SECURITIES - Schedule of Securities Pledged (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Pledged against derivatives, to qualify for fiduciary powers, or to secure public and other deposits as required by law
Financial Instruments Owned and Pledged as Collateral [Line Items]
Debt securities at amortized cost	$ 3,966	$ 4,816
Debt securities at fair value	3,527	4,782
Pledged as collateral for FHLB borrowing capacity
Financial Instruments Owned and Pledged as Collateral [Line Items]
Debt securities at amortized cost	244	325
Debt securities at fair value	217	333
Pledged against repurchase agreements
Financial Instruments Owned and Pledged as Collateral [Line Items]
Debt securities at amortized cost	0	1
Debt securities at fair value	$ 0	$ 1