DERIVATIVES - Schedule of Fair Value Hedges (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Derivative	$ 38	$ 22	$ 43	$ 32
Hedge of interest rate risk | Other Income
Derivative Instruments, Gain (Loss) [Line Items]
Derivative	12	16	(26)	10
Hedged Item	(13)	(15)	24	(9)
Hedge Ineffectiveness	$ (1)	$ 1	$ (2)	$ 1