CONTINGENCIES (Details) In Millions, unless otherwise specified	12 Months Ended																		1 Months Ended		3 Months Ended																																												12 Months Ended
	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Dec. 31, 2012 USD ($)	Dec. 31, 2014 Cerro Verde [Member] USD ($)	Dec. 31, 2014 Cerro Verde [Member] Minimum [Member]	Dec. 31, 2014 Cerro Verde [Member] Maximum [Member]	Dec. 31, 2014 PT Freeport Indonesia [Member] USD ($)	Dec. 31, 2014 Tax Years 2002 To 2005 [Member] Cerro Verde [Member] USD ($)	Dec. 31, 2014 Tax Year 2005 [Member] PT Freeport Indonesia [Member] USD ($)	Dec. 31, 2014 Tax Year 2006 [Member] Cerro Verde [Member] USD ($)	Dec. 31, 2014 Tax Year 2006 [Member] PT Freeport Indonesia [Member] USD ($)	Dec. 31, 2014 Tax Year 2007 [Member] Cerro Verde [Member] USD ($)	Dec. 31, 2014 Tax Year 2007 [Member] PT Freeport Indonesia [Member] USD ($)	Dec. 31, 2014 Tax Year 2008 [Member] Cerro Verde [Member] USD ($)	Dec. 31, 2014 Tax Year 2008 [Member] PT Freeport Indonesia [Member] USD ($)	Dec. 31, 2014 Tax Year 2009 [Member] Cerro Verde [Member] USD ($)	Dec. 31, 2014 Tax Year 2010 [Member] Cerro Verde [Member] USD ($)		Jul. 31, 2013 Tax Year 2011 [Member] PT Freeport Indonesia [Member] USD ($)	Dec. 31, 2014 Tax Year 2011 [Member] PT Freeport Indonesia [Member] USD ($)	Jun. 30, 2014 Tax Year 2012 [Member] PT Freeport Indonesia [Member] USD ($)	Dec. 31, 2014 Tax Year 2012 [Member] PT Freeport Indonesia [Member] USD ($)	Dec. 31, 2014 Tax Year 2014 [Member] Cerro Verde [Member] USD ($)	Dec. 31, 2014 Tax Year 2014 [Member] PT Freeport Indonesia [Member] USD ($)	Dec. 31, 2014 Relating To 2005 and 2007 [Member] PT Freeport Indonesia [Member] USD ($)	Dec. 31, 2014 Relating to the Period October 2006 through December 2008 [Member] Cerro Verde [Member] USD ($)	Dec. 31, 2014 Relating to the Period October 2006 through December 2008 [Member] Cerro Verde [Member] PEN	Dec. 31, 2014 Tax Assessment [Member] Cerro Verde [Member] USD ($)	Dec. 31, 2014 Tax Assessment [Member] PT Freeport Indonesia [Member] USD ($)	Dec. 31, 2014 Tax Assessment [Member] Tax Years 2002 To 2005 [Member] Cerro Verde [Member] USD ($)	Dec. 31, 2014 Tax Assessment [Member] Tax Year 2005 [Member] PT Freeport Indonesia [Member] USD ($)	Dec. 31, 2014 Tax Assessment [Member] Tax Year 2006 [Member] Cerro Verde [Member] USD ($)	Dec. 31, 2014 Tax Assessment [Member] Tax Year 2006 [Member] PT Freeport Indonesia [Member] USD ($)	Dec. 31, 2014 Tax Assessment [Member] Tax Year 2007 [Member] Cerro Verde [Member] USD ($)	Dec. 31, 2014 Tax Assessment [Member] Tax Year 2007 [Member] PT Freeport Indonesia [Member] USD ($)	Dec. 31, 2014 Tax Assessment [Member] Tax Year 2008 [Member] Cerro Verde [Member] USD ($)	Dec. 31, 2014 Tax Assessment [Member] Tax Year 2008 [Member] PT Freeport Indonesia [Member] USD ($)	Dec. 31, 2014 Tax Assessment [Member] Tax Year 2009 [Member] Cerro Verde [Member] USD ($)	Dec. 31, 2014 Tax Assessment [Member] Tax Year 2010 [Member] Cerro Verde [Member] USD ($)	Dec. 31, 2014 Tax Assessment [Member] Tax Year 2011 [Member] PT Freeport Indonesia [Member] USD ($)	Dec. 31, 2014 Tax Assessment [Member] Tax Year 2012 [Member] PT Freeport Indonesia [Member] USD ($)	Jun. 30, 2014 Tax Assessment [Member] Tax Year 2012 [Member] PT Freeport Indonesia [Member] USD ($)	Dec. 31, 2014 Tax Assessment [Member] Tax Year 2014 [Member] Cerro Verde [Member] USD ($)	Dec. 31, 2014 Interest and Penalties Assessment [Member] Cerro Verde [Member] USD ($)	Dec. 31, 2014 Interest and Penalties Assessment [Member] PT Freeport Indonesia [Member] USD ($)	Dec. 31, 2014 Interest and Penalties Assessment [Member] Tax Years 2002 To 2005 [Member] Cerro Verde [Member] USD ($)	Dec. 31, 2014 Interest and Penalties Assessment [Member] Tax Year 2005 [Member] PT Freeport Indonesia [Member] USD ($)	Dec. 31, 2014 Interest and Penalties Assessment [Member] Tax Year 2006 [Member] Cerro Verde [Member] USD ($)	Dec. 31, 2014 Interest and Penalties Assessment [Member] Tax Year 2006 [Member] PT Freeport Indonesia [Member] USD ($)	Dec. 31, 2014 Interest and Penalties Assessment [Member] Tax Year 2007 [Member] Cerro Verde [Member] USD ($)	Dec. 31, 2014 Interest and Penalties Assessment [Member] Tax Year 2007 [Member] PT Freeport Indonesia [Member] USD ($)	Dec. 31, 2014 Interest and Penalties Assessment [Member] Tax Year 2008 [Member] Cerro Verde [Member] USD ($)	Dec. 31, 2014 Interest and Penalties Assessment [Member] Tax Year 2008 [Member] PT Freeport Indonesia [Member] USD ($)	Dec. 31, 2014 Interest and Penalties Assessment [Member] Tax Year 2009 [Member] Cerro Verde [Member] USD ($)	Dec. 31, 2014 Interest and Penalties Assessment [Member] Tax Year 2010 [Member] Cerro Verde [Member] USD ($)	Dec. 31, 2014 Interest and Penalties Assessment [Member] Tax Year 2011 [Member] PT Freeport Indonesia [Member] USD ($)	Dec. 31, 2014 Interest and Penalties Assessment [Member] Tax Year 2012 [Member] PT Freeport Indonesia [Member] USD ($)	Dec. 31, 2014 Interest and Penalties Assessment [Member] Tax Year 2014 [Member] Cerro Verde [Member] USD ($)	Dec. 31, 2014 Interest and Penalties Assessment [Member] Relating to the Period October 2006 through December 2008 [Member] Cerro Verde [Member] USD ($)	Dec. 31, 2014 Royalty Tax [Member] Tax Year 2009 [Member] Cerro Verde [Member] USD ($)	Dec. 31, 2014 Royalty Tax [Member] Tax Year 2009 [Member] Cerro Verde [Member] PEN	Jun. 30, 2014 Other Assessments [Member] Tax Year 2012 [Member] PT Freeport Indonesia [Member] USD ($)	Dec. 31, 2014 Other Assets [Member] Cerro Verde [Member] USD ($)	Dec. 31, 2014 Other Assets [Member] PT Freeport Indonesia [Member] USD ($)	Dec. 31, 2014 Other Assets [Member] Royalty Tax [Member] Cerro Verde [Member] USD ($)	Dec. 31, 2014 Other Assets [Member] Royalty Tax [Member] Cerro Verde [Member] PEN	Dec. 31, 2015 Subsequent Event [Member] USD ($)
Site Contingency [Line Items]
Minimum number of active remediation projects in the United States (in number of projects)	100
Approximate number of states with active remediation projects (in number of states)	27
Proceeds from Legal Settlements																																																																			$ 115
Payments for Legal Settlements																																																																			22.5
Reasonably Possible Interest Penalties					7.00%	18.00%
Assessment By Foreign Government of Alleged Obligations, Expressed in Foreign Currency																											492																																		226
Assessment By Foreign Government Of Alleged Obligations				442			639	65	152	52	32	30	135	34	114	108	148	[1]		69		137	5			165		183	471	16	103	7	22	12	91	21	62	59	63	56	137	137	5	259	168	49	49	45	10	18	44	13	52	49	85	13	0	0	97	76		15
Assessment By Foreign Government Of Alleged Obligations, Net of Noncontrolling Interest																										88																																		41
Duration of Deferred Payment under Installment Program																																																																	6 months	6 months
Number of Installment Payments under Installment Program																																																																	66	66
Disputed Tax Assessments Receivable							359													22					126																																						192	279	40
Disputed Tax Assessments Receivable, Expressed in Foreign Currency																																																																		113
Tax Overpayment, Amount Agreed to by Tax Authority							291
Tax Overpayment																				313		303		267
Proceeds from Income Tax Refunds	257	270	69																165		151
Value Added Tax Receivable							$ 269

[1] The tax assessment for the year 2010 was issued in February 2015.