LAWSUITS, CLAIMS, COMMITMENTS AND CONTINGENCIES - LEGAL MATTERS (Details) - Arbitration Demand Filed By Andes Petroleum Ecuador Ltd - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Long-term Purchase Commitment [Line Items]
Proceeds from settlement		$ 1.0
Recovery of amount awarded in settlement amount (as a percent)		60.00%
Claim to a settlement amount (as a percent)	40.00%
Own economic interest (as a percent)	60.00%