Derivative Instruments and Hedging Activities - Fair Values of Derivative Contracts (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Derivative Assets
Total gross derivatives	$ 316,860	$ 326,450
Counterparty netting	(238,420)	(246,914)
Cash collateral netting	(39,835)	(42,223)
Total in Trading assets	38,605	37,313
Financial instruments collateral	(18,113)	(15,690)
Net amounts	20,492	21,623
Net amounts for which master netting or collateral agreements are not in place or may not be legally enforceable	2,581	2,641
Derivative Liabilities
Total gross derivatives	315,868	324,254
Counterparty netting	(238,420)	(246,914)
Cash collateral netting	(45,085)	(42,065)
Total in Trading liabilities	32,363	35,275
Cash collateral netting	(4,782)	(6,909)
Net amounts	27,581	28,366
Net amounts for which master netting or collateral agreements are not in place or may not be legally enforceable	5,426	5,911
Designated as accounting hedges
Derivative Assets
Total gross derivatives	207	35
Derivative Liabilities
Total gross derivatives	545	924
Designated as accounting hedges | Interest rate
Derivative Assets
Total gross derivatives	3	25
Derivative Liabilities
Total gross derivatives	514	467
Designated as accounting hedges | Foreign exchange
Derivative Assets
Total gross derivatives	204	10
Derivative Liabilities
Total gross derivatives	31	457
Not designated as accounting hedges
Derivative Assets
Total gross derivatives	316,653	326,415
Derivative Liabilities
Total gross derivatives	315,323	323,330
Economic hedges of loans | Credit
Derivative Assets
Total gross derivatives	43	29
Derivative Liabilities
Total gross derivatives	816	745
Other derivatives | Interest rate
Derivative Assets
Total gross derivatives	136,075	148,182
Derivative Liabilities
Total gross derivatives	125,877	138,373
Other derivatives | Credit
Derivative Assets
Total gross derivatives	9,147	10,608
Derivative Liabilities
Total gross derivatives	8,774	10,347
Other derivatives | Foreign exchange
Derivative Assets
Total gross derivatives	78,955	93,240
Derivative Liabilities
Total gross derivatives	73,446	89,904
Other derivatives | Equity
Derivative Assets
Total gross derivatives	76,221	58,075
Derivative Liabilities
Total gross derivatives	92,001	68,894
Other derivatives | Commodity and other
Derivative Assets
Total gross derivatives	16,212	16,281
Derivative Liabilities
Total gross derivatives	14,409	15,067
Bilateral OTC
Derivative Assets
Total gross derivatives	238,289	258,078
Counterparty netting	(165,846)	(184,553)
Cash collateral netting	(38,098)	(39,493)
Total in Trading assets	34,345	34,032
Financial instruments collateral	(18,113)	(15,690)
Net amounts	16,232	18,342
Derivative Liabilities
Total gross derivatives	239,305	258,334
Counterparty netting	(165,846)	(184,553)
Cash collateral netting	(44,244)	(41,082)
Total in Trading liabilities	29,215	32,699
Cash collateral netting	(4,474)	(6,864)
Net amounts	24,741	25,835
Bilateral OTC | Designated as accounting hedges
Derivative Assets
Total gross derivatives	141	30
Derivative Liabilities
Total gross derivatives	528	881
Bilateral OTC | Designated as accounting hedges | Interest rate
Derivative Assets
Total gross derivatives	3	25
Derivative Liabilities
Total gross derivatives	513	467
Bilateral OTC | Designated as accounting hedges | Foreign exchange
Derivative Assets
Total gross derivatives	138	5
Derivative Liabilities
Total gross derivatives	15	414
Bilateral OTC | Not designated as accounting hedges
Derivative Assets
Total gross derivatives	238,148	258,048
Derivative Liabilities
Total gross derivatives	238,777	257,453
Bilateral OTC | Economic hedges of loans | Credit
Derivative Assets
Total gross derivatives	0	2
Derivative Liabilities
Total gross derivatives	54	43
Bilateral OTC | Other derivatives | Interest rate
Derivative Assets
Total gross derivatives	119,039	127,414
Derivative Liabilities
Total gross derivatives	110,719	120,604
Bilateral OTC | Other derivatives | Credit
Derivative Assets
Total gross derivatives	5,513	5,712
Derivative Liabilities
Total gross derivatives	5,412	5,920
Bilateral OTC | Other derivatives | Foreign exchange
Derivative Assets
Total gross derivatives	75,928	90,654
Derivative Liabilities
Total gross derivatives	70,296	87,104
Bilateral OTC | Other derivatives | Equity
Derivative Assets
Total gross derivatives	24,099	20,338
Derivative Liabilities
Total gross derivatives	40,693	31,545
Bilateral OTC | Other derivatives | Commodity and other
Derivative Assets
Total gross derivatives	13,569	13,928
Derivative Liabilities
Total gross derivatives	11,603	12,237
Cleared OTC
Derivative Assets
Total gross derivatives	23,508	27,412
Counterparty netting	(20,798)	(23,851)
Cash collateral netting	(1,737)	(2,730)
Total in Trading assets	973	831
Financial instruments collateral	0	0
Net amounts	973	831
Derivative Liabilities
Total gross derivatives	21,976	25,045
Counterparty netting	(20,798)	(23,851)
Cash collateral netting	(841)	(983)
Total in Trading liabilities	337	211
Cash collateral netting	0	(8)
Net amounts	337	203
Cleared OTC | Designated as accounting hedges
Derivative Assets
Total gross derivatives	66	5
Derivative Liabilities
Total gross derivatives	17	43
Cleared OTC | Designated as accounting hedges | Interest rate
Derivative Assets
Total gross derivatives	0	0
Derivative Liabilities
Total gross derivatives	1	0
Cleared OTC | Designated as accounting hedges | Foreign exchange
Derivative Assets
Total gross derivatives	66	5
Derivative Liabilities
Total gross derivatives	16	43
Cleared OTC | Not designated as accounting hedges
Derivative Assets
Total gross derivatives	23,442	27,407
Derivative Liabilities
Total gross derivatives	21,959	25,002
Cleared OTC | Economic hedges of loans | Credit
Derivative Assets
Total gross derivatives	43	27
Derivative Liabilities
Total gross derivatives	762	702
Cleared OTC | Other derivatives | Interest rate
Derivative Assets
Total gross derivatives	16,808	19,914
Derivative Liabilities
Total gross derivatives	14,912	17,179
Cleared OTC | Other derivatives | Credit
Derivative Assets
Total gross derivatives	3,634	4,896
Derivative Liabilities
Total gross derivatives	3,362	4,427
Cleared OTC | Other derivatives | Foreign exchange
Derivative Assets
Total gross derivatives	2,957	2,570
Derivative Liabilities
Total gross derivatives	2,923	2,694
Cleared OTC | Other derivatives | Equity
Derivative Assets
Total gross derivatives	0	0
Derivative Liabilities
Total gross derivatives	0	0
Cleared OTC | Other derivatives | Commodity and other
Derivative Assets
Total gross derivatives	0	0
Derivative Liabilities
Total gross derivatives	0	0
Exchange- Traded
Derivative Assets
Total gross derivatives	55,063	40,960
Counterparty netting	(51,776)	(38,510)
Cash collateral netting	0	0
Total in Trading assets	3,287	2,450
Financial instruments collateral	0	0
Net amounts	3,287	2,450
Derivative Liabilities
Total gross derivatives	54,587	40,875
Counterparty netting	(51,776)	(38,510)
Cash collateral netting	0	0
Total in Trading liabilities	2,811	2,365
Cash collateral netting	(308)	(37)
Net amounts	2,503	2,328
Exchange- Traded | Designated as accounting hedges
Derivative Assets
Total gross derivatives	0	0
Derivative Liabilities
Total gross derivatives	0	0
Exchange- Traded | Designated as accounting hedges | Interest rate
Derivative Assets
Total gross derivatives	0	0
Derivative Liabilities
Total gross derivatives	0	0
Exchange- Traded | Designated as accounting hedges | Foreign exchange
Derivative Assets
Total gross derivatives	0	0
Derivative Liabilities
Total gross derivatives	0	0
Exchange- Traded | Not designated as accounting hedges
Derivative Assets
Total gross derivatives	55,063	40,960
Derivative Liabilities
Total gross derivatives	54,587	40,875
Exchange- Traded | Economic hedges of loans | Credit
Derivative Assets
Total gross derivatives	0	0
Derivative Liabilities
Total gross derivatives	0	0
Exchange- Traded | Other derivatives | Interest rate
Derivative Assets
Total gross derivatives	228	854
Derivative Liabilities
Total gross derivatives	246	590
Exchange- Traded | Other derivatives | Credit
Derivative Assets
Total gross derivatives	0	0
Derivative Liabilities
Total gross derivatives	0	0
Exchange- Traded | Other derivatives | Foreign exchange
Derivative Assets
Total gross derivatives	70	16
Derivative Liabilities
Total gross derivatives	227	106
Exchange- Traded | Other derivatives | Equity
Derivative Assets
Total gross derivatives	52,122	37,737
Derivative Liabilities
Total gross derivatives	51,308	37,349
Exchange- Traded | Other derivatives | Commodity and other
Derivative Assets
Total gross derivatives	2,643	2,353
Derivative Liabilities
Total gross derivatives	$ 2,806	$ 2,830