MORTGAGE LOAN SALES AND SERVICING RIGHTS - Narrative (Details) - Residential mortgage - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Servicing Assets at Fair Value [Line Items]
Servicing income	$ 24	$ 23	$ 48	$ 45
Unpaid principal balance of third party serviced loans	$ 32,700		$ 32,700		$ 32,400