Credit Risk Concentrations (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2023	Dec. 31, 2022
Concentration Risk [Line Items]
Credit exposure	$ 2,899,289	$ 2,582,566
On-balance sheet, Loans	1,310,059	1,135,647
On-balance sheet, Derivatives	67,070	70,880
Off-balance sheet	1,478,784	1,326,782
Available-for-sale securities	197,119	205,857
HTM securities	388,261	425,305
Cash placed with banks	502,800	556,600
First Republic
Concentration Risk [Line Items]
Available-for-sale securities	22,900
Obligations of U.S. states and municipalities
Concentration Risk [Line Items]
Trading assets	6,300	6,600
Available-for-sale securities	19,662	6,786
HTM securities	10,730	19,747
Credit Concentration Risk
Concentration Risk [Line Items]
On-balance sheet, Derivatives	67,070	70,880
Total consumer | Credit Concentration Risk
Concentration Risk [Line Items]
Credit exposure	1,552,920	1,351,352
On-balance sheet, Loans	605,704	496,550
Off-balance sheet	947,216	854,802
Consumer, excluding credit card
Concentration Risk [Line Items]
On-balance sheet, Loans	408,769	311,375
Consumer, excluding credit card | Credit Concentration Risk
Concentration Risk [Line Items]
Credit exposure	457,082	344,893
On-balance sheet, Loans	408,769	311,375
Off-balance sheet	48,313	33,518
Consumer, excluding credit card | Credit Concentration Risk | First Republic
Concentration Risk [Line Items]
Credit exposure	103,300
Credit card
Concentration Risk [Line Items]
On-balance sheet, Loans	196,935	185,175
Credit card | Credit Concentration Risk
Concentration Risk [Line Items]
Credit exposure	1,095,838	1,006,459
On-balance sheet, Loans	196,935	185,175
Off-balance sheet	898,903	821,284
Wholesale
Concentration Risk [Line Items]
On-balance sheet, Loans	704,355	639,097
Wholesale | Credit Concentration Risk
Concentration Risk [Line Items]
Credit exposure	1,346,369	1,231,214
On-balance sheet, Loans	704,355	639,097
Off-balance sheet	531,568	471,980
Wholesale | Credit Concentration Risk | First Republic
Concentration Risk [Line Items]
Credit exposure	95,200
Wholesale-related | Credit Concentration Risk
Concentration Risk [Line Items]
On-balance sheet, Derivatives	67,070	70,880
Wholesale-related | Wholesale | Credit Concentration Risk
Concentration Risk [Line Items]
Credit exposure	1,270,590	1,146,530
On-balance sheet, Loans	671,952	603,670
Off-balance sheet	531,568	471,980
Real Estate | Credit Concentration Risk
Concentration Risk [Line Items]
On-balance sheet, Derivatives	292	249
Real Estate | Wholesale | Credit Concentration Risk
Concentration Risk [Line Items]
Credit exposure	206,067	170,857
On-balance sheet, Loans	166,446	131,681
Off-balance sheet	39,329	38,927
Asset Managers | Credit Concentration Risk
Concentration Risk [Line Items]
On-balance sheet, Derivatives	18,893	16,397
Asset Managers | Wholesale | Credit Concentration Risk
Concentration Risk [Line Items]
Credit exposure	145,707	95,656
On-balance sheet, Loans	54,485	40,511
Off-balance sheet	72,329	38,748
Individuals and Individual Entities | Credit Concentration Risk
Concentration Risk [Line Items]
On-balance sheet, Derivatives	720	434
Individuals and Individual Entities | Wholesale | Credit Concentration Risk
Concentration Risk [Line Items]
Credit exposure	143,786	130,815
On-balance sheet, Loans	124,859	120,424
Off-balance sheet	18,207	9,957
Consumer & Retail | Credit Concentration Risk
Concentration Risk [Line Items]
On-balance sheet, Derivatives	1,905	1,650
Consumer & Retail | Wholesale | Credit Concentration Risk
Concentration Risk [Line Items]
Credit exposure	127,978	120,555
On-balance sheet, Loans	47,013	45,867
Off-balance sheet	79,060	73,038
Industrials | Credit Concentration Risk
Concentration Risk [Line Items]
On-balance sheet, Derivatives	2,058	1,770
Industrials | Wholesale | Credit Concentration Risk
Concentration Risk [Line Items]
Credit exposure	75,865	72,483
On-balance sheet, Loans	26,958	26,960
Off-balance sheet	46,849	43,753
Technology, Media & Telecommunications | Credit Concentration Risk
Concentration Risk [Line Items]
On-balance sheet, Derivatives	2,525	2,950
Technology, Media & Telecommunications | Wholesale | Credit Concentration Risk
Concentration Risk [Line Items]
Credit exposure	73,047	72,286
On-balance sheet, Loans	20,151	21,622
Off-balance sheet	50,371	47,714
Healthcare | Credit Concentration Risk
Concentration Risk [Line Items]
On-balance sheet, Derivatives	1,111	1,683
Healthcare | Wholesale | Credit Concentration Risk
Concentration Risk [Line Items]
Credit exposure	62,126	62,613
On-balance sheet, Loans	23,947	22,970
Off-balance sheet	37,068	37,960
Banks & Finance Companies | Credit Concentration Risk
Concentration Risk [Line Items]
On-balance sheet, Derivatives	3,510	3,246
Banks & Finance Companies | Wholesale | Credit Concentration Risk
Concentration Risk [Line Items]
Credit exposure	56,886	51,816
On-balance sheet, Loans	33,769	32,172
Off-balance sheet	19,607	16,398
State & Municipal Govt | Credit Concentration Risk
Concentration Risk [Line Items]
On-balance sheet, Derivatives	275	585
State & Municipal Govt | Wholesale | Credit Concentration Risk
Concentration Risk [Line Items]
Credit exposure	37,016	33,847
On-balance sheet, Loans	20,827	18,147
Off-balance sheet	15,914	15,115
Utilities | Credit Concentration Risk
Concentration Risk [Line Items]
On-balance sheet, Derivatives	2,852	3,269
Utilities | Wholesale | Credit Concentration Risk
Concentration Risk [Line Items]
Credit exposure	36,454	36,218
On-balance sheet, Loans	7,666	9,107
Off-balance sheet	25,936	23,842
Automotive | Credit Concentration Risk
Concentration Risk [Line Items]
On-balance sheet, Derivatives	469	529
Automotive | Wholesale | Credit Concentration Risk
Concentration Risk [Line Items]
Credit exposure	34,217	33,287
On-balance sheet, Loans	15,813	14,735
Off-balance sheet	17,935	18,023
Oil & Gas | Credit Concentration Risk
Concentration Risk [Line Items]
On-balance sheet, Derivatives	2,386	5,121
Oil & Gas | Wholesale | Credit Concentration Risk
Concentration Risk [Line Items]
Credit exposure	33,253	38,668
On-balance sheet, Loans	9,117	9,632
Off-balance sheet	21,750	23,915
Insurance | Credit Concentration Risk
Concentration Risk [Line Items]
On-balance sheet, Derivatives	10,085	8,081
Insurance | Wholesale | Credit Concentration Risk
Concentration Risk [Line Items]
Credit exposure	23,733	21,045
On-balance sheet, Loans	2,753	2,387
Off-balance sheet	10,895	10,577
Chemicals & Plastics | Credit Concentration Risk
Concentration Risk [Line Items]
On-balance sheet, Derivatives	448	407
Chemicals & Plastics | Wholesale | Credit Concentration Risk
Concentration Risk [Line Items]
Credit exposure	20,261	20,030
On-balance sheet, Loans	6,393	5,771
Off-balance sheet	13,420	13,852
Central Govt | Credit Concentration Risk
Concentration Risk [Line Items]
On-balance sheet, Derivatives	9,944	12,955
Central Govt | Wholesale | Credit Concentration Risk
Concentration Risk [Line Items]
Credit exposure	15,819	19,095
On-balance sheet, Loans	4,078	3,167
Off-balance sheet	1,797	2,973
Transportation | Credit Concentration Risk
Concentration Risk [Line Items]
On-balance sheet, Derivatives	507	567
Transportation | Wholesale | Credit Concentration Risk
Concentration Risk [Line Items]
Credit exposure	15,180	15,009
On-balance sheet, Loans	5,174	5,005
Off-balance sheet	9,499	9,437
Metals & Mining | Credit Concentration Risk
Concentration Risk [Line Items]
On-balance sheet, Derivatives	237	475
Metals & Mining | Wholesale | Credit Concentration Risk
Concentration Risk [Line Items]
Credit exposure	15,136	15,915
On-balance sheet, Loans	4,606	5,398
Off-balance sheet	10,293	10,042
Securities Firms | Credit Concentration Risk
Concentration Risk [Line Items]
On-balance sheet, Derivatives	3,442	3,387
Securities Firms | Wholesale | Credit Concentration Risk
Concentration Risk [Line Items]
Credit exposure	8,928	8,066
On-balance sheet, Loans	860	556
Off-balance sheet	4,626	4,123
Financial Markets Infrastructure | Credit Concentration Risk
Concentration Risk [Line Items]
On-balance sheet, Derivatives	1,672	3,050
Financial Markets Infrastructure | Wholesale | Credit Concentration Risk
Concentration Risk [Line Items]
Credit exposure	4,096	4,962
On-balance sheet, Loans	67	13
Off-balance sheet	2,357	1,899
All other | Credit Concentration Risk
Concentration Risk [Line Items]
On-balance sheet, Derivatives	3,739	4,075
All other | Wholesale | Credit Concentration Risk
Concentration Risk [Line Items]
Credit exposure	135,035	123,307
On-balance sheet, Loans	96,970	87,545
Off-balance sheet	$ 34,326	$ 31,687
All other | Wholesale | Credit Concentration Risk | SPEs and Private education
Concentration Risk [Line Items]
Percentage of exposure secured	94.00%	95.00%
All other | Wholesale | Credit Concentration Risk | Civic organizations
Concentration Risk [Line Items]
Percentage of exposure secured	6.00%	5.00%
Loans held-for-sale and loans at fair value | Wholesale | Credit Concentration Risk
Concentration Risk [Line Items]
Credit exposure	$ 32,403	$ 35,427
On-balance sheet, Loans	32,403	35,427
Receivables from customers | Wholesale | Credit Concentration Risk
Concentration Risk [Line Items]
Credit exposure	$ 43,376	$ 49,257