DERIVATIVES - Effect of Derivative Instruments on Net Income and Stockholders' Equity (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Derivative Instruments, Gain (Loss) [Line Items]
Amount of pre-tax net gains (losses) recognized in OCI	$ (145)	$ (1,806)	$ (66)
Interest Income
Derivative Instruments, Gain (Loss) [Line Items]
Amount of pre-tax net losses reclassified from AOCI	(596)	(111)	183
Interest expense - long-term borrowed funds
Derivative Instruments, Gain (Loss) [Line Items]
Amount of pre-tax net losses reclassified from AOCI	$ 0	$ (4)	$ (48)