EMPLOYEE BENEFITS - Schedule of Net Periodic (Income) Cost (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 3	$ 3	$ 3
Interest cost	45	43	46
Expected return on plan assets	(72)	(79)	(69)
Amortization of actuarial loss	19	17	18
Net periodic pension (income) cost	(5)	(16)	(2)
Qualified Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	3	3	3
Interest cost	41	39	42
Expected return on plan assets	(72)	(79)	(69)
Amortization of actuarial loss	17	15	16
Net periodic pension (income) cost	(11)	(22)	(8)
Non-Qualified Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0	0
Interest cost	4	4	4
Expected return on plan assets	0	0	0
Amortization of actuarial loss	2	2	2
Net periodic pension (income) cost	$ 6	$ 6	$ 6