DISPOSITIONS AND ACQUISITIONS (Timok) (Details) - USD ($) $ in Millions		1 Months Ended	12 Months Ended
	Dec. 21, 2018	May 31, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	May 02, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from divestiture, net	$ 350
Net gain (loss) on sales of assets			$ 208	$ 81	$ 649
Timok
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from divestiture, net		$ 135
Amount of contingent liabilities remaining						$ 107
Net gain (loss) on sales of assets					$ 133