Fair Value Option - Gains and Losses on Other Financial Assets and Financial Liabilities at Fair Value (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair value option gains/(losses)	$ 3,993	$ 801	$ 14,950	$ (2,782)
Unsecured short-term borrowings
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair value option gains/(losses)	1,114	875	5,379	(935)
Unsecured long-term borrowings
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair value option gains/(losses)	2,445	(128)	8,316	(1,830)
Other
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair value option gains/(losses)	$ 434	$ 54	$ 1,255	$ (17)