Amount of assessment by government agencies in connection with alleged obligations.

No definition available.

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Namespace Prefix:	fcx_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of assessment by government agencies in connection with alleged obligations, expressed in foreign currency.

+ References

No definition available.

+ Details

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Namespace Prefix:	fcx_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

- Definition

Disputed tax assessments (including interest and penalties) receivable.

+ References

No definition available.

+ Details

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Namespace Prefix:	fcx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The estimated interest penalties the entity will owe the government agency in the event the outcome of the formal assessment is not in the entity's favor.

+ References

No definition available.

+ Details

Name:	fcx_ReasonablyPossibleInterestPenalties
Namespace Prefix:	fcx_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Total tax payments made in excess of corresponding tax obligation as of the period end date.

+ References

No definition available.

+ Details

Name:	fcx_TaxOverpayment
Namespace Prefix:	fcx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Total tax payments made in excess of corresponding tax obligation as agreed to by tax authority as of the period end date.

+ References

No definition available.

+ Details

Name:	fcx_TaxOverpaymentAmountAgreedtobyTaxAuthority
Namespace Prefix:	fcx_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_LossContingenciesLineItems
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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of cash received during the period as refunds for the overpayment of taxes.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4297-108586

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 25

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3536-108585

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of the fixed and determinable portion of the unrecorded unconditional purchase obligation maturing in the fifth fiscal year following the latest fiscal year.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 440

-SubTopic 10

-Section 50

-Paragraph 4

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6394976&loc=d3e25336-109308

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of the fixed and determinable portion of the unrecorded unconditional purchase obligation maturing in the next fiscal year following the latest fiscal year.

+ References

+ Details

Name:	us-gaap_UnrecordedUnconditionalPurchaseObligationBalanceOnFirstAnniversary
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of the fixed and determinable portion of the unrecorded unconditional purchase obligation maturing in the four fiscal year following the latest fiscal year.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of the fixed and determinable portion of the unrecorded unconditional purchase obligation maturing in the second fiscal year following the latest fiscal year.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of the fixed and determinable portion of the unrecorded unconditional purchase obligation maturing in the third fiscal year following the latest fiscal year.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of the unrecorded obligation to transfer funds in the future for fixed or minimum amounts or quantities of goods or services at fixed or minimum prices (for example, as in take-or-pay contracts or throughput contracts).

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of the fixed and determinable portion of the unrecorded unconditional purchase obligation maturing after the fifth fiscal year following the latest fiscal year.

+ References

+ Details

Name:	us-gaap_UnrecordedUnconditionalPurchaseObligationDueAfterFiveYears
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Contingencies and Commitments (Unaudited) (Details) In Millions, unless otherwise specified						1 Months Ended
	Sep. 30, 2012 Cerro Verde [Member] Relating to the Period October 2006 through December 2008 [Member] USD ($)	Sep. 30, 2012 Cerro Verde [Member] Relating to the Period October 2006 through December 2008 [Member] PEN	Sep. 30, 2012 Cerro Verde [Member] Relating to the Period October 2006 through December 2008 [Member] Interest Assessment [Member] USD ($)	Sep. 30, 2012 Cerro Verde [Member] Relating to the Period October 2006 through December 2009 [Member] USD ($)	Sep. 30, 2012 Cerro Verde [Member] Relating to the Period October 2006 through December 2009 [Member] PEN	Jul. 31, 2013 PT Freeport Indonesia [Member] USD ($)	Sep. 30, 2013 PT Freeport Indonesia [Member] USD ($)	Sep. 30, 2013 PT Freeport Indonesia [Member] Relating To 2008 [Member] Tax Assessment [Member] USD ($)	Sep. 30, 2013 PT Freeport Indonesia [Member] Relating To 2008 [Member] Interest Assessment [Member] USD ($)	Sep. 30, 2013 PT Freeport Indonesia [Member] Relating To 2011 [Member] USD ($)	Sep. 30, 2013 PT Freeport Indonesia [Member] Relating To 2005 and 2007 [Member] USD ($)	Sep. 30, 2013 Freeport-McMoRan Oil & Gas [Member] USD ($)	Sep. 30, 2012 Minimum [Member] Cerro Verde [Member]	Sep. 30, 2012 Maximum [Member] Cerro Verde [Member]	Sep. 30, 2013 Other Assets [Member] PT Freeport Indonesia [Member] USD ($)	Sep. 30, 2013 Ultra-deepwater Drillship Contracts [Member] Freeport-McMoRan Oil & Gas [Member] USD ($)	Sep. 30, 2013 Deferred Option Premiums and Accrued Interest [Member] Freeport-McMoRan Oil & Gas [Member] USD ($)
Loss Contingencies [Line Items]
Reasonably Possible Interest Penalties													7.00%	18.00%
Foreign government assessment in connection with alleged obligations (in Peruvian nuevo soles)		492			200
Foreign government assessment in connection with alleged obligations	176		104	72				59	55
Tax Overpayment, Amount Agreed to by Tax Authority							291
Tax Overpayment							320
Disputed tax assessments paid										22	126				284
Proceeds from Income Tax Refunds						165
Unconditional Purchase Obligations												2,300				1,500	472
Contractual Obligation, Fiscal Year Maturity Schedule [Abstract]
2013												72
2014												340
2015												704
2016												565
2017												493
Thereafter												$ 166