Trading Arrangements, by Individual Trading Arrangements, by Individual [Table] EPS denominator: Weighted Average Number of Shares Outstanding, Diluted [Abstract] Trading Arrangement: Trading Arrangement [Axis] Maximum Maximum [Member] Portion at Fair Value Measurement Portion at Fair Value Measurement [Member] Provision type [Domain] Provision type [Domain] Provision type [Domain] Statistical Measurement [Domain] Statistical Measurement [Domain] Title of 12(b) Security Title of 12(b) Security Subsequent Event Subsequent Event [Member] Net Income (Loss) Available to Common Stockholders, Diluted Net Income (Loss) Available to Common Stockholders, Diluted Carrying amount Reported Value Measurement [Member] Document Fiscal Year Focus Document Fiscal Year Focus Costs related to terminated acquisition Costs related to terminated acquisition Business Combination, Acquisition-Related Cost, Expense Derivative Assets (Liabilities), at Fair Value, Net Total net assets Derivative Assets (Liabilities), at Fair Value, Net Derivative Instruments, Gain (Loss) by Hedging Relationship, by Income Statement Location, by Derivative Instrument Risk [Table] Derivative Instruments, Gain (Loss) [Table] Adjustment to Compensation, Amount Adjustment to Compensation Amount Financial Instrument [Axis] Financial Instrument [Axis] Segment Reporting [Abstract] Segment Reporting [Abstract] Other Commercial Events [Line Items] OtherCommercialEvents [Line Items] [Line Items] for Other Commercial Events [Table] Interest expense, net of capitalized interest Interest expense, net of capitalized interest Interest Expense, Operating and Nonoperating Asset Acquisition, Consideration Transferred, Excluding Transaction Cost Asset Acquisition, Consideration Transferred, Excluding Transaction Cost Asset Acquisition, Consideration Transferred, Excluding Transaction Cost Wards Well coal deposit Wards Well coal deposit [Member] Wards Well coal deposit Schedule of Long-term Debt Instruments Schedule of Long-Term Debt Instruments [Table Text Block] Derivative, Floor Price Derivative, Floor Price Restatement Determination Date Restatement Determination Date Expected return on plan assets Defined Benefit Plan, Expected Return (Loss) on Plan Assets Total debt at par value Long-Term Debt and Lease Obligation, Including Current Maturities Derivative Instrument [Axis] Derivative Instrument [Axis] Collateral arrangements Proceeds From Release Of Collateral Proceeds From Release Of Collateral Measurement Frequency [Axis] Measurement Frequency [Axis] Accounts receivable, allowance for credit loss Accounts Receivable, Allowance for Credit Loss Other Payments to Acquire Businesses Other Payments to Acquire Businesses Schedule of Interest Charges Schedule of Interest Charges [Table Text Block] Schedule of Interest Charges Debt Instrument, Convertible, Conversion Price Debt Instrument, Convertible, Conversion Price Contributions to joint ventures Contributions to joint ventures Contributions to joint ventures Amendment Flag Amendment Flag Current liabilities Liabilities, Current [Abstract] Accounts receivable, credit loss expense (reversal) Accounts Receivable, Credit Loss Expense (Reversal) Inventory [Axis] Inventory [Axis] Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Seaborne Mining Seaborne Mining [Member] Seaborne Mining Shoal Creek Mine Shoal Creek [Member] Shoal Creek Derivative, exchange rate cap (in dollars per share) Derivative, Exchange Rate Cap External Credit Rating, Moody's [Domain] External Credit Rating, Moody's [Domain] Sales related costs Sales related costs Sales related costs Loss Contingencies [Table] Loss Contingencies [Table] (Loss) income from continuing operations: Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest [Abstract] Leases [Abstract] Leases [Abstract] Share-based compensation awards Share-based compensation awards [Member] Share-based compensation awards Surety Bonds and Letters of Credit Outstanding for Other Support Surety Bonds and Letters of Credit Outstanding for Other Support Surety Bonds and Letters of Credit Outstanding for Other Support Restricted cash and collateral restricted cash and collateral restricted cash and collateral Adjustment to Non-PEO NEO Compensation Footnote Adjustment to Non-PEO NEO Compensation Footnote [Text Block] Credit Rating, Fitch [Axis] Credit Rating, Fitch [Axis] Property, Plant, and Equipment [Abstract] Property, Plant, and Equipment [Abstract] Entity Address, State or Province Entity Address, State or Province PEO Total Compensation Amount PEO Total Compensation Amount Common stock, par value per share (in dollars per share) Common Stock, Par or Stated Value Per Share Additions to property, plant, equipment and mine development Segment Reporting, Long-Lived Asset, Expenditure for Addition Asset Acquisition [Axis] Asset Acquisition [Axis] Weighted average shares outstanding — basic Weighted Average Number of Shares Outstanding, Basic Income Taxes Income Tax Contingency [Line Items] Notional amount Derivative, Notional Amount Retirement Benefits [Abstract] Retirement Benefits [Abstract] inventory reserves Inventory Valuation Reserves Outstanding Aggregate Erroneous Compensation Amount Outstanding Aggregate Erroneous Compensation Amount Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [Table] Total current liabilities Liabilities, Current Subsegments Consolidation Items [Axis] Subsegments Consolidation Items [Axis] Regulatory Liability [Axis] Regulatory Liability [Axis] Total reportable segment revenue Total segment revenue excluding corporate and other operating segment Total segment revenue excluding corporate and other operating segment Net Leverage Ratio Debt Instrument Covenant, Net Leverage Ratio Debt Instrument Covenant, Net Leverage Ratio Entity Address, City or Town Entity Address, City or Town Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan Disclosure [Line Items] Statement of Financial Position [Abstract] Statement of Financial Position [Abstract] Other Operating Income Loss [Abstract] Other Operating Income Loss [Abstract] Other Operating Income. 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Fair Value, Inputs, Level 1, 2 and 3 Fair Value, Inputs, Level 1, Level 2, and Level 3 [Member] Trading Activity, by Type [Domain] Trading Activity, by Type [Domain] Changes in amortization of basis difference related to equity affiliates Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount Segment Adjusted EBITDA excluding corporate and other segment Segment Reporting Information Adjusted EBITDA excluding corporate and other segment Segment Reporting Information Adjusted EBITDA excluding corporate and other segment Debt Covenant Terms [Domain] Debt Covenant Terms [Domain] [Domain] for Debt Covenant Terms [Axis] Excess aggregate principal amount [Domain] Excess aggregate principal amount [Domain] Excess aggregate principal amount [Domain] Accumulated other comprehensive income Accumulated Other Comprehensive Income (Loss), Net of Tax Entity Shell Company Entity Shell Company Consolidation Items [Domain] Consolidation Items [Domain] Raw coal Raw Coal Raw coal. Revenue Recognition Revenues [Text Block] Revenues [Text Block] Coal Contract [Member] Coal Contract [Member] Schedule of Property, Plant, Equipment and Mine Development Property, Plant, and Equipment [Table Text Block] Statement of Comprehensive Income [Abstract] Statement of Comprehensive Income [Abstract] Earnings per Share (EPS) Earnings Per Share [Text Block] Name Outstanding Recovery, Individual Name Outside services Outside services Outside services Postretirement benefit obligations Increase (Decrease) in Obligation, Other Postretirement Benefits Net (loss) income attributable to common stockholders: Earnings Per Share [Abstract] Earnings Per Share [Abstract] Award Timing, How MNPI Considered Award Timing, How MNPI Considered [Text Block] Document Fiscal Period Focus Document Fiscal Period Focus Peer Group Issuers, Footnote Peer Group Issuers, Footnote [Text Block] Total liabilities Liabilities Trading Symbol Trading Symbol Debt Instrument, Convertible, If-converted Value in Excess of Principal Debt Instrument, Convertible, If-converted Value in Excess of Principal Prior Year End Fair Value of Equity Awards Granted in Any Prior Year that Fail to Meet Applicable Vesting Conditions During Covered Year Prior Year End Fair Value of Equity Awards Granted in Any Prior Year that Fail to Meet Applicable Vesting Conditions During Covered Year [Member] Surety Trust Account Surety Trust Account [Member] Surety Trust Account Pension Adjustments Prior Service Cost Pension Adjustments Prior Service Cost [Member] Business interruption and property loss limits on insurance claim, amount Loss limits on insurance claim, amount Loss limits on insurance claim, amount Company Selected Measure Name Company Selected Measure Name Sale of Stock [Domain] Sale of Stock [Domain] Aggregate principal amount [Axis] Aggregate principal amount [Axis] Aggregate principal amount Income Tax Disclosure [Abstract] Income Tax Disclosure [Abstract] Accounts Receivable from Securitization Accounts Receivable from Securitization Noncash interest expense, net Other Noncash Expense Number of reportable segments not disclosed flag Number of reportable segments not disclosed flag Number of reportable segments not disclosed flag Diluted EPS attributable to common stockholders: Earnings Per Share, Diluted [Abstract] Debt Conversion, Converted Instrument, Rate Debt Conversion, Converted Instrument, Rate Less: Letters of Credit in Support of Surety Bonds Letters of Credit in Support of Surety Bonds Letters of Credit in Support of Surety Bonds Loss from discontinued operations Discontinued Operation, Income (Loss) from Discontinued Operation, Net of Tax, Per Basic Share Provision type [Axis] Provision type [Axis] Provision type Deductible amount Deductible amount Deductible amount Excess aggregate principal amount [Axis] Excess aggregate principal amount [Axis] Excess aggregate principal amount Total Obligations Supported, Net Total Obligations Supported, Net Total Obligations Supported, Net 2028 Convertible Notes Long-Term Debt, Gross 2028 Convertible Notes 2028 Convertible Notes [Member] 2028 Convertible Notes Line of Credit Facility, Commitment Fee Percentage Line of Credit Facility, Commitment Fee Percentage Credit Facility [Domain] Credit Facility [Domain] Equity Ownership, Excluding Consolidated Entity and Equity Method Investee, Percentage Equity Ownership, Excluding Consolidated Entity and Equity Method Investee, Percentage Cash Flows From Operating Activities Cash Provided by (Used in) Operating Activity, Including Discontinued Operation [Abstract] Miscellaneous receivables, net Other Receivables, Net, Current Compensation Amount Outstanding Recovery Compensation Amount Individual: Individual [Axis] Weighted average shares outstanding — diluted Weighted Average Number of Shares Outstanding, Diluted Defined Benefit Plan Termination, Final Contribution Amount Defined Benefit Plan Termination, Final Contribution Amount Defined Benefit Plan Termination, Final Contribution Amount Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Restricted Cash and Collateral Restricted Cash and Collateral [Table Text Block] Restricted Cash and Collateral Entity Emerging Growth Company Entity Emerging Growth Company Equity Valuation Assumption Difference, Footnote Equity Valuation Assumption Difference, Footnote [Text Block] Other Events Other Events [Text Block] Other Events [Text Block] Derivatives, Policy Derivatives, Policy [Policy Text Block] Underlying Security Market Price Change Underlying Security Market Price Change, Percent Dividends declared ($0.075 and $0.075 per share, respectively) Dividends Difference between penal sum of all surety bonds and amount of collateral posted in favor of surety providers Difference between penal sum of all surety bonds and amount of collateral posted in favor of surety providers Difference between penal sum of all surety bonds and amount of collateral posted in favor of surety providers Deferred income taxes Deferred Income Taxes and Tax Credits Property, plant, equipment and mine development, net Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, after Accumulated Depreciation and Amortization Credit Facility Amendment [Axis] Credit Facility Amendment [Axis] Credit Facility Amendment Regulatory Asset [Axis] Regulatory Asset [Axis] Less: Accumulated depreciation, depletion and amortization Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, Accumulated Depreciation and Amortization Award Timing Predetermined Award Timing Predetermined [Flag] Treasury Stock, Common Treasury Stock, Common [Member] Letters of credit outstanding, amount Letters of Credit Outstanding, Amount Net cash used in discontinued operations Cash Provided by (Used in) Operating Activity, Discontinued Operation Adjustment To PEO Compensation, Footnote Adjustment To PEO Compensation, Footnote [Text Block] Debt and Lease Obligation, Net Total debt Debt and Lease Obligation Level 1 Fair Value, Inputs, Level 1 [Member] Commitment and Duration fees Commitment and Duration fees Commitment and Duration fees Organization, Consolidation and Presentation of Financial Statements [Abstract] Organization, Consolidation and Presentation of Financial Statements [Abstract] Debt Instrument, Convertible, Conversion Ratio Debt Instrument, Convertible, Conversion Ratio Take-or-pay contract-based intangible recognition Fresh Start Adjustment, Fair Value Adjustment Fresh Start Adjustment, Fair Value Adjustment Capitalized debt issuance costs related to ARS amendment Capitalized debt issuance costs related to ARS amendment Capitalized debt issuance costs related to ARS amendment Dilutive impact of share-based compensation awards Incremental Common Shares Attributable to Dilutive Effect of Share-Based Payment Arrangements Collateral Held [Domain] Collateral Held [Domain] Series Common Stock — $0.01 per share par value; 50.0 shares authorized, no shares issued or outstanding as of March 31, 2026 or December 31, 2025 Series Common Stock, Value, Issued Series Common Stock, Value, Issued (Loss) income from continuing operations, net of income taxes (Loss) income from continuing operations, net of income taxes Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest Derivative, Cap Price Derivative, Cap Price Inventory, Current [Table] Inventory, Current [Table] All Executive Categories All Executive Categories [Member] Mine Location [Axis] Mine Location [Axis] Mine Location [Axis] Changes in accrued expenses related to capital expenditures Increase (Decease) in Accrued Liabilities Related to Capital Expenditures, Investing Activities Increase (Decease) in Accrued Liabilities Related to Capital Expenditures, Investing Activities Pension Adjustments Service Cost Pension Adjustments Service Cost [Member] Distributions to noncontrolling interests Minority Interest, Increase from Contributions to Noncontrolling Interest Holders Minority Interest, Increase from Contributions to Noncontrolling Interest Holders Preferred stock, par value per share (in dollars per share) Preferred Stock, Par or Stated Value Per Share Schedule of Net Benefit Costs Schedule of Net Benefit Costs [Table Text Block] External Credit Rating, Fitch [Domain] External Credit Rating, Fitch [Domain] Antidilutive Securities [Axis] Antidilutive Securities [Axis] Asset Acquisition [Domain] Asset Acquisition [Domain] Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation [Abstract] Operating lease right-of-use assets Operating Lease, Right-of-Use Asset Guarantor Obligations, Nature [Axis] Guarantor Obligations, Nature [Axis] Earnings Allocation Method Utilized in the Calculation of Basic and Diluted EPS Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Fair Value Disclosures [Abstract] Fair Value Disclosures [Abstract] Debt Disclosure [Abstract] Debt Disclosure [Abstract] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Current portion of long-term debt Less: Current portion of long-term debt Long-Term Debt and Lease Obligation, Current Segment Information Segment Reporting [Text Block] Minimum Minimum [Member] Dividends paid Payments of Ordinary Dividends, Common Stock Expiration Date Trading Arrangement Expiration Date R3 Renewables R3 Renewables [Member] R3 Renewables Newly Adopted Accounting Standards and Accounting Standards Not Yet Implemented [Abstract] Newly Adopted Accounting Standards and Accounting Standards Not Yet Implemented [Abstract] Indebtedness Indebtedness [Member] Indebtedness Disaggregation of Revenue Disaggregation of Revenue [Table Text Block] Asset retirement obligations Increase (Decrease) in Asset Retirement Obligations Amount Classification [Domain] Amount Classification [Domain] Amount Classification [Domain] Metallurgical coal Metallurgical Coal [Member] Metallurgical Coal [Member] Diluted (loss) income per share (Loss) income from continuing operations Income (Loss) from Continuing Operations, Per Diluted Share Basic (loss) income per share Income (Loss) from Continuing Operations, Per Basic Share Non-Rule 10b5-1 Arrangement Adopted Non-Rule 10b5-1 Arrangement Adopted [Flag] Total stockholders’ equity Balance, beginning of period Balance, end of period Equity, Including Portion Attributable to Noncontrolling Interest Aggregate Grant Date Fair Value of Equity Award Amounts Reported in Summary Compensation Table Aggregate Grant Date Fair Value of Equity Award Amounts Reported in Summary Compensation Table [Member] Remeasurement of foreign income tax accounts [Axis] Remeasurement of foreign income tax accounts [Axis] Remeasurement of foreign income tax accounts Reconciliation of Segment Totals Reconciliation Of Adjusted EBITDA To Consolidated Income From Continuing Operations Net Of Income Taxes [Table Text Block] Reconciliation Of Adjusted EBITDA To Consolidated Income From Continuing Operations Net Of Income Taxes. Buildings and improvements Building and Building Improvements [Member] Net periodic benefit credit, excluding service cost Net periodic postretirement benefit credit Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Aggregate Pension Adjustments Service Cost Aggregate Pension Adjustments Service Cost [Member] Derivative [Table] Derivative [Table] Common stock, shares authorized (in shares) Common Stock, Shares Authorized Earnings allocation method utilized in the calculation of basic and diluted EPS Earnings Per Share Reconciliation [Abstract] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Antidilutive Security, Excluded EPS Calculation [Table] Exercise Price Award Exercise Price Cash Flows From Investing Activities Cash Provided by (Used in) Investing Activity, Including Discontinued Operation [Abstract] Fair Value, Measurements, Recurring Fair Value, Recurring [Member] Schedule of Equity Method Investments [Line Items] Schedule of Equity Method Investments [Line Items] Segment Reporting [Line Items] Segment Reporting [Line Items] Document Quarterly Report Document Quarterly Report Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested [Member] Segments [Domain] Segments [Domain] Pension and Postretirement Benefit Costs Compensation and Employee Benefit Plans [Text Block] James C. Grech [Member] James C. Grech Material and supplies Material And Supplies [Member] Material And Supplies Finance lease obligations Capital Lease, Liability [Member] Capital Lease, Liability Long-term Debt Debt Disclosure [Text Block] Restricted Cash and Cash Equivalents [Axis] Restricted Cash and Cash Equivalents [Axis] Surety bonds amount Financial Instrument, Surety Bonds Amount Financial Instrument, Surety Bonds Amount Debt issuance cost Debt Issuance Costs, Net Financial Instruments and Guarantees with Off Balance Sheet Risk Financial Instruments and Guarantees with Off Balance Sheet Risk [Table Text Block] Financial Instruments and Guarantees with Off Balance Sheet Risk Awards Close in Time to MNPI Disclosures, Table Awards Close in Time to MNPI Disclosures [Table Text Block] Equity method investments Equity Method Investments Equity Component [Domain] Equity Component [Domain] PEO Actually Paid Compensation Amount PEO Actually Paid Compensation Amount Secured debt Secured Debt [Member] Foreign Exchange Contract [Member] Foreign Exchange Contract [Member] Adoption Date Trading Arrangement Adoption Date Stated interest rate Debt Instrument, Interest Rate, Stated Percentage Peabody Energy Corporation stockholders’ equity Equity, Attributable to Parent Repurchase of employee common stock relinquished for tax withholding Payments For Repurchase Of Common Stock Relinquished For Tax Withholding Payments for Repurchase of common stock relinquished for tax withholding. ASSETS Assets [Abstract] Title Trading Arrangement, Individual Title Forgone Recovery due to Disqualification of Tax Benefits, Amount Forgone Recovery due to Disqualification of Tax Benefits, Amount Export Geographic Distribution, Foreign [Member] Accounting Policies [Abstract] Accounting Policies [Abstract] Restatement does not require Recovery Restatement Does Not Require Recovery [Text Block] Insider Trading Policies and Procedures [Line Items] Finance lease obligations Finance lease obligations Finance Lease, Liability Allowance for credit losses Accounts Receivable, Allowance for Credit Loss, Current Insider Trading Policies and Procedures Adopted Insider Trading Policies and Procedures Adopted [Flag] Derivative Instruments, Gain (Loss) [Line Items] Derivative Instruments, Gain (Loss) [Line Items] Selling and administrative expenses Selling, General and Administrative Expense Defined Benefit Plan, Expected Future Employer Contributions, Current Fiscal Year Defined Benefit Plan, Expected Future Employer Contributions, Current Fiscal Year Business Combination [Domain] Business Combination [Domain] Fair Value Transfer, Policy Fair Value Transfer, Policy [Policy Text Block] Letter of Credit Letter of Credit [Member] Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Compensation Actually Paid vs. Net Income Compensation Actually Paid vs. Net Income [Text Block] Antidilutive shares excluded from EPS calculation (in shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Foreign Exchange Option Foreign Exchange Option [Member] Entity Central Index Key Entity Central Index Key Common Stock — $0.01 per share par value; 450.0 shares authorized, 189.6 shares issued and 121.8 shares outstanding as of March 31, 2026 and 189.3 shares issued and 121.6 shares outstanding as of December 31, 2025 Common Stock, Value, Outstanding Underlying Asset Class [Axis] Underlying Asset Class [Axis] Additional paid-in capital Additional Paid in Capital, Common Stock All Adjustments to Compensation All Adjustments to Compensation [Member] Other, net Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity, Other Item Schedule of Guarantee Obligations [Table] Guarantor Obligation [Table] Business Combination [Axis] Business Combination [Axis] Equity [Abstract] Equity [Abstract] Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year [Member] Net cash provided by operating activities Cash Provided by (Used in) Operating Activity, Including Discontinued Operation Stockholders' equity Equity, Attributable to Parent [Abstract] Income Statement [Abstract] Income Statement [Abstract] Document Transition Report Document Transition Report Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Investment, Name [Axis] Investment, Name [Axis] Designated as Hedging Instrument Designated as Hedging Instrument [Member] Deferred income taxes Deferred Income Tax Assets, Net Scott T. Jarboe [Member] Scott T. Jarboe Stock Appreciation Rights (SARs) Stock Appreciation Rights (SARs) [Member] Series Common Stock Series Common Stock [Member] Series Common Stock Member. Basis spread on variable rate Debt Instrument, Basis Spread on Variable Rate City Area Code City Area Code Variable Rate [Domain] Variable Rate [Domain] Asset Retirement and Other Obligations Asset Retirement and Other Obligations [Member] Asset Retirement and Other Obligations Property, Plant, Equipment, and mine development, gross Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, before Accumulated Depreciation and Amortization Accumulated other comprehensive income AOCI Attributable to Parent [Member] Trading and Brokerage Coal Deliveries Trading and Brokerage Coal Deliveries [Member] Trading and Brokerage Coal Deliveries All Individuals All Individuals [Member] Estimated fair value Debt Instrument, Fair Value Disclosure Name Forgone Recovery, Individual Name Regulatory Liability [Domain] Regulatory Liability [Domain] Non-GAAP Measure Description Non-GAAP Measure Description [Text Block] Statement [Line Items] Statement [Line Items] Total assets Total assets Assets Schedule of Defined Benefit Plans Disclosures [Table] Defined Benefit Plan [Table] Debt Covenant Terms [Axis] Debt Covenant Terms [Axis] Debt Covenant Terms [Axis] Preferred stock, shares issued (in shares) Preferred Stock, Shares Issued Internal Credit Assessment [Domain] Internal Credit Assessment [Domain] Amortization of prior service credit Defined Benefit Plan, Amortization of Prior Service Cost (Credit) Long-term Purchase Commitment, Category of Item Purchased [Domain] Long-Term Purchase Commitment, Category of Item Purchased [Domain] Cash backed bank guarantees Cash backed bank guarantees [Member] Cash backed bank guarantees Carrying Amounts And Estimated Fair Values Of Companys Debt Carrying Amounts And Estimated Fair Values Of Companys Debt [Table Text Block] Carrying amounts and estimated fair values of the Company's debt. PEO PEO [Member] Cash and Cash Equivalents [Domain] Cash and Cash Equivalents [Domain] Financial assurance instruments Financial assurance instruments [Member] Financial assurance instruments Measurement Basis [Axis] Measurement Basis [Axis] Other noncurrent liabilities Other Liabilities, Noncurrent Retirement Plan Type [Axis] Retirement Plan Type [Axis] Amount Classification [Axis] Amount Classification [Axis] Amount Classification Forgone Recovery due to Violation of Home Country Law, Amount Forgone Recovery due to Violation of Home Country Law, Amount Subsequent Event Type [Domain] Subsequent Event Type [Domain] Retained earnings Retained Earnings [Member] Operating lease liabilities, less current portion Operating Lease, Liability, Noncurrent Cash-backed bank guarantee facilities Cash-backed bank guarantee facilities Cash-backed bank guarantee facilities Revision of Prior Period [Domain] Revision of Prior Period [Domain] Revolving credit facility Revolving Credit Facility [Member] Erroneously Awarded Compensation Recovery Erroneously Awarded Compensation Recovery [Table] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Common stock, shares outstanding (in shares) Common Stock, Shares, Outstanding Award Timing Disclosures [Line Items] Payment of debt issuance and other deferred financing costs Payments of Debt Issuance Costs Diluted (loss) income per share Net income attribute to common stockholders per share Earnings Per Share, Diluted Entity Current Reporting Status Entity Current Reporting Status Net cash used in financing activities Cash Provided by (Used in) Financing Activity, Including Discontinued Operation Internal Credit Assessment [Axis] Internal Credit Assessment [Axis] Total Shareholder Return Amount Total Shareholder Return Amount Loss from discontinued operations Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Diluted Share Interest Costs Capitalized Interest Costs Capitalized Interest Costs Capitalized Litigation Case [Domain] Litigation Case [Domain] Inventory [Domain] Inventory [Domain] Interest on Convertible Debt, Net of Tax Interest on Convertible Debt, Net of Tax Financial Instruments and Other Guarantees Financial Instruments And Guarantees With Off Balance Sheet Risk Disclosure [Text Block] Financial Instruments And Guarantees With Off Balance Sheet Risk Disclosure [Text Block] Adjustments to reconcile (loss) income from continuing operations, net of income taxes to net cash provided by operating activities: Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity [Abstract] Long-term Purchase Commitment [Line Items] Long-Term Purchase Commitment [Line Items] Cash Flows From Financing Activities Cash Provided by (Used in) Financing Activity, Including Discontinued Operation [Abstract] Interest cost on accumulated postretirement benefit obligation Defined Benefit Plan, Interest Cost Financial Instruments [Domain] Financial Instruments [Domain] Surety Bond Surety Bond [Member] Equity Method Investments Equity Method Investments [Table Text Block] Basic EPS numerator: Net Income (Loss) Available to Common Stockholders, Basic [Abstract] Inventories Inventory Disclosure [Text Block] Segment Reporting, as if Old Segmentation Basis [Domain] Segment Reporting, as if Old Segmentation Basis [Domain] Equity Awards Adjustments, Footnote Equity Awards Adjustments, Footnote [Text Block] Underlying Securities Award Underlying Securities Amount Estimated fair value Estimate of Fair Value Measurement [Member] Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Subsegments [Domain] Subsegments [Domain] Domestic Domestic Destination [Member] 2024 Credit Agreement Availability 2024 Credit Agreement Availability 2024 Credit Agreement Availability Subsegments [Axis] Subsegments [Axis] Remeasurement of foreign income tax accounts [Domain] Remeasurement of foreign income tax accounts [Domain] Remeasurement of foreign income tax accounts [Domain] Preferred Stock Preferred Stock [Member] US Thermal Mining US Thermal Mining [Member] US Thermal Mining Materials and supplies, net Inventory, Raw Materials and Supplies, Net of Reserves Other, net Payment for (Proceeds from) Other Investing Activity Inventories Increase (Decrease) in Inventories Segment Reporting [Table] Segment Reporting [Table] Schedule of Equity Method Investments [Table] Equity Method Investment [Table] Sale of Stock [Axis] Sale of Stock [Axis] Other current assets Other Assets, Current Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Disclosure [Abstract] All Trading Arrangements All Trading Arrangements [Member] Foreign Tax Authority Income Tax Jurisdiction, Foreign [Member] Derivative, Gain (Loss) on Derivative, Net Derivative, Gain (Loss) on Derivative, Net Other Performance Measure, Amount Other Performance Measure, Amount Award Timing MNPI Considered Award Timing MNPI Considered [Flag] Operating (loss) profit Operating Income (Loss) Current Fiscal Year End Date Current Fiscal Year End Date Revenue Recognition [Abstract] Revenue Recognition [Abstract] Non-PEO NEO Average Total Compensation Amount Non-PEO NEO Average Total Compensation Amount LC Agreement [Domain] LC Agreement [Domain] LC Agreement [Domain] Derivative [Line Items] Derivative [Line Items] Segment Reporting, as if Old Segmentation Basis [Axis] Segment Reporting, as if Old Segmentation Basis [Axis] Collateral Held [Axis] Collateral Held [Axis] Unrecorded unconditional purchase obligation (within next 12 months) Unrecorded Unconditional Purchase Obligation Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year [Member] Dividends declared per share Common Stock, Dividends, Per Share, Declared Entity File Number Entity File Number Credit Facility Amendment [Domain] Credit Facility Amendment [Domain] Credit Facility Amendment [Domain] Rule 10b5-1 Arrangement Adopted Rule 10b5-1 Arrangement Adopted [Flag] Service cost for benefits earned Defined Benefit Plan, Service Cost Share-based compensation for equity-classified awards Shares Issued, Value, Share-Based Payment Arrangement, after Forfeiture Debt Instrument, Collateral Debt Instrument, Collateral Equity securities Equity Securities [Member] Commodities expense Commodities expense Commodities expense Surety Bonds and Letters of Credit Outstanding for Reclamation Support Surety Bonds and Letters of Credit Outstanding for Reclamation Support Surety Bonds and Letters of Credit Outstanding for Reclamation Support Schedule of Impaired Long-Lived Assets Held and Used [Table] Long-Lived Asset, Held and Used, Impairment [Table] Distributions to noncontrolling interests Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax Asset impairment Asset, Impairment Loss Recovery of Erroneously Awarded Compensation Disclosure [Line Items] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Seaborne Thermal Seaborne Thermal Mining [Member] Seaborne Thermal Mining [Member] Common stock, shares issued (in shares) Common Stock, Shares, Issued Measure: Measure [Axis] Equity Method Investments Equity Method Investments and Joint Ventures Disclosure [Text Block] Unrealized gains on foreign currency option contracts Gain (Loss) on Sale of Commodity Contracts Treasury stock, shares (in shares) Treasury Stock, Common, Shares Asset retirement obligations, less current portion Asset Retirement Obligations, Noncurrent Equity Components [Axis] Equity Components [Axis] Fair Value, Assets, Transfers Between Levels Fair Value, Assets, Transfers Between Levels [Policy Text Block] Fair Value, Assets, Transfers Between Levels Accounts receivable Increase (Decrease) in Accounts Receivable Product and Service [Domain] Product and Service [Domain] Total Segment Excluding Corporate and Other Operating Segment Total Segment Excluding Corporate Segment and Other Operating Segment [Domain] Total Segment Excluding Corporate Segment and Other Operating Segment Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] Entity Interactive Data Current Entity Interactive Data Current Variable Rate [Axis] Variable Rate [Axis] Less: Net income attributable to noncontrolling interests Less: Net income attributable to noncontrolling interests Net Income (Loss) Attributable to Noncontrolling Interest Deferred income taxes Deferred Income Tax Liabilities, Net Compensation Actually Paid vs. Other Measure Compensation Actually Paid vs. Other Measure [Text Block] Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net Other Other [Member] Other Accounts payable and accrued expenses Accounts Payable and Accrued Liabilities, Current At-risk assets At-risk assets At-risk assets Entity Small Business Entity Small Business Financial trading contracts Financial trading contracts [Member] Financial trading contracts Termination Date Trading Arrangement Termination Date Property, Plant, and Equipment [Line Items] Property, Plant, and Equipment [Line Items] Contingent royalty Contingent royalty Contingent royalty Compensation Actually Paid vs. Total Shareholder Return Compensation Actually Paid vs. Total Shareholder Return [Text Block] Postretirement plans (net of $0.0 tax provisions in each period) Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax MNPI Disclosure Timed for Compensation Value MNPI Disclosure Timed for Compensation Value [Flag] Investments and other assets Other Assets, Noncurrent Document Type Document Type Other U.S. Thermal Other U.S. Thermal Mining [Member] Other U.S. Thermal Mining [Member] Credit Rating, Moody's [Axis] Credit Rating, Moody's [Axis] Net loss on early debt extinguishment Gain (Loss) on Extinguishment of Debt Fair Value as of Grant Date Award Grant Date Fair Value LC Agreement [Axis] LC Agreement [Axis] LC Agreement Net gain on disposals Net gain on disposals Gain (Loss) on Disposition of Assets Deposits with Regulatory Authorities Deposits with Regulatory Authorities [Member] Deposits with Regulatory Authorities Pay vs Performance Disclosure, Table Pay vs Performance [Table Text Block] Stock Repurchase Program, Remaining Authorized Repurchase Amount Share Repurchase Program, Remaining Authorized, Amount Foreign currency translation adjustment Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax Operating costs and expenses (exclusive of items shown separately below) Operating Costs and Expenses Arrangement Duration Trading Arrangement Duration Statement of Stockholders' Equity [Abstract] Statement of Stockholders' Equity [Abstract] Local Phone Number Local Phone Number Postretirement benefit plans Other Postretirement Benefits Plan [Member] Consolidation Items [Axis] Consolidation Items [Axis] Entity Address, Postal Zip Code Entity Address, Postal Zip Code Entity Registrant Name Entity Registrant Name Aggregate principal amount [Domain] Aggregate principal amount [Domain] Aggregate principal amount [Domain] (Loss) income from continuing operations before income taxes (Loss) income from continuing operations before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Insider Trading Policies and Procedures Not Adopted Insider Trading Policies and Procedures Not Adopted [Text Block] Revenues Revenues Revenues Antidilutive Securities, Name [Domain] Antidilutive Securities, Name [Domain] Changed Peer Group, Footnote Changed Peer Group, Footnote [Text Block] Loss from equity affiliates Income (Loss) from Equity Method Investments Accounts payable and accrued expenses Increase (Decrease) in Accounts Payable and Accrued Liabilities Net Income (Loss) from Continuing Operations Available to Common Shareholders, Diluted Net Income (Loss) from Continuing Operations Available to Common Shareholders, Diluted Income Tax Contingency [Table] Income Tax Contingency [Table] Machinery and equipment Machinery and Equipment [Member] Forgone Recovery due to Expense of Enforcement, Amount Forgone Recovery due to Expense of Enforcement, Amount External Credit Rating, Standard & Poor's [Domain] External Credit Rating, Standard & Poor's [Domain] 3.250% Convertible Senior Notes due March 2028 (2028 Convertible Notes) 3.250% Convertible Senior Notes due March 2028 [Member] 3.250% Convertible Senior Notes due March 2028 Executive Category: Executive Category [Axis] LIABILITIES AND STOCKHOLDERS’ EQUITY Liabilities and Equity [Abstract] Costs and expenses Operating Costs and Expenses [Abstract] Corporate and Other Corporate and Other Corporate and Other Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Inventories, net Inventories, net Inventory, Net All Award Types Award Type [Domain] Non-PEO NEO Average Compensation Actually Paid Amount Non-PEO NEO Average Compensation Actually Paid Amount Unrealized gains on foreign currency option contracts Monetization of foreign currency hedge positions Monetization of foreign currency hedge positions Thermal coal Thermal Coal [Member] Thermal Coal [Member] Level 3 Fair Value, Inputs, Level 3 [Member] Guarantees and Product Warranties [Abstract] Anglo American Acquisition Anglo American Acquisition [Member] Anglo American Acquisition Transaction support agreements, additional collateral demands Debt Instrument, Transaction Support Agreement, Additional Collateral Demands Debt Instrument, Transaction Support Agreement, Additional Collateral Demands PEO Name PEO Name Debt Instrument, Principle Amount Debt Instrument, Principle Amount Debt Instrument, Principle Amount Restricted Cash Restricted Cash Property, Plant and Equipment, Type [Axis] Long-Lived Asset, Class [Axis] Stock Price or TSR Estimation Method Stock Price or TSR Estimation Method [Text Block] Surety Agreement Liquidity Covenant, Amount Surety Agreement Liquidity Covenant, Amount Surety Agreement Liquidity Covenant, Amount Entity Tax Identification Number Entity Tax Identification Number Letter of credit amendment Letter of credit amendment [Member] Letter of credit amendment Collateralized Letter of Credit Agreement Collateralized Letter of Credit Agreement [Member] Collateralized Letter of Credit Agreement Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation, Beginning Balance Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation, Ending Balance Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Aggregate Erroneous Compensation Not Yet Determined Aggregate Erroneous Compensation Not Yet Determined [Text Block] Material Terms of Trading Arrangement Material Terms of Trading Arrangement [Text Block] Non-NEOs Non-NEOs [Member] Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year [Member] Basis of Presentation Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Comprehensive (loss) income Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Debt Instrument [Axis] Debt Instrument [Axis] Measurement Frequency [Domain] Measurement Frequency [Domain] Equity Method Investment, Ownership Percentage Equity Method Investment, Ownership Percentage Noncash share-based compensation Share-Based Payment Arrangement, Noncash Expense Other Commercial Events [Table] OtherCommercialEvents [Table] Other Commercial Events [Table] Interest Paid, Capitalized, Investing Activity Interest Paid, Capitalized, Investing Activity Subsegments Consolidation Items [Domain] Subsegments Consolidation Items [Domain] Investment, Name [Domain] Investment, Name [Domain] Schedule of Inventories Schedule of Inventory, Current [Table Text Block] Long-term Debt, Type [Domain] Long-Term Debt, Type [Domain] Basic (loss) income per share Net income attribute to common stockholders per share Earnings Per Share, Basic Common stock repurchases Payments for Repurchase of Common Stock Total current assets Assets, Current Statistical Measurement [Axis] Statistical Measurement [Axis] Insider Trading Arrangements [Line Items] Repayments of long-term debt Repayment of Long-Term Debt, Long-Term Lease Obligation, and Capital Security Derivative Instruments, Gain (Loss) Derivative Instruments, Gain (Loss) [Table Text Block] Award Type Award Type [Axis] Additions to property, plant, equipment and mine development Increase (Decrease) in Property, Plant and Equipment, Investing Activities Increase (Decrease) in Property, Plant and Equipment, Investing Activities Named Executive Officers, Footnote Named Executive Officers, Footnote [Text Block] Accounts receivable, net of allowance for credit losses of $0.0 at March 31, 2026 and December 31, 2025 Accounts receivable, net Accounts Receivable, after Allowance for Credit Loss, Current Retained earnings Retained Earnings (Accumulated Deficit) Distributions from joint ventures Distributions from joint ventures Distributions from joint ventures Product and Service [Axis] Product and Service [Axis] Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table [Member] Awards Close in Time to MNPI Disclosures Awards Close in Time to MNPI Disclosures [Table] Pension Plan Pension Plan [Member] Common Stock Common Stock [Member] External Credit Rating by Grouping [Axis] External Credit Rating by Grouping [Axis] Fair Value Measurement [Domain] Fair Value Measurement [Domain] Reportable segment results Segment Reporting, Operating Income (Loss) [Abstract] Compensation Actually Paid vs. Company Selected Measure Compensation Actually Paid vs. Company Selected Measure [Text Block] Cover [Abstract] Cover [Abstract] incremental repair costs Incremental Repair Costs [Member] Incremental Repair Costs Derivative Contract [Domain] Derivative Contract [Domain] Tax provision (benefit) due to remeasurement Remeasurement of income tax Remeasurement of income tax Transfers Between Fair Value Measurement Hierarchy Levels Transfers Between Fair Value Measurement Hierarchy Levels Transfers Between Fair Value Measurement Hierarchy Levels Equity Awards Adjustments Equity Awards Adjustments [Member] Land and coal interests Land and Coal [Member] Land and Coal Letter of Credit Release Letter of Credit Release Letter of Credit Release R3 Renewables II R3 Renewables II [Member] R3 Renewables II Total liabilities and stockholders’ equity Liabilities and Equity Regulatory Asset [Domain] Regulatory Asset [Domain] Other revenue Other revenue [Member] Other revenue Employee Stock Option Share-Based Payment Arrangement, Option [Member] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Noncontrolling interests Equity, Attributable to Noncontrolling Interest Debt Instrument, Funded, Percent Debt Instrument, Funded, Percent Debt outstanding deemed to be funded Segments [Axis] Segments [Axis] Segments [Axis] Additional 402(v) Disclosure Additional 402(v) Disclosure [Text Block] Mine Location [Domain] Mine Location [Domain] [Domain] for Mine Location [Axis] Related Party [Domain] Related and Nonrelated Parties [Domain] Restructuring charges Restructuring charges Restructuring Charges Underlying Asset Class [Domain] Underlying Asset Class [Domain] Geographic Distribution [Domain] Geographic Distribution [Domain] Schedule of Accounts Receivable Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block] Income Tax Authority [Domain] Income Tax Jurisdiction [Domain] Inventory Disclosure [Abstract] Inventory Disclosure [Abstract] Tabular List, Table Tabular List [Table Text Block] Cash Collateral, Percentage of the aggregate amount of letters of credit outstanding Cash Collateral, Percentage of the aggregate amount of letters of credit outstanding Cash Collateral, Percentage of the aggregate amount of letters of credit outstanding Debt Instrument, Number of Days Following Closing Date Debt Instrument, Number of Days Following Closing Date Debt Instrument, Number of Days Following Closing Date Deposits Assets Deposits Assets Asset retirement obligation expenses Asset retirement obligation expenses Asset Retirement Obligation, Accretion Expense Dilutive impact of 2028 Convertible Notes Incremental Common Shares Attributable to Dilutive Effect of Conversion of Debt Securities Duration fee Duration fee Duration fee Name Awards Close in Time to MNPI Disclosures, Individual Name Stockholders’ equity Equity, Including Portion Attributable to Noncontrolling Interest [Abstract] Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested [Member] Property, Plant and Equipment, Type [Domain] Long-Lived Asset, Class [Domain] Derivatives and Fair Value Measurements Derivatives and Fair Value [Text Block] Preferred stock, shares authorized (in shares) Preferred Stock, Shares Authorized Derivatives, Fair Value [Line Items] Derivatives, Fair Value [Line Items] Trade receivables, net Receivables, Net, Current Property, Plant, and Equipment [Table] Property, Plant, and Equipment [Table] Collateralized letters of credit funding Collateralized letters of credit funding [Member] Collateralized letters of credit funding Preferred Stock — $0.01 per share par value; 100.0 shares authorized, no shares issued or outstanding as of March 31, 2026 or December 31, 2025 Preferred Stock, Value, Issued Labor costs Labor costs Labor costs Adjustment to Compensation: Adjustment to Compensation [Axis] Provision for NARM loss Provision for equipment loss Provision for equipment loss Hedging Designation [Domain] Hedging Designation [Domain] Class of Stock [Domain] Class of Stock [Domain] Rule 10b5-1 Arrangement Terminated Rule 10b5-1 Arrangement Terminated [Flag] Aggregate Erroneous Compensation Amount Aggregate Erroneous Compensation Amount Statement of Cash Flows [Abstract] Statement of Cash Flows [Abstract] Hedging Designation [Axis] Hedging Designation [Axis] Inventory [Line Items] Inventory [Line Items] Credit Facility [Axis] Credit Facility [Axis] Aggregate Available Trading Arrangement, Securities Aggregate Available Amount Long-term debt, less current portion Long-term debt Long-Term Debt and Lease Obligation Income Tax Authority [Axis] Income Tax Jurisdiction [Axis] Name Measure Name Debt Instrument, base rate plus applicable margin Debt Instrument, base rate plus applicable margin Debt Instrument, base rate plus applicable margin Other Events [Abstract] Other Events [Abstract] Other Events [Abstract] Income Tax Disclosure [Text Block] Income Tax Disclosure [Text Block] Debt instrument, fronting fee Debt instrument, fronting fee Debt instrument, fronting fee Pay vs Performance Disclosure [Line Items] Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] Debt Instrument [Line Items] Debt Instrument [Line Items] Other current assets Increase (Decrease) in Other Current Assets Pay vs Performance Disclosure Pay vs Performance Disclosure [Table] Corporate and Other (1) Corporate Segment and Other Operating Segment [Member] Retirement Plan Type [Domain] Retirement Plan Type [Domain] Additional paid-in capital Additional Paid-in Capital [Member] Entity Filer Category Entity Filer Category Guarantor Obligations, Nature [Domain] Guarantor Obligations, Nature [Domain] Physical commodity purchase / sale contracts [Member] Physical commodity purchase / sale contracts [Member] Physical commodity purchase / sale contracts. At-Risk for Impairment of Long-Lived Assets Held and Used [Line Items] Long-Lived Asset, Held and Used, Impairment [Line Items] Dividends [Axis] Dividends [Axis] Revision of Prior Period [Axis] Revision of Prior Period [Axis] Name Trading Arrangement, Individual Name Cash and cash equivalents Cash and Cash Equivalent Comprehensive (loss) income attributable to common stockholders Comprehensive Income (Loss) Attributable to Common Stockholders Comprehensive Income (Loss) Attributable to Common Stockholders Repair costs Repair costs Repair costs Company Selected Measure Amount Company Selected Measure Amount Equity Method Investments and Joint Ventures [Abstract] Equity Method Investments and Joint Ventures [Abstract] Depreciation, depletion and amortization Depreciation, depletion and amortization Depreciation, Depletion and Amortization Total Letters of Credit in Support of Surety Bonds Total Letters of Credit in Support of Surety Bonds Total Letters of Credit in Support of Surety Bonds (Loss) income from continuing operations attributable to common stockholders Net Income (Loss) from Continuing Operations Available to Common Shareholders, Basic Amortization of debt issuance costs Amortization of debt issuance costs [Member] Amortization of debt issuance costs Net (loss) income Net (loss) income Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Other Obligations Other Obligations [Member] Other Obligations Current assets Assets, Current [Abstract] Shoal Creek insurance recovery Shoal Creek insurance recovery Insurance Recoveries Non-PEO NEO Non-PEO NEO [Member] Senior Notes Senior Notes [Member] Entity Address, Address Line One Entity Address, Address Line One Income tax (benefit) provision Income tax provision (benefit) Income Tax Expense (Benefit) Additions to property, plant, equipment and mine development excluding corporate and other segment Additions to property, plant, equipment and mine development excluding corporate and other segment Additions to property, plant, equipment and mine development excluding corporate and other segment Arbitration Relating to Terminated Anglo American Acquisition Arbitration Relating to Terminated Anglo American Acquisition [Member] Arbitration Relating to Terminated Anglo American Acquisition Award Timing Method Award Timing Method [Text Block] Total Surety Bonds and Letters of Credit Outstanding Total Surety Bonds and Letters of Credit Outstanding Total Surety Bonds and Letters of Credit Outstanding Net change in cash, cash equivalents and restricted cash Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Period Increase (Decrease), Including Exchange Rate Effect and Discontinued Operation Forgone Recovery, Explanation of Impracticability Forgone Recovery, Explanation of Impracticability [Text Block] Collateral amount held in letters of credit Collateral amount held as letters of credit Collateral amount held as letters of credit Asset Retirement Obligations Asset Retirement Obligations [Member] Asset Retirement Obligations Debt Instrument, Convertible, Revised Conversion Ratio Debt Instrument, Convertible, Revised Conversion Ratio Debt Instrument, Convertible, Revised Conversion Ratio LC Facility LC Facility [Member] LC Facility Newly Adopted Accounting Standards and Accounting Standards Not Yet Implemented Accounting Standards Update and Change in Accounting Principle [Text Block] Returned deposit related to terminated acquisition Returned deposit related to terminated acquisition Returned deposit related to terminated acquisition Net (loss) income attributable to common stockholders Net Income (Loss) Attributable to Parent Long-term Debt, Type [Axis] Long-Term Debt, Type [Axis] Erroneous Compensation Analysis Erroneous Compensation Analysis [Text Block] Less: Unamortized debt issuance costs Unamortized Debt Issuance Expense Middlemount Mine Middlemount Mine Middlemount Mine [Member] Middlemount Mine [Member] Balance Sheet Location [Axis] Location, Statement of Financial Position, Balance [Axis] Proceeds from disposal of assets, net of receivables Proceeds from Sale of Property, Plant, and Equipment Statement [Table] Statement [Table] Loss from discontinued operations, net of income taxes Loss from discontinued operations, net of income taxes Loss from discontinued operations, net of income taxes Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest Restatement Determination Date: Restatement Determination Date [Axis] Trading Activity [Axis] Trading Activity [Axis] Interest income Interest income Investment Income, Interest Proceeds from Buma loan note Proceeds from Notes Payable Upfront cash payment for planned acquisition Upfront cash payment for planned acquisition Upfront cash payment for planned acquisition Credit Rating, Standard & Poor's [Axis] Credit Rating, Standard & Poor's [Axis] Derivative Asset, Fair Value, Gross Asset Derivative Asset, Subject to Master Netting Arrangement, before Offset Powder River Basin Powder River Basin Mining [Member] Powder River Basin Mining [Member] Geographic Distribution [Axis] Geographic Distribution [Axis] Long-term Purchase Commitment by Category of Item Purchased [Axis] Category of Item Purchased [Axis] Accrued postretirement benefit costs Liability, Other Postretirement Defined Benefit Plan, Noncurrent Pension Benefits Adjustments, Footnote Pension Benefits Adjustments, Footnote [Text Block] Diluted EPS numerator: Net Income (Loss) Available to Common Stockholders, Diluted [Abstract] Derivative Instruments and Hedging Activities Disclosure [Abstract]