Derivative Instruments and Hedging Activities - Fair Values of Derivative Contracts (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Derivative Assets
Total gross derivatives	$ 312,895	$ 326,450
Counterparty netting	(236,106)	(246,914)
Cash collateral netting	(39,357)	(42,223)
Total in Trading assets	37,432	37,313
Financial instruments collateral	(17,375)	(15,690)
Net amounts	20,057	21,623
Net amounts for which master netting or collateral agreements are not in place or may not be legally enforceable	2,798	2,641
Derivative Liabilities
Total gross derivatives	310,502	324,254
Counterparty netting	(236,106)	(246,914)
Cash collateral netting	(42,386)	(42,065)
Total in Trading liabilities	32,010	35,275
Cash collateral netting	(4,433)	(6,909)
Net amounts	27,577	28,366
Net amounts for which master netting or collateral agreements are not in place or may not be legally enforceable	4,950	5,911
Designated as accounting hedges
Derivative Assets
Total gross derivatives	107	35
Derivative Liabilities
Total gross derivatives	510	924
Designated as accounting hedges | Interest rate
Derivative Assets
Total gross derivatives	4	25
Derivative Liabilities
Total gross derivatives	482	467
Designated as accounting hedges | Foreign exchange
Derivative Assets
Total gross derivatives	103	10
Derivative Liabilities
Total gross derivatives	28	457
Not designated as accounting hedges
Derivative Assets
Total gross derivatives	312,788	326,415
Derivative Liabilities
Total gross derivatives	309,992	323,330
Economic hedges of loans | Credit
Derivative Assets
Total gross derivatives	33	29
Derivative Liabilities
Total gross derivatives	823	745
Other derivatives | Interest rate
Derivative Assets
Total gross derivatives	136,863	148,182
Derivative Liabilities
Total gross derivatives	126,963	138,373
Other derivatives | Credit
Derivative Assets
Total gross derivatives	10,418	10,608
Derivative Liabilities
Total gross derivatives	10,074	10,347
Other derivatives | Foreign exchange
Derivative Assets
Total gross derivatives	72,249	93,240
Derivative Liabilities
Total gross derivatives	66,894	89,904
Other derivatives | Equity
Derivative Assets
Total gross derivatives	76,460	58,075
Derivative Liabilities
Total gross derivatives	90,829	68,894
Other derivatives | Commodity and other
Derivative Assets
Total gross derivatives	16,765	16,281
Derivative Liabilities
Total gross derivatives	14,409	15,067
Bilateral OTC
Derivative Assets
Total gross derivatives	235,270	258,078
Counterparty netting	(163,903)	(184,553)
Cash collateral netting	(37,516)	(39,493)
Total in Trading assets	33,851	34,032
Financial instruments collateral	(17,375)	(15,690)
Net amounts	16,476	18,342
Derivative Liabilities
Total gross derivatives	233,638	258,334
Counterparty netting	(163,903)	(184,553)
Cash collateral netting	(41,077)	(41,082)
Total in Trading liabilities	28,658	32,699
Cash collateral netting	(4,092)	(6,864)
Net amounts	24,566	25,835
Bilateral OTC | Designated as accounting hedges
Derivative Assets
Total gross derivatives	87	30
Derivative Liabilities
Total gross derivatives	498	881
Bilateral OTC | Designated as accounting hedges | Interest rate
Derivative Assets
Total gross derivatives	4	25
Derivative Liabilities
Total gross derivatives	482	467
Bilateral OTC | Designated as accounting hedges | Foreign exchange
Derivative Assets
Total gross derivatives	83	5
Derivative Liabilities
Total gross derivatives	16	414
Bilateral OTC | Not designated as accounting hedges
Derivative Assets
Total gross derivatives	235,183	258,048
Derivative Liabilities
Total gross derivatives	233,140	257,453
Bilateral OTC | Economic hedges of loans | Credit
Derivative Assets
Total gross derivatives	3	2
Derivative Liabilities
Total gross derivatives	44	43
Bilateral OTC | Other derivatives | Interest rate
Derivative Assets
Total gross derivatives	120,182	127,414
Derivative Liabilities
Total gross derivatives	112,206	120,604
Bilateral OTC | Other derivatives | Credit
Derivative Assets
Total gross derivatives	5,522	5,712
Derivative Liabilities
Total gross derivatives	5,550	5,920
Bilateral OTC | Other derivatives | Foreign exchange
Derivative Assets
Total gross derivatives	70,243	90,654
Derivative Liabilities
Total gross derivatives	64,588	87,104
Bilateral OTC | Other derivatives | Equity
Derivative Assets
Total gross derivatives	24,722	20,338
Derivative Liabilities
Total gross derivatives	38,982	31,545
Bilateral OTC | Other derivatives | Commodity and other
Derivative Assets
Total gross derivatives	14,511	13,928
Derivative Liabilities
Total gross derivatives	11,770	12,237
Cleared OTC
Derivative Assets
Total gross derivatives	23,284	27,412
Counterparty netting	(20,569)	(23,851)
Cash collateral netting	(1,841)	(2,730)
Total in Trading assets	874	831
Financial instruments collateral	0	0
Net amounts	874	831
Derivative Liabilities
Total gross derivatives	21,924	25,045
Counterparty netting	(20,569)	(23,851)
Cash collateral netting	(1,309)	(983)
Total in Trading liabilities	46	211
Cash collateral netting	0	(8)
Net amounts	46	203
Cleared OTC | Designated as accounting hedges
Derivative Assets
Total gross derivatives	20	5
Derivative Liabilities
Total gross derivatives	12	43
Cleared OTC | Designated as accounting hedges | Interest rate
Derivative Assets
Total gross derivatives	0	0
Derivative Liabilities
Total gross derivatives	0	0
Cleared OTC | Designated as accounting hedges | Foreign exchange
Derivative Assets
Total gross derivatives	20	5
Derivative Liabilities
Total gross derivatives	12	43
Cleared OTC | Not designated as accounting hedges
Derivative Assets
Total gross derivatives	23,264	27,407
Derivative Liabilities
Total gross derivatives	21,912	25,002
Cleared OTC | Economic hedges of loans | Credit
Derivative Assets
Total gross derivatives	30	27
Derivative Liabilities
Total gross derivatives	779	702
Cleared OTC | Other derivatives | Interest rate
Derivative Assets
Total gross derivatives	16,370	19,914
Derivative Liabilities
Total gross derivatives	14,460	17,179
Cleared OTC | Other derivatives | Credit
Derivative Assets
Total gross derivatives	4,896	4,896
Derivative Liabilities
Total gross derivatives	4,524	4,427
Cleared OTC | Other derivatives | Foreign exchange
Derivative Assets
Total gross derivatives	1,968	2,570
Derivative Liabilities
Total gross derivatives	2,149	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	54,341	40,960
Counterparty netting	(51,634)	(38,510)
Cash collateral netting	0	0
Total in Trading assets	2,707	2,450
Financial instruments collateral	0	0
Net amounts	2,707	2,450
Derivative Liabilities
Total gross derivatives	54,940	40,875
Counterparty netting	(51,634)	(38,510)
Cash collateral netting	0	0
Total in Trading liabilities	3,306	2,365
Cash collateral netting	(341)	(37)
Net amounts	2,965	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	54,341	40,960
Derivative Liabilities
Total gross derivatives	54,940	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	311	854
Derivative Liabilities
Total gross derivatives	297	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	38	16
Derivative Liabilities
Total gross derivatives	157	106
Exchange- Traded | Other derivatives | Equity
Derivative Assets
Total gross derivatives	51,738	37,737
Derivative Liabilities
Total gross derivatives	51,847	37,349
Exchange- Traded | Other derivatives | Commodity and other
Derivative Assets
Total gross derivatives	2,254	2,353
Derivative Liabilities
Total gross derivatives	$ 2,639	$ 2,830