DISPOSITIONS AND ACQUISITIONS (Oil and Gas Operations) (Details) $ in Millions	1 Months Ended			3 Months Ended								12 Months Ended
	Dec. 31, 2016 USD ($)	Jul. 31, 2016 USD ($)	Jun. 30, 2016 USD ($)	Dec. 31, 2018 USD ($) $ / bbl	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2018 USD ($) $ / bbl	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net gain on sales of assets				$ 82	$ 70	$ 45	$ 11	$ 15	$ 33	$ 10	$ 23	$ 208	$ 81	$ 649
Net gain (loss) on sales of assets												208	81	649
Other current assets				(422)				(286)				(422)	(286)
Other assets				(2,172)				(2,273)				(2,172)	(2,273)
Deepwater Gulf of Mexico and onshore California oil and gas properties
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sales												0	0	2,272
Freeport-McMoRan Oil & Gas
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sales													80
Net gain (loss) on sales of assets												27
Freeport-McMoRan Oil & Gas | Deepwater Gulf of Mexico and onshore California oil and gas properties
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net gain (loss) on sales of assets														(9)
Preferred stock redemption amount	$ 582													582
Gain on redemption of preferred stock	199
Freeport-McMoRan Oil & Gas | Onshore California
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sales	592
Contingent receivable	33			150								150		33
Contingent consideration asset, per year												50
Other assets				$ (16)				(34)				$ (16)	(34)
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
Freeport-McMoRan Oil & Gas | Deepwater Gulf of Mexico Interests
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sales	2,000
Contingent receivable	$ 150													$ 150
Contingent payments, collections												$ 7
Other current assets				$ (27)				(24)				(27)	(24)
Other assets				$ (116)				$ (126)				$ (116)	$ (126)
Freeport-McMoRan Oil & Gas | Haynesville
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sales		$ 87
Freeport-McMoRan Oil & Gas | Black Stone Minerals, L.P.
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sales			$ 102
Scenario, Forecast [Member] | Freeport-McMoRan Oil & Gas | Onshore California
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Contingent receivable															$ 50	$ 50