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Copper Concentrate, Export Quota, Revised

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Contingencies and Commitments (Unaudited) - Tax and Other Matters (Details) T in Thousands, $ in Millions, Rp in Billions	1 Months Ended						3 Months Ended			9 Months Ended		12 Months Ended	13 Months Ended
	Feb. 28, 2021 USD ($)	Feb. 28, 2021 IDR (Rp)	Oct. 31, 2019 USD ($)	Oct. 31, 2019 IDR (Rp)	May 31, 2019 USD ($)	May 31, 2019 IDR (Rp)	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Dec. 31, 2018 USD ($)	Mar. 08, 2020 T	Jan. 01, 2023	Mar. 31, 2019	Dec. 21, 2018
Loss Contingencies [Line Items]
Production and delivery							$ 2,665		$ 3,069	$ 8,584	$ 8,790
Forecast
Loss Contingencies [Line Items]
Concentrate, export quota, original \| T													180
Concentrate, export quota, revised \| T													680
Surface Water Taxes, Papua, Indonesia
Loss Contingencies [Line Items]
Production and delivery								$ 28
Surface Water Taxes, Papua, Indonesia \| PT Freeport Indonesia \| Annual surface water tax payments
Loss Contingencies [Line Items]
Payments for taxes										$ 15
Surface Water Taxes, Papua, Indonesia \| PT Freeport Indonesia \| Tax Authority, In Papau, Indonesia \| Penalties
Loss Contingencies [Line Items]
Litigation settlement, agreed to pay					$ 99	Rp 1,394.0
Loss contingency, offer												$ 69
Surface Water Taxes, Papua, Indonesia \| PT Freeport Indonesia \| Tax Authority, In Papau, Indonesia \| Penalties \| Forecast
Loss Contingencies [Line Items]
Payments for legal settlements	$ 49	Rp 685.5
PT Freeport Indonesia
Loss Contingencies [Line Items]
Investment owned, percent																81.00%
PT Freeport Indonesia \| Forecast
Loss Contingencies [Line Items]
Investment owned, percent														48.76%
PT Freeport Indonesia \| PT Smelting
Loss Contingencies [Line Items]
Investment owned, percent															25.00%
Subsequent event \| Surface Water Taxes, Papua, Indonesia \| PT Freeport Indonesia \| Tax Authority, In Papau, Indonesia \| Penalties
Loss Contingencies [Line Items]
Payments for legal settlements			$ 50	Rp 708.5