| COVER PAGE - USD ($) $ in Billions | 12 Months Ended | ||
| Dec. 31, 2021 | Jan. 31, 2022 | Jun. 30, 2021 | |
| Cover [Abstract] | |||
| Document Type | 10-K/A | ||
| Document Annual Report | true | ||
| Document Period End Date | Dec. 31, 2021 | ||
| Document Transition Report | false | ||
| Entity File Number | 001-11307-01 | ||
| Entity Registrant Name | Freeport-McMoRan Inc. | ||
| Entity Incorporation, State or Country Code | DE | ||
| Entity Tax Identification Number | 74-2480931 | ||
| Entity Address, Address Line One | 333 North Central Avenue | ||
| Entity Address, City or Town | Phoenix | ||
| Entity Address, State or Province | AZ | ||
| Entity Address, Postal Zip Code | 85004-2189 | ||
| City Area Code | (602) | ||
| Local Phone Number | 366-8100 | ||
| Title of 12(b) Security | Common Stock, par value $0.10 per share | ||
| Trading Symbol | FCX | ||
| Security Exchange Name | NYSE | ||
| Entity Well-known Seasoned Issuer | Yes | ||
| Entity Voluntary Filers | No | ||
| Entity Current Reporting Status | Yes | ||
| Entity Interactive Data Current | Yes | ||
| Entity Filer Category | Large Accelerated Filer | ||
| Entity Small Business | false | ||
| Entity Emerging Growth Company | false | ||
| Entity Shell Company | false | ||
| Entity Public Float | $ 48.6 | ||
| Entity Common Stock, Shares Outstanding | 1,454,781,055 | ||
| Documents Incorporated by Reference [Text Block] | Portions of the registrant’s proxy statement for its 2022 annual meeting of stockholders are incorporated by reference into Part III of this report. | ||
| Entity Central Index Key | 0000831259 | ||
| Current Fiscal Year End Date | --12-31 | ||
| Document Fiscal Year Focus | 2021 | ||
| Document Fiscal Period Focus | FY | ||
| Amendment Flag | false | ||
| ICFR Auditor Attestation Flag | true | ||
| Auditor Name | Ernst & Young LLP | ||
| Auditor Location | Phoenix, Arizona | ||
| Auditor Firm ID | 42 |
| SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS (Notes) | 12 Months Ended |
| Dec. 31, 2021 | |
| SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract] | |
| SEC Schedule, 12-09, Schedule of Valuation and Qualifying Accounts Disclosure [Text Block] | Additions (Deductions) Balance at Charged to Charged to Other Balance at Beginning of Costs and Other (Deductions) End of Year Expense Accounts Additions Year Reserves and allowances deducted from asset accounts: Valuation allowance for deferred tax assets Year Ended December 31, 2021 $ 4,732 $ (596) a $ (49) b $ — $ 4,087 Year Ended December 31, 2020 4,576 200 c (16) b (28) d 4,732 Year Ended December 31, 2019 4,507 50 e 19 b — 4,576 Reserves for non-income taxes: Year Ended December 31, 2021 $ 82 $ 18 $ — $ (41) f $ 59 Year Ended December 31, 2020 58 21 (1) 4 f 82 Year Ended December 31, 2019 62 — — (4) f 58 a. Primarily relates to a $219 million decrease associated with U.S. federal net operating losses (NOLs) utilized during 2021, a $105 million decrease related to expiration of U.S. foreign tax credits, and a $228 million decrease associated with PT Rio Tinto NOLs resulting from positive evidence supporting future taxable income against which NOLs can be used. b. Relates to a valuation allowance for tax benefits primarily associated with actuarial (gains) losses for U.S. defined benefit plans included in other comprehensive income (loss). c. Primarily relates to a $250 million increase in U.S. federal NOL carryforwards, partly offset by a $75 million decrease in U.S. foreign tax credits associated with expirations, and a $11 million decrease in U.S. deferred tax assets for which no benefit is expected to be realized. d. Relates to sale of interest in Kisanfu. e. Primarily relates to a $208 million increase in U.S. federal deferred tax assets for which no benefit is expected to be realized, partly offset by a $98 million decrease in U.S. foreign tax credits associated with expirations and prior-year adjustments, and a $44 million decrease in U.S. federal and state NOL carryforwards f. Represents amounts paid or adjustments to reserves based on revised estimates. |
| SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS (Details) - USD ($) $ in Millions | 12 Months Ended | ||
| Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019 | |
| Net Operating Losses | |||
| SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward] | |||
| Valuation allowance, increase (decrease) | $ 219 | $ 250 | $ 44 |
| Domestic Deferred Tax Assets | |||
| SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward] | |||
| Valuation allowance, increase (decrease) | (11) | 208 | |
| Foreign Tax Authority | |||
| SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward] | |||
| Income Tax Credits and Adjustments | (105) | (75) | (98) |
| PT Rio Tinto | Net Operating Losses | |||
| SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward] | |||
| Valuation allowance, increase (decrease) | 228 | ||
| Valuation allowance for deferred tax assets | |||
| SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward] | |||
| Balance at Beginning of Year | 4,732 | 4,576 | 4,507 |
| Other Additions (Deductions) | (596) | 200 | 50 |
| Additons Charged to Other Accounts | (49) | (16) | 19 |
| SEC Schedule, 12-09, Valuation Allowances and Reserves, Period Increase (Decrease) | 0 | (28) | 0 |
| Balance at End of Year | 4,087 | 4,732 | 4,576 |
| Reserve for Taxes, Other than Income Taxes | |||
| SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward] | |||
| Balance at Beginning of Year | 82 | 58 | 62 |
| Other Additions (Deductions) | 18 | 21 | 0 |
| SEC Schedule, 12-09, Valuation Allowances and Reserves, Deduction | 0 | (1) | 0 |
| SEC Schedule, 12-09, Valuation Allowance and Reserves, Deduction, Other | (41) | 4 | (4) |
| Balance at End of Year | $ 59 | $ 82 | $ 58 |
