BASIS OF PRESENTATION, UPDATED ACCOUNTING POLICIES AND ACCOUNTING CHANGES - Accounting Changes (Details) - USD ($) $ in Millions		Sep. 30, 2023	Jun. 30, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Dec. 31, 2021
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for credit losses		$ (17,629)	$ (17,496)	$ (16,974)	$ (16,309)	$ (15,952)	$ (16,455)
Other assets, at fair value		96,824		103,743
Stockholders’ equity		210,195		201,838	199,117
Other liabilities		(69,380)		(87,873)
Cumulative Effect, Period of Adoption, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for credit losses			0	352		0	0
Other assets, at fair value				44
Deferred tax assets				106
Other liabilities				39
Retained earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stockholders’ equity		202,135	199,976	194,734	193,462	191,261	184,948
Retained earnings | Cumulative Effect, Period of Adoption, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stockholders’ equity	[1]		0	290		0	0
Accumulated other comprehensive income (loss)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stockholders’ equity		$ (46,177)	(45,865)	(47,062)	$ (48,298)	(45,495)	(38,765)
Accumulated other comprehensive income (loss) | Cumulative Effect, Period of Adoption, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stockholders’ equity	[1]		$ 0	$ 27		$ 0	$ 0

[1] See Note 1 for additional details.