COMMITMENTS AND GUARANTEES (Mining Contracts) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	6 Months Ended	12 Months Ended
	Sep. 30, 2014	Jun. 30, 2014	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012	Jul. 25, 2014	Mar. 26, 2012
Contractual obligations mining contracts [line items]
Number of Extention Periods Available Under Mining Contract			2
Assurance Bond, Smelter Development			$ 115	[1]	$ 0	[1]
PT Freeport Indonesia [Member]
Contractual obligations mining contracts [line items]
Period For Option To Extend Mining Contract			10 years
Copper Royalty Rate Payable (in hundredths)	4.00%	3.50%
Gold And Silver Sales Royalty Rate (in hundredths)	3.75%	1.00%			1.00%
Quantity of ore produced subject to additional royalties			200,000
Product Exports Ban, Date			Jan. 12, 2017
Effective Date, Memorandum of Understanding with Foreign Government	Jul. 25, 2014
Expiration Date, Memorandum of Understanding with Foreign Government			Jul. 25, 2015
Percentage of undivided interest owned by third party								30.00%
Incremental Percent of Undivided Interest Owned by Third Party								20.64%
Expiration Date, Contract of Work	Dec. 31, 2021
Assurance Bond, Smelter Development			115
Royalty Expense			115		109		93
Export Duties Expense			77
Export Permit Renewal Term			6 months
Tenke Fungurume [Member]
Contractual obligations mining contracts [line items]
Royalty Expense			29		29		25
Royalty Rate Payable Under Amended And Restated Mining Convention (in hundredths)			2.00%
Percentage of mining property owned by the company			56.00%						57.75%
Conversion of intercompany loans							$ 50
Stage 1 [Member] | PT Freeport Indonesia [Member]
Contractual obligations mining contracts [line items]
Progressive Export Duty on Copper Concentrates, Percent	7.50%
Stage 2 [Member] | PT Freeport Indonesia [Member]
Contractual obligations mining contracts [line items]
Progressive Export Duty on Copper Concentrates, Percent	5.00%
Smelter Development Progress, Percent	7.50%
Stage 3 [Member] | PT Freeport Indonesia [Member]
Contractual obligations mining contracts [line items]
Progressive Export Duty on Copper Concentrates, Percent	0.00%
Smelter Development Progress, Percent	30.00%
Maximum [Member] | PT Freeport Indonesia [Member]
Contractual obligations mining contracts [line items]
Copper Royalty Rate Payable (in hundredths)					3.50%
Price Of Copper Per Pound					1.10
Progressive Export Duty on Copper Concentrates, Percent			60.00%
Date, Contract of Work Extension	Dec. 31, 2041
Minimum [Member] | PT Freeport Indonesia [Member]
Contractual obligations mining contracts [line items]
Copper Royalty Rate Payable (in hundredths)					1.50%
Price Of Copper Per Pound					0.90
Progressive Export Duty on Copper Concentrates, Percent			25.00%
Date, Contract of Work Extension	Dec. 31, 2022

[1] Relates to PT-FI's commitment for smelter development in Indonesia at December 31, 2014 (refer to Note 13 for further discussion).