Fair Value Measurement - Recurring Basis (Details) - USD ($) $ in Millions	Sep. 30, 2025	Jun. 30, 2025	Dec. 31, 2024	Sep. 30, 2024	Jun. 30, 2024	Dec. 31, 2023
Assets and liabilities measured at fair value on a recurring basis
Gross derivative receivables	$ 627,898		$ 665,587
Derivative netting adjustments	(568,049)		(604,620)
Total derivative receivables	59,849		60,967
Total trading assets	952,777		637,784
Available-for-sale securities	490,499		406,852
Loans	54,686		41,350
Mortgage servicing rights	9,110	$ 8,996	9,121	$ 8,753	$ 8,847	$ 8,522
Gross derivative payables	618,318		653,218
Derivative netting adjustments	(571,915)		(613,557)
Total derivative payables	46,403		39,661
Interest rate
Assets and liabilities measured at fair value on a recurring basis
Gross derivative receivables	296,564		290,734
Derivative netting adjustments	(271,468)		(265,789)
Total derivative receivables	25,096		24,945
Gross derivative payables	272,931		274,228
Derivative netting adjustments	(265,134)		(264,989)
Total derivative payables	7,797		9,239
Credit
Assets and liabilities measured at fair value on a recurring basis
Gross derivative receivables	13,123		11,087
Derivative netting adjustments	(12,691)		(10,273)
Total derivative receivables	432		814
Gross derivative payables	19,443		13,796
Derivative netting adjustments	(16,388)		(11,898)
Total derivative payables	3,055		1,898
Foreign exchange
Assets and liabilities measured at fair value on a recurring basis
Gross derivative receivables	164,193		262,920
Derivative netting adjustments	(144,169)		(237,608)
Total derivative receivables	20,024		25,312
Gross derivative payables	156,442		254,567
Derivative netting adjustments	(143,875)		(238,970)
Total derivative payables	12,567		15,597
Equity
Assets and liabilities measured at fair value on a recurring basis
Gross derivative receivables	130,266		85,220
Derivative netting adjustments	(122,470)		(79,935)
Total derivative receivables	7,796		5,285
Gross derivative payables	150,483		96,139
Derivative netting adjustments	(133,056)		(87,491)
Total derivative payables	17,427		8,648
Commodity
Assets and liabilities measured at fair value on a recurring basis
Gross derivative receivables	23,752		15,626
Derivative netting adjustments	(17,251)		(11,015)
Total derivative receivables	6,501		4,611
Gross derivative payables	19,019		14,488
Derivative netting adjustments	(13,462)		(10,209)
Total derivative payables	5,557		4,279
Total mortgage-backed securities
Assets and liabilities measured at fair value on a recurring basis
Available-for-sale securities	102,393		100,769
Mortgage-backed securities, Commercial - nonagency
Assets and liabilities measured at fair value on a recurring basis
Available-for-sale securities	4,521		4,065
U.S. Treasury, GSEs and government agencies
Assets and liabilities measured at fair value on a recurring basis
Available-for-sale securities	301,886		234,779
Obligations of U.S. states and municipalities
Assets and liabilities measured at fair value on a recurring basis
Available-for-sale securities	19,968		17,913
Non-U.S. government debt securities
Assets and liabilities measured at fair value on a recurring basis
Available-for-sale securities	44,279		36,245
Corporate debt securities
Assets and liabilities measured at fair value on a recurring basis
Available-for-sale securities	125		70
Asset-backed securities
Assets and liabilities measured at fair value on a recurring basis
Available-for-sale securities	21,848
Asset-backed securities, Collateralized loan obligations
Assets and liabilities measured at fair value on a recurring basis
Available-for-sale securities	19,754		14,943
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	839		1,000
Recurring
Assets and liabilities measured at fair value on a recurring basis
Federal funds sold and securities purchased under resale agreements	404,609		286,771
Securities borrowed	104,757		83,962
Total debt and equity instruments	892,928		576,817
Derivative netting adjustments	(568,049)		(604,620)
Total derivative receivables	59,849		60,967
Total trading assets	952,777		637,784
Available-for-sale securities	490,499		406,852
Loans	54,686		41,350
Mortgage servicing rights	9,110		9,121
Total assets measured at fair value on a recurring basis	2,032,740		1,479,913
Deposits	36,018		33,768
Federal funds purchased and securities loaned or sold under repurchase agreements	489,189		226,329
Short-term borrowings	36,638		26,521
Trading liabilities, debt and equity instruments	195,859		153,222
Derivative netting adjustments	(571,915)		(613,557)
Total derivative payables	46,403		39,661
Total trading liabilities	242,262		192,883
Accounts payable and other liabilities	8,157		5,893
Beneficial interests issued by consolidated VIEs	8		1
Long-term debt	124,178		100,780
Total liabilities measured at fair value on a recurring basis	936,450		586,175
Recurring | Interest rate
Assets and liabilities measured at fair value on a recurring basis
Derivative netting adjustments	(271,468)		(265,789)
Total derivative receivables	25,096		24,945
Derivative netting adjustments	(265,134)		(264,989)
Total derivative payables	7,797		9,239
Recurring | Credit
Assets and liabilities measured at fair value on a recurring basis
Derivative netting adjustments	(12,691)		(10,273)
Total derivative receivables	432		814
Derivative netting adjustments	(16,388)		(11,898)
Total derivative payables	3,055		1,898
Recurring | Foreign exchange
Assets and liabilities measured at fair value on a recurring basis
Derivative netting adjustments	(144,169)		(237,608)
Total derivative receivables	20,024		25,312
Derivative netting adjustments	(143,875)		(238,970)
Total derivative payables	12,567		15,597
Recurring | Equity
Assets and liabilities measured at fair value on a recurring basis
Derivative netting adjustments	(122,470)		(79,935)
Total derivative receivables	7,796		5,285
Derivative netting adjustments	(133,056)		(87,491)
Total derivative payables	17,427		8,648
Recurring | Commodity
Assets and liabilities measured at fair value on a recurring basis
Derivative netting adjustments	(17,251)		(11,015)
Total derivative receivables	6,501		4,611
Derivative netting adjustments	(13,462)		(10,209)
Total derivative payables	5,557		4,279
Recurring | Other assets
Assets and liabilities measured at fair value on a recurring basis
Other assets	16,302		14,073
Recurring | Total debt instruments
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	605,145		417,428
Recurring | Total mortgage-backed securities
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	162,142		108,380
Available-for-sale securities	102,393		100,769
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	158,036		104,800
Available-for-sale securities	91,853		91,893
Recurring | Mortgage-backed securities, Residential - nonagency
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	2,488		2,287
Available-for-sale securities	6,019		4,811
Recurring | Mortgage-backed securities, Commercial - nonagency
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	1,618		1,293
Available-for-sale securities	4,521		4,065
Recurring | U.S. Treasury, GSEs and government agencies
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	213,730		162,282
Available-for-sale securities	301,886		234,779
Recurring | Obligations of U.S. states and municipalities
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	6,346		6,101
Available-for-sale securities	19,968		17,913
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	5,119		3,950
Recurring | Non-U.S. government debt securities
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	147,892		88,595
Available-for-sale securities	44,279		36,245
Recurring | Corporate debt securities
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	52,115		33,981
Available-for-sale securities	125		70
Recurring | Loans
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	13,228		11,316
Recurring | Asset-backed securities
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	4,573		2,823
Recurring | Equity securities
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	267,252		131,728
Recurring | Physical commodities
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	6,849		7,516
Recurring | Other
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	13,682		20,145
Recurring | Asset-backed securities, Collateralized loan obligations
Assets and liabilities measured at fair value on a recurring basis
Available-for-sale securities	19,754		14,943
Recurring | Asset-backed securities, Other
Assets and liabilities measured at fair value on a recurring basis
Available-for-sale securities	2,094		2,133
Recurring | U.S. GSE obligations
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	162,900		120,100
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	530,103		320,952
Gross derivative receivables	2,408		5,130
Total trading assets	532,511		326,082
Available-for-sale securities	335,871		258,464
Loans	0		0
Mortgage servicing rights	0		0
Total assets measured at fair value on a recurring basis	876,231		590,278
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	152,491		120,719
Gross derivative payables	2,728		4,168
Total trading liabilities	155,219		124,887
Accounts payable and other liabilities	4,685		3,100
Beneficial interests issued by consolidated VIEs	0		0
Long-term debt	0		0
Total liabilities measured at fair value on a recurring basis	159,904		127,987
Recurring | Level 1 | Interest rate
Assets and liabilities measured at fair value on a recurring basis
Gross derivative receivables	2,264		4,934
Gross derivative payables	2,584		3,981
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	144		196
Gross derivative payables	144		187
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	7,849		5,732
Recurring | Level 1 | Total debt instruments
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	258,915		184,688
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	194,952		150,580
Available-for-sale securities	301,600		234,491
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	63,963		34,108
Available-for-sale securities	34,271		23,973
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	265,489		130,307
Recurring | Level 1 | Physical commodities
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	5,698		5,957
Recurring | Level 1 | Other
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	1		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	404,609		286,771
Securities borrowed	104,757		83,962
Total debt and equity instruments	360,136		253,423
Gross derivative receivables	615,823		652,005
Total trading assets	975,959		905,428
Available-for-sale securities	154,527		148,380
Loans	52,192		38,934
Mortgage servicing rights	0		0
Total assets measured at fair value on a recurring basis	1,699,117		1,470,472
Deposits	33,490		31,583
Federal funds purchased and securities loaned or sold under repurchase agreements	489,189		226,329
Short-term borrowings	32,084		23,045
Trading liabilities, debt and equity instruments	43,270		32,457
Gross derivative payables	603,332		637,617
Total trading liabilities	646,602		670,074
Accounts payable and other liabilities	3,439		2,717
Beneficial interests issued by consolidated VIEs	8		1
Long-term debt	80,424		66,216
Total liabilities measured at fair value on a recurring basis	1,285,236		1,019,965
Recurring | Level 2 | Interest rate
Assets and liabilities measured at fair value on a recurring basis
Gross derivative receivables	290,037		282,019
Gross derivative payables	267,589		266,767
Recurring | Level 2 | Credit
Assets and liabilities measured at fair value on a recurring basis
Gross derivative receivables	12,316		10,379
Gross derivative payables	17,404		12,725
Recurring | Level 2 | Foreign exchange
Assets and liabilities measured at fair value on a recurring basis
Gross derivative receivables	162,252		261,520
Gross derivative payables	154,831		253,196
Recurring | Level 2 | Equity
Assets and liabilities measured at fair value on a recurring basis
Gross derivative receivables	128,047		82,855
Gross derivative payables	144,950		90,908
Recurring | Level 2 | Commodity
Assets and liabilities measured at fair value on a recurring basis
Gross derivative receivables	23,171		15,232
Gross derivative payables	18,558		14,021
Recurring | Level 2 | Other assets
Assets and liabilities measured at fair value on a recurring basis
Other assets	7,073		6,997
Recurring | Level 2 | Total debt instruments
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	344,168		230,596
Recurring | Level 2 | Total mortgage-backed securities
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	161,807		107,877
Available-for-sale securities	102,386		100,761
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	157,712		104,312
Available-for-sale securities	91,853		91,893
Recurring | Level 2 | Mortgage-backed securities, Residential - nonagency
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	2,483		2,282
Available-for-sale securities	6,019		4,811
Recurring | Level 2 | Mortgage-backed securities, Commercial - nonagency
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	1,612		1,283
Available-for-sale securities	4,514		4,057
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	18,778		11,702
Available-for-sale securities	286		288
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	6,345		6,100
Available-for-sale securities	19,968		17,913
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	5,119		3,950
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	83,710		54,335
Available-for-sale securities	10,008		12,272
Recurring | Level 2 | Corporate debt securities
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	51,661		33,591
Available-for-sale securities	31		70
Recurring | Level 2 | Loans
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	12,177		10,228
Recurring | Level 2 | Asset-backed securities
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	4,571		2,813
Recurring | Level 2 | Equity securities
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	1,664		1,359
Recurring | Level 2 | Physical commodities
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	1,134		1,533
Recurring | Level 2 | Other
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	13,170		19,935
Recurring | Level 2 | Asset-backed securities, Collateralized loan obligations
Assets and liabilities measured at fair value on a recurring basis
Available-for-sale securities	19,754		14,943
Recurring | Level 2 | Asset-backed securities, Other
Assets and liabilities measured at fair value on a recurring basis
Available-for-sale securities	2,094		2,133
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	2,689		2,442
Gross derivative receivables	9,667		8,452
Total trading assets	12,356		10,894
Available-for-sale securities	101		8
Loans	2,494		2,416
Mortgage servicing rights	9,110		9,121
Total assets measured at fair value on a recurring basis	25,441		23,783
Deposits	2,528		2,185
Federal funds purchased and securities loaned or sold under repurchase agreements	0		0
Short-term borrowings	4,554		3,476
Trading liabilities, debt and equity instruments	98		46
Gross derivative payables	12,258		11,433
Total trading liabilities	12,356		11,479
Accounts payable and other liabilities	33		76
Beneficial interests issued by consolidated VIEs	0		0
Long-term debt	43,754		34,564
Total liabilities measured at fair value on a recurring basis	63,225		51,780
Recurring | Level 3 | Interest rate
Assets and liabilities measured at fair value on a recurring basis
Gross derivative receivables	4,263		3,781
Gross derivative payables	2,758		3,480
Recurring | Level 3 | Credit
Assets and liabilities measured at fair value on a recurring basis
Gross derivative receivables	807		708
Gross derivative payables	2,039		1,071
Recurring | Level 3 | Foreign exchange
Assets and liabilities measured at fair value on a recurring basis
Gross derivative receivables	1,797		1,204
Gross derivative payables	1,467		1,184
Recurring | Level 3 | Equity
Assets and liabilities measured at fair value on a recurring basis
Gross derivative receivables	2,219		2,365
Gross derivative payables	5,533		5,231
Recurring | Level 3 | Commodity
Assets and liabilities measured at fair value on a recurring basis
Gross derivative receivables	581		394
Gross derivative payables	461		467
Recurring | Level 3 | Other assets
Assets and liabilities measured at fair value on a recurring basis
Other assets	1,380		1,344
Recurring | Level 3 | Total debt instruments
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	2,062		2,144
Recurring | Level 3 | Total mortgage-backed securities
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	335		503
Available-for-sale securities	7		8
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	324		488
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	6		10
Available-for-sale securities	7		8
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	1		1
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	219		152
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	454		390
Available-for-sale securities	94		0
Recurring | Level 3 | Loans
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	1,051		1,088
Recurring | Level 3 | Asset-backed securities
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	2		10
Recurring | Level 3 | Equity securities
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	99		62
Recurring | Level 3 | Physical commodities
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	17		26
Recurring | Level 3 | Other
Assets and liabilities measured at fair value on a recurring basis
Total debt and equity instruments	511		210
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