SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended															12 Months Ended
	Dec. 31, 2011		Sep. 30, 2011		Jun. 30, 2011		Mar. 31, 2011		Dec. 31, 2010		Sep. 30, 2010	Jun. 30, 2010		Mar. 31, 2010		Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009		May 01, 2010
Accounting Policies [Abstract]
Minimum ownership percentage of subsidiary for inclusion in consolidated financial statements (in hundredths)																50.00%
Ownership percentage of subsidiary PT Freeport Indonesia (in hundredths)																90.64%
Minimum ownership percentage for investment in unconsolidated companies accounted for using the equity method	20.00%															20.00%
Maximum ownership percentage for investments in unconsolidated companies carried at cost	20.00%															20.00%
Percentage of ultimate copper recovery from leach stockpiles (in hundredths)																90.00%
Percentage of the copper ultimately recoverable from newly placed material on active stockpiles (in hundredths)																70.00%
Pounds of copper under outstanding provisionally priced sales (net of noncontrolling interests) (in pounds of copper)																252,000,000
Average price per pound of outstanding provisionally priced copper sales (in dollars per pound)																$ 3.44
Earnings Per Share [Abstract]
Net income	$ 866		$ 1,294	[1]	$ 1,726		$ 1,861		$ 1,964		$ 1,533	$ 832		$ 1,215		$ 5,747	[1]	$ 5,544		$ 3,534
Net income attributable to noncontrolling interests	(226)		(241)		(358)		(362)		(415)		(355)	(168)		(270)		(1,187)		(1,208)		(785)
Preferred dividends																0		(63)		(222)
Net income attributable to FCX common stockholders	640	[2]	1,053	[1]	1,368	[3]	1,499	[3]	1,549	[4]	1,178	649	[4]	897	[4]	4,560	[1],[2],[3]	4,273	[4]	2,527
Plus income impact of assumed conversion of: [Abstract]
6 3/4% Mandatory Convertible Preferred Stock																0	[5]	63	[5]	194	[5]
5 1/2% Convertible Perpetual Preferred Stock																0	[6]	0	[6]	28	[6]
Diluted net income attributable to FCX common stockholders																$ 4,560		$ 4,336		$ 2,749
Weighted-average shares of common stock outstanding (in shares)																947,000,000		915,000,000		829,000,000
Add stock issuable upon conversion, exercise or vesting of: [Abstract]
6 3/4% Mandatory Convertible Preferred Stock (in shares)																0	[5]	26,000,000	[5]	79,000,000	[5]
5 1/2% Convertible Perpetual Preferred Stock (in shares)																0	[6]	0	[6]	25,000,000	[6]
Dilutive stock options																7,000,000	[7]	6,000,000		3,000,000
Restricted stock units																1,000,000		2,000,000		2,000,000
Weighted-average shares of common stock outstanding for purposes of calculating diluted net income per share (in shares)																955,000,000		949,000,000		938,000,000
Diluted net income per share attributable to FCX common stockholders	$ 0.67	[2]	$ 1.10	[1]	$ 1.43	[3]	$ 1.57	[3]	$ 1.63	[4]	$ 1.24	$ 0.70	[4]	$ 1.00	[4]	$ 4.78	[1],[2],[3]	$ 4.57	[4]	$ 2.93
Actual conversion rate of preferred stock into common stock (in shares)																						2.7432
Mandatory Convertible Preferred Stock Dividend Rate Percentage																		6.75%		6.75%
Convertible Perpetual Preferred Stock Dividend Rate Percentage																				5.50%
Potential anti-dilutive additional shares of common stock from stock options and restricted stock units																2,000,000
Outstanding stock options with exercise prices greater than average market price of common stock (in shares)																4,000,000		10,000,000		13,000,000
Weighted-average exercise price of stock options excluded																$ 53.91		$ 38.56		$ 36.27

[1] Includes additional taxes of $57 million ($50 million net of noncontrolling interests or $0.05 per share) in the third quarter and $53 million ($49 million net of noncontrolling interests or $0.05 per share) for the year associated with Peru's new mining tax and royalty regime. Refer to Note 12 for for further discussion.

[2] Includes charges totaling $116 million ($50 million to net income attributable to common stock or $0.05 per share) for the fourth quarter and the year primarily associated with bonuses for new labor agreements and other employee costs at PT Freeport Indonesia, Cerro Verde and El Abra.

[3] Includes losses on early extinguishment of debt totaling $6 million ($0.01 per share) in the first quarter, $54 million ($0.06 per share) in the second quarter and $60 million ($0.06 per share) for the year. Refer to Note 9 for further discussion.

[4] Includes losses on early extinguishment of debt totaling $23 million ($0.02 per share) in the first quarter, $42 million ($0.05 per share) in the second quarter, $3 million (less than $0.01 per share) in the fourth quarter and $71 million ($0.07 per share) for the year. Refer to Note 9 for further discussion.

[5] All outstanding 6¾% Mandatory Convertible Preferred Stock automatically converted on May 1, 2010, into FCX common stock at a conversion rate of 2.7432 shares of FCX common stock.

[6] In September 2009, FCX redeemed the remaining outstanding shares of its 5½% Convertible Perpetual Preferred Stock.

[7] Potential additional shares of common stock that were anti-dilutive totaled approximately two million.