Fair Value Hierarchy - Fair Value of Derivatives by Level (Detail) - USD ($) $ in Millions	Sep. 30, 2023	Jun. 30, 2023	Dec. 31, 2022
Derivative [Line Items]
Total financial assets at fair value	$ 758,400	$ 722,276	$ 650,966
Total financial liabilities at fair value	(588,532)	(577,513)	(447,584)
Fair value included in financial instruments	(195,123)		(191,324)
Level 1
Derivative [Line Items]
Total financial assets at fair value	318,535	270,334	194,698
Total financial liabilities at fair value	(123,428)	(125,540)	(119,578)
Level 2
Derivative [Line Items]
Total financial assets at fair value	471,365	478,619	485,134
Total financial liabilities at fair value	(481,831)	(469,090)	(353,060)
Level 3
Derivative [Line Items]
Total financial assets at fair value	24,862	25,945	26,048
Total financial liabilities at fair value	(27,659)	(26,159)	(22,830)
Derivatives
Derivative [Line Items]
Total financial assets at fair value	108,461		117,268
Fair value included in financial instruments	49,062		59,413
Total financial liabilities at fair value	(99,203)		(102,619)
Fair value included in financial instruments	(54,817)		(54,735)
Derivatives | Gross fair value
Derivative [Line Items]
Total financial assets at fair value	448,568		477,071
Total financial liabilities at fair value	(439,310)		(462,422)
Derivatives | Interest rates
Derivative [Line Items]
Total financial assets at fair value	264,697		270,359
Total financial liabilities at fair value	(242,026)		(249,062)
Derivatives | Credit
Derivative [Line Items]
Total financial assets at fair value	12,649		12,267
Total financial liabilities at fair value	(10,300)		(11,280)
Derivatives | Currencies
Derivative [Line Items]
Total financial assets at fair value	101,531		103,944
Total financial liabilities at fair value	(101,477)		(112,172)
Derivatives | Commodities
Derivative [Line Items]
Total financial assets at fair value	20,715		39,940
Total financial liabilities at fair value	(19,866)		(33,125)
Derivatives | Equities
Derivative [Line Items]
Total financial assets at fair value	48,976		50,561
Total financial liabilities at fair value	(65,641)		(56,783)
Derivatives | Counterparty netting in levels
Derivative [Line Items]
Total financial assets at fair value	(340,107)		(359,803)
Total financial liabilities at fair value	340,107		359,803
Derivatives | Cross-level counterparty netting
Derivative [Line Items]
Total financial assets at fair value	(963)		(1,079)
Total financial liabilities at fair value	963		1,079
Derivatives | Cash collateral netting
Derivative [Line Items]
Cash collateral netting	(58,436)		(56,776)
Cash collateral netting	43,423		46,805
Derivatives | Level 1
Derivative [Line Items]
Total financial assets at fair value	119		182
Total financial liabilities at fair value	(135)		(47)
Derivatives | Level 1 | Gross fair value
Derivative [Line Items]
Total financial assets at fair value	119		182
Total financial liabilities at fair value	(135)		(47)
Derivatives | Level 1 | Interest rates
Derivative [Line Items]
Total financial assets at fair value	112		69
Total financial liabilities at fair value	(126)		(32)
Derivatives | Level 1 | Credit
Derivative [Line Items]
Total financial assets at fair value	0		0
Total financial liabilities at fair value	0		0
Derivatives | Level 1 | Currencies
Derivative [Line Items]
Total financial assets at fair value	0		0
Total financial liabilities at fair value	0		0
Derivatives | Level 1 | Commodities
Derivative [Line Items]
Total financial assets at fair value	0		0
Total financial liabilities at fair value	0		0
Derivatives | Level 1 | Equities
Derivative [Line Items]
Total financial assets at fair value	7		113
Total financial liabilities at fair value	(9)		(15)
Derivatives | Level 1 | Counterparty netting in levels
Derivative [Line Items]
Total financial assets at fair value	0		0
Total financial liabilities at fair value	0		0
Derivatives | Level 2
Derivative [Line Items]
Total financial assets at fair value	103,685		111,625
Total financial liabilities at fair value	(94,770)		(98,632)
Derivatives | Level 2 | Gross fair value
Derivative [Line Items]
Total financial assets at fair value	442,775		470,542
Total financial liabilities at fair value	(433,860)		(457,549)
Derivatives | Level 2 | Interest rates
Derivative [Line Items]
Total financial assets at fair value	264,074		269,590
Total financial liabilities at fair value	(240,782)		(247,871)
Derivatives | Level 2 | Credit
Derivative [Line Items]
Total financial assets at fair value	9,900		9,690
Total financial liabilities at fair value	(9,161)		(10,163)
Derivatives | Level 2 | Currencies
Derivative [Line Items]
Total financial assets at fair value	101,232		103,450
Total financial liabilities at fair value	(101,326)		(111,840)
Derivatives | Level 2 | Commodities
Derivative [Line Items]
Total financial assets at fair value	19,310		38,331
Total financial liabilities at fair value	(19,051)		(32,435)
Derivatives | Level 2 | Equities
Derivative [Line Items]
Total financial assets at fair value	48,259		49,481
Total financial liabilities at fair value	(63,540)		(55,240)
Derivatives | Level 2 | Counterparty netting in levels
Derivative [Line Items]
Total financial assets at fair value	(339,090)		(358,917)
Total financial liabilities at fair value	339,090		358,917
Derivatives | Level 3
Derivative [Line Items]
Total financial assets at fair value	4,657	$ 4,776	5,461
Total financial liabilities at fair value	(4,298)		(3,940)
Derivatives | Level 3 | Gross fair value
Derivative [Line Items]
Total financial assets at fair value	5,674		6,347
Total financial liabilities at fair value	(5,315)		(4,826)
Derivatives | Level 3 | Interest rates
Derivative [Line Items]
Total financial assets at fair value	511		700
Total financial liabilities at fair value	(1,118)		(1,159)
Derivatives | Level 3 | Credit
Derivative [Line Items]
Total financial assets at fair value	2,749		2,577
Total financial liabilities at fair value	(1,139)		(1,117)
Derivatives | Level 3 | Currencies
Derivative [Line Items]
Total financial assets at fair value	299		494
Total financial liabilities at fair value	(151)		(332)
Derivatives | Level 3 | Commodities
Derivative [Line Items]
Total financial assets at fair value	1,405		1,609
Total financial liabilities at fair value	(815)		(690)
Derivatives | Level 3 | Equities
Derivative [Line Items]
Total financial assets at fair value	710		967
Total financial liabilities at fair value	(2,092)		(1,528)
Derivatives | Level 3 | Counterparty netting in levels
Derivative [Line Items]
Total financial assets at fair value	(1,017)		(886)
Total financial liabilities at fair value	$ 1,017		$ 886