PROPERTY AND EQUIPMENT - Carrying Value of Property and Equipment and Estimated Service Lives (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Property and equipment, at cost	$ 4,956	$ 4,868
Accumulated depreciation and amortization	(3,338)	(3,306)
Property and equipment, net	1,618	1,562
Land
Property, Plant and Equipment [Line Items]
Property and equipment, at cost	88	90
Buildings and improvements
Property, Plant and Equipment [Line Items]
Property and equipment, at cost	867	789
Machinery and equipment
Property, Plant and Equipment [Line Items]
Property and equipment, at cost	3,037	3,022
Roads
Property, Plant and Equipment [Line Items]
Property and equipment, at cost	782	773
Other
Property, Plant and Equipment [Line Items]
Property and equipment, at cost	$ 182	$ 194
Minimum | Buildings and improvements
Property, Plant and Equipment [Line Items]
Estimated service lives	15 years
Minimum | Machinery and equipment
Property, Plant and Equipment [Line Items]
Estimated service lives	5 years
Minimum | Roads
Property, Plant and Equipment [Line Items]
Estimated service lives	10 years
Minimum | Other
Property, Plant and Equipment [Line Items]
Estimated service lives	3 years
Maximum | Buildings and improvements
Property, Plant and Equipment [Line Items]
Estimated service lives	35 years
Maximum | Machinery and equipment
Property, Plant and Equipment [Line Items]
Estimated service lives	25 years
Maximum | Roads
Property, Plant and Equipment [Line Items]
Estimated service lives	35 years
Maximum | Other
Property, Plant and Equipment [Line Items]
Estimated service lives	10 years