CONTINGENCIES (Tax and Other Matters) (Details) $ in Millions, Rp in Billions		1 Months Ended								3 Months Ended	12 Months Ended			21 Months Ended	36 Months Ended	60 Months Ended
	Jan. 01, 2014	Feb. 28, 2021 USD ($)	Feb. 28, 2021 IDR (Rp)	Oct. 31, 2019 USD ($)	Oct. 31, 2019 IDR (Rp)	May 31, 2019 USD ($)	May 31, 2019 IDR (Rp)	Dec. 31, 2018 USD ($)	Dec. 31, 2018 IDR (Rp)	Sep. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 21, 2018 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Income Tax Examination [Line Items]
Provision for income taxes											$ 510	$ 991	$ 883
Net income (Net income from continuing operations attributable to noncontrolling interests											50	292	274
Long-term receivable for taxes								$ 260			290	260			$ 290	$ 260
Other assets								2,172			$ 1,885	2,172			1,885	2,172
Smelter development export duty, threshold											50.00%
Production and delivery											$ 11,514	11,687	10,258
Export Duties Expense											221	180	115
Cerro Verde
Income Tax Examination [Line Items]
Loss contingency, loss in period											(16)
Stability agreement, term	15 years
Provision for income taxes											(2)
Cerro Verde | Tax Year 2012 to Tax Year 2013
Income Tax Examination [Line Items]
Provision for income taxes												17
Gain in period												14
Cerro Verde Royalty Dispute
Income Tax Examination [Line Items]
Payments for legal settlements											187	56	53
Cerro Verde Royalty Dispute | Cerro Verde | Royalty Assessments
Income Tax Examination [Line Items]
Provision for income taxes											(2)	(35)	7		(30)
Net income (Net income from continuing operations attributable to noncontrolling interests											(7)	(176)	(169)		(352)
Production and delivery											6	14	203		223
Cerro Verde Royalty Dispute | Cerro Verde | December 2006 to Tax Year 2013 | Royalty Assessments
Income Tax Examination [Line Items]
Provision for income taxes													(129)
Surface Water Taxes, Papua, Indonesia [Member]
Income Tax Examination [Line Items]
Production and delivery						$ 28		69
Judicial Ruling | Cerro Verde Royalty Dispute | Tax Year 2006 To Tax Year 2008 | Royalty Assessments
Income Tax Examination [Line Items]
Payments for legal settlements																354
Judicial Ruling | Cerro Verde Royalty Dispute | December 2006 to Tax Year 2013 | Unfavorable Regulatory Actions
Income Tax Examination [Line Items]
Loss contingency, loss in period													(348)
Loss contingency, loss in period, including tax charges													(186)
Provision for income taxes												35	7
Net income (Net income from continuing operations attributable to noncontrolling interests													(169)
Judicial Ruling | Cerro Verde Royalty Dispute | Tax Year 2009 to Tax Year 2013 | Unfavorable Regulatory Actions
Income Tax Examination [Line Items]
Loss contingency, loss in period												(420)
Loss contingency, loss in period, including tax charges												(211)
Provision for income taxes												(18)
Net income (Net income from continuing operations attributable to noncontrolling interests												(191)
PT-FI
Income Tax Examination [Line Items]
Loss contingency, loss in period, including tax charges											$ (304)
Progressive export duty on copper concentrates, lower threshold, percent											2.50%
Progressive export duty on copper concentrates, higher threshold, percent											5.00%			7.50%
Export Duties Expense											$ 66	180	$ 115
PT-FI | Surface Water Taxes, Papua, Indonesia [Member]
Income Tax Examination [Line Items]
Loss contingency, loss in period, including tax charges											(28)
SUNAT | Cerro Verde | October 2011 to September 2012
Income Tax Examination [Line Items]
Tax refund, requested											57				57
SUNAT | Cerro Verde
Income Tax Examination [Line Items]
Long-term receivable for taxes											397				397
Increase (decrease) in income taxes receivable											210				210
Tax Authority, In Papau, Indonesia | PT-FI | Surface Water Taxes, Papua, Indonesia [Member] | Penalties
Income Tax Examination [Line Items]
Payments for legal settlements				$ 50	Rp 708.5
Settlement amount						$ 99	Rp 1,394.0		Rp 1,000,000,000,000,000.0
Indonesian Supreme Court | PT-FI | The year 2005 and the year 2007
Income Tax Examination [Line Items]
Loss contingency, loss in period											(46)	(61)
Cerro Verde
Income Tax Examination [Line Items]
Long-term receivable for taxes								183			187	183			187	183
PT-FI
Income Tax Examination [Line Items]
Long-term receivable for taxes								$ 493			178	493			$ 178	$ 493
FCX | Cerro Verde
Income Tax Examination [Line Items]
Loss contingency, loss in period, including tax charges											(7)
FCX | Cerro Verde | Tax Year 2012 to Tax Year 2013
Income Tax Examination [Line Items]
Gain in period, including tax charges												16
Noncontrolling Interests | Cerro Verde
Income Tax Examination [Line Items]
Net income (Net income from continuing operations attributable to noncontrolling interests											7
Noncontrolling Interests | Cerro Verde | Tax Year 2012 to Tax Year 2013
Income Tax Examination [Line Items]
Net income (Net income from continuing operations attributable to noncontrolling interests												15
Annual Surface Water Tax Payments [Member] | PT-FI
Income Tax Examination [Line Items]
Acquire water systems											15
Forecast [Member] | Tax Authority, In Papau, Indonesia | PT-FI | Surface Water Taxes, Papua, Indonesia [Member] | Penalties
Income Tax Examination [Line Items]
Payments for legal settlements		$ 50	Rp 685.5
Indonesia Tax Authority | PT-FI | Memorandum of Understanding with the Indonesian Government [Member]
Income Tax Examination [Line Items]
Progressive export duty on copper concentrates, lower threshold, percent													5.00%
Progressive export duty on copper concentrates, higher threshold, percent														7.50%
Export Duties Expense														$ 155
Litigation Settlement, Amount Awarded from Other Party												$ 29
Indonesia Tax Authority | PT-FI | Memorandum of Understanding with the Indonesian Government, Indonesia Supreme Court Appeal [Member]
Income Tax Examination [Line Items]
Loss contingency, loss in period										$ (155)	$ (155)
Progressive export duty on copper concentrates, lower threshold, percent											5.00%