INCOME TAXES (Details) (USD $)	3 Months Ended		12 Months Ended					1 Months Ended	3 Months Ended	12 Months Ended
	Sep. 30, 2012		Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010	Jul. 31, 2012 Cerro Verde [Member]	Sep. 30, 2011 Cerro Verde [Member]	Dec. 31, 2012 Cerro Verde [Member]	Dec. 31, 2011 Cerro Verde [Member]	Dec. 31, 2011 Current [Member] Cerro Verde [Member]	Dec. 31, 2011 Deferred [Member] Cerro Verde [Member]
Income before income taxes and equity in affiliated companies' net earnings [Abstract]
United States			$ 1,539,000,000		$ 2,112,000,000		$ 1,307,000,000
Foreign			3,948,000,000		6,706,000,000		7,205,000,000
Total			5,487,000,000		8,818,000,000		8,512,000,000
Current income taxes:
Federal			238,000,000		394,000,000		207,000,000
State			7,000,000		21,000,000		27,000,000
Foreign			1,002,000,000		1,934,000,000		2,500,000,000
Total current			1,247,000,000		2,349,000,000		2,734,000,000
Deferred income taxes (benefits):
Federal			87,000,000		82,000,000		20,000,000
State			18,000,000		(19,000,000)		(10,000,000)
Foreign			363,000,000		622,000,000		239,000,000
Total deferred			468,000,000		685,000,000		249,000,000
Changes in Peruvian taxes	208,000,000	[1],[2]	(205,000,000)	[1],[2]	53,000,000	[3]	0
Provision for income taxes			1,510,000,000		3,087,000,000		2,983,000,000
Term of Stability Agreement								15 years
Foreign Income Tax Rate Under Old Stability Agreement								30.00%
Foreign Income Tax Rate Under New Stability Agreegment								32.00%
Deferred Foreign Income Tax Expense from New Stability Agreement										29,000,000
Deferred Foreign Income Tax Expense from New Stability Agreement Net of Noncontrolling Interest										25,000,000
Deferred Foreign Income Tax Expense (Benefit) Associated with Foreign Reinvested Profits										234,000,000
Deferred Foreign Income Tax Expense (Benefit) Associated with Foreign Reinvested Profits, Net of Noncontrolling Interest										123,000,000
Additional Tax Expense From New Legislation On Mining Royalties											53,000,000	14,000,000	39,000,000
Additional Tax Expense From New Legislation On Mining Royalties Net Of Noncontrolling Interests									50,000,000		49,000,000
Income tax expense (benefit), reconciliation [Abstract]
U.S. federal statutory tax rate			1,920,000,000		3,086,000,000		2,979,000,000
Foreign tax credit limitation			110,000,000		163,000,000		93,000,000
Percentage depletion			(263,000,000)		(283,000,000)		(263,000,000)
Withholding and other impacts on foreign earnings			(221,000,000)	[4]	170,000,000		174,000,000
Valuation allowance on minimum tax credits			(9,000,000)		(47,000,000)		18,000,000
State income taxes			17,000,000		0		17,000,000
Other items, net			(44,000,000)		(2,000,000)		(35,000,000)
Provision for income taxes			1,510,000,000		3,087,000,000		2,983,000,000
Effective income tax rate, reconciliation [Abstract]
U.S. federal statutory tax rate			35.00%		35.00%		35.00%
Foreign tax credit limitation			2.00%		2.00%		1.00%
Percentage depletion			(5.00%)		(3.00%)		(3.00%)
Withholding taxes			(4.00%)		2.00%		2.00%
Valuation allowance on minimum tax credits			0.00%		(1.00%)		0.00%
State income taxes			0.00%		0.00%		0.00%
Other items, net			0.00%		0.00%		0.00%
Provision for income taxes			28.00%		35.00%		35.00%
Total income taxes paid to all jurisdictions			1,800,000,000		3,400,000,000		2,600,000,000
Tax refunds received from all jurisdictions			69,000,000		15,000,000		26,000,000
Deferred tax assets:
Foreign tax credits			2,022,000,000		2,011,000,000
Minimum tax credits			474,000,000		406,000,000
Net operating loss carryforwards			343,000,000		356,000,000
Accrued expenses			910,000,000		962,000,000
Employee benefit plans			315,000,000		245,000,000
Inventory			118,000,000		161,000,000
Other			256,000,000		276,000,000
Deferred tax assets			4,438,000,000		4,417,000,000
Valuation allowances			(2,443,000,000)		(2,393,000,000)
Net deferred tax assets			1,995,000,000		2,024,000,000
Deferred tax liabilities:
Property, plant, equipment and development costs			(4,563,000,000)		(4,227,000,000)
Undistributed earnings			(884,000,000)		(1,010,000,000)
Other			(60,000,000)		(72,000,000)
Total deferred tax liabilities			(5,507,000,000)		(5,309,000,000)
Net deferred tax liabilities			(3,512,000,000)		(3,285,000,000)
Amount of valuation allowance, that if recognized, would be recorded directly to other comprehensive			82,000,000
Valuation allowance on deferred tax asset increase (decrease) during period			$ 50,000,000

[1] In July 2012, Sociedad Minera Cerro Verde S.A.A. (Cerro Verde) signed a new 15-year mining stability agreement with the Peruvian government, which is expected to become effective when the current mining stability agreement expires on December 31, 2013. In connection with the new mining stability agreement, Cerro Verde's income tax rate will increase from 30 percent to 32 percent. As a result of the change in the income tax rate, FCX recognized additional deferred tax expense of $29 million ($25 million net of noncontrolling interests) in 2012, which relates primarily to the assets recorded in connection with the 2007 acquisition of FMC.

[2] With the exception of TFM, FCX has not elected to permanently reinvest earnings from its foreign subsidiaries and has recorded deferred tax liabilities for foreign earnings that are available to be repatriated to the U.S. Cerro Verde previously recorded deferred Peruvian income tax liabilities for income taxes that would become payable if the reinvested profits used to fund the initial Cerro Verde sulfide expansion are distributed prior to the expiration of Cerro Verde's current stability agreement on December 31, 2013. Because reinvested profits at Cerro Verde are not expected to be distributed prior to December 31, 2013, a net deferred income tax liability of $234 million ($123 million net of noncontrolling interests) was reversed and recognized as an income tax benefit in 2012.

[3] In September 2011, Peru enacted a new mining tax and royalty regime and also created a special mining burden that companies with stability agreements can elect to pay. Cerro Verde elected to pay this special mining burden during the remaining term of its stability agreement. As a result, Cerro Verde recognized additional current ($14 million) and deferred ($39 million) tax expense totaling $53 million ($49 million net of noncontrolling interests) for the year 2011. The deferred portion of this accrual related primarily to the assets recorded in connection with the 2007 acquisition of FMC.

[4] Included the reversal of Cerro Verde's deferred income tax liability of $234 million.