Fair Value Measurement - Recurring Basis (Details) - USD ($) $ in Millions	Sep. 30, 2024	Jun. 30, 2024	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Dec. 31, 2022
Assets and liabilities measured at fair value on a recurring basis
Gross derivative receivables	$ 633,736		$ 539,248
Derivative netting adjustments	(581,175)		(484,384)
Total derivative receivables	52,561		54,864
Total trading assets	787,489		540,607
Available-for-sale securities	334,548		201,704
Loans	42,137		38,851
Mortgage servicing rights	8,753	$ 8,847	8,522	$ 9,109	$ 8,229	$ 7,973
Gross derivative payables	633,885		546,972
Derivative netting adjustments	(595,220)		(506,125)
Total derivative payables	38,665		40,847
Interest rate
Assets and liabilities measured at fair value on a recurring basis
Gross derivative receivables	306,252		250,691
Derivative netting adjustments	(282,118)		(224,367)
Total derivative receivables	24,134		26,324
Gross derivative payables	288,845		240,482
Derivative netting adjustments	(280,237)		(228,586)
Total derivative payables	8,608		11,896
Credit
Assets and liabilities measured at fair value on a recurring basis
Gross derivative receivables	10,522		9,654
Derivative netting adjustments	(9,913)		(9,103)
Total derivative receivables	609		551
Gross derivative payables	13,973		12,038
Derivative netting adjustments	(12,247)		(10,949)
Total derivative payables	1,726		1,089
Foreign exchange
Assets and liabilities measured at fair value on a recurring basis
Gross derivative receivables	196,473		205,775
Derivative netting adjustments	(179,484)		(187,756)
Total derivative receivables	16,989		18,019
Gross derivative payables	199,996		212,263
Derivative netting adjustments	(187,348)		(199,643)
Total derivative payables	12,648		12,620
Equity
Assets and liabilities measured at fair value on a recurring basis
Gross derivative receivables	98,845		57,689
Derivative netting adjustments	(93,494)		(52,761)
Total derivative receivables	5,351		4,928
Gross derivative payables	111,659		65,811
Derivative netting adjustments	(101,049)		(56,443)
Total derivative payables	10,610		9,368
Commodity
Assets and liabilities measured at fair value on a recurring basis
Gross derivative receivables	21,644		15,439
Derivative netting adjustments	(16,166)		(10,397)
Total derivative receivables	5,478		5,042
Gross derivative payables	19,412		16,378
Derivative netting adjustments	(14,339)		(10,504)
Total derivative payables	5,073		5,874
Total mortgage-backed securities
Assets and liabilities measured at fair value on a recurring basis
Available-for-sale securities	89,529		91,612
Mortgage-backed securities, Commercial - nonagency
Assets and liabilities measured at fair value on a recurring basis
Available-for-sale securities	3,609		2,803
U.S. Treasury, GSEs and government agencies
Assets and liabilities measured at fair value on a recurring basis
Available-for-sale securities	172,182		57,805
Obligations of U.S. states and municipalities
Assets and liabilities measured at fair value on a recurring basis
Available-for-sale securities	18,205		21,367
Non-U.S. government debt securities
Assets and liabilities measured at fair value on a recurring basis
Available-for-sale securities	42,553		21,282
Corporate debt securities
Assets and liabilities measured at fair value on a recurring basis
Available-for-sale securities	61		100
Asset-backed securities
Assets and liabilities measured at fair value on a recurring basis
Available-for-sale securities	12,018
Asset-backed securities, Collateralized loan obligations
Assets and liabilities measured at fair value on a recurring basis
Available-for-sale securities	9,682		6,752
Fair Value Measured at Net Asset Value Per Share
Fair value assets and liabilities measured on recurring basis - supplemental data
Alternative investments, net asset value, fair value	802		1,000
Recurring
Assets and liabilities measured at fair value on a recurring basis
Federal funds sold and securities purchased under resale agreements	368,964		259,813
Securities borrowed	107,599		70,086
Total debt and equity instruments	734,928		485,701
Derivative netting adjustments	(581,175)		(484,384)
Total derivative receivables	52,561		54,864
Total trading assets	787,489		540,565
Available-for-sale securities	334,548		201,704
Loans	42,137		38,851
Mortgage servicing rights	8,753		8,522
Total assets measured at fair value on a recurring basis	1,662,857		1,130,863
Deposits	51,284		78,384
Federal funds purchased and securities loaned or sold under repurchase agreements	320,406		169,003
Short-term borrowings	28,307		20,042
Trading liabilities, debt and equity instruments	204,593		139,581
Derivative netting adjustments	(595,220)		(506,125)
Total derivative payables	38,665		40,847
Total trading liabilities	243,258		180,428
Accounts payable and other liabilities	5,865		5,637
Beneficial interests issued by consolidated VIEs	1		1
Long-term debt	102,129		87,924
Total liabilities measured at fair value on a recurring basis	751,250		541,419
Recurring | Interest rate
Assets and liabilities measured at fair value on a recurring basis
Derivative netting adjustments	(282,118)		(224,367)
Total derivative receivables	24,134		26,324
Derivative netting adjustments	(280,237)		(228,586)
Total derivative payables	8,608		11,896
Recurring | Credit
Assets and liabilities measured at fair value on a recurring basis
Derivative netting adjustments	(9,913)		(9,103)
Total derivative receivables	609		551
Derivative netting adjustments	(12,247)		(10,949)
Total derivative payables	1,726		1,089
Recurring | Foreign exchange
Assets and liabilities measured at fair value on a recurring basis
Derivative netting adjustments	(179,484)		(187,756)
Total derivative receivables	16,989		18,019
Derivative netting adjustments	(187,348)		(199,643)
Total derivative payables	12,648		12,620
Recurring | Equity
Assets and liabilities measured at fair value on a recurring basis
Derivative netting adjustments	(93,494)		(52,761)
Total derivative receivables	5,351		4,928
Derivative netting adjustments	(101,049)		(56,443)
Total derivative payables	10,610		9,368
Recurring | Commodity
Assets and liabilities measured at fair value on a recurring basis
Derivative netting adjustments	(16,166)		(10,397)
Total derivative receivables	5,478		5,042
Derivative netting adjustments	(14,339)		(10,504)
Total derivative payables	5,073		5,874
Recurring | Other assets
Assets and liabilities measured at fair value on a recurring basis
Other assets	13,367		11,322
Recurring | Total debt instruments
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	487,634		353,198
Recurring | Total mortgage-backed securities
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	140,620		77,898
Available-for-sale securities	89,529		91,612
Recurring | Mortgage-backed securities, U.S. GSEs and government agencies
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	137,285		74,598
Available-for-sale securities	81,863		85,170
Recurring | Mortgage-backed securities, Residential - nonagency
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	2,056		1,926
Available-for-sale securities	4,057		3,639
Recurring | Mortgage-backed securities, Commercial - nonagency
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	1,279		1,374
Available-for-sale securities	3,609		2,803
Recurring | U.S. Treasury, GSEs and government agencies
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	161,941		143,995
Available-for-sale securities	172,182		57,805
Recurring | Obligations of U.S. states and municipalities
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	5,652		5,868
Available-for-sale securities	18,205		21,367
Recurring | Certificates of deposit, bankers’ acceptances and commercial paper
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	2,851		756
Recurring | Non-U.S. government debt securities
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	119,553		80,582
Available-for-sale securities	42,553		21,282
Recurring | Corporate debt securities
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	44,179		33,338
Available-for-sale securities	61		100
Recurring | Loans
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	10,022		8,556
Recurring | Asset-backed securities
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	2,816		2,205
Recurring | Equity securities
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	225,188		108,732
Recurring | Physical commodities
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	3,189		5,791
Recurring | Other
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	18,917		17,980
Recurring | Asset-backed securities, Collateralized loan obligations
Assets and liabilities measured at fair value on a recurring basis
Available-for-sale securities	9,682		6,752
Recurring | Asset-backed securities, Other
Assets and liabilities measured at fair value on a recurring basis
Available-for-sale securities	2,336		2,786
Recurring | U.S. GSE obligations
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	144,200		78,500
Recurring | Residential mortgage
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	13,300		10,200
Recurring | Commercial mortgage
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	6,000		6,000
Recurring | Residential conforming mortgage intended for sale to U.S. GSEs and government agencies
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	5,800		2,900
Recurring | Level 1
Assets and liabilities measured at fair value on a recurring basis
Federal funds sold and securities purchased under resale agreements	0		0
Securities borrowed	0		0
Total debt and equity instruments	424,023		269,248
Gross derivative receivables	2,399		2,964
Total trading assets	426,422		272,212
Available-for-sale securities	191,803		70,778
Loans	0		0
Mortgage servicing rights	0		0
Total assets measured at fair value on a recurring basis	625,403		349,625
Deposits	0		0
Federal funds purchased and securities loaned or sold under repurchase agreements	0		0
Short-term borrowings	0		0
Trading liabilities, debt and equity instruments	166,655		107,292
Gross derivative payables	3,208		4,556
Total trading liabilities	169,863		111,848
Accounts payable and other liabilities	4,256		3,968
Beneficial interests issued by consolidated VIEs	0		0
Long-term debt	0		0
Total liabilities measured at fair value on a recurring basis	174,119		115,816
Recurring | Level 1 | Interest rate
Assets and liabilities measured at fair value on a recurring basis
Gross derivative receivables	2,073		2,815
Gross derivative payables	2,873		4,409
Recurring | Level 1 | Credit
Assets and liabilities measured at fair value on a recurring basis
Gross derivative receivables	0		0
Gross derivative payables	0		0
Recurring | Level 1 | Foreign exchange
Assets and liabilities measured at fair value on a recurring basis
Gross derivative receivables	326		149
Gross derivative payables	335		147
Recurring | Level 1 | Equity
Assets and liabilities measured at fair value on a recurring basis
Gross derivative receivables	0		0
Gross derivative payables	0		0
Recurring | Level 1 | Commodity
Assets and liabilities measured at fair value on a recurring basis
Gross derivative receivables	0		0
Gross derivative payables	0		0
Recurring | Level 1 | Other assets
Assets and liabilities measured at fair value on a recurring basis
Other assets	7,178		6,635
Recurring | Level 1 | Total debt instruments
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	198,201		158,843
Recurring | Level 1 | Total mortgage-backed securities
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	0		0
Available-for-sale securities	0		0
Recurring | Level 1 | Mortgage-backed securities, U.S. GSEs and government agencies
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	0		0
Available-for-sale securities	0		0
Recurring | Level 1 | Mortgage-backed securities, Residential - nonagency
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	0		0
Available-for-sale securities	0		0
Recurring | Level 1 | Mortgage-backed securities, Commercial - nonagency
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	0		0
Available-for-sale securities	0		0
Recurring | Level 1 | U.S. Treasury, GSEs and government agencies
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	148,160		133,997
Available-for-sale securities	171,878		57,683
Recurring | Level 1 | Obligations of U.S. states and municipalities
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	0		0
Available-for-sale securities	0		0
Recurring | Level 1 | Certificates of deposit, bankers’ acceptances and commercial paper
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	0		0
Recurring | Level 1 | Non-U.S. government debt securities
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	50,041		24,846
Available-for-sale securities	19,925		13,095
Recurring | Level 1 | Corporate debt securities
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	0		0
Available-for-sale securities	0		0
Recurring | Level 1 | Loans
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	0		0
Recurring | Level 1 | Asset-backed securities
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	0		0
Recurring | Level 1 | Equity securities
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	223,651		107,926
Recurring | Level 1 | Physical commodities
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	2,171		2,479
Recurring | Level 1 | Other
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	0		0
Recurring | Level 1 | Asset-backed securities, Collateralized loan obligations
Assets and liabilities measured at fair value on a recurring basis
Available-for-sale securities	0		0
Recurring | Level 1 | Asset-backed securities, Other
Assets and liabilities measured at fair value on a recurring basis
Available-for-sale securities	0		0
Recurring | Level 2
Assets and liabilities measured at fair value on a recurring basis
Federal funds sold and securities purchased under resale agreements	368,964		259,813
Securities borrowed	107,599		70,086
Total debt and equity instruments	308,468		214,080
Gross derivative receivables	620,627		527,360
Total trading assets	929,095		741,440
Available-for-sale securities	142,745		130,926
Loans	39,650		35,772
Mortgage servicing rights	0		0
Total assets measured at fair value on a recurring basis	1,593,056		1,241,966
Deposits	49,065		76,551
Federal funds purchased and securities loaned or sold under repurchase agreements	320,406		169,003
Short-term borrowings	24,660		18,284
Trading liabilities, debt and equity instruments	37,866		32,252
Gross derivative payables	618,555		531,640
Total trading liabilities	656,421		563,892
Accounts payable and other liabilities	1,567		1,617
Beneficial interests issued by consolidated VIEs	1		1
Long-term debt	68,656		60,198
Total liabilities measured at fair value on a recurring basis	1,120,776		889,546
Recurring | Level 2 | Interest rate
Assets and liabilities measured at fair value on a recurring basis
Gross derivative receivables	298,544		243,578
Gross derivative payables	283,166		232,277
Recurring | Level 2 | Credit
Assets and liabilities measured at fair value on a recurring basis
Gross derivative receivables	9,567		8,644
Gross derivative payables	12,919		11,293
Recurring | Level 2 | Foreign exchange
Assets and liabilities measured at fair value on a recurring basis
Gross derivative receivables	195,081		204,737
Gross derivative payables	198,635		211,289
Recurring | Level 2 | Equity
Assets and liabilities measured at fair value on a recurring basis
Gross derivative receivables	96,107		55,167
Gross derivative payables	105,111		60,887
Recurring | Level 2 | Commodity
Assets and liabilities measured at fair value on a recurring basis
Gross derivative receivables	21,328		15,234
Gross derivative payables	18,724		15,894
Recurring | Level 2 | Other assets
Assets and liabilities measured at fair value on a recurring basis
Other assets	5,003		3,929
Recurring | Level 2 | Total debt instruments
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	287,290		192,217
Recurring | Level 2 | Total mortgage-backed securities
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	139,913		77,123
Available-for-sale securities	89,529		91,612
Recurring | Level 2 | Mortgage-backed securities, U.S. GSEs and government agencies
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	136,594		73,840
Available-for-sale securities	81,863		85,170
Recurring | Level 2 | Mortgage-backed securities, Residential - nonagency
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	2,051		1,921
Available-for-sale securities	4,057		3,639
Recurring | Level 2 | Mortgage-backed securities, Commercial - nonagency
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	1,268		1,362
Available-for-sale securities	3,609		2,803
Recurring | Level 2 | U.S. Treasury, GSEs and government agencies
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	13,781		9,998
Available-for-sale securities	304		122
Recurring | Level 2 | Obligations of U.S. states and municipalities
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	5,645		5,858
Available-for-sale securities	18,205		21,367
Recurring | Level 2 | Certificates of deposit, bankers’ acceptances and commercial paper
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	2,851		756
Recurring | Level 2 | Non-U.S. government debt securities
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	69,339		55,557
Available-for-sale securities	22,628		8,187
Recurring | Level 2 | Corporate debt securities
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	43,744		32,854
Available-for-sale securities	61		100
Recurring | Level 2 | Loans
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	9,203		7,872
Recurring | Level 2 | Asset-backed securities
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	2,814		2,199
Recurring | Level 2 | Equity securities
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	1,436		679
Recurring | Level 2 | Physical commodities
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	1,008		3,305
Recurring | Level 2 | Other
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	18,734		17,879
Recurring | Level 2 | Asset-backed securities, Collateralized loan obligations
Assets and liabilities measured at fair value on a recurring basis
Available-for-sale securities	9,682		6,752
Recurring | Level 2 | Asset-backed securities, Other
Assets and liabilities measured at fair value on a recurring basis
Available-for-sale securities	2,336		2,786
Recurring | Level 3
Assets and liabilities measured at fair value on a recurring basis
Federal funds sold and securities purchased under resale agreements	0		0
Securities borrowed	0		0
Total debt and equity instruments	2,437		2,373
Gross derivative receivables	10,710		8,924
Total trading assets	13,147		11,297
Available-for-sale securities	0		0
Loans	2,487		3,079
Mortgage servicing rights	8,753		8,522
Total assets measured at fair value on a recurring basis	25,573		23,656
Deposits	2,219		1,833
Federal funds purchased and securities loaned or sold under repurchase agreements	0		0
Short-term borrowings	3,647		1,758
Trading liabilities, debt and equity instruments	72		37
Gross derivative payables	12,122		10,776
Total trading liabilities	12,194		10,813
Accounts payable and other liabilities	42		52
Beneficial interests issued by consolidated VIEs	0		0
Long-term debt	33,473		27,726
Total liabilities measured at fair value on a recurring basis	51,575		42,182
Recurring | Level 3 | Interest rate
Assets and liabilities measured at fair value on a recurring basis
Gross derivative receivables	5,635		4,298
Gross derivative payables	2,806		3,796
Recurring | Level 3 | Credit
Assets and liabilities measured at fair value on a recurring basis
Gross derivative receivables	955		1,010
Gross derivative payables	1,054		745
Recurring | Level 3 | Foreign exchange
Assets and liabilities measured at fair value on a recurring basis
Gross derivative receivables	1,066		889
Gross derivative payables	1,026		827
Recurring | Level 3 | Equity
Assets and liabilities measured at fair value on a recurring basis
Gross derivative receivables	2,738		2,522
Gross derivative payables	6,548		4,924
Recurring | Level 3 | Commodity
Assets and liabilities measured at fair value on a recurring basis
Gross derivative receivables	316		205
Gross derivative payables	688		484
Recurring | Level 3 | Other assets
Assets and liabilities measured at fair value on a recurring basis
Other assets	1,186		758
Recurring | Level 3 | Total debt instruments
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	2,143		2,138
Recurring | Level 3 | Total mortgage-backed securities
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	707		775
Available-for-sale securities	0		0
Recurring | Level 3 | Mortgage-backed securities, U.S. GSEs and government agencies
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	691		758
Available-for-sale securities	0		0
Recurring | Level 3 | Mortgage-backed securities, Residential - nonagency
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	5		5
Available-for-sale securities	0		0
Recurring | Level 3 | Mortgage-backed securities, Commercial - nonagency
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	11		12
Available-for-sale securities	0		0
Recurring | Level 3 | U.S. Treasury, GSEs and government agencies
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	0		0
Available-for-sale securities	0		0
Recurring | Level 3 | Obligations of U.S. states and municipalities
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	7		10
Available-for-sale securities	0		0
Recurring | Level 3 | Certificates of deposit, bankers’ acceptances and commercial paper
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	0		0
Recurring | Level 3 | Non-U.S. government debt securities
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	173		179
Available-for-sale securities	0		0
Recurring | Level 3 | Corporate debt securities
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	435		484
Available-for-sale securities	0		0
Recurring | Level 3 | Loans
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	819		684
Recurring | Level 3 | Asset-backed securities
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	2		6
Recurring | Level 3 | Equity securities
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	101		127
Recurring | Level 3 | Physical commodities
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	10		7
Recurring | Level 3 | Other
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	183		101
Recurring | Level 3 | Asset-backed securities, Collateralized loan obligations
Assets and liabilities measured at fair value on a recurring basis
Available-for-sale securities	0		0
Recurring | Level 3 | Asset-backed securities, Other
Assets and liabilities measured at fair value on a recurring basis
Available-for-sale securities	$ 0		$ 0