EMPLOYEE BENEFITS - Plan Amounts Recognized in OCI (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Retirement Benefits [Abstract]
Net periodic pension income	$ (16)	$ (2)	$ (1)
Net actuarial loss (gain)	49	(31)	54
Amortization of prior service credit	1	1	1
Amortization of net actuarial loss	(17)	(18)	(16)
Total recognized in other comprehensive income (loss)	33	(48)	39
Total recognized in net periodic pension cost and other comprehensive income (loss)	$ 17	$ (50)	$ 38