The average market price for a group of price risk forward or futures contracts, such as gas futures contracts.

No definition available.

Name:	fcx_DerivativeAverageMarketPrice
Namespace Prefix:	fcx_
Data Type:	srt-types:perUnitItemType
Balance Type:	na
Period Type:	instant

- Definition

Percent of Copper Sale Volume

+ References

No definition available.

+ Details

Name:	fcx_PercentOfCopperSaleVolume
Namespace Prefix:	fcx_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of gain (loss) from the increase (decrease) in fair value of derivative and nonderivative instruments designated as fair value hedging instruments recognized in the income statement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 25
-Section 50
-Paragraph 1
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=121577467&loc=d3e76258-113986

+ Details

Name:	us-gaap_ChangeInUnrealizedGainLossOnFairValueHedgingInstruments1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of the increase (decrease) in fair value of the hedged item in a fair value hedge recognized in the income statement.

+ References

+ Details

Name:	us-gaap_ChangeInUnrealizedGainLossOnHedgedItemInFairValueHedge1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The average forward price on the group of price risk forward or futures contracts, such as gas futures contracts.

+ References

No definition available.

+ Details

Name:	us-gaap_DerivativeAverageForwardPrice
Namespace Prefix:	us-gaap_
Data Type:	srt-types:perUnitItemType
Balance Type:	na
Period Type:	instant

- Definition

The forward price on the price risk forward or futures contract, such as a gas futures contract.

+ References

No definition available.

+ Details

Name:	us-gaap_DerivativeForwardPrice
Namespace Prefix:	us-gaap_
Data Type:	srt-types:perUnitItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4A
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5618551-113959

+ Details

Name:	us-gaap_DerivativeGainLossOnDerivativeNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_DerivativeInstrumentsGainLossLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Nominal mass used to calculate payments on a derivative instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DerivativeNonmonetaryNotionalAmountMass
Namespace Prefix:	us-gaap_
Data Type:	num:massItemType
Balance Type:	na
Period Type:	duration

- Definition

Net Increase or Decrease in the fair value of the embedded derivative or group of embedded derivatives included in earnings in the period.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 15
-URI http://asc.fasb.org/subtopic&trid=2229187

+ Details

Name:	us-gaap_EmbeddedDerivativeGainLossOnEmbeddedDerivativeNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- References

No definition available.

+ Details

Name:	us-gaap_HeldToMaturitySecuritiesGrossGainsLossesDerivativesAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

+ Details

Name:	us-gaap_UnrealizedGainLossOnDerivativesAndCommodityContractsAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	srt_StatementGeographicalAxis=srt_NorthAmericaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_HedgingDesignationAxis=us-gaap_NondesignatedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeStatementLocationAxis=us-gaap_SalesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_CommodityContractMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_HedgingDesignationAxis=us-gaap_DesignatedAsHedgingInstrumentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_ForwardContractsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeStatementLocationAxis=us-gaap_CostOfSalesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PublicUtilitiesInventoryAxis=fcx_CopperMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PositionAxis=us-gaap_ShortMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_EmbeddedDerivativeFinancialInstrumentsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PositionAxis=us-gaap_LongMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PublicUtilitiesInventoryAxis=us-gaap_GoldMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PublicUtilitiesInventoryAxis=fcx_GoldandotherMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Financial Instruments (Unrealized gains losses) (Details) oz in Thousands, lb in Millions, $ in Millions	1 Months Ended	2 Months Ended	3 Months Ended		6 Months Ended	9 Months Ended
	Apr. 30, 2020 lb	Jun. 30, 2020	Sep. 30, 2021 USD ($) $ / lb $ / oz $ / lb	Sep. 30, 2020 USD ($) $ / lb	Jun. 30, 2020 USD ($)	Sep. 30, 2021 USD ($) oz lb $ / lb $ / oz $ / lb	Sep. 30, 2020 USD ($) $ / lb
North America
Realized gains (losses):
Percent of Copper Sale Volume		60.00%
Not Designated as Hedging Instrument [Member] \| Amounts recorded in Sales [Member]
Realized gains (losses):
Embedded Derivative, Gain (Loss) on Embedded Derivative, Net			$ (111)	$ 109		$ 201	$ 57
Commodity Contract [Member]
Unrealized gains (losses):
Derivative financial instruments			(20)	1		(28)	8
Hedged item – firm sales commitments			20	(1)		28	(8)
Realized gains (losses):
Matured derivative financial instruments			$ 5	$ 15		$ 57	$ (1)
Commodity Contract [Member] \| Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Nonmonetary Notional Amount, Mass \| lb						84
Derivative, Average Forward Price \| $ / lb			4.23			4.23
Copper Forward Contracts [Member]
Unrealized gains (losses):
Derivative financial instruments					$ 24
Realized gains (losses):
Derivative, Forward Price \| $ / lb				2.34			2.34
Copper Forward Contracts [Member] \| Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Nonmonetary Notional Amount, Mass \| lb	150
Copper Forward Contracts [Member] \| Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Nonmonetary Notional Amount, Mass \| lb						9
Derivative, Average Forward Price \| $ / lb			4.23			4.23
Copper Forward Contracts [Member] \| Not Designated as Hedging Instrument [Member] \| Amounts recorded in Cost of Sales
Realized gains (losses):
Matured derivative financial instruments			$ 1	$ (7)		$ (12)	$ 12
Copper \| Not Designated as Hedging Instrument [Member] \| Amounts recorded in Sales [Member]
Realized gains (losses):
Embedded Derivative, Gain (Loss) on Embedded Derivative, Net			$ (102)	94		$ 223	18
Copper \| Short [Member] \| Embedded Derivative Financial Instruments [Member] \| Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Nonmonetary Notional Amount, Mass \| lb						548
Derivative, Average Forward Price \| $ / lb			4.28			4.28
Realized gains (losses):
Derivative Average Market Price \| $ / lb			4.05			4.05
Copper \| Long [Member] \| Embedded Derivative Financial Instruments [Member] \| Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Nonmonetary Notional Amount, Mass \| lb						116
Derivative, Average Forward Price \| $ / lb			4.31			4.31
Realized gains (losses):
Derivative Average Market Price \| $ / lb			4.05			4.05
Gold \| Short [Member] \| Embedded Derivative Financial Instruments [Member] \| Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Nonmonetary Notional Amount, Mass \| oz						196
Derivative, Average Forward Price \| $ / oz			1,790			1,790
Realized gains (losses):
Derivative Average Market Price \| $ / oz			1,738			1,738
gold and other \| Not Designated as Hedging Instrument [Member] \| Amounts recorded in Sales [Member]
Realized gains (losses):
Embedded Derivative, Gain (Loss) on Embedded Derivative, Net			$ (9)	$ 15		$ (22)	$ 39