DISPOSITIONS AND ACQUISITIONS (Oil and Gas Operations) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($) $ / bbl	Dec. 31, 2019 USD ($) $ / bbl	Dec. 31, 2018 USD ($) $ / bbl	Dec. 31, 2016 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sales	$ 0
Net gain on sales of assets	473	$ 417	$ 208
Other current assets	(341)	(655)
Other assets	(1,560)	(1,885)
Freeport-McMoRan Oil & Gas
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sales		36
Net gain (loss) on sales of assets			27
Freeport-McMoRan Oil & Gas | Onshore California
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Contingent receivable	50			$ 150
Contingent consideration asset, per year	$ 50	50	$ 50
Other assets		$ (11)
Freeport-McMoRan Oil & Gas | Onshore California | Crude Oil
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Contingent consideration, reference threshold, price per barrel (in us dollars per pound) | $ / bbl	70	70	70
Freeport-McMoRan Oil & Gas | Deepwater Gulf of Mexico Interests
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Contingent receivable				$ 150
Other current assets	$ (12)	$ (18)
Other assets	(96)	(104)
Corporate And Eliminations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net gain on sales of assets	$ 473	417	$ 208
Corporate And Eliminations [Member] | Gulf of Mexico Shelf and Madden properties [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net gain on sales of assets		$ 20