Trading Cash Instruments - Schedule of Trading Cash Instruments by Level (Detail) - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Trading cash instruments assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument assets at fair value	$ 303,854	$ 311,956
Trading cash instruments assets | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument assets at fair value	198,846	204,564
Trading cash instruments assets | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument assets at fair value	103,180	105,503
Trading cash instruments assets | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument assets at fair value	1,828	1,889
Trading cash instruments assets | U.S. government and agency obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument assets at fair value	90,482	90,815
Trading cash instruments assets | U.S. government and agency obligations | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument assets at fair value	62,481	63,388
Trading cash instruments assets | U.S. government and agency obligations | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument assets at fair value	28,001	27,427
Trading cash instruments assets | U.S. government and agency obligations | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument assets at fair value	0	0
Trading cash instruments assets | Non-U.S. government and agency obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument assets at fair value	69,846	48,814
Trading cash instruments assets | Non-U.S. government and agency obligations | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument assets at fair value	52,260	35,284
Trading cash instruments assets | Non-U.S. government and agency obligations | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument assets at fair value	17,548	13,511
Trading cash instruments assets | Non-U.S. government and agency obligations | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument assets at fair value	38	19
Trading cash instruments assets | Loans and securities backed by commercial real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument assets at fair value	1,490	1,854
Trading cash instruments assets | Loans and securities backed by commercial real estate | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument assets at fair value	0	0
Trading cash instruments assets | Loans and securities backed by commercial real estate | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument assets at fair value	1,435	1,717
Trading cash instruments assets | Loans and securities backed by commercial real estate | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument assets at fair value	55	137
Trading cash instruments assets | Loans and securities backed by residential real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument assets at fair value	9,555	13,235
Trading cash instruments assets | Loans and securities backed by residential real estate | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument assets at fair value	0	0
Trading cash instruments assets | Loans and securities backed by residential real estate | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument assets at fair value	9,445	13,083
Trading cash instruments assets | Loans and securities backed by residential real estate | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument assets at fair value	110	152
Trading cash instruments assets | Corporate debt instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument assets at fair value	34,981	38,782
Trading cash instruments assets | Corporate debt instruments | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument assets at fair value	282	590
Trading cash instruments assets | Corporate debt instruments | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument assets at fair value	33,347	36,874
Trading cash instruments assets | Corporate debt instruments | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument assets at fair value	1,352	1,318
Trading cash instruments assets | State and municipal obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument assets at fair value	595	604
Trading cash instruments assets | State and municipal obligations | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument assets at fair value	0	0
Trading cash instruments assets | State and municipal obligations | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument assets at fair value	563	568
Trading cash instruments assets | State and municipal obligations | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument assets at fair value	32	36
Trading cash instruments assets | Other debt obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument assets at fair value	3,776	1,699
Trading cash instruments assets | Other debt obligations | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument assets at fair value	254	69
Trading cash instruments assets | Other debt obligations | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument assets at fair value	3,387	1,564
Trading cash instruments assets | Other debt obligations | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument assets at fair value	135	66
Trading cash instruments assets | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument assets at fair value	85,618	108,347
Trading cash instruments assets | Equity securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument assets at fair value	83,569	105,233
Trading cash instruments assets | Equity securities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument assets at fair value	1,947	2,958
Trading cash instruments assets | Equity securities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument assets at fair value	102	156
Trading cash instruments assets | Commodities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument assets at fair value	7,511	7,806
Trading cash instruments assets | Commodities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument assets at fair value	0	0
Trading cash instruments assets | Commodities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument assets at fair value	7,507	7,801
Trading cash instruments assets | Commodities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument assets at fair value	4	5
Trading cash instruments liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument liabilities at fair value	(160,944)	(129,471)
Trading cash instruments liabilities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument liabilities at fair value	(137,917)	(109,999)
Trading cash instruments liabilities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument liabilities at fair value	(22,916)	(19,368)
Trading cash instruments liabilities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument liabilities at fair value	(111)	(104)
Trading cash instruments liabilities | U.S. government and agency obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument liabilities at fair value	(24,028)	(21,027)
Trading cash instruments liabilities | U.S. government and agency obligations | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument liabilities at fair value	(24,009)	(21,002)
Trading cash instruments liabilities | U.S. government and agency obligations | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument liabilities at fair value	(19)	(25)
Trading cash instruments liabilities | U.S. government and agency obligations | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument liabilities at fair value	0	0
Trading cash instruments liabilities | Non-U.S. government and agency obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument liabilities at fair value	(40,125)	(42,585)
Trading cash instruments liabilities | Non-U.S. government and agency obligations | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument liabilities at fair value	(37,453)	(39,983)
Trading cash instruments liabilities | Non-U.S. government and agency obligations | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument liabilities at fair value	(2,672)	(2,602)
Trading cash instruments liabilities | Non-U.S. government and agency obligations | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument liabilities at fair value	0	0
Trading cash instruments liabilities | Loans and securities backed by commercial real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument liabilities at fair value	(32)	(42)
Trading cash instruments liabilities | Loans and securities backed by commercial real estate | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument liabilities at fair value	0	0
Trading cash instruments liabilities | Loans and securities backed by commercial real estate | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument liabilities at fair value	(31)	(40)
Trading cash instruments liabilities | Loans and securities backed by commercial real estate | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument liabilities at fair value	(1)	(2)
Trading cash instruments liabilities | Loans and securities backed by residential real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument liabilities at fair value	(11)	(5)
Trading cash instruments liabilities | Loans and securities backed by residential real estate | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument liabilities at fair value	0	0
Trading cash instruments liabilities | Loans and securities backed by residential real estate | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument liabilities at fair value	(10)	(5)
Trading cash instruments liabilities | Loans and securities backed by residential real estate | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument liabilities at fair value	(1)	0
Trading cash instruments liabilities | Corporate debt instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument liabilities at fair value	(19,340)	(15,875)
Trading cash instruments liabilities | Corporate debt instruments | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument liabilities at fair value	(32)	(23)
Trading cash instruments liabilities | Corporate debt instruments | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument liabilities at fair value	(19,229)	(15,781)
Trading cash instruments liabilities | Corporate debt instruments | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument liabilities at fair value	(79)	(71)
Trading cash instruments liabilities | Other debt obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument liabilities at fair value	(143)
Trading cash instruments liabilities | Other debt obligations | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument liabilities at fair value	0
Trading cash instruments liabilities | Other debt obligations | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument liabilities at fair value	(143)
Trading cash instruments liabilities | Other debt obligations | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument liabilities at fair value	0
Trading cash instruments liabilities | Equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument liabilities at fair value	(77,239)	(49,937)
Trading cash instruments liabilities | Equity securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument liabilities at fair value	(76,423)	(48,991)
Trading cash instruments liabilities | Equity securities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument liabilities at fair value	(786)	(915)
Trading cash instruments liabilities | Equity securities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument liabilities at fair value	(30)	$ (31)
Trading cash instruments liabilities | Commodities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument liabilities at fair value	(26)
Trading cash instruments liabilities | Commodities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument liabilities at fair value	0
Trading cash instruments liabilities | Commodities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument liabilities at fair value	(26)
Trading cash instruments liabilities | Commodities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading cash instrument liabilities at fair value	$ 0