SHORT-TERM BORROWINGS (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Short-term Debt [Line Items]
Total short-term borrowings	$ 2,606	$ 2,017
Federal funds purchased and securities sold under agreements to repurchase
Short-term Debt [Line Items]
Total short-term borrowings	1,041	2,004
Federal Home Loan Bank advances
Short-term Debt [Line Items]
Total short-term borrowings	1,500	0
Other borrowings
Short-term Debt [Line Items]
Total short-term borrowings	$ 65	$ 13