CASH AND DUE FROM BANKS (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash and Cash Equivalents [Abstract]
Deposits on FRB balances	$ 2,100	$ 3,000
Interest rate on FRB balances	1.55%
Interest earned on FRB balances	$ 28	$ 28	$ 16