INCOME TAXES (Narrative) (Details) - USD ($) $ in Millions			3 Months Ended		12 Months Ended
	Dec. 30, 2019	Jan. 01, 2017	Dec. 31, 2020	Dec. 31, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2014
Schedule Of Income Taxes [Line Items]
Total income taxes paid to all jurisdictions					$ 397	$ 610	$ 2,000
Tax refunds received from all jurisdictions					265	306	108
Tax Attributes
Foreign tax credits			$ 1,641		1,641	1,716
Valuation allowances			4,732		4,732	4,576
Valuation allowance, increase (decrease)					156
Deferred tax assets, alternative minimum tax refunds			244		244
Increase in unrecognized tax benefits expected			24		24
Tax Cuts and Jobs Act of 2017, provisional income tax expense (benefit)					0	0	(123)
Tax Cuts and Jobs Act of 2017, change in tax rate, provisional income tax expense (benefit)							29
Income (loss) from continuing operation, foreign					1,837	593	3,502
Income (loss) from continuing operations, domestic					(40)	(287)	$ 390
Change in PT-FI tax rates				$ 504	$ 0	$ 0
U.S. federal statutory tax rate					21.00%	21.00%	21.00%
Interest on income taxes accrued			163	186	$ 163	$ 231	$ 186
Unrecognized tax benefits			295	$ 404	295	376	404	$ 390
Unrecognized tax benefits that would impact the effective tax rate			254		254
Unrecognized tax benefits that would impact the effective tax rate, net of tax benefits			168		168
PT Freeport Indonesia [Member]
Tax Attributes
Change in PT-FI tax rates					0	0	504
Loss Contingency, Loss in Period, Including Tax Charges			42			304
Valuation allowance for operating loss carryforwards
Tax Attributes
Valuation allowances			2,400		2,400
Net Operating Losses
Tax Attributes
Valuation allowance, increase (decrease)					250			$ (45)
Domestic Deferred Tax Assets [Member]
Tax Attributes
Valuation allowance, increase (decrease)					$ (11)	208	(44)
SUNAT | Cerro Verde
Tax Attributes
Foreign income tax rate under new stability agreement					32.00%
Foreign Tax Authority
Tax Attributes
Tax Credit Carryforward, Valuation Allowance			1,600		$ 1,600
Income Tax Credits and Adjustments					$ 75	$ 98	315
Foreign Tax Authority | Tax Authority, In Papua, Indonesia | 2019 and thereafter
Tax Attributes
U.S. federal statutory tax rate					25.00%
Profits income tax rate					10.00%
Foreign Tax Authority | Settlement with Taxing Authority [Member] | Tax Years 2012 to 2018
Tax Attributes
Payments for legal settlements	$ 250
Foreign Tax Authority | Tax Authority, Spain
Tax Attributes
Operating Loss Carryforwards			559		$ 559
Foreign Tax Authority | Tax Authority, In Papau, Indonesia
Tax Attributes
Operating Loss Carryforwards			910		$ 910
Foreign Tax Authority | Chili - Service of Internal Taxes
Tax Attributes
U.S. federal statutory tax rate						35.00%
Foreign Tax Authority | Chili - Service of Internal Taxes | Prior to September 2014 [Member]
Tax Attributes
U.S. federal statutory tax rate					35.00%
Foreign Tax Authority | Chili - Service of Internal Taxes | 2020 and thereafter
Tax Attributes
U.S. federal statutory tax rate					44.50%
Foreign Tax Authority | Chili - Service of Internal Taxes | Tax years 2017 through 2021 [Member]
Tax Attributes
U.S. federal statutory tax rate					35.00%
Foreign Tax Authority | Chili - Service of Internal Taxes | Tax Year 2022 and Thereafter
Tax Attributes
U.S. federal statutory tax rate					44.50%
Foreign Tax Authority | Chili - Service of Internal Taxes | Tax Years 2013 to 2017
Tax Attributes
Mining royalty tax rate					4.00%
Foreign Tax Authority | Chili - Service of Internal Taxes | Tax Years 2018 to 2023 | Minimum
Tax Attributes
Mining royalty tax rate					5.00%
Foreign Tax Authority | Chili - Service of Internal Taxes | Tax Years 2018 to 2023 | Maximum
Tax Attributes
Mining royalty tax rate					14.00%
Foreign Tax Authority | SUNAT | 2014
Tax Attributes
U.S. federal statutory tax rate									30.00%
Dividend tax rate									4.10%
Foreign Tax Authority | SUNAT | 2019 and thereafter
Tax Attributes
U.S. federal statutory tax rate						26.00%
Dividend tax rate						9.30%
Foreign Tax Authority | SUNAT | 2017
Tax Attributes
Dividend tax rate		5.00%
Corporate Income Tax Rate		29.50%
Domestic Tax Authority
Tax Attributes
Operating Loss Carryforwards			7,000		$ 7,000
Valuation allowances			647		647
State and Local Jurisdiction
Tax Attributes
Operating Loss Carryforwards			10,800		10,800
Alternative Minimum Tax Credit
Tax Attributes
Tax Cuts and Jobs Act of 2017, provisional income tax expense (benefit)							$ 123
Reserve for Taxes, Other than Income Taxes [Member]
Tax Attributes
Tax Cuts and Jobs Act of 2017, provisional income tax expense (benefit)						$ 29
Indefinite-Lived Carryforward [Member]
Tax Attributes
Operating Loss Carryforwards			305		$ 305
Other (expense) benefit | PT Freeport Indonesia [Member]
Tax Attributes
Loss Contingency, Loss in Period, Including Tax Charges			9			123
Interest expense | PT Freeport Indonesia [Member]
Tax Attributes
Loss Contingency, Loss in Period, Including Tax Charges			35			78
Income expense (benefit) | PT Freeport Indonesia [Member]
Tax Attributes
Loss Contingency, Loss in Period, Including Tax Charges			$ 2			$ 103