PENSION AND OTHER POSTRETIREMENT BENEFIT PLANS - Funded Status of Our Pension and Other Postretirement Benefit Plans (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Current liabilities	$ (44)	$ (47)
Pension
Defined Benefit Plan Disclosure [Line Items]
Noncurrent assets	70	8
Current liabilities	(21)	(21)
Noncurrent liabilities	(769)	(1,042)
Funded status	(720)	(1,055)
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Noncurrent assets	0	0
Current liabilities	(22)	(26)
Noncurrent liabilities	(218)	(277)
Funded status	$ (240)	$ (303)