DISPOSITIONS AND ACQUISITIONS (Timok) (Details) - USD ($) $ in Millions		12 Months Ended
	May 02, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net gain on sales of assets		$ 81	$ 649	$ 39
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 on sales of assets			$ 133