Property, Plant and Equipment [Abstract] Property, Plant and Equipment Property, Plant and Equipment [Table Text Block] Statement of Stockholders' Equity [Abstract] Statement [Table] Statement [Table] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Parent Net Investment Net Investment From Parent [Member] Net Investment From Parent [Member] Accumulated Other Comprehensive (Loss) Income AOCI Attributable to Parent [Member] Noncontrolling Interest Noncontrolling Interest [Member] Statement [Line Items] Statement [Line Items] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Beginning balance Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Net Income Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Actuarially Determined Long-Term Liability Adjustments (Net of ($5,679) Tax) Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, after Tax Comprehensive Income Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Distributions to Noncontrolling Interest Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders Amortization of Stock/Unit-Based Compensation Awards Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition Treasury Stock Activity Adjustments Related to Tax Withholding for Share-based Compensation Net Parent Distributions Net Parent Distributions Net Parent Distributions Ending balance Debt Disclosure [Abstract] Schedule of Debt Schedule of Long-term Debt Instruments [Table Text Block] Related Party Transactions [Abstract] Schedule of Related Party Transactions, by Related Party [Table] Schedule of Related Party Transactions, by Related Party [Table] Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] CNX Thermal CONSOL Thermal [Member] CONSOL Thermal [Member] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsequent Event Subsequent Event [Member] Limited Partners' Capital Account by Class [Axis] Limited Partners' Capital Account by Class [Axis] Limited Partners' Capital Account, Class [Domain] Limited Partners' Capital Account, Class [Domain] Preferred Units Preferred Class A [Member] Common Units Common Units [Member] Common Units [Member] Related Party Transaction [Line Items] Related Party Transaction [Line Items] Undivided interest acquired (as a percent) Transactions Between Entities Under Common Control, Percentage of Undivided Interest Transactions Between Entities Under Common Control, Percentage of Undivided Interest Cash consideration Transactions Between Entities Under Common Control, Payments to Acquire Assets, Gross Transactions Between Entities Under Common Control, Payments to Acquire Assets, Gross Conversion of preferred shares to common units (in shares) Stock Issued During Period, Shares, Conversion of Convertible Securities Issuance price (in dollars per share) Transactions Between Entities Under Common Control, Share Issue Price Transactions Between Entities Under Common Control, Share Issue Price Aggregate equity consideration Transactions Between Entities Under Common Control, Consideration Transferred, Equity Interest Issued and Issuable Transactions Between Entities Under Common Control, Consideration Transferred, Equity Interest Issued and Issuable Volume-weighted average trading price (in dollars per share) Transactions Between Entities Under Common Control, Consideration Transferred, Volume Weighted-average Trading Price Per Share Transactions Between Entities Under Common Control, Consideration Transferred, Volume Weighted-average Trading Price Per Share Volume-weighted average trading price premium (as a percent) Transactions Between Entities Under Common Control, Consideration Transferred, Volume Weighted-average Trading Price, Premium Transactions Between Entities Under Common Control, Consideration Transferred, Volume Weighted-average Trading Price, Premium Net payable Accounts Payable, Related Parties, Current Retirement Benefits [Abstract] Schedule of Defined Benefit Plans Disclosures [Table] Schedule of Defined Benefit Plans Disclosures [Table] Retirement Plan Type [Axis] Retirement Plan Type [Axis] Retirement Plan Type [Domain] Retirement Plan Type [Domain] Pension Benefits Pension Plan [Member] Other Post-Employment Benefits Other Postretirement Benefits Plan [Member] Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan Disclosure [Line Items] Service Cost Defined Benefit Plan, Service Cost Interest Cost Defined Benefit Plan, Interest Cost Expected Return on Plan Assets Defined Benefit Plan, Expected Return (Loss) on Plan Assets Amortization of Prior Service Credits Defined Benefit Plan, Amortization of Prior Service Cost (Credit) Recognized Net Actuarial Loss Defined Benefit Plan, Amortization of Gain (Loss) Settlement Loss Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement Net Periodic Benefit (Credit) Cost Defined Benefit Plan, Net Periodic Benefit Cost (Credit) LONG-TERM DEBT Debt Disclosure [Text Block] Commitments and Contingencies Disclosure [Abstract] Schedule of Commitment Expiration Schedule of Guarantor Obligations [Table Text Block] Segment Reporting [Abstract] SEGMENT INFORMATION Segment Reporting Disclosure [Text Block] Other Income and Expenses [Abstract] MISCELLANEOUS OTHER INCOME Interest and Other Income [Text Block] COMMITMENTS AND CONTINGENT LIABILITIES Commitments Contingencies and Guarantees [Text Block] Schedule of Components of Net Periodic Benefit (Credit) Cost Schedule of Defined Benefit Plans Disclosures [Table Text Block] Accounting Policies [Abstract] Basis of Presentation Basis of Accounting, Policy [Policy Text Block] Principles of Combination Consolidation, Policy [Policy Text Block] Cost Allocations Cost Allocations Policy [Policy Text Block] Cost Allocations Policy [Policy Text Block] Recent Accounting Pronouncements New Accounting Pronouncements, Policy [Policy Text Block] Fair Value Disclosures [Abstract] Schedule of Fair Value of Financial Instruments Schedule of Carrying Values and Estimated Fair Values of Debt Instruments [Table Text Block] Schedule of Components of Net Periodic Benefit Cost Schedule of Changes in Accumulated Postemployment Benefit Obligations [Table Text Block] Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Customer [Axis] Customer [Axis] Customer [Domain] Customer [Domain] Duke Energy Duke Energy [Member] Duke Energy [Member] GenOn Energy Management, LLC GenOn Energy Management, LLC [Member] GenOn Energy Management, LLC [Member] Xcoal Energy Resources Xcoal Energy Resources [Member] Xcoal Energy Resources [Member] Consolidation Items [Axis] Consolidation Items [Axis] Consolidation Items [Domain] Consolidation Items [Domain] Operating Segments Operating Segments [Member] Segments [Axis] Segments [Axis] Segments [Domain] Segments [Domain] PAMC Pennsylvania Mining Complex [Member] Pennsylvania Mining Complex [Member] Corporate and Other Corporate and Other [Member] Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Domain] Concentration Risk Benchmark [Domain] Sales Revenue, Goods, Net Sales Revenue, Goods, Net [Member] Concentration Risk Type [Axis] Concentration Risk Type [Axis] Concentration Risk Type [Domain] Concentration Risk Type [Domain] Customer Concentration Risk Customer Concentration Risk [Member] Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] Coal Sales Coal Products and Services Revenue Other Outside Sales Other Revenue, Net Freight Revenue Cargo and Freight Revenue Total Sales and Freight Sales and Freight Revenue Sales and Freight Revenue Earnings (Loss) Before Income Tax Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Segment Assets Assets Depreciation, Depletion and Amortization Depreciation, Depletion and Amortization Capital Expenditures Payments to Acquire Productive Assets Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [Table] Fair Value, Hierarchy [Axis] Fair Value, Hierarchy [Axis] Fair Value Hierarchy [Domain] Fair Value Hierarchy [Domain] Level 2 Fair Value, Inputs, Level 2 [Member] Measurement Basis [Axis] Measurement Basis [Axis] Fair Value Measurement [Domain] Fair Value Measurement [Domain] Portion at Fair Value Measurement Portion at Fair Value Measurement [Member] Carrying Amount Reported Value Measurement [Member] Fair Value Estimate of Fair Value Measurement [Member] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Fair Value Long-term Debt, Fair Value RELATED PARTY TRANSACTIONS Related Party Transactions Disclosure [Text Block] PROPERTY, PLANT AND EQUIPMENT Property, Plant and Equipment Disclosure [Text Block] Income Statement [Abstract] Revenue and Other Income: Revenues [Abstract] Coal Sales Other Outside Sales Freight Revenue Miscellaneous Other Income Other Income (Loss) Gain on Sale of Assets Gain (Loss) on Disposition of Assets Total Revenue and Other Income Revenue, Net Costs and Expenses: Costs and Expenses [Abstract] Operating and Other Costs Operating Costs and Expenses Freight Expense Freight Costs Selling, General and Administrative Costs Selling, General and Administrative Expense Interest Expense Interest Expense Total Costs and Expenses Costs and Expenses Earnings Before Income Tax Income Tax Expense (Benefit) Income Tax Expense (Benefit) Net Income Less: Net Income Attributable to Noncontrolling Interest Net Income (Loss) Attributable to Noncontrolling Interest Net Income Attributable to CONSOL Energy Inc. Shareholder Net Income (Loss) Attributable to Parent Statement of Comprehensive Income [Abstract] Actuarially Determined Long-Term Liability Adjustments, Tax Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, Tax Payables and Accruals [Abstract] Schedule of Accrued Liabilities Schedule of Accrued Liabilities [Table Text Block] Income Tax Disclosure [Abstract] Effective tax rate (as a percent) Effective Income Tax Rate Reconciliation, Percent Statutory rate (as a percent) Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent Related Party [Axis] Related Party [Axis] Related Party [Domain] Related Party [Domain] CONSOL Energy Majority Shareholder [Member] Income Statement Location [Axis] Income Statement Location [Axis] Income Statement Location [Domain] Income Statement Location [Domain] Operating and Other Costs Operating And Other Costs [Member] Operating And Other Costs [Member] Selling, General and Administrative Expenses Selling, General and Administrative Expenses [Member] Expenses from transactions with related party Related Party Transaction, Expenses from Transactions with Related Party Subsidence Liability Accrued Subsidence Liability, Current Accrued Subsidence Liability, Current Accrued Payroll and Benefits Accrued Payroll And Employee Benefits, Current Accrued Payroll And Employee Benefits, Current Equipment Lease Rental Accrued Rent, Current Deferred Revenue Deferred Revenue, Current Accrued Other Taxes Accrual for Taxes Other than Income Taxes, Current Litigation Estimated Litigation Liability, Current Short-Term Incentive Compensation Accrued Bonuses, Current Other Other Accrued Liabilities, Current Current Portion of Long-Term Liabilities: Long-Term Liabilities, Current [Abstract] Long-Term Liabilities, Current [Abstract] Postretirement Benefits Other than Pensions Liability, Other Postretirement Defined Benefit Plan, Current Liability, Other Postretirement Defined Benefit Plan, Current Asset Retirement Obligations Asset Retirement Obligation, Current Workers' Compensation Workers' Compensation Liability, Current Pneumoconiosis Benefits Employee Related Liabilities, Medical And Disability Benefits, Current Employee Related Liabilities, Medical And Disability Benefits, Current Total Other Accrued Liabilities Accrued Liabilities, Current Subsequent Events [Abstract] SUBSEQUENT EVENTS Subsequent Events [Text Block] Contract Buyout Gain (Loss) on Contract Termination Purchased Coal Sales Revenue, Coal Services Royalty Income - Non-Operated Coal Royalty Revenue from Coal Rental Income Rental Income, Nonoperating Right of Way Issuance Right of Way Income Right of Way Income Interest Income Interest Income, Other Other Other Nonoperating Income Miscellaneous Other Income Inventory Disclosure [Abstract] Schedule of Inventory Schedule of Inventory, Current [Table Text Block] INCOME TAXES Income Tax Disclosure [Text Block] Schedule of Guarantor Obligations [Table] Schedule of Guarantor Obligations [Table] Guarantor Obligations, Nature [Axis] Guarantor Obligations, Nature [Axis] Guarantor Obligations, Nature [Domain] Guarantor Obligations, Nature [Domain] Letters of Credit Standby Letters of Credit [Member] Surety Bonds Surety Bond [Member] Guarantees Other Guarantee Obligations [Member] Other Guarantee Obligations [Member] Loss Contingency Nature [Axis] Loss Contingency Nature [Axis] Loss Contingency, Nature [Domain] Loss Contingency, Nature [Domain] Employee-Related Employee-Related Commitment [Member] Employee-Related Commitment [Member] Environmental Environmental Commitment [Member] Environmental Commitment [Member] Other Other Commitment [Member] Other Commitment [Member] Guarantor Obligations [Line Items] Guarantor Obligations [Line Items] Total Amounts Committed Guarantor Obligations, Maximum Exposure, Undiscounted Less Than 1 Year Guarantor Obligations, Maximum Exposure, Undiscounted, Due in Next Twelve Months Guarantor Obligations, Maximum Exposure, Undiscounted, Due in Next Twelve Months 1-3 Years Guarantor Obligations, Maximum Exposure, Undiscounted, Due in Second and Third Year Guarantor Obligations, Maximum Exposure, Undiscounted, Due in Second and Third Year 3-5 Years Guarantor Obligations, Maximum Exposure, Undiscounted, Due in Fourth and Fifth Year Guarantor Obligations, Maximum Exposure, Undiscounted, Due in Fourth and Fifth Year Beyond 5 Years Guarantor Obligations, Maximum Exposure, Undiscounted, Due after Fifth Year Guarantor Obligations, Maximum Exposure, Undiscounted, Due after Fifth Year Loss Contingencies [Table] Loss Contingencies [Table] Litigation Case [Axis] Litigation Case [Axis] Litigation Case [Domain] Litigation Case [Domain] Fitzwater Litigation Fitzwater Litigation [Member] Fitzwater Litigation [Member] Casey Litigation Casey Litigation [Member] Casey Litigation [Member] Litigation Status [Axis] Litigation Status [Axis] Litigation Status [Domain] Litigation Status [Domain] Pending Litigation Pending Litigation [Member] Loss Contingencies [Line Items] Loss Contingencies [Line Items] Number of plaintiffs Loss Contingency, Number of Plaintiffs INVENTORIES Inventory Disclosure [Text Block] Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] Line of Credit Line of Credit [Member] Loans Payable Loans Payable [Member] Credit Facility [Axis] Credit Facility [Axis] Credit Facility [Domain] Credit Facility [Domain] Revolving Credit Facility - CONSOL Coal Resources LP Revolving Credit Facility [Member] Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] MEDCO Revenue Bonds in Series due September 2025 at 5.75% MEDCO Revenue Bonds in Series due September 2025 at 5.75% [Member] MEDCO Revenue Bonds in Series due September 2025 at 5.75% [Member] Advance Royalty Commitments (7.73% Weighted Average Interest Rate) Advance Royalty Commitments [Member] Advance Royalty Commitments [Member] Debt Instrument [Line Items] Debt Instrument [Line Items] Long-term debt, gross Long-term Debt, Gross Less: Unamortized Debt Issuance Costs Debt Issuance Costs, Net Total Amounts Committed Long-term Debt Less: Amounts Due in One Year Long-term Debt, Current Maturities Long-Term Debt Long-term Debt, Excluding Current Maturities Current portion of capital lease obligations Capital Lease Obligations, Current Stated interest rate Debt Instrument, Interest Rate, Stated Percentage Weighted average interest rate Debt, Weighted Average Interest Rate Statement of Cash Flows [Abstract] Cash Flows from Operating Activities: Net Cash Provided by (Used in) Operating Activities [Abstract] Adjustments to Reconcile Net Income to Net Cash Provided by Operating Activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Gain on Sale of Assets Stock/Unit Based Compensation Share-based Compensation Deferred Income Taxes Deferred Income Tax Expense (Benefit) Changes in Operating Assets: Increase (Decrease) in Operating Capital [Abstract] Accounts and Notes Receivable Increase (Decrease) in Accounts and Notes Receivable Inventories Increase (Decrease) in Inventories Prepaid Expenses Increase (Decrease) in Prepaid Expense Changes in Other Assets Increase (Decrease) in Other Operating Assets Changes in Operating Liabilities: Increase (Decrease) in Operating Liabilities [Abstract] Accounts Payable Increase (Decrease) in Accounts Payable Other Operating Liabilities Increase (Decrease) in Other Current Liabilities Changes in Other Liabilities Increase (Decrease) in Other Noncurrent Liabilities Other Other Operating Activities, Cash Flow Statement Net Cash Provided by Operating Activities Net Cash Provided by (Used in) Operating Activities Cash Flows from Investing Activities: Net Cash Provided by (Used in) Investing Activities [Abstract] Capital Expenditures Proceeds from Sales of Assets Proceeds from Sale of Productive Assets Net Cash Used in Investing Activities Net Cash Provided by (Used in) Investing Activities Cash Flows from Financing Activities: Net Cash Provided by (Used in) Financing Activities [Abstract] Payments on Miscellaneous Borrowings Proceeds from (Repayments of) Other Debt Net (Payments on) Proceeds from Revolver Proceeds from (Repayments of) Lines of Credit Distributions to Noncontrolling Interest Payments to Noncontrolling Interests Parent Net Investment Payments Of Distributions To Parent Payments Of Distributions To Parent Tax Cost from Unit-Based Compensation Payments Related to Tax Withholding for Share-based Compensation Net Cash Used in Financing Activities Net Cash Provided by (Used in) Financing Activities Net Decrease in Cash Cash and Cash Equivalents, Period Increase (Decrease) Cash at Beginning of Period Cash and Cash Equivalents, at Carrying Value Cash at End of Period Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Table] Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Table] Retirement Plan Name [Axis] Retirement Plan Name [Axis] Retirement Plan Name [Domain] Retirement Plan Name [Domain] Coal Workers Pneumoconiosis Coal Workers Pneumoconiosis [Member] Coal Workers' Pneumoconiosis Workers Compensation Workers Compensation [Member] Workers' Compensation Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] Amortization of Actuarial Gain Administrative Fees Defined Benefit Plan, Plan Assets, Administration Expense State Administrative Fees and Insurance Bond Premiums Post Employment Benefit Plan, State Administrative Fees and Insurance Bond Premiums Post Employment Benefit Plan, State Administrative Fees and Insurance Bond Premiums Curtailment Gain Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Curtailment Benefit claims paid Defined Benefit Plan, Benefit Obligation, Benefits Paid Property, Plant and Equipment [Table] Property, Plant and Equipment [Table] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Domain] Property, Plant and Equipment, Type [Domain] Plant and Equipment Coal And Other Plant And Equipment [Member] Coal And Other Plant And Equipment [Member] Airshafts Airshafts [Member] Airshafts [Member] Coal Properties and Surface Lands Mining Properties and Mineral Rights [Member] Mine Development Mine Development [Member] Advance Mining Royalties Coal Advance Mining Royalties [Member] Coal Advance Mining Royalties [Member] Property, Plant and Equipment [Line Items] Property, Plant and Equipment [Line Items] Total Property, Plant and Equipment Property, Plant and Equipment, Gross Less: Accumulated Depreciation, Depletion and Amortization Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Total Property, Plant and Equipment—Net Property, Plant and Equipment, Net Gross assets under capital lease Capital Leased Assets, Gross Accumulated amortization for capital leases Capital Leases, Lessee Balance Sheet, Assets by Major Class, Accumulated Depreciation Amortization expense for assets under capital lease Capital Leases, Income Statement, Amortization Expense COMPONENTS OF COAL WORKERS’ PNEUMOCONIOSIS (CWP) AND WORKERS’ COMPENSATION NET PERIODIC BENEFIT COSTS Pneumoconiosis Benefits And Workers Compensation Disclosure [Text Block] Pneumoconiosis Benefits And Workers Compensation Disclosure [Text Block] OTHER ACCRUED LIABILITIES Accounts Payable and Accrued Liabilities Disclosure [Text Block] FAIR VALUE OF FINANCIAL INSTRUMENTS Fair Value Disclosures [Text Block] Schedule of Related Party Transactions Schedule of Related Party Transactions [Table Text Block] Statement of Financial Position [Abstract] ASSETS Assets [Abstract] Current Assets: Assets, Current [Abstract] Cash and Cash Equivalents Trade Accounts Receivable Accounts Receivable, Net, Current Other Receivables Other Receivables, Net, Current Other Receivables - Related Party Accounts Receivable, Related Parties, Current Inventories Inventory, Net Prepaid Expenses Prepaid Expense, Current Total Current Assets Assets, Current Property, Plant and Equipment: Property, Plant and Equipment, Net [Abstract] Property, Plant and Equipment Less—Accumulated Depreciation, Depletion and Amortization Other Assets: Other Assets [Abstract] Deferred Tax Asset Deferred Income Tax Assets, Net Other Assets Other Assets, Miscellaneous, Noncurrent Total Other Assets Other Assets, Noncurrent Total Combined Assets LIABILITIES AND EQUITY Liabilities and Equity [Abstract] Current Liabilities: Liabilities, Current [Abstract] Accounts Payable Accounts Payable, Current Current Portion of Long-Term Debt Long-term Debt and Capital Lease Obligations, Current Other Accrued Liabilities Total Current Liabilities Liabilities, Current Long-Term Debt: Liabilities, Noncurrent [Abstract] Capital Lease Obligations Capital Lease Obligations, Noncurrent Total Long-Term Debt Long-term Debt and Capital Lease Obligations Deferred Credits and Other Liabilities: Deferred Credits and Other Liabilities [Abstract] Postretirement Benefits Other Than Pensions Liability, Other Postretirement Defined Benefit Plan, Noncurrent Pneumoconiosis Benefits Employee Related Liabilities, Medical and Disability Benefits, Noncurrent Employee Related Liabilities, Medical and Disability Benefits, Noncurrent Workers’ Compensation Workers' Compensation Liability, Noncurrent Asset Retirement Obligations Asset Retirement Obligations, Noncurrent Salary Retirement Liability, Defined Benefit Pension Plan, Noncurrent Other Other Liabilities, Noncurrent Total Deferred Credits and Other Liabilities Liabilities, Other than Long-term Debt, Noncurrent TOTAL LIABILITIES Liabilities Equity: Partners' Capital [Abstract] Parent Net Investment Net Investment From Parent Net Investment From Parent Accumulated Other Comprehensive Loss Accumulated Other Comprehensive Income (Loss), Net of Tax Total Parent Net Investment and Other Comprehensive Loss Stockholders' Equity Attributable to Parent Noncontrolling Interest Stockholders' Equity Attributable to Noncontrolling Interest TOTAL EQUITY TOTAL LIABILITIES AND EQUITY Liabilities and Equity Document and Entity Information [Abstract] Document and Entity Information [Abstract] Entity Registrant Name Entity Registrant Name Entity Central Index Key Entity Central Index Key Current Fiscal Year End Date Current Fiscal Year End Date Entity Filer Category Entity Filer Category Document Type Document Type Document Period End Date Document Period End Date Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Amendment Flag Amendment Flag Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Purchased goods and services related to capital projects Capital Expenditures Incurred but Not yet Paid Capital equipment transfers Capital Equipment Transfers Capital Equipment Transfers Investment, Name [Axis] Investment, Name [Axis] Investment, Name [Domain] Investment, Name [Domain] Pennsylvania Mining Operations Pennsylvania Mining Operations [Member] Pennsylvania Mining Operations [Member] CNX Coal Resources LP CNX Coal Resources LP [Member] CNX Coal Resources LP [Member] ParentCo ParentCo [Member] ParentCo [Member] Number of independent businesses Separation, Number Of Independent Businesses Separation, Number Of Independent Businesses Ownership percentage Equity Method Investment, Ownership Percentage Contributions to pension trust Defined Benefit Plan, Plan Assets, Contributions by Employer Expected remaining contributions Defined Benefit Plan, Expected Future Benefit Payment, Remainder of Fiscal Year Settlement expense Postemployment benefits paid Defined Benefit Plan, Plan Assets, Benefits Paid Schedule of Industry Segment Results Schedule of Segment Reporting Information, by Segment [Table Text Block] Schedule of Total Assets Reconciliation of Assets from Segment to Consolidated [Table Text Block] Coal Inventory, Raw Materials, Net of Reserves Supplies Inventory, Supplies, Net of Reserves Total Inventories Reconciliation of Assets from Segment to Consolidated [Table] Reconciliation of Assets from Segment to Consolidated [Table] Reportable Segments Reportable Segments [Member] Reportable Segments [Member] All Other Segments Other Segments [Member] Corporate Reconciling Items and Eliminations Corporate Reconciling Items And Eliminations [Member] Corporate Reconciling Items and Eliminations [Member] Segment Reporting, Asset Reconciling Item [Line Items] Segment Reporting, Asset Reconciling Item [Line Items] Items excluded from segment assets: Segment Reporting, Other Significant Reconciling Item, Consolidated [Abstract] Cash and other investments Investments and Cash Deferred tax assets Segment Assets Other Comprehensive Income: Other Comprehensive Income (Loss), Net of Tax [Abstract] Actuarially Determined Long-Term Liability Adjustments (Net of Tax: ($1,893), ($820), ($5,679), ($4,441)) Other Comprehensive Income Other Comprehensive Income (Loss), Net of Tax Comprehensive Income Less: Comprehensive Income Attributable to Noncontrolling Interest Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest Comprehensive Income Attributable to CONSOL Energy Inc. Shareholder Comprehensive Income (Loss), Net of Tax, Attributable to Parent Schedule of Miscellaneous Other Income Interest and Other Income [Table Text Block] COMPONENTS OF PENSION AND OTHER POSTRETIREMENT BENEFIT (OPEB) PLANS NET PERIODIC BENEFIT COSTS Pension and Other Postretirement Benefits Disclosure [Text Block] Subsequent Event [Table] Subsequent Event [Table] CONSOL Coal Resources LP CONSOL Coal Resources LP [Member] CONSOL Coal Resources LP [Member] Term Loan A Facility Term Loan A Facility [Member] Term Loan A Facility [Member] Term Loan B Facility Term Loan B Facility [Member] Term Loan B Facility [Member] Second Lien Secured Notes Second Lien Secured Notes [Member] Second Lien Secured Notes [Member] Revolving Credit Facility Accounts Receivable Securitization Facility Accounts Receivable Securitization Facility [Member] Accounts Receivable Securitization Facility [Member] Secured Debt Secured Debt [Member] Affiliated Entity Affiliated Entity [Member] Subsequent Event [Line Items] Subsequent Event [Line Items] Cash distribution declared (per common unit) Distribution Made to Limited Partner, Distributions Declared, Per Unit Conversion basis Convertible Preferred Stock, Shares Issued upon Conversion Preferred units outstanding (in shares) Preferred Units, Outstanding Preferred dividend rate (as a percent) Preferred Stock, Dividend Rate, Percentage Debt instrument face amount Debt Instrument, Face Amount Debt maturity term Debt Instrument, Term Issuance discount (as a percent) Debt Instrument, Discount Percentage Debt Instrument, Discount Percentage Line of credit (up to) Line of Credit Facility, Maximum Borrowing Capacity Line of credit amount outstanding Long-term Line of Credit Aggregate principal amount Related Party Transaction, Line of Credit Extended, Maximum Draw Capacity Related Party Transaction, Line of Credit Extended, Maximum Draw Capacity Distribution Intercompany loan Notes Receivable, Related Parties Gross proceeds from borrowings Proceeds from Issuance of Long-term Debt BASIS OF PRESENTATION Organization, Consolidation and Presentation of Financial Statements Disclosure and Significant Accounting Policies [Text Block]