EMPLOYEE BENEFITS - Schedule of Net Periodic (Income) Cost (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 3	$ 3	$ 3
Interest cost	48	52	53
Expected return on plan assets	(74)	(73)	(73)
Amortization of actuarial loss	15	10	14
Net periodic pension (income) cost	(8)	(8)	(3)
Qualified Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	3	3	3
Interest cost	44	47	48
Expected return on plan assets	(74)	(73)	(73)
Amortization of actuarial loss	13	9	13
Net periodic pension (income) cost	(14)	(14)	(9)
Non-Qualified Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0	0
Interest cost	4	5	5
Expected return on plan assets	0	0	0
Amortization of actuarial loss	2	1	1
Net periodic pension (income) cost	$ 6	$ 6	$ 6