DISPOSITIONS AND ACQUISITIONS (PT-FI Divestment) (Details)		3 Months Ended								12 Months Ended
	Dec. 21, 2018 USD ($) $ / lb $ / oz	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Jan. 01, 2023	Jan. 01, 2020
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income tax rate											21.00%	21.00%	35.00%
Proceeds from divestiture, net	$ 350,000,000
Accounts payable and accrued liabilities		$ 2,491,000,000				$ 2,230,000,000				$ 2,491,000,000	$ 2,491,000,000	$ 2,230,000,000
Net (loss) income		43,000,000	$ (234,000,000)	$ (74,000,000)	$ 76,000,000	378,000,000	$ 664,000,000	$ 1,035,000,000	$ 817,000,000		(189,000,000)	2,894,000,000	$ 2,095,000,000
Other current assets		655,000,000				422,000,000				655,000,000	655,000,000	422,000,000
Property, plant, equipment and mine development costs, net		29,584,000,000				28,010,000,000				29,584,000,000	29,584,000,000	28,010,000,000
Noncontrolling interests		8,150,000,000				8,094,000,000				8,150,000,000	8,150,000,000	8,094,000,000
Capital in excess of par value		$ 25,830,000,000				$ 26,013,000,000				$ 25,830,000,000	$ 25,830,000,000	$ 26,013,000,000
Rio Tinto Share In Joint Venture
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from divestiture, net	$ 107,000,000
PT-FI
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Ownership percentage	81.28%	48.76%								48.76%	48.76%
Net (loss) income										$ 339,000,000	$ 203,000,000
Net Income (Loss) Attributable to Parent										$ 276,000,000	165,000,000
PT-FI | Scenario, forecast
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Ownership percentage														48.76%
PT Freeport Indonesia, Subsidiary | PT-FI
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Ownership percentage	19.00%
PT Indonesia Papua Metal dan Mineral | PT-FI
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Ownership interest by parent subsequent to business acquisition	25.00%
PT Indonesia Papua Metal dan Mineral | PT-FI | Scenario, forecast
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Ownership percentage														25.00%
Rio Tinto | Rio Tinto Share In Joint Venture
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from divestiture, net	$ 3,500,000,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Liability, Transfers Into Level 3											$ 0.14
PT Indonesia Asahan Aluminium (Persero) (Inalum) | PT-FI
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from divestiture, net	$ 3,850,000,000
PT Indonesia Asahan Aluminium (Persero) (Inalum) | Interest In PT Indocopper Investama
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Percentage of voting interest	100.00%
PT Indonesia Asahan Aluminium (Persero) (Inalum) | PT-FI
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Percentage of voting interest	40.00%
Ownership interest by parent subsequent to business acquisition	26.24%
PT Indonesia Asahan Aluminium (Persero) (Inalum) | PT-FI | Scenario, forecast
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Ownership percentage														26.24%
PT-FI
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Ownership percentage of subsidiary		48.76%								48.76%	48.76%
PT-FI | Rio Tinto Share In Joint Venture
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Current assets	$ 25,000,000
Mineral reserves	3,056,000,000
Mine development, infrastructure and other	1,559,000,000
Asset Acquisition, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities, Excluding Taxes	77,000,000
Asset Acquisition, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Liabilities	1,063,000,000
Asset Acquisition, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net	$ 3,500,000,000
PT-FI | PT-FI
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Ownership interest by parent subsequent to business acquisition	51.24%
PT-FI
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Ownership percentage of subsidiary	48.76%
PT-FI | Scenario, forecast
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Ownership percentage of subsidiary														48.76%	81.00%
PT-FI | PT Indonesia Papua Metal dan Mineral
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Ownership percentage	9.36%
Copper | PT-FI | Rio Tinto Share In Joint Venture
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Price assumption per unit (in dollars per unit) | $ / lb	3.00
Gold | PT-FI | Rio Tinto Share In Joint Venture
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Price assumption per unit (in dollars per unit) | $ / oz	1,300
Tax Authority, In Papua, Indonesia
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income tax rate	25.00%
PT-FI | Rio Tinto Share In Joint Venture
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash	$ 458,000,000
Other current assets	23,000,000
Liabilities, Excluding Tax	77,000,000
Deferred Income Tax Liabilities, Net	788,000,000
Noncontrolling interests	4,762,000,000
Capital in excess of par value	531,000,000
PT-FI | Mineral reserves | Rio Tinto Share In Joint Venture
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Property, plant, equipment and mine development costs, net	3,056,000,000
PT-FI | Mine development, infrastructure and other | Rio Tinto Share In Joint Venture
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Property, plant, equipment and mine development costs, net	$ 1,559,000,000
Indemnification Agreement [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Accounts payable and accrued liabilities		$ 33,000,000								$ 33,000,000	$ 33,000,000