INVESTMENT SECURITIES - Gains (Losses) on Equity Securities (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Investments, Debt and Equity Securities [Abstract]
Net gains (losses) recognized on equity securities during the period	$ 1	$ (123)	$ (341)
Less: Net gains (losses) recognized on equity securities sold during the period	1	(105)	(13)
Unrealized losses recognized on equity securities still held at the end of the period	$ 0	$ (18)	$ (328)