DERIVATIVES - Schedule of Fair Value Hedges (Details) - Interest rate swap - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Interest expense - borrowed funds
Derivative Instruments, Gain (Loss) [Line Items]
Derivative	$ 64	$ 12	$ 104	$ (26)
Hedged Item	(64)	(13)	(103)	24
Interest and fees on loans and leases
Derivative Instruments, Gain (Loss) [Line Items]
Derivative	(16)	0	(16)	0
Hedged Item	$ 16	$ 0	$ 16	$ 0