CONTINGENCIES (Other Contingencies) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2011 Subsidiary FMC [Member]	Dec. 31, 2011 Cerro Verde Mine - Mining Royalties and Penalties [Member]	Dec. 31, 2011 Relating To 2005 [Member] PT Freeport Indonesia - Taxes [Member]	Oct. 31, 2010 Relating To 2005 [Member] PT Freeport Indonesia - Taxes [Member]	Oct. 31, 2010 Relating To 2005 [Member] PT Freeport Indonesia - Interest [Member]	Nov. 30, 2011 Relating To 2006 [Member] PT Freeport Indonesia - Taxes [Member]	Nov. 30, 2011 Relating To 2006 [Member] PT Freeport Indonesia - Interest [Member]
Other contingencies by location [Line Items]
Foreign government assessment in connection with alleged obligations				$ 190		$ 106	$ 52	$ 22	$ 10
Low range interest rate for penalties in connection with the alleged obligations for mining royalties (in hundredths)				7.00%
High range interest rate for penalties in connection with the alleged obligations for mining royalties (in hundredths)				18.00%
Aggregate cap for indemnity obligations under 2005 sale agreement of Columbian Chemicals Company			110
Disputed tax assessments paid	$ 109	$ 0			$ 109