SUPPLEMENTARY MINERAL RESERVE INFORMATION (UNAUDITED) (Recoverable Reserves) (Details)	Dec. 31, 2011 oz lb
North America [Member]
Estimated Recoverable Proven and Probable Reserves [Line Items]
Estimated Recoverable Proven and Probable Copper Reserves (in pounds)	40,600,000,000	[1]
Estimated Recoverable Proven And Probable Gold Reserves (in ounces)	400,000
Estimated Recoverable Proven And Probable Molybdenum Reserves (in pounds)	2,710,000,000
South America [Member]
Estimated Recoverable Proven and Probable Reserves [Line Items]
Estimated Recoverable Proven and Probable Copper Reserves (in pounds)	39,100,000,000	[1]
Estimated Recoverable Proven And Probable Gold Reserves (in ounces)	1,300,000
Estimated Recoverable Proven And Probable Molybdenum Reserves (in pounds)	710,000,000
Indonesia [Member]
Estimated Recoverable Proven and Probable Reserves [Line Items]
Estimated Recoverable Proven and Probable Copper Reserves (in pounds)	31,600,000,000	[1]
Estimated Recoverable Proven And Probable Gold Reserves (in ounces)	32,200,000
Estimated Recoverable Proven And Probable Molybdenum Reserves (in pounds)	0
Africa [Member]
Estimated Recoverable Proven and Probable Reserves [Line Items]
Estimated Recoverable Proven and Probable Copper Reserves (in pounds)	8,400,000,000	[1]
Estimated Recoverable Proven And Probable Gold Reserves (in ounces)	0
Estimated Recoverable Proven And Probable Molybdenum Reserves (in pounds)	0
Consolidated basis [Member]
Estimated Recoverable Proven and Probable Reserves [Line Items]
Estimated Recoverable Proven and Probable Copper Reserves (in pounds)	119,700,000,000	[1],[2],[3],[4]
Estimated Recoverable Proven And Probable Gold Reserves (in ounces)	33,900,000	[2],[3],[4]
Estimated Recoverable Proven And Probable Molybdenum Reserves (in pounds)	3,420,000,000	[2],[3],[4]
Estimated Recoverable Proven And Probable Cobalt Reserves (in pounds)	860,000,000
Estimated Recoverable Proven and Probable Silver Reserves (in ounces)	330,300,000
Net Equity Interest [Member]
Estimated Recoverable Proven and Probable Reserves [Line Items]
Estimated Recoverable Proven and Probable Copper Reserves (in pounds)	96,100,000,000	[1],[4],[5],[6]
Estimated Recoverable Proven And Probable Gold Reserves (in ounces)	30,600,000	[4],[5],[6]
Estimated Recoverable Proven And Probable Molybdenum Reserves (in pounds)	3,090,000,000	[4],[5],[6]
Estimated Recoverable Proven And Probable Cobalt Reserves (in pounds)	490,000,000
Estimated Recoverable Proven and Probable Silver Reserves (in ounces)	272,100,000

[1] Consolidated recoverable copper reserves include 3.1 billion pounds in leach stockpiles and 1.3 billion pounds in mill stockpiles.

[2] Consolidated basis reserves represent estimated metal quantities after reduction for joint venture partner interests at the Morenci mine in North America and the Grasberg minerals district in Indonesia. Excluded from the table above are FCX’s estimated recoverable proven and probable reserves of 0.86 billion pounds of cobalt at Tenke Fungurume and 330.3 million ounces of silver in Indonesia, South America and North America.

[3] Consolidated basis reserves represent estimated metal quantities after reduction for joint venture partner interests at the Morenci mine in North America and the Grasberg minerals district in Indonesia.

[4] Includes estimated recoverable metals contained in stockpiles.

[5] Net equity interest reserves represent estimated consolidated basis metal quantities further reduced for noncontrolling interest ownership.

[6] Net equity interest reserves represent estimated consolidated basis metal quantities further reduced for noncontrolling interest ownership. Excluded from the table above are FCX’s estimated recoverable proven and probable reserves of 0.49 billion pounds of cobalt at Tenke Fungurume and 272.1 million ounces of silver in Indonesia, South America and North America.