MORTGAGE BANKING AND OTHER SERVICED LOANS - Changes Related to MSRs - Fair Value Method (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
MSRs
Fair value as of beginning of the period			$ 1,530
Fair value at end of the period	$ 1,620		1,620
Residential mortgages
MSRs
Fair value as of beginning of the period	1,524	$ 1,411	1,530	$ 1,029
Amounts capitalized	47	70	104	244
Servicing rights acquired	0	0	0	16
Changes in unpaid principal balance during the period	(42)	(31)	(124)	(102)
Changes in fair value during the period	91	74	110	337
Fair value at end of the period	$ 1,620	$ 1,524	$ 1,620	$ 1,524