SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Earnings Per Share) (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended																12 Months Ended
	Dec. 31, 2014		Sep. 30, 2014		Jun. 30, 2014		Mar. 31, 2014		Dec. 31, 2013		Sep. 30, 2013		Jun. 30, 2013		Mar. 31, 2013		Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Summary of Significant Accounting Policies [Abstract]
Net (loss) income	$ (2,735)	[1],[2]	$ 704	[1],[2]	$ 660	[1],[2]	$ 626		$ 959	[3]	$ 1,048		$ 610	[3]	$ 824		$ (745)	[1],[2]	$ 3,441	[3]	$ 3,980
Net income attributable to noncontrolling interests																	523		761		939
Preferred dividends attributable to redeemable noncontrolling interest																	(40)		(22)		0
Undistributed earnings allocable to participating securities																	(3)		0		0
Net (loss) income allocable to FCX common stockholders																	$ (1,311)		$ 2,658		$ 3,041
Basic weighted-average shares of common stock outstanding																	1,039,000,000		1,002,000,000		949,000,000
Add shares issuable upon exercise or vesting of dilutive stock options and RSUs																	0	[4]	4,000,000	[4]	5,000,000	[4]
Diluted weighted-average shares of common stock outstanding																	1,039,000,000		1,006,000,000		954,000,000
Basic net (loss) income per share attributable to FCX common stockholders	$ (2.75)		$ 0.53		$ 0.46		$ 0.49		$ 0.68		$ 0.79		$ 0.49		$ 0.68		$ (1.26)		$ 2.65		$ 3.20
Diluted net (loss) income per share attributable to FCX common stockholders	$ (2.75)	[1],[2],[5],[6],[7]	$ 0.53	[1],[2],[5],[6],[7]	$ 0.46	[1],[2],[5]	$ 0.49	[5]	$ 0.68	[10],[11],[3],[8],[9]	$ 0.79	[11],[8]	$ 0.49	[11],[12],[3],[8],[9]	$ 0.68	[8],[9]	$ (1.26)	[1],[2],[5],[6],[7]	$ 2.64	[10],[11],[12],[3],[8],[9]	$ 3.19
Potential anti-dilutive additional shares of common stock from stock options and restricted stock units																	10,000,000		1,000,000		1,000,000
Outstanding stock options with exercise prices greater than average market price of common stock (in shares)																	31,000,000		30,000,000		17,000,000
Weighted-average exercise price of stock options excluded (in dollars per share)																	$ 40.52		$ 40.23		$ 44.73

[1] Includes a tax charge of $57 million ($0.06 per share) in the second quarter, $5 million in the third quarter, $22 million ($0.02 per share) in the fourth quarter and $84 million ($0.08 per share) for the year associated with deferred taxes recorded in connection with the allocation of goodwill to the sale of the Eagle Ford properties. Additionally, includes a net tax charge (benefit) of $54 million ($7 million attributable to noncontrolling interests and $47 million to net income attributable to common stockholders or $0.04 per share) in the third quarter, $(17) million ($11 million attributable to noncontrolling interests and $(28) million to net loss attributable to common stockholders or $(0.03) per share) in the fourth quarter and $37 million ($18 million attributable to noncontrolling interests and $19 million to net loss attributable to common stockholders or $0.02 per share) for the year associated with changes in Chilean tax rules, U.S. federal income tax regulations and Peruvian tax rules, partially offset by a tax benefit related to changes in U.S. state income tax filing positions.

[2] Includes net gains (losses) on early extinguishment of debt totaling $4 million in the second quarter, $17 million ($0.02 per share) in the third quarter, $(18) million ($(0.02) per share) in the fourth quarter and $3 million for the year. Refer to Note 8 for further discussion.

[3] Includes a net tax benefit of $183 million ($0.19 per share) in the second quarter, $16 million ($0.01 per share) in the fourth quarter and $199 million ($0.20 per share) for the year associated with net reductions in FCX's deferred tax liabilities and deferred tax asset valuation allowances related to the acquisitions of PXP and MMR.

[4] Excludes shares of common stock associated with outstanding stock options with exercise prices less than the average market price of FCX's common stock and RSUs that were anti-dilutive, with related amounts totaling approximately ten million for the year ended December 31, 2014, and one million for the years ended December 31, 2013 and 2012.

[5] Includes credits (charges) of $15 million ($9 million to net income attributable to common stockholders or $0.01 per share) in the first quarter, $(7) million ($(4) million to net income attributable to common stockholders) in the second quarter, $122 million ($76 million to net income attributable to common stockholders or $0.07 per share) in the third quarter, $497 million ($309 million to net loss attributable to common stockholders or $0.30 per share) in the fourth quarter and $627 million ($389 million to net loss attributable to common stockholders or $0.37 per share) for the year for net unrealized and noncash realized gains (losses) on crude oil and natural gas derivative contracts.

[6] Includes net gains of $46 million ($31 million to net income attributable to common stockholders or $0.03 per share) in third quarter, $671 million ($450 million to net loss attributable to common stockholders or $0.43 per share) in the fourth quarter and $717 million ($481 million to net loss attributable to common stockholders or $0.46 per share) for the year primarily from the sale of the Candelaria and Ojos del Salado copper mining operations in the fourth quarter (refer to Note 2 for further discussion) and the sale of a metals injection molding plant in the third quarter.

[7] Includes a charge of $308 million ($192 million to net income attributable to common stockholders or $0.18 per share) in the third quarter, $3.4 billion ($2.1 billion to net loss attributable to common stockholders or $2.05 per share) in the fourth quarter and $3.7 billion ($2.3 billion to net loss attributable to common stockholders or $2.24 per share) for the year to reduce the carrying value of oil and gas properties pursuant to full cost accounting rules. Additionally, the fourth quarter and the year includes a goodwill impairment charge of $1.7 billion ($1.65 per share) for the full carrying value of goodwill.

[8] Includes charges of $14 million ($10 million to net income attributable to common stockholders or $0.01 per share) in the first quarter, $61 million ($36 million to net income attributable to common stockholders or $0.04 per share) in the second quarter, $1 million ($1 million to net income attributable to common stockholders) in the third quarter, $4 million ($3 million to net income attributable to common stockholders) in the fourth quarter and $80 million ($50 million to net income attributable to common stockholders or $0.05 per share) for the year for transaction and related costs principally associated with the acquisitions of PXP and MMR.

[9] Includes net (losses) gains on early extinguishment of debt totaling $(40) million ($(0.04) per share) in the first quarter, $5 million ($0.01 per share) in the second quarter for an adjustment related to taxes on the first quarter losses, $7 million ($0.01 per share) in the fourth quarter and $(28) million ($(0.03) per share) for the year. Refer to Note 8 for further discussion.

[10] Includes charges in the fourth quarter and for the year of (i) $76 million ($49 million to net income attributable to common stockholders or $0.05 per share) associated with updated mine plans at Morenci that resulted in a loss in recoverable copper in leach stockpiles, (ii) $37 million ($23 million to net income attributable to common stockholders or $0.02 per share) associated with the restructuring of an executive employment arrangement and (iii) $36 million ($13 million to net income attributable to common stockholders or $0.01 per share) associated with a new labor agreement at Cerro Verde.

[11] Includes charges of $36 million ($23 million to net income attributable to common stockholders or $0.02 per share) in the second quarter, $158 million ($98 million to net income attributable to common stockholders or $0.09 per share) in the third quarter, $118 million ($73 million to net income attributable to common stockholders or $0.07 per share) in the fourth quarter and $312 million ($194 million to net income attributable to common stockholders or $0.19 per share) for the year (reflecting the seven-month period from June 1, 2013, to December 31, 2013) for unrealized and noncash realized losses on crude oil and natural gas derivative contracts.

[12] Includes a gain of $128 million ($0.13 per share) in the second quarter and for the year related to FCX's preferred stock investment in and the subsequent acquisition of MMR. Refer to Note 2 for further discussion.