DISPOSITIONS AND ACQUISITIONS (Pro Forma) (Details) (USD $)	3 Months Ended					12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2013	Dec. 31, 2014	Dec. 31, 2013		Dec. 31, 2012
Business Acquisition [Line Items]
Revenues							$ 23,075,000,000		$ 22,713,000,000
Operating income							6,267,000,000		6,815,000,000
Income from continuing operations							3,626,000,000		4,277,000,000
Net income attributable to FCX common stockholders							2,825,000,000		3,301,000,000
Net income per share attributable to FCX common stockholders, basic							$ 2.71		$ 3.17
Net income per share attributable to FCX common stockholders, diluted							$ 2.70		$ 3.16
Business Combination, Acquisition Related Costs, Including Acquiree Costs							519,000,000
Income Tax Expense (Benefit) Adjustments				(16,000,000)	(183,000,000)	0	(199,000,000)	[1]	(205,000,000)	[2],[3]
Income Tax Expense (Benefit), Changes in Deferred Tax Liabilities and Deferred Tax Asset Valuation Allowances	(22,000,000)	(5,000,000)	(57,000,000)			(84,000,000)	190,000,000
Gain on investment in McMoRan Exploration Co. (MMR)						0	128,000,000		0
Gain (Loss) on Disposition of Oil and Gas Property							$ 77,000,000

[1] As a result of the oil and gas acquisitions, FCX recognized a net tax benefit of $199 million consisting of income tax benefits of $190 million associated with net reductions in FCX's valuation allowances, $69 million related to the release of the deferred tax liability on PXP's investment in MMR common stock and $16 million associated with the revaluation of state deferred tax liabilities, partially offset by income tax expense of $76 million associated with the write off of deferred tax assets related to environmental liabilities.

[2] 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 were distributed prior to the expiration of Cerro Verde's 1998 stability agreement on December 31, 2013. Because reinvested profits at Cerro Verde were not expected to be distributed prior to December 31, 2013, a net deferred income tax liability of $234 million was reversed and recognized as an income tax benefit in 2012.

[3] In 2012, Cerro Verde signed a new 15-year mining stability agreement with the Peruvian government, which became effective January 1, 2014. In connection with the new mining stability agreement, Cerro Verde's income tax rate increased from 30 percent to 32 percent, and FCX recognized additional deferred tax expense of $29 million.