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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
	Jan. 07, 2021 USD ($)	Feb. 28, 2021 USD ($)	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 ($)	Dec. 31, 2018 IDR (Rp)	Dec. 31, 2020 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 21, 2018 USD ($)	Dec. 31, 2019 USD ($)
Income Tax Examination [Line Items]
Provision for income taxes											$ 944	$ 510	$ 991
Net income (Net income from continuing operations attributable to noncontrolling interests											266	50	292
Long-term receivable for taxes										$ 106	106	290				$ 290
Other assets										1,560	$ 1,560	1,885				1,885
Smelter development export duty, threshold											50.00%
Production and delivery											$ 10,031	11,534	11,708
Export Duties Expense											92	221	180
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
Loss contingency, loss In period, attributable to parent												7	195	$ 186		388
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											$ 477
Judicial Ruling \| Cerro Verde Royalty Dispute \| December 2006 to Tax Year 2013 \| Unfavorable Regulatory Actions
Income Tax Examination [Line Items]
Provision for income taxes													(35)
PT-FI
Income Tax Examination [Line Items]
Loss contingency, loss in period, including tax charges										(42)		(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											$ 92	66	180
PT-FI \| Subsequent Event [Member]
Income Tax Examination [Line Items]
Administrative Fees Expense	$ 149
Cerro Verde
Income Tax Examination [Line Items]
Interest Expense											44	58
SUNAT \| Cerro Verde
Income Tax Examination [Line Items]
Long-term receivable for taxes										433	433
Increase (decrease) in income taxes receivable										243	243
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												(47)	$ (61)
Cerro Verde
Income Tax Examination [Line Items]
Long-term receivable for taxes										190	190	187				187
PT-FI
Income Tax Examination [Line Items]
Long-term receivable for taxes										$ 143	143	178				$ 178
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		$ 49	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)
Progressive export duty on copper concentrates, lower threshold, percent												5.00%