EMPLOYEE BENEFIT PLANS - Net Periodic Benefit Cost, Change in Benefit Obligation (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	$ 8	$ 9	$ 40
Interest cost	93	107	99
Expected return on assets	(159)	(155)	(155)
Actuarial (gain) loss	1	1	1
Net amortization	110	111	155
Curtailment	0	0	3
Net Periodic Pension Expense	$ 53	$ 73	$ 143