EMPLOYEE BENEFITS - Schedule of Net Periodic (Income) Cost (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 2	$ 2
Interest cost	24	24
Expected return on plan assets	(37)	(35)
Amortization of actuarial loss	7	5
Net periodic pension (income) cost	(4)	(4)
Qualified Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	2	2
Interest cost	22	22
Expected return on plan assets	(37)	(35)
Amortization of actuarial loss	6	4
Net periodic pension (income) cost	(7)	(7)
Non-Qualified Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0
Interest cost	2	2
Expected return on plan assets	0	0
Amortization of actuarial loss	1	1
Net periodic pension (income) cost	$ 3	$ 3