EMPLOYEE BENEFIT PLANS - AMOUNTS RECOGNIZED IN CONSOLIDATED BALANCE SHEETS (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Pension and Other Postretirement Defined Benefit Plans, Liabilities [Abstract]
Accrued benefit liability-long term	$ 270	$ 246
Qualified Defined Benefit [Member]
Pension and Other Postretirement Defined Benefit Plans, Liabilities [Abstract]
Accrued benefit liability-long term	173	133
Plan assets-long term (within noncurrent Other Assets)	(12)	0
Total liability recognized	161	133
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax [Abstract]
Prior service cost (credit)	(11)	(12)
Net gain	499	514
Amount recognized in AOCI (pretax)	$ 488	$ 502