Recurring | Total | Interest rate
Assets at fair value
Derivative and other contracts	133,512	148,207
Liabilities at fair value
Derivative and other contracts	120,264	138,840
Recurring | Total | Credit
Assets at fair value
Derivative and other contracts	10,504	10,637
Liabilities at fair value
Derivative and other contracts	10,958	11,092
Recurring | Total | Foreign exchange
Assets at fair value
Derivative and other contracts	81,632	93,250
Liabilities at fair value
Derivative and other contracts	79,908	90,361
Recurring | Total | Equity
Assets at fair value
Derivative and other contracts	93,110	58,075
Liabilities at fair value
Derivative and other contracts	108,195	68,894
Recurring | Total | Commodity and other
Assets at fair value
Derivative and other contracts	17,181	16,281
Liabilities at fair value
Derivative and other contracts	15,017	15,067
Recurring | Total | U.S. Treasury and agency securities
Liabilities at fair value
Trading liabilities	24,286	27,724
Recurring | Total | Other sovereign government obligations
Liabilities at fair value
Trading liabilities	29,025	30,790
Recurring | Total | Corporate and other debt
Liabilities at fair value
Trading liabilities	13,242	10,569
Recurring | Total | Corporate equities
Liabilities at fair value
Trading liabilities	53,066	47,154
Recurring | Total | U.S. Treasury and agency securities
Assets at fair value
Trading assets	108,252	110,200
Recurring | Total | Other sovereign government obligations
Assets at fair value
Trading assets	46,737	32,620
Recurring | Total | State and municipal securities
Assets at fair value
Trading assets	2,671	2,182
Recurring | Total | MABS
Assets at fair value
Trading assets	1,875	2,029
Recurring | Total | Loans and lending commitments
Assets at fair value
Trading assets	8,886	8,188
Recurring | Total | Corporate and other debt
Assets at fair value
Trading assets	39,213	37,816
Recurring | Total | Corporate equities
Assets at fair value
Equity securities	108,388	127,900
Recurring | Level 1
Assets at fair value
Derivative and other contracts	1,367	3,430
Netting	(5,185)	(7,643)
Investments	930	781
Physical commodities	0	0
Total trading assets	201,245	210,022
Investment securities—AFS	67,986	57,405
Securities purchased under agreements to resell		0
Total assets at fair value	269,231	267,427
Liabilities at fair value
Deposits	0	0
Trading liabilities	103,400	105,852
Derivative and other contracts	2,056	4,506
Netting	(5,185)	(7,643)
Securities sold under agreements to repurchase	0	0
Other secured financings	0	0
Borrowings	0	0
Total liabilities at fair value	103,400	105,852
Recurring | Level 1 | Interest rate
Assets at fair value
Derivative and other contracts	2,904	7,284
Liabilities at fair value
Derivative and other contracts	2,771	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	118	12
Liabilities at fair value
Derivative and other contracts	287	96
Recurring | Level 1 | Equity
Assets at fair value
Derivative and other contracts	1,869	2,169
Liabilities at fair value
Derivative and other contracts	2,478	2,411
Recurring | Level 1 | Commodity and other
Assets at fair value
Derivative and other contracts	1,661	1,608
Liabilities at fair value
Derivative and other contracts	1,705	1,642
Recurring | Level 1 | U.S. Treasury and agency securities
Liabilities at fair value
Trading liabilities	24,264	27,708
Recurring | Level 1 | Other sovereign government obligations
Liabilities at fair value
Trading liabilities	24,765	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	52,315	46,809
Recurring | Level 1 | U.S. Treasury and agency securities
Assets at fair value
Trading assets	59,122	56,459
Recurring | Level 1 | Other sovereign government obligations
Assets at fair value
Trading assets	32,916	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	106,910	126,772
Recurring | Level 2
Assets at fair value
Derivative and other contracts	72,134	73,285
Netting	(253,149)	(237,497)
Investments	962	836
Physical commodities	603	736
Total trading assets	186,706	185,116
Investment securities—AFS	29,842	30,708
Securities purchased under agreements to resell		7
Total assets at fair value	216,548	215,831
Liabilities at fair value
Deposits	7,326	6,439
Trading liabilities	88,516	84,690
Derivative and other contracts	70,313	69,859
Netting	(253,149)	(237,497)
Securities sold under agreements to repurchase	543	571
Other secured financings	13,980	9,807
Borrowings	106,076	92,022
Total liabilities at fair value	216,441	193,529
Recurring | Level 2 | Interest rate
Assets at fair value
Derivative and other contracts	130,161	140,139
Liabilities at fair value
Derivative and other contracts	117,046	129,983
Recurring | Level 2 | Credit
Assets at fair value
Derivative and other contracts	10,115	10,244
Liabilities at fair value
Derivative and other contracts	10,683	10,795
Recurring | Level 2 | Foreign exchange
Assets at fair value
Derivative and other contracts	81,209	93,218
Liabilities at fair value
Derivative and other contracts	79,411	89,880
Recurring | Level 2 | Equity
Assets at fair value
Derivative and other contracts	90,559	55,319
Liabilities at fair value
Derivative and other contracts	104,267	64,794
Recurring | Level 2 | Commodity and other
Assets at fair value
Derivative and other contracts	13,239	11,862
Liabilities at fair value
Derivative and other contracts	12,055	11,904
Recurring | Level 2 | U.S. Treasury and agency securities
Liabilities at fair value
Trading liabilities	22	16
Recurring | Level 2 | Other sovereign government obligations
Liabilities at fair value
Trading liabilities	4,258	3,955
Recurring | Level 2 | Corporate and other debt
Liabilities at fair value
Trading liabilities	13,199	10,560
Recurring | Level 2 | Corporate equities
Liabilities at fair value
Trading liabilities	724	300
Recurring | Level 2 | U.S. Treasury and agency securities
Assets at fair value
Trading assets	49,130	53,741
Recurring | Level 2 | Other sovereign government obligations
Assets at fair value
Trading assets	13,712	9,946
Recurring | Level 2 | State and municipal securities
Assets at fair value
Trading assets	2,658	2,148
Recurring | Level 2 | MABS
Assets at fair value
Trading assets	1,434	1,540
Recurring | Level 2 | Loans and lending commitments
Assets at fair value
Trading assets	7,302	6,122
Recurring | Level 2 | Corporate and other debt
Assets at fair value
Trading assets	37,487	35,833
Recurring | Level 2 | Corporate equities
Assets at fair value
Equity securities	1,284	929
Recurring | Level 3
Assets at fair value
Equity securities	194	199
Derivative and other contracts	3,334	3,513
Netting	(770)	(1,082)
Investments	810	949
Physical commodities	0	0
Total trading assets	8,211	9,327
Investment securities—AFS	0	0
Securities purchased under agreements to resell		0
Total assets at fair value	8,211	9,327
Liabilities at fair value
Deposits	1	33
Trading liabilities	2,941	3,727
Derivative and other contracts	2,869	3,667
Netting	(770)	(1,082)
Securities sold under agreements to repurchase	453	449
Other secured financings	147	92
Borrowings	1,471	1,878
Total liabilities at fair value	5,013	6,179
Recurring | Level 3 | Interest rate
Assets at fair value
Derivative and other contracts	447	784
Liabilities at fair value
Derivative and other contracts	447	857
Recurring | Level 3 | Credit
Assets at fair value
Derivative and other contracts	389	393
Liabilities at fair value
Derivative and other contracts	275	297
Recurring | Level 3 | Foreign exchange
Assets at fair value
Derivative and other contracts	305	20
Liabilities at fair value
Derivative and other contracts	210	385
Recurring | Level 3 | Equity
Assets at fair value
Derivative and other contracts	682	587
Liabilities at fair value
Derivative and other contracts	1,450	1,689
Recurring | Level 3 | Commodity and other
Assets at fair value
Derivative and other contracts	2,281	2,811
Liabilities at fair value
Derivative and other contracts	1,257	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	43	9
Recurring | Level 3 | Corporate equities
Liabilities at fair value
Trading liabilities	27	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	109	94
Recurring | Level 3 | State and municipal securities
Assets at fair value
Trading assets	13	34
Recurring | Level 3 | MABS
Assets at fair value
Trading assets	441	489
Recurring | Level 3 | Loans and lending commitments
Assets at fair value
Trading assets	1,584	2,066
Recurring | Level 3 | Corporate and other debt
Assets at fair value
Trading assets	1,726	1,983
Recurring | Level 3 | Corporate equities
Assets at fair value
Equity securities	$ 194	$ 199