DISPOSITIONS AND ACQUISITIONS (Morenci) (Details) - USD ($) $ in Millions	Dec. 21, 2018	Dec. 31, 2019	May 31, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from divestiture, net	$ 350
Morenci
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Ownership percentage		72.00%
Morenci | SMM Morenci Inc.
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Ownership percentage			13.00%
Morenci | Sumitomo Metal Mining Co., Ltd.
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Ownership percentage		15.00%