LAWSUITS, CLAIMS, COMMITMENTS AND CONTINGENCIES - LEGAL MATTERS (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Long-term Purchase Commitment [Line Items]
Potential income tax expense	$ 925
Federal
Long-term Purchase Commitment [Line Items]
Potential income tax expense	898
State
Long-term Purchase Commitment [Line Items]
Potential income tax expense	27
Anadarko Petroleum Corporation
Long-term Purchase Commitment [Line Items]
Tax refund	881		$ 881
Accrued interest on potential income tax expense	$ 255
Arbitration Demand Filed By Andes Petroleum Ecuador Ltd
Long-term Purchase Commitment [Line Items]
Proceeds from settlement			$ 1,000
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%
Tronox Settlement
Long-term Purchase Commitment [Line Items]
Payments for settlement				$ 5,200