Subsequent Events (Unaudited)	9 Months Ended
Subsequent Events (Unaudited)	Sep. 30, 2019
Subsequent Events [Abstract]
Subsequent Events	SUBSEQUENT EVENTS FCX evaluated events after September 30, 2019, and through the date the consolidated financial statements were issued, and took into account events and transactions occurring during this period requiring recognition or disclosure in these consolidated financial statements. Timok Transaction. In 2016, FCX sold an interest in the upper zone of the Timok exploration project in Serbia for cash consideration of $135 million and contingent consideration of up to $107 million payable to FCX in stages upon achievement of defined development milestones. In November 2019, FCX entered into an agreement to sell its interest in the lower zone of the Timok exploration project to an affiliate of the purchaser in the 2016 transaction, for cash consideration of $240 million at closing plus deferred payments of up to $150 million. The deferred payments will be based on the future sale of products (as defined in the agreement) from the Timok lower zone. For a period of 12 months after the third anniversary of the initial sale of products from the Timok exploration project, the purchaser can settle, or FCX can demand payment of, such deferred payment obligation, in each case, for a total of $60 million. In addition, in lieu of such payment upon achievement of defined development milestones, the purchaser agreed to pay the $107 million contingent consideration provided for in the 2016 transaction in three installment payments of $45 million by July 31, 2020, $50 million by December 31, 2021, and $12 million by March 31, 2022. Upon closing, FCX expects to record a gain of approximately $340 million, consisting of the cash consideration payment ($240 million) and the aggregate amount of the three installment payments (approximately $100 million after discounting). The transaction is expected to close by first-quarter 2020, subject to receipt of customary regulatory approvals. PT-FI Export Duty Matter. As discussed in Note 12 of FCX’s 2018 Form 10-K, in accordance with PT-FI’s 2017 Memorandum of Understanding with the Indonesian government, PT-FI agreed to pay export duties of 5 percent on the value of copper concentrate export sales until completion of the divestment and new IUPK. The Indonesia Customs Office applied a 7.5 percent duty. PT-FI paid the 2.5 percent difference for the period between April 2017 and December 21, 2018, totaling $155 million, under protest and appealed the disputed amounts to the Indonesia Tax Court. The Indonesia Tax Court subsequently announced rulings in favor of PT-FI related to individual cases involving $29 million of the disputed amounts, which were refunded by the Indonesia Customs Office to PT-FI. The Indonesia Customs Office appealed the Indonesia Tax Court decisions on these cases to the Indonesia Supreme Court. On October 29, 2019, the Indonesia Supreme Court posted on its website rulings unfavorable to PT-FI for certain of the appealed cases involving approximately half of the $29 million that had been refunded to PT-FI. As a result of the October 2019 ruling, under applicable accounting guidance, FCX recorded a charge of $155 million ($76 million to net loss attributable to common stock or $0.05 per share) during third-quarter 2019 to fully reserve for this matter. PT-FI continues to believe that a 5 percent export duty was applicable during this period and is evaluating options to recover these overpayments. Under PT-FI’s IUPK entered into on December 21, 2018, the applicable export duty is 5 percent, declining to 2.5 percent when smelter development progress exceeds 30 percent and eliminated when smelter development progress exceeds 50 percent. PT-FI Mine Development Cost Tax Matters. As discussed in Note 12 of FCX’s 2018 Form 10-K, PT-FI received unfavorable decisions from the Indonesia Tax Court with respect to its appeal of disallowed items on its 2012 and 2014 corporate income tax returns related to the tax treatment of mine development costs. On October 31, 2019, the Indonesia Supreme Court posted on its website a ruling unfavorable to PT-FI regarding its appeal of the Indonesia Tax Court decision regarding the tax treatment of mine development costs in its 2014 tax return. PT-FI is working with its advisors to estimate the aggregate potential exposure of this ruling, which could be significant after taking into account potential applicable penalties and interest and potential application to other years under dispute. PT-FI believes its treatment of mine development costs were appropriate under applicable provisions of the Contract of Work. The IUPK entered into on December 21, 2018, also provides for deductibility of mine development costs. Under applicable accounting guidelines, adjustments for income tax matters such as this are reflected in the period in which the item becomes known and will be incorporated in FCX’s fourth-quarter 2019 results. PT-FI will continue to defend its positions on these matters.