Proceeds from Divestiture of Businesses Proceeds from Divestiture of Businesses Non-trade receivables, net Nontrade Receivables, Current As of December 31, 2025 As of March 31, 2026 Finite-Lived Intangible Assets, Accumulated Amortization Revision of Prior Period [Axis] Revision of Prior Period [Axis] Total expected contributions in current fiscal year Defined Benefit Plan, Expected Future Employer Contributions, Current Fiscal Year Statistical Measurement [Domain] Statistical Measurement [Domain] Other Current Assets Other Current Assets [Member] Restructuring and Related Cost, Expected Cost Remaining Restructuring and Related Cost, Expected Cost Remaining Schedule of Short-term Debt Schedule of Short-Term Debt [Table Text Block] Commodity Contract Commodity Contract [Member] Expected return on plan assets Defined Benefit Plan, Expected Return (Loss) on Plan Assets Gross amount not offset in the consolidated balance sheets Derivative Asset, Subject to Master Netting Arrangement, Collateral, Obligation to Return Cash, Offset Against Derivative Asset Award Timing Predetermined Award Timing Predetermined [Flag] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis] Long-term debt, weighted average interest rate, at point in time Long-Term Debt, Weighted Average Interest Rate, at Point in Time Indefinite-lived Intangible Assets [Axis] Indefinite-Lived Intangible Assets [Axis] Indemnification ceiling amount Indemnification ceiling amount Ceiling amount above which the Company will indemnify Hoechst for. Entity File Number Entity File Number Additional Paid-In Capital Additional Paid-in Capital [Member] Other Noncurrent Assets Other Noncurrent Assets [Member] Interest Rate Swap [Member] Interest Rate Swap [Member] Equity in net earnings (loss) of affiliates Income (Loss) from Equity Method Investments Tabular List, Table Tabular List [Table Text Block] Total other comprehensive income (loss), tax Income tax (provision) benefit Other Comprehensive Income (Loss), Tax Earnings (loss) per common share - basic Earnings Per Share, Basic [Abstract] New Accounting Pronouncements, Policy New Accounting Pronouncements, Policy [Policy Text Block] Pollution control and industrial revenue bonds due at various dates through 2030(2) Pollution Control and Industrial Revenue Bonds [Member] Pollution Control and Industrial Revenue Bonds [Member]. Trade payables - third party and affiliates Increase (Decrease) in Accounts Payable Schedule of Carrying Values and Fair Values of Financial Instruments Fair Value, by Balance Sheet Grouping [Table Text Block] Schedule of Exit and Shutdown Cost Related to Closure Disposal Groups, Including Discontinued Operations [Table Text Block] Type of Restructuring [Domain] Type of Restructuring [Domain] Guarantor obligations, maximum exposure Guarantor Obligations, Maximum Exposure, Undiscounted Goodwill [Line Items] Goodwill [Line Items] Unrecorded Unconditional Purchase Obligations Disclosure Unrecorded Unconditional Purchase Obligations Disclosure [Table Text Block] CNCC Working Capital Loan Agreement Due July 3, 2028 [Member] CNCC Working Capital Loan Agreement Due July 3, 2028 [Member] Celanese (Nanjing) Chemical Co., Ltd ("CNCC") senior unsecured working capital loan agreement with a borrowing capacity of CNY 300 million, maturing on July 3, 2028. Trading Arrangements, by Individual Trading Arrangements, by Individual [Table] Net earnings (loss) - basic (in dollars per share) Earnings Per Share, Basic Adjustment to Compensation: Adjustment to Compensation [Axis] Gain (Loss) Recognized in Other Comprehensive Income (Loss) Other Comprehensive Income (Loss), Net Investment Hedge, Gain (Loss), before Reclassification and Tax Schedule of Line of Credit Facilities Schedule of Line of Credit Facilities [Table Text Block] Named Executive Officers, Footnote Named Executive Officers, Footnote [Text Block] Revenue Recognition Revenue from Contract with Customer [Text Block] Stock, Class of Stock [Table] Stock, Class of Stock [Table] Total other comprehensive income (loss), net of tax Other comprehensive income (loss), net of tax Total other comprehensive income (loss), net of tax Other Comprehensive Income (Loss), Net of Tax Schedule of Business Segments Schedule of Segment Reporting Information, by Segment [Table Text Block] Discontinued operations - diluted (in dollars per share) Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Diluted Share Inventory Disclosure [Abstract] Inventory Disclosure [Abstract] Gross amount not offset in the consolidated balance sheets Derivative Liability, Subject to Master Netting Arrangement, Collateral, Right to Reclaim Cash Offset Intangible Asset, Indefinite-Lived [Table] Intangible Asset, Indefinite-Lived [Table] Stock awards (in shares) Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures Benefit obligations Liability, Pension and Other Postretirement and Postemployment Benefits, Noncurrent Revenue, remaining performance obligation, amount Revenue, Remaining Performance Obligation, Amount Pension and postretirement contributions Payment for Pension and Other Postretirement Benefits Adjustment to Compensation, Amount Adjustment to Compensation Amount Pension Benefits Cash contributions to defined benefit pension plans Pension Plan [Member] Net change in short-term borrowings with maturities of 3 months or less Proceeds from (Repayments of) Short-Term Debt, Maturing in Three Months or Less Other assets Increase (Decrease) in Other Operating Assets Stock-based compensation Share-Based Payment Arrangement, Noncash Expense Indefinite-lived Intangible Assets [Line Items] Indefinite-Lived Intangible Assets [Line Items] Acquisitions, Dispositions and Plant Closures [Abstract] Acquisitions, Dispositions and Plant Closures [Abstract] Acquisitions, Dispositions and Plant Closures [Abstract]. Share-Based Payment Arrangement, Option Share-Based Payment Arrangement, Option [Member] Award Timing MNPI Disclosure Award Timing MNPI Disclosure [Text Block] Foreign currency translation gain (loss), income tax (provision) benefit Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax Antidilutive Securities [Axis] Antidilutive Securities [Axis] Dividends, common stock, cash Dividends, Common Stock, Cash Total Celanese Corporation shareholders' equity Balance as of the beginning of the period Balance as of the end of the period Equity, Attributable to Parent Measurement Frequency [Axis] Measurement Frequency [Axis] Other comprehensive income (loss), net of tax Other Comprehensive Income (Loss), Net of Tax [Abstract] Insider Trading Policies and Procedures [Line Items] Common stock, shares authorized (in shares) Common Stock, Shares Authorized Hedging Designation [Domain] Hedging Designation [Domain] Goodwill and Intangible Assets Disclosure [Abstract] Goodwill and Intangible Assets Disclosure [Abstract] Current Assets Assets, Current [Abstract] Total liabilities and equity Liabilities and Equity Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Fair Value, Recurring Fair Value, Recurring [Member] CNCC Term Loan Agreement Due March 11, 2031 CNCC Term Loan Agreement Due March 11, 2031 [Member] Celanese (Nanjing) Chemical Co., Ltd ("CNCC") senior unsecured term loan agreement with a borrowing capacity of CNY 600 million, maturing on March 11, 2031. Pension and Postretirement Benefits Gain (Loss) (Note 8) Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] Variable Interbank Interest Rate Variable Interbank Interest Rate [Member] Certain interbank rates at current Company credit ratings Licenses Licensing Agreements [Member] LIABILITIES AND EQUITY Liabilities and Equity [Abstract] Amended restated receivable purchasing facility Amended Restated Receivable Purchasing Facility [Member] An accounts receivable purchasing facility which allows a wholly owned, bankruptcy-remote subsidiary to sell an undivided interest in a pool of trade receivables (received through contribution from certain subsidiaries that retain the responsibility of servicing the receivables) to financial institutions participating in the facility. Cover [Abstract] Cover [Abstract] Senior unsecured notes due 2033, interest rate of 7.200%(1) USD Senior Unsecured Notes Due 2033 [Member] USD 1 Billion 6.700% Senior Unsecured Notes Due 2033 Maximum Maximum [Member] Trade Receivables Pledged As Collateral Trade Receivables Pledged As Collateral The amount of trade receivables pledged as collateral. Debt Instrument, Interest Rate, Increase (Decrease) Debt Instrument, Interest Rate, Increase (Decrease) Net (earnings) loss attributable to noncontrolling interests Net earnings (loss) attributable to noncontrolling interests Net Income (Loss) Attributable to Noncontrolling Interest Capital expenditures Segment, Expenditure, Addition to Long-Lived Assets Net book value Finite-Lived Intangible Assets, Net Revenue Recognition and Deferred Revenue [Abstract] Revenue Recognition and Deferred Revenue [Abstract] Non-PEO NEO Average Total Compensation Amount Non-PEO NEO Average Total Compensation Amount Debt Instrument [Line Items] Debt Instrument [Line Items] Treasury Stock, Common Treasury Stock, Common [Member] Earnings (loss) from continuing operations Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest Adjustment to Non-PEO NEO Compensation Footnote Adjustment to Non-PEO NEO Compensation Footnote [Text Block] Pay vs Performance Disclosure [Line Items] Retirement Benefits [Abstract] Retirement Benefits [Abstract] Forgone Recovery due to Disqualification of Tax Benefits, Amount Forgone Recovery due to Disqualification of Tax Benefits, Amount Non-Rule 10b5-1 Arrangement Terminated Non-Rule 10b5-1 Arrangement Terminated [Flag] Earnings (loss) from continuing operations before tax Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Entity Shell Company Entity Shell Company Foreign Currency Denominated Debt Foreign Currency Denominated Debt [Member] Foreign Currency Denominated Debt [Member] Schedule of Revenue by Major Customers, by Reporting Segments [Table] Schedule of Revenue by Major Customers, by Reporting Segments [Table] Gain (loss) on derivative hedges, income tax (provision) benefit Other Comprehensive Income (Loss), Derivative, Excluded Component, Increase (Decrease), after Adjustments, Tax Environmental Remediation Site [Domain] Environmental Remediation Site [Domain] Other liabilities Other Liabilities, Noncurrent Schedule of Long-term Debt Instruments [Table] Schedule of Long-Term Debt Instruments [Table] Site Contingency [Table] Site Contingency [Table] Loss Contingencies by Nature of Contingency [Axis] Loss Contingency Nature [Axis] Statement of Stockholders' Equity [Abstract] Statement of Stockholders' Equity [Abstract] Operating Segments Operating Segments [Member] Variable Interest Entity [Table] Variable Interest Entity [Table] Lanaken Belgium Lanaken Belgium [Member] Lanaken Belgium Statement of Cash Flows [Abstract] Statement of Cash Flows [Abstract] Company Selected Measure Amount Company Selected Measure Amount Total contributions year-to-date Defined Benefit Plan, Plan Assets, Contributions by Employer Comprehensive (income) loss attributable to noncontrolling interests Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest Award Timing MNPI Considered Award Timing MNPI Considered [Flag] Line of Credit Facility [Table] Line of Credit Facility [Table] Debt Issuance Costs, Gross Debt Issuance Costs, Gross Comprehensive income (loss) attributable to Celanese Corporation Comprehensive Income (Loss), Net of Tax, Attributable to Parent Disposal Group Name [Domain] Disposal Group Name [Domain] Name Measure Name Reserve as of the beginning of the period Reserve as of the end of the period Restructuring Reserve Earnings (loss) from continuing operations Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent CNCC Working Capital Loan Agreement Due June 28, 2027 [Member] CNCC Working Capital Loan Agreement Due June 28, 2027 [Member] Celanese (Nanjing) Chemical Co., Ltd ("CNCC") senior unsecured working capital loan agreement with a borrowing capacity of CNY 800 million, maturing on June 28, 2027. Secured Debt Secured Debt [Member] Operating leases Operating Lease, Liability, Current Proceeds collected on accounts receivable sold under factoring facilities Proceeds Collected on Accounts Receivable Sold under Factoring Facilities Proceeds Collected on Accounts Receivable Sold under Factoring Facilities Finite-Lived Intangible Assets [Roll Forward] Finite-Lived Intangible Assets [Roll Forward] Class of Stock [Line Items] Class of Stock [Line Items] Deferred income taxes Deferred Income Tax Liabilities, Net Exchange rate changes Finite-Lived Intangible Assets, Translation and Purchase Accounting Adjustments Document Fiscal Period Focus Document Fiscal Period Focus Earnings (loss) from discontinued operations Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent Goodwill and intangible assets, net Intangible Assets, Net (Including Goodwill) Award Timing Method Award Timing Method [Text Block] Continuing operations - basic (in dollars per share) Income (Loss) from Continuing Operations, Per Basic Share Award Type Award Type [Axis] Hedging Relationship [Domain] Hedging Relationship [Domain] Foreign Currency Translation Gain (Loss) Accumulated Foreign Currency Adjustment Attributable to Parent [Member] Long-term debt, including current installments of long-term debt, carrying amount Long-Term Debt Schedule of Components of Other Comprehensive Income (Loss), Net Comprehensive Income (Loss) [Table Text Block] Engineered Materials Engineered Materials [Member] Engineered Materials Total assets Total assets Assets CNCC CNY950M Term Loan Agreement CNCC CNY950M Term Loan Agreement [Member] Celanese (Nanjing) Chemical Co., Ltd ("CNCC") senior unsecured term loan agreement with a borrowing capacity of CNY 950 million, maturing 5 years from drawdown date. 2027 Finite-Lived Intangible Asset, Expected Amortization, Year One Trading Symbol Trading Symbol Plant Shutdown Costs Plant Shutdown Costs Amount of plant shutdown and exist costs. Japan, Yen Japan, Yen Geographical [Domain] Geographical [Domain] Issuance of treasury stock under stock plans (in shares) Shares Issued, Shares, Share-Based Payment Arrangement, after Forfeiture Environmental Remediation Obligations [Abstract] Environmental Remediation Obligations [Abstract] Entity Address, City or Town Entity Address, City or Town Operating Activities Cash Provided by (Used in) Operating Activity, Including Discontinued Operation [Abstract] Other segment items(2) Segment Reporting, Other Segment Item, Amount Exchange rate effects on cash and cash equivalents Effect of Exchange Rate on Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation Inventories Inventory Disclosure [Text Block] Non-PEO NEO Average Compensation Actually Paid Amount Non-PEO NEO Average Compensation Actually Paid Amount Restricted Stock Units (RSUs) Restricted Stock Units (RSUs) [Member] 2026 Unrecorded Unconditional Purchase Obligation, to be Paid, Remainder of Fiscal Year Compensation Actually Paid vs. Other Measure Compensation Actually Paid vs. Other Measure [Text Block] 2030 Finite-Lived Intangible Asset, Expected Amortization, Year Four Variable Interest Entity [Line Items] Variable Interest Entity [Line Items] Emerging Growth Company Entity Emerging Growth Company Restructuring (Note 18) Restructuring Reserve, Current Common stock, dividends, declared (in dollar per share) Common Stock, Dividends, Per Share, Declared Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding 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] Gain (Loss) Recognized in Other Comprehensive Income (Loss) Other Comprehensive Income (Loss), Derivative, Excluded Component, Increase (Decrease), before Adjustments and Tax Senior unsecured notes due 2031, interest rate of 7.000% USD Senior Unsecured Notes Due 2031 [Member] USD 600 Million 7.000% Senior Unsecured Notes Due 2031 Fair Value, Inputs, Level 2 Fair Value, Inputs, Level 2 [Member] Unamortized debt issuance costs Debt Issuance Costs, Net Gain (Loss) Recognized in Earnings (Loss) Derivative, Gain (Loss) on Derivative, Net Restructuring Reserve [Roll Forward] Restructuring Reserve [Roll Forward] Insider Trading Policies and Procedures Not Adopted Insider Trading Policies and Procedures Not Adopted [Text Block] Number of parties included in USEPA order Number of Parties included in USEPA order Number of Parties included in USEPA order. As of December 31, 2025 As of March 31, 2026 Indefinite-Lived Intangible Assets (Excluding Goodwill) Schedule of Other (Charges) Gains, Net Schedule of Other (Charges) Gains, Net [Table Text Block] Schedule of Other (Charges) Gains, Net [Table Text Block]. PEO PEO [Member] Gain (loss) on derivative hedges Gain (loss) on derivative hedges Other Comprehensive Income (Loss), Derivative, Excluded Component, Increase (Decrease), after Adjustments and Tax Number of divestiture agreements Number of divestiture agreements Number of divestiture agreements. Common stock, dividends, decrease, percentage Common Stock, Dividends, Decrease, Percentage Percentage decrease of new quarterly dividend payment per share as approved by the Board of Directors. Loss Contingency, Pending Claims, Number Loss Contingency, Pending Claims, Number Disaggregation of Revenue Disaggregation of Revenue [Table Text Block] Employee Severance Employee Severance [Member] Interest income Investment Income, Interest Noncurrent Other assets Assets for Plan Benefits, Defined Benefit Plan March 2022 U.S. Term Loan Credit Agreement March 2022 U.S. Term Loan Credit Agreement [Member] March 2022 U.S. Term Loan Credit Agreement Income taxes payable Accrued Income Taxes, Current Other Corporate Segment and Other Operating Segment [Member] Changes in operating assets and liabilities Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity, Increase (Decrease) in Operating Capital [Abstract] Senior unsecured notes due 2033, interest rate of 6.750% USD 1.1B Senior Unsecured Notes Due 2033 [Member] USD 1.1 Billion 6.750% Senior Unsecured Notes Due 2033 Stock option exercises Stock Issued During Period, Value, Stock Options Exercised 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] Schedule of Finite-Lived Intangible Assets, Future Amortization Expense Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block] Derivative Instruments and Hedging Activities Disclosure [Abstract] Derivative Instruments and Hedging Activities Disclosure [Abstract] Retained Earnings Retained Earnings [Member] Entity Address, Postal Zip Code Entity Address, Postal Zip Code Restatement Determination Date Restatement Determination Date Cash and cash equivalents Cash and cash equivalents as of beginning of period Cash and cash equivalents as of end of period Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation Income Statement [Abstract] Income Statement [Abstract] Net amount Derivative Asset Derivative Asset Income tax (provision) benefit Income Tax Expense (Benefit) Revenue, Major Customer [Line Items] Revenue, Major Customer [Line Items] Debt instrument, basis spread on variable rate Debt Instrument, Basis Spread on Variable Rate Discontinued operations - basic (in dollars per share) Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Basic Share Demerger obligations (Note 14) Demerger obligations Demerger obligations. Senior unsecured debt Unsecured Debt Intangible assets, net Intangible Assets, Net (Excluding Goodwill) Pension Adjustments Service Cost Pension Adjustments Service Cost [Member] Designated as Hedging Instrument Designated as Hedging Instrument [Member] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] March 2025 Offering of USD Senior Unsecured Notes March 2025 Offering of USD Senior Unsecured Notes [Member] The March 2025 Offering of USD senior unsecured notes by Celanese completed in March 2025. The USD notes in the March 2025 offering consisted of: USD 700 Million 6.500% Senior Unsecured Notes Due 2030 and USD 1.1 Billion 6.750% Senior Unsecured Notes Due 2033. The total of the USD senior unsecured notes in the March 2025 Offering was USD 1.8 Billion. Hedging Relationship [Axis] Hedging Relationship [Axis] Continuing operations - diluted (in dollars per share) Income (Loss) from Continuing Operations, Per Diluted Share Net earnings (loss) Net earnings (loss) Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Restatement does not require Recovery Restatement Does Not Require Recovery [Text Block] Liabilities, Fair Value Disclosure Liabilities, Fair Value Disclosure Business Combination [Table] Business Combination [Table] Master Discounting Agreement Master Discounting Agreement [Member] Master Discounting Agreement Derivative, notional amount Derivative, Notional Amount Derivative, Notional Amount Organization, Consolidation and Presentation of Financial Statements [Abstract] Organization, Consolidation and Presentation of Financial Statements [Abstract] Compensation Actually Paid vs. Company Selected Measure Compensation Actually Paid vs. Company Selected Measure [Text Block] City Area Code City Area Code Award Timing, How MNPI Considered Award Timing, How MNPI Considered [Text Block] All Trading Arrangements All Trading Arrangements [Member] Equity Awards Adjustments, Footnote Equity Awards Adjustments, Footnote [Text Block] Total Shareholder Return Vs Peer Group Total Shareholder Return Vs Peer Group [Text Block] Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Disclosure [Abstract] Investing Activities Cash Provided by (Used in) Investing Activity, Including Discontinued Operation [Abstract] Pay vs Performance Disclosure Pay vs Performance Disclosure [Table] Net cash provided by (used in) operating activities Cash Provided by (Used in) Operating Activity, Including Discontinued Operation Repayments of short-term borrowings Repayments of Short-Term Debt Fair Value Hedging Fair Value Hedging [Member] Disposal Group, Disposed of by Sale, Not Discontinued Operations Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] Debt instrument, term Debt Instrument, Term Subsequent Event Subsequent Event [Member] Cash Flow Hedging Cash Flow Hedging [Member] Goodwill Beginning balance Ending balance Goodwill Equity Valuation Assumption Difference, Footnote Equity Valuation Assumption Difference, Footnote [Text Block] PEO Total Compensation Amount PEO Total Compensation Amount Gross amount recognized Derivative Liability, Subject to Master Netting Arrangement, before Offset Equity Components [Axis] Equity Components [Axis] Active sites Active sites Active sites. Non-Rule 10b5-1 Arrangement Adopted Non-Rule 10b5-1 Arrangement Adopted [Flag] Number of Reportable Segments Number of Reportable Segments Restructuring Cost and Reserve [Line Items] Restructuring Cost and Reserve [Line Items] Goodwill, Impaired, Accumulated Impairment Loss Goodwill, Impaired, Accumulated Impairment Loss Other Performance Measure, Amount Other Performance Measure, Amount Short-term borrowings and current installments of long-term debt - third party and affiliates Total Debt, Current Entity Address, State or Province Entity Address, State or Province Antidilutive Security, Excluded EPS Calculation [Table] Antidilutive Security, Excluded EPS Calculation [Table] Common stock dividends Dividends, Common Stock Euro Member Countries, Euro Euro Member Countries, Euro Total current liabilities Liabilities, Current Other Current Liabilities Other Current Liabilities [Member] Derivative Instrument [Axis] Derivative Instrument [Axis] Derivative Instrument [Axis] Individual: Individual [Axis] Common stock dividends Payments of Ordinary Dividends, Common Stock Other assets Other Assets, Current Entities [Table] Entities [Table] Customer rebates Accrued Marketing Costs, Current Net cash provided by (used in) investing activities Cash Provided by (Used in) Investing Activity, Including Discontinued Operation Investments in affiliates Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures Revenue, remaining performance obligation, expected timing of satisfaction, period Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period 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] Document Fiscal Year Focus Document Fiscal Year Focus Basis of Presentation Basis of Accounting, Policy [Policy Text Block] China, Europe, Japan and Singapore Factoring Agreements China, Europe, Japan and Singapore Factoring Agreements [Member] China, Europe, Japan and Singapore Factoring Agreements Operating lease right-of-use assets Operating Lease, Right-of-Use Asset Forgone Recovery, Explanation of Impracticability Forgone Recovery, Explanation of Impracticability [Text Block] Repayments of long-term debt Repayments of Long-Term Debt Effective income tax rate Effective Income Tax Rate Reconciliation, Percent Entity Interactive Data Current Entity Interactive Data Current CNCC Working Capital Loan Agreement Due December 25, 2026 [Member] CNCC Working Capital Loan Agreement Due December 25, 2026 [Member] Celanese (Nanjing) Chemical Co., Ltd ("CNCC") senior unsecured working capital loan agreement with a borrowing capacity of CNY 800 million, maturing on December 25, 2026. Loss Contingency, Nature [Domain] Loss Contingency, Nature [Domain] Stock option exercises, shares Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercises in Period Foreign currency translation gain (loss), gross amount Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, before Tax Net amount recognized Defined Benefit Plan, Funded (Unfunded) Status of Plan CNCC Working Capital Loan Agreement Due October 20, 2028 CNCC Working Capital Loan Agreement Due October 20, 2028 [Member] Celanese (Nanjing) Chemical Co., Ltd ("CNCC") senior unsecured working capital loan agreement with a borrowing capacity of CNY 300 million, maturing on October 20, 2028. North America North America [Member] Divestiture obligations (Note 14) Divestiture obligations Divestiture obligations. Senior unsecured notes due 2030, interest rate of 6.500% USD 700M Senior Unsecured Notes Due 2030 [Member] USD 700 Million 6.500% Senior Unsecured Notes Due 2030 Segment Information Segment Reporting Disclosure [Text Block] Goodwill [Table] Goodwill [Table] 2029 Unrecorded Unconditional Purchase Obligation, to be Paid, Year Three Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Not Designated as Hedging Instrument Not Designated as Hedging Instrument [Member] Current installments of long-term debt Long-Term Debt and Lease Obligation, Current Long-Term Debt and Lease Obligation, Current Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Finite-Lived Intangible Assets [Line Items] Finite-Lived Intangible Assets [Line Items] Ownership [Domain] Ownership [Domain] Schedule of Net Periodic Benefit Costs Recognized Schedule of Net Benefit Costs [Table Text Block] Distributions/dividends to noncontrolling interests Proceeds from (Payments to) Noncontrolling Interests Pension and postretirement net periodic benefit cost Pension and Other Postretirement Benefits Expense (Reversal of Expense), Noncash Compensation Actually Paid vs. Total Shareholder Return Compensation Actually Paid vs. Total Shareholder Return [Text Block] Fair Value, Recurring and Nonrecurring [Table] Fair Value, Recurring and Nonrecurring [Table] Senior Notes [Abstract] Senior Notes [Abstract] Benefit obligations (Note 8) Liability, Pension and Other Postretirement and Postemployment Benefits, Current Amortization of intangible assets Amortization Amortization of Intangible Assets Selling, general and administrative expenses Selling, general and administrative expenses Selling, General and Administrative Expense Deferred income taxes Deferred Income Tax Assets, Net Schedule of Adjustments to Accumulated Other Comprehensive Income (Loss), Net Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Depreciation and amortization Depreciation, Depletion and Amortization Other assets Other Assets, Noncurrent Interest (Note 7) Interest Payable, Current Entity Central Index Key Entity Central Index Key PEO Name PEO Name 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] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Currency Swap Currency Swap [Member] Outstanding Aggregate Erroneous Compensation Amount Outstanding Aggregate Erroneous Compensation Amount Revolving Credit Facility Revolving Credit Facility [Member] Refinancing expense Deferred Debt Issuance Cost, Writeoff Defined Benefit Plan [Table] Defined Benefit Plan [Table] CNCC Working Capital Loan Agreement Due June 9, 2028 [Member] CNCC Working Capital Loan Agreement Due June 9, 2028 [Member] Celanese (Nanjing) Chemical Co., Ltd ("CNCC") senior unsecured working capital loan agreement with a borrowing capacity of CNY 1.0 billion, maturing on June 9, 2028. Obligations under finance leases due at various dates through 2054 Finance Lease, Liability Acetyl Chain Acetyl Chain Acetyl Chain [Member] Acetyl Chain [Member] Arrangement Duration Trading Arrangement Duration Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Derivative, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] Derivative, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration] Segments [Axis] Segments [Axis] Immaterial Revision of Prior Period Financial Statements Comparability of Prior Year Financial Data, Policy [Policy Text Block] Work-in-process Inventory, Work in Process, Net of Reserves Exercise Price Award Exercise Price Entity Filer Category Entity Filer Category Amounts attributable to Celanese Corporation Income Amounts Attributable to Parent, Disclosures [Abstract] Local Phone Number Local Phone Number Class of Stock [Domain] Class of Stock [Domain] Additional 402(v) Disclosure Additional 402(v) Disclosure [Text Block] Other, net Payment for (Proceeds from) Other Investing Activity Other, net Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity, Other Item Subsequent Event Type [Axis] Subsequent Event Type [Axis] November 2024 US Term Loan November 2024 US Term Loan Credit Agreement [Member] November 2024 U.S. Term Loan Credit Agreement for up to $1.0 billion; due 364 days from borrowing. Bearing an interest rate equal to the Secured Overnight Financing Rate with an interest period of one or three months ("Term SOFR") plus a margin of 1.300% to 2.250% per annum, or the base rate plus a margin of 0.300% to 1.250%; based on the Company's senior unsecured debt rating. South America South America [Member] China, Yuan Renminbi China, Yuan Renminbi ASSETS Assets [Abstract] Credit Facility [Axis] Credit Facility [Axis] Underlying Security Market Price Change Underlying Security Market Price Change, Percent Statement of Financial Position Location, Balance [Axis] Statement of Financial Position Location, Balance [Axis] 2029 Finite-Lived Intangible Asset, Expected Amortization, Year Three Debt Instrument [Axis] Debt Instrument [Axis] Fair Value Measurements Fair Value Disclosures [Text Block] Benefit Obligations Retirement Benefits [Text Block] Business Combination [Line Items] Business Combination [Line Items] Amounts reclassified from accumulated other comprehensive income (loss) Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax Credit Facility [Domain] Credit Facility [Domain] As of December 31, 2025 As of March 31, 2026 Finite-Lived Intangible Assets, Gross Derivatives (Note 12) Derivative Liability, Current 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] Indemnification Agreements Hoechst Indemnification Agreements Hoechst [Member] Indemnification Agreements Hoechst [Member]. Proceeds from short-term borrowings Proceeds from Short-Term Debt Earnings (loss) from operation of discontinued operations Discontinued Operation, Income (Loss) from Discontinued Operation During Phase-out Period, before Income Tax Entity Address, Address Line One Entity Address, Address Line One Amount spent on repurchased shares (in $ millions) Treasury Stock, Value, Acquired, Cost Method Research and development expenses Research and development expenses Research and Development Expense Accumulated Other Comprehensive Income (Loss), Net AOCI Attributable to Parent [Member] Debt Instrument, Interest Rate, Stated Percentage Debt Instrument, Interest Rate, Stated Percentage Operating lease liabilities Operating Lease, Liability, Noncurrent Divestiture Agreements Divestiture Agreements [Member] Divestiture Agreements [Member]. Business Combination, Asset Acquisition, Transaction between Entities under Common Control, and Joint Venture Formation [Abstract] Micromax Micromax [Member] Micromax® portfolio of products Ownership [Axis] Ownership [Axis] Derivative Financial Instruments Derivative Instruments and Hedging Activities Disclosure [Text Block] Gross amount recognized Derivative Asset, Subject to Master Netting Arrangement, before Offset Depreciation, amortization and accretion Depreciation, Amortization and Accretion, Net Fair Value as of Grant Date Award Grant Date Fair Value Entity Registrant Name Entity Registrant Name Stock Price or TSR Estimation Method Stock Price or TSR Estimation Method [Text Block] Total Defined Benefit Plan, Net Periodic Benefit Cost (Credit) CSIT Revolving Credit Agreement CSIT Revolving Credit Agreement [Member] Celanese (Shanghai) International Trading Co., Ltd ("CSIT") revolving credit agreement with a borrowing capacity of CNY 550 million, maturing on January 13, 2026. Schedule of Long-term Debt Schedule of Long-Term Debt Instruments [Table Text Block] Incremental shares attributable to equity awards(1) Incremental Common Shares Attributable to Dilutive Effect of Share-Based Payment Arrangements Restructuring One Time Termination Benefits The charge against earnings in the period for known and estimated costs of one time termination benefits provided to current employees that are involuntarily terminated under a benefit arrangement associated with exit from or disposal of business activities or restructurings pursuant to a duly authorized plan. Document Quarterly Report Document Quarterly Report Foreign Currency Contract, Asset, Fair Value Disclosure Foreign Currency Contract, Asset, Fair Value Disclosure Assets, Fair Value Disclosure Assets, Fair Value Disclosure Long-term debt, including current installments of long-term debt, fair value Long-Term Debt, Fair Value Revision of Prior Period [Domain] Revision of Prior Period [Domain] Changed Peer Group, Footnote Changed Peer Group, Footnote [Text Block] Equity investments without readily determinable fair values, carrying amount Equity Securities without Readily Determinable Fair Value, Amount Adjustment To PEO Compensation, Footnote Adjustment To PEO Compensation, Footnote [Text Block] Non-operating pension and other postretirement employee benefit (expense) income Non-operating pension and other postretirement employee benefit (expense) income Non-operating pension and other postretirement employee benefit (expense) income Interest cost Defined Benefit Plan, Interest Cost Title Trading Arrangement, Individual Title Peer Group Total Shareholder Return Amount Peer Group Total Shareholder Return Amount Other Noncurrent Liabilities Other Noncurrent Liabilities [Member] Schedule of Finite-Lived Intangible Assets Schedule of Finite-Lived Intangible Assets [Table Text Block] Restatement Determination Date: Restatement Determination Date [Axis] Issuance of treasury stock under stock plans Shares Issued, Value, Share-Based Payment Arrangement, after Forfeiture Non-PEO NEO Non-PEO NEO [Member] Accumulated Other Comprehensive Income (Loss) [Table] Accumulated Other Comprehensive Income (Loss) [Table] Other (Charges) Gains, Net Other (Charges) Gains, Net [Text Block] Other (Charges) Gains, Net [Text Block]. Other, net Proceeds from (Payment for) Other Financing Activity December 2025 Tender Offers December 2025 Tender Offers [Member] The December 2025 Tender offers by Celanese were completed on December 2025 for $1.2 billion in aggregate principal amounts of senior unsecured notes. Accumulated Other Comprehensive Income (Loss), net [Line Items] Accumulated Other Comprehensive Income (Loss) [Line Items] Proceeds from sale of businesses and assets, net Payments For (Proceeds From) Sale Of Business And Assets, Net The net cash outflow or inflow from the sale of businesses, property, plant and equipment (capital expenditures), software, and other intangible assets. All Currencies [Domain] All Currencies [Domain] Covenants Not to Compete and Other Other Intangible Assets [Member] Offsetting Assets Offsetting Assets [Table Text Block] Name Trading Arrangement, Individual Name All Award Types Award Type [Domain] Gain (Loss) Recognized in Other Comprehensive Income (Loss) Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification and Tax Schedule of Short-term Debt [Table] Short-Term Debt [Table] Noncontrolling interests Balance as of the beginning of the period, noncontrolling interest Balance as of the end of the period, noncontrolling interest Equity, Attributable to Noncontrolling Interest Equity Awards Adjustments Equity Awards Adjustments [Member] Indemnification percentage, other Indemnification percentage, other Percentage of other liabilities the Company has agreed to indemnify Hoechst for as part of the Demerger Agreement. Pension Benefits Adjustments, Footnote Pension Benefits Adjustments, Footnote [Text Block] Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan Disclosure [Line Items] Compensation Amount Outstanding Recovery Compensation Amount Debt instrument, face amount Debt Instrument, Face Amount CNCC Working Capital Loan Agreement Due March 6, 2028 [Member] CNCC Working Capital Loan Agreement Due March 6, 2028 [Member] Celanese (Nanjing) Chemical Co., Ltd ("CNCC") senior unsecured working capital loan agreement with a borrowing capacity of CNY 750 million, maturing on March 6, 2028. Pension and postretirement benefits gain (loss), income tax (provision) benefit Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, Tax Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Statement of Comprehensive Income [Abstract] Statement of Comprehensive Income [Abstract] Foreign Exchange Contract [Member] Foreign Exchange Contract [Member] Recovery of Erroneously Awarded Compensation Disclosure [Line Items] Retirement Plan Type [Domain] Retirement Plan Type [Domain] March 2025 Tender Offers March 2025 Tender Offers [Member] The March 2025 Tender offers by Celanese were completed on March 21, 2025 for €552 million and $500 million in aggregate principal amounts of senior unsecured notes. Senior unsecured notes due 2032, interest rate of 7.379%(1) USD Senior Unsecured Notes Due 2032 [Member] USD 1 Billion 6.379% Senior Unsecured Notes Due 2032 Income tax (provision) benefit from discontinued operations Discontinued Operation, Tax Effect of Discontinued Operation MNPI Disclosure Timed for Compensation Value MNPI Disclosure Timed for Compensation Value [Flag] Net amount presented in the consolidated balance sheets Derivative Asset, Subject to Master Netting Arrangement, before Offset of Collateral Name Awards Close in Time to MNPI Disclosures, Individual Name Current Other Liabilities Accounts Payable, Accrued Liabilities, and Other Liabilities Disclosure, Current [Text Block] Cash payments Payments for Restructuring Restructuring Type [Axis] Restructuring Type [Axis] Aggregate Erroneous Compensation Not Yet Determined Aggregate Erroneous Compensation Not Yet Determined [Text Block] Other comprehensive income (loss), net of tax Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest Passaic River, New Jersey Passaic River, New Jersey [Member] Passaic River, New Jersey [Member]. Stock-based compensation, net of tax APIC, Share-Based Payment Arrangement, Increase for Cost Recognition Treasury stock, at cost Treasury Stock, Value Accumulated other comprehensive income (loss), net Accumulated Other Comprehensive Income (Loss), Net of Tax Long-term debt, net of unamortized deferred financing costs Long-Term Debt and Lease Obligation Segments [Domain] Segments [Domain] Schedule of Indefinite-Lived Intangible Assets Schedule of Indefinite-Lived Intangible Assets [Table Text Block] Europe and Africa EMEA [Member] Indemnification amount Indemnification floor amount The amount that the Company will indemnify Hoechst for in full. Short-term borrowings Short-Term Debt [Member] Available for borrowing Line of Credit Facility, Remaining Borrowing Capacity Aggregate Pension Adjustments Service Cost Aggregate Pension Adjustments Service Cost [Member] Environmental Loss Contingency, Statement of Financial Position [Extensible Enumeration] Environmental Loss Contingency, Statement of Financial Position [Extensible Enumeration] Environmental Remediation Site [Axis] Environmental Remediation Site [Axis] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table Text Block] Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] Postemployment Benefits [Abstract] Statement of Financial Position Location, Balance [Domain] Statement of Financial Position Location, Balance [Domain] Revolving credit facilities(2) Line of Credit, Current Inventories Increase (Decrease) in Inventories Inventories Total Inventory, Net Developed Technology Developed Technology Rights [Member] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets by Major Class [Axis] Minimum Minimum [Member] Derivative Assets [Abstract] Derivative Asset [Abstract] Sales and use tax/foreign withholding tax payable Sales and Excise Tax Payable, Current Company Selected Measure Name Company Selected Measure Name Total Accrual for Environmental Loss Contingencies Long-Term Debt and Lease Obligation, Including Current Maturities Long-Term Debt and Lease Obligation, Including Current Maturities Gross amount offset in the consolidated balance sheets Derivative Liability, Subject to Master Netting Arrangement, Asset Offset Debt Debt Disclosure [Text Block] Aggregate Available Trading Arrangement, Securities Aggregate Available Amount Trade payables - third party and affiliates Accounts Payable, Current Stock Appreciation Rights (SARs) Stock Appreciation Rights (SARs) [Member] Total other comprehensive income (loss), before tax Other Comprehensive Income (Loss), before Tax Short-Term Borrowings and Current Installments of Long-Term Debt - Third Party and Affiliates Debt, Current [Abstract] Japan Factoring Agreements Japan Factoring Agreements [Member] Japan Factoring Agreements All Executive Categories All Executive Categories [Member] Other (charges) gains, net Other (charges) gains, net (Note 18) Total Other Nonrecurring (Income) Expense Stockholders' Equity Note [Abstract] Stockholders' Equity Note [Abstract] Finished goods Inventory, Finished Goods, Net of Reserves Common stock, $0.0001 par value, 400,000,000 shares authorized (2026: 171,009,402 issued and 2025: 170,918,221 issued) Common Stock, Value, Issued Goodwill [Roll Forward] Goodwill [Roll Forward] Undistributed earnings in unconsolidated affiliates Income (Loss) from Equity Method Investments, Net of Dividends or Distributions Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Weighted average shares - diluted (in shares) Weighted average shares - diluted Weighted Average Number of Shares Outstanding, Diluted Weighted average interest rate, short-term borrowings Short-Term Debt, Weighted Average Interest Rate, at Point in Time Commitments and Contingencies Commitments and Contingencies Non-GAAP Measure Description Non-GAAP Measure Description [Text Block] Derivative [Table] Derivative [Table] Raw materials and supplies Inventory, Raw Materials and Supplies, Net of Reserves Total comprehensive income (loss), net of tax Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Bank loans due at various dates through 2031(3) Loans Payable [Member] Small Reporting Company Entity Small Business Other long-term debt Other Long-Term Debt Income Tax Disclosure [Abstract] Income Tax Disclosure [Abstract] Benefit payments to nonqualified pension plans Supplemental Employee Retirement Plan [Member] Senior unsecured notes due 2026, interest rate of 1.400% USD Senior Unsecured Notes Due 2026 [Member] USD Senior Unsecured Notes Due 2026 [Member] Document Transition Report Document Transition Report Consolidated Ventures Consolidated Ventures [Member] Consolidated Ventures Recent Accounting Pronouncements Accounting Standards Update and Change in Accounting Principle [Text Block] Various senior notes Various senior notes [Member] Various senior unsecured notes impacted by an increase of up to 50 basis points beginning in the years ended December 31, 2025 and 2026, as applicable. Underlying Securities Award Underlying Securities Amount Short-term Debt [Line Items] Short-Term Debt [Line Items] Other comprehensive income (loss) before reclassifications Other Comprehensive Income (Loss), before Reclassifications, before Tax Finite-Lived Intangible Assets, Cost Incurred to Renew or Extend Finite-Lived Intangible Assets, Cost Incurred to Renew or Extend Equity Component [Domain] Equity Component [Domain] Document Period End Date Document Period End Date Gain (Loss) Recognized in Other Comprehensive Income (Loss) Gain (Loss) On Non-Derivatives and Derivatives Used In Net Investment Hedge Adjustment in other comprehensive income reflecting gains (losses) on foreign currency transactions that are designated as, and are effective as, hedges of net investment in foreign entity, gross of tax effect. PEO Actually Paid Compensation Amount PEO Actually Paid Compensation Amount Insurance contracts in nonqualified trusts, fair value Cash Surrender Value, Fair Value Disclosure Income Taxes Income Tax Disclosure [Text Block] Earnings (loss) per common share - diluted Earnings Per Share, Diluted [Abstract] Awards Close in Time to MNPI Disclosures, Table Awards Close in Time to MNPI Disclosures [Table Text Block] Hedging Designation [Axis] Hedging Designation [Axis] Total equity Total equity Balance as of the beginning of the period Balance as of the end of the period Equity, Including Portion Attributable to Noncontrolling Interest Average purchase price (in dollar per share) Shares Acquired, Average Cost Per Share Document Type Document Type Unobservable Inputs (Level 3) Fair Value, Inputs, Level 3 [Member] Earnings (Loss) Per Share Earnings Per Share [Text Block] Name Outstanding Recovery, Individual Name Loss Contingencies [Table] Loss Contingencies [Table] Additional paid-in capital Additional Paid in Capital Pension and postretirement benefits Pension and postretirement benefits Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax Schedule of Defined Benefit Plans Disclosures Schedule of Defined Benefit Plans Disclosures [Table Text Block] Derivative Contract [Domain] Derivative Contract [Domain] Net Investment Hedging Net Investment Hedging [Member] Net sales Revenue from Contract with Customer, Excluding Assessed Tax All Individuals All Individuals [Member] Fair Value Disclosures [Abstract] Fair Value Disclosures [Abstract] Trade receivables - third party and affiliates, net Increase (Decrease) in Receivables Capital expenditures on property, plant and equipment Payments to Acquire Property, Plant, and Equipment Name Forgone Recovery, Individual Name Total current assets Assets, Current 2030 Unrecorded Unconditional Purchase Obligation, to be Paid, Year Four Statistical Measurement [Axis] Statistical Measurement [Axis] 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] Operating cash provided by (used in) discontinued operations Cash Provided by (Used in) Operating Activity, Discontinued Operation Disposal Group Classification [Axis] Disposal Group Classification [Axis] Aggregate Board of Directors repurchase authorizations during the period (in $ millions) Share Repurchase Program, Authorized, Amount U.S. Superfund sites US Superfund sites US Superfund sites. Aggregate Erroneous Compensation Amount Aggregate Erroneous Compensation Amount Disposal Group Name [Axis] Disposal Group Name [Axis] Peer Group Issuers, Footnote Peer Group Issuers, Footnote [Text Block] Entity Information [Line Items] Entity Information [Line Items] Erroneous Compensation Analysis Erroneous Compensation Analysis [Text Block] Intangible Asset, Finite-Lived [Table] Intangible Asset, Finite-Lived [Table] Current Liabilities Liabilities, Current [Abstract] Line of Credit Facility [Line Items] Line of Credit Facility [Line Items] Geographical [Axis] Geographical [Axis] Derivative Liabilities [Abstract] Derivative Liability [Abstract] Schedule of Changes in Fair Value of Derivatives Derivative Instruments, Gain (Loss) [Table Text Block] Senior unsecured notes due 2030, interest rate of 7.050%(1) USD Senior Unsecured Notes Due 2030 [Member] USD 1 Billion 6.550% Senior Unsecured Notes Due 2030 Rule 10b5-1 Arrangement Terminated Rule 10b5-1 Arrangement Terminated [Flag] Gain (loss) on disposition of business and assets, net Gain (Loss) on Disposition of Assets Foreign exchange gain (loss), net Gain (Loss), Foreign Currency Transaction, before Tax Environmental liability percentage Environmental Liability Percentage Estimated ultimate allocable share of cleanup costs. Asia-Pacific Asia Pacific [Member] Net earnings (loss) - diluted (in dollars per share) Earnings Per Share, Diluted Erroneously Awarded Compensation Recovery Erroneously Awarded Compensation Recovery [Table] Trade receivables - third party and affiliates Accounts Receivable, after Allowance for Credit Loss, Current Accelerated depreciation expense Restructuring and Related Cost, Accelerated Depreciation Title of 12(b) Security Title of 12(b) Security Transfer of financial assets accounted for as sales, amount derecognized Transfer of Financial Assets Accounted for as Sales, Amount Derecognized Equity investments without readily determinable fair values, fair value Equity Securities, FV-NI and without Readily Determinable Fair Value Other environmental remediation liabilities Other environmental remediation reserves Other environmental remediation reserves. Balance as of the beginning of the period (in shares) Balance as of the end of the period (in shares) Treasury Stock, Common, Shares Earnings Per Share [Abstract] Earnings Per Share [Abstract] Consolidation Items [Domain] Consolidation Items [Domain] Derivative liability, statement of financial position [Extensible Enumeration] Derivative Liability, Statement of Financial Position [Extensible Enumeration] Noncontrolling interest, ownership percentage by parent Subsidiary, Ownership Percentage, Parent Earnings (loss) from discontinued operations Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest Schedule of Company Commitments to Fund Benefit Obligations Schedule of Company Commitments to Fund Benefit Obligations [Table Text Block] Schedule of Company Commitments to Fund Benefit Obligations [Table Text Block]. Gross profit Gross profit Gross Profit CNCC Working Capital Loan Agreement Due June 17, 2027 [Member] CNCC Working Capital Loan Agreement Due June 17, 2027 [Member] Celanese (Nanjing) Chemical Co., Ltd ("CNCC") senior unsecured working capital loan agreement with a borrowing capacity of CNY 200 million, maturing on June 17, 2027. Indemnification percentage exceeding ceiling amount Indemnification percentage exceeding ceiling amount The percentage of the amount above the ceiling that the Company will indemnify Hoechst for. 0.625% Senior Notes due 2028 Senior unsecured notes due 2028, interest rate of 0.625% EUR Senior Unsecured Notes Due 2028 [Member] EUR Senior Unsecured Notes Due 2028 Insurance contracts in nonqualified trusts, carrying amount Cash Surrender Value of Life Insurance Investment in affiliates Equity Method Investment Liability, Current Equity Method Investment Liability, Current Shares repurchased (in shares) Treasury Stock, Shares, Acquired Environmental Environmental Loss Contingency Disclosure [Text Block] 2028 Finite-Lived Intangible Asset, Expected Amortization, Year Two JPY Denominated Borrowings JPY Denominated Borrowings [Member] The amount of the 2025 Offering converted to JPY denominated borrowings. Maturing on April 15, 2030. Award Timing Disclosures [Line Items] Schedule of Inventories Schedule of Inventory, Current [Table Text Block] Assets held for sale Disposal Group, Including Discontinued Operation, Assets, Current Service cost Defined Benefit Plan, Service Cost Increase (decrease) in accrued capital expenditures Increase (Decrease) of Accrued Capital Expenditures Increase (Decrease) of Accrued Capital Expenditures. Measurement Frequency [Domain] Measurement Frequency [Domain] Salaries and benefits Employee-related Liabilities, Current Senior unsecured notes due 2027, interest rate of 7.165%(1) USD Senior Unsecured Notes Due 2027 [Member] USD 2 Billion 6.165% Senior Unsecured Notes Due 2027 Stockholders' Equity Equity [Text Block] Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, before Tax, Portion Attributable to Noncontrolling Interest Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, before Tax, Portion Attributable to Noncontrolling Interest Schedule of Environmental Remediation Reserves Environmental Exit Costs by Cost [Table Text Block] Distributions/dividends to noncontrolling interests Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders Schedule of Current Other Liabilities Other Current Liabilities [Table Text Block] Pension and postretirement benefits gain (loss), gross amount Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax Net earnings (loss) attributable to Celanese Corporation Net earnings (loss) Net earnings (loss) attributable to Celanese Corporation Net Income (Loss) Attributable to Parent Eliminations Intersegment Eliminations Intersegment Eliminations [Member] Expiration Date Trading Arrangement Expiration Date Senior unsecured notes due 2034, interest rate of 7.375% USD Senior Unsecured Notes Due 2034 [Member] USD 800 Million 7.375% Senior Unsecured Notes Due 2034 Other liabilities Increase (Decrease) in Other Operating Liabilities 2031 Finite-Lived Intangible Asset, Expected Amortization, Year Five Schedule of Effective Tax Rate Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] Shareholders' Equity Equity, Including Portion Attributable to Noncontrolling Interest [Abstract] Exchange rate changes Indefinite-Lived Intangible Assets, Foreign Currency Translation Gain (Loss) Property, plant and equipment, net Property, Plant and Equipment, Net Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] Additions Restructuring Charges Adoption Date Trading Arrangement Adoption Date Base Rate Base Rate [Member] 2027 Unrecorded Unconditional Purchase Obligation, to be Paid, Year One Compensation Actually Paid vs. Net Income Compensation Actually Paid vs. Net Income [Text Block] Restructuring Cost [Table] Restructuring Cost [Table] 5.337% Senior Notes due 2029 Senior unsecured notes due 2029, interest rate of 6.337%(1) EUR Senior Unsecured Notes Due 2029 [Member] EUR 500 Million 5.337% Senior Unsecured Notes Due 2029 [Member] Europe Factoring Agreements Europe Factoring Agreements [Member] Europe Factoring Agreements Entity Current Reporting Status Entity Current Reporting Status Derivative [Line Items] Derivative [Line Items] Senior unsecured notes due 2028, interest rate of 6.850%(1) USD Senior Unsecured Notes Due 2028 [Member] USD 1 Billion 6.350% Senior Unsecured Notes Due 2028 Awards Close in Time to MNPI Disclosures Awards Close in Time to MNPI Disclosures [Table] Customer- Related Intangible Assets Customer Relationships [Member] Operating profit (loss) Operating profit (loss) Operating Income (Loss) Offsetting Liabilities Offsetting Liabilities [Table Text Block] CNCC Revolving Credit Agreement CNCC Revolving Credit Agreement [Member] Celanese (Nanjing) Chemical Co., Ltd ("CNCC") revolving credit agreement with a borrowing capacity of CNY 100 million expiring 12 months from drawdown date. Retained earnings Retained Earnings (Accumulated Deficit) Retained Earnings (Accumulated Deficit) Schedule of Treasury Stock Class of Treasury Stock [Table Text Block] (Gain) loss on disposition of businesses and assets, net Gain (Loss) on Disposition of Property Plant Equipment Singapore Factoring Agreements Singapore Factoring Agreements [Member] Singapore Factoring Agreements Statement of Financial Position [Abstract] Statement of Financial Position [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] Executive Category: Executive Category [Axis] Proceeds from long-term debt Proceeds from Issuance of Long-Term Debt Interest expense Interest Expense, Operating and Nonoperating Current Fiscal Year End Date Current Fiscal Year End Date Class of Stock [Axis] Class of Stock [Axis] Revision of Prior Period, Adjustment [Member] Revision of Prior Period, Error Correction, Adjustment [Member] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Finite-Lived Intangible Assets, Major Class Name [Domain] Finite-Lived Intangible Assets, Major Class Name [Domain] Dividend income - equity investments Investment Income, Dividend 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] Liabilities held for sale Disposal Group, Including Discontinued Operation, Liabilities, Current Retirement Plan Type [Axis] Retirement Plan Type [Axis] Transfer Goodwill, Transfers Statement [Table] Statement [Table] Other income (expense), net Other Nonoperating Income (Expense) Thereafter Unrecorded Unconditional Purchase Obligation, To Be Paid, After Year Four Amount of fixed and determinable portion of unrecorded unconditional purchase obligation to be paid after the fourth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach). Includes, but is not limited to, lease not yet commenced. Net amount Derivative Liability Derivative Liability Adjustments to reconcile net earnings (loss) to net cash provided by (used in) operating activities Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity [Abstract] Financing Activities Cash Provided by (Used in) Financing Activity, Including Discontinued Operation [Abstract] Equity Awards Adjustments, Excluding Value Reported in Compensation Table Equity Awards Adjustments, Excluding Value Reported in the Compensation Table [Member] Cost of EPA's plan estimate Environmental Loss exposure for environmental contingencies at an individual site for which no accrual has been recorded based upon EPA determination. Balance as of the beginning of the period (in shares) Balance as of the end of the period (in shares) Shares, Issued Variable Rate [Domain] Variable Rate [Domain] Schedule of Assets and Liabilities Measured at Fair Value on a Recurring Basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Description of the Company and Basis of Presentation Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Site Contingency [Line Items] Site Contingency [Line Items] 5.000% Senior Notes due 2031 Senior unsecured notes due 2031, interest rate of 5.000% EUR Senior Unsecured Notes Due 2031 [Member] EUR 750 Million 5.000% Senior Unsecured Notes Due 2031 Antidilutive securities excluded from computation of earnings per share, amount Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Senior unsecured notes due 2029, interest rate of 7.330%(1) USD Senior Unsecured Notes Due 2029 [Member] USD 750 Million 6.330% Senior Unsecured Notes Due 2029 Total Unrecorded Unconditional Purchase Obligation All Adjustments to Compensation All Adjustments to Compensation [Member] Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [Table] Net amount presented in the consolidated balance sheets Derivative Liability, Subject to Master Netting Arrangement, before Offset of Collateral Amendment Flag Amendment Flag Other Liabilities, Current [Abstract] Other Liabilities, Current [Abstract] Post-retirement Benefits Benefit payments to other postretirement benefit plans Other Postretirement Benefits Plan [Member] Gain (Loss) Recognized in Other Comprehensive Income (Loss) Gain (Loss) On Non-Derivative Used In Net Investment Hedge Adjustment in other comprehensive income reflecting gains or losses on foreign currency transactions that are designated as, and are effective as, hedges of net investment in foreign entity, gross of tax effect. China Credit Facilities China Credit Facilities [Member] Arrangement in which senior unsecured bank obligations proceeds can continuously be obtained following repayments, but the total amount borrowed cannot exceed a specified maximum amount. Termination Date Trading Arrangement Termination Date Net cash provided by (used in) financing activities Cash Provided by (Used in) Financing Activity, Including Discontinued Operation Insider Trading Policies and Procedures Adopted Insider Trading Policies and Procedures Adopted [Flag] Measure: Measure [Axis] Transfer of financial assets accounted for as sales, non-recourse basis, account receivable percentage Transfer Of Financial Assets Treated As Sales, Non-recourse or Limited recourse Basis, Accounts Receivable Percentage The percentage of accounts receivable, treated as Sales, transferred on a non-recourse or limited recourse basis, as part of a factoring or discounting agreement. Uncertain tax positions Liability for Uncertainty in Income Taxes, Noncurrent Gain (Loss) on Derivative Hedges (Note 12) AOCI, Derivative Qualifying as Hedge, Excluded Component, Parent [Member] 2028 Unrecorded Unconditional Purchase Obligation, to be Paid, Year Two Exchange rate changes Goodwill, Foreign Currency Translation and Measurement Period Adjustments Stock awards Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures Weighted average shares - basic (in shares) Weighted Average Number of Shares Outstanding, Basic Cost of sales Cost of sales Cost of Product and Service Sold Acquisitions, Dispositions and Plant Closures Acquisitions, Dispositions and Plant Closures [Text Block] Acquisitions, Dispositions and Plant Closures [Text Block]. Disposal Group Classification [Domain] Disposal Group Classification [Domain] Schedule of Earnings (Loss) Per Share Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Subsequent Events [Abstract] Subsequent Events [Abstract] Segment Reporting [Abstract] Segment Reporting [Abstract] Pay vs Performance Disclosure, Table Pay vs Performance [Table Text Block] Debt Disclosure [Abstract] Debt Disclosure [Abstract] Forgone Recovery due to Violation of Home Country Law, Amount Forgone Recovery due to Violation of Home Country Law, Amount Recent Accounting Pronouncements [Abstract] Recent Accounting Pronouncements [Abstract] Recent Accounting Pronouncements [Abstract] Entity Tax Identification Number Entity Tax Identification Number Percentage of fair value of sales receivables Percentage of Fair Value of Sales Receivables Percentage of fair value of sales receivables. China Revolving Credit Facility China Revolving Credit Facilities [Member] Arrangement in which loan proceeds can continuously be obtained following repayments, but the total amount borrowed cannot exceed a specified maximum amount. CNCC Working Capital Loan Agreement Due December 21, 2027 [Member] CNCC Working Capital Loan Agreement Due December 21, 2027 [Member] Celanese (Nanjing) Chemical Co., Ltd ("CNCC") senior unsecured working capital loan agreement with a borrowing capacity of CNY 500 million, maturing on December 21, 2027. Restructuring and Related Activities [Abstract] Restructuring and Related Activities [Abstract] Forgone Recovery due to Expense of Enforcement, Amount Forgone Recovery due to Expense of Enforcement, Amount March 2025 Offering of Senior Unsecured Notes March 2025 Offering of Senior Unsecured Notes [Member] The March 2025 Offering of senior unsecured notes by Celanese completed on March 14, 2025. This offering consisted of: USD 700 Million 6.500% Senior Unsecured Notes Due 2030, EUR 750 Million 5.000% Senior Unsecured Notes Due 2031 and USD 1.1 Billion 6.750% Senior Unsecured Notes Due 2033. Common stock, par value (in dollars per share) Common Stock, Par or Stated Value Per Share Common stock, shares issued (in shares) Common Stock, Shares, Issued Derivative Asset, Statement of Financial Position [Extensible Enumeration] Derivative Asset, Statement of Financial Position [Extensible Enumeration] 4.777% Senior Notes due 2026 Senior unsecured notes due 2026, interest rate of 5.277%(1) EUR Senior Unsecured Notes Due 2026 [Member] EUR 1 Billion 4.777% Senior Unsecured Notes Due 2026 Goodwill and Intangible Assets, Net Goodwill and Intangible Assets Disclosure [Text Block] Gain (loss) on derivative hedges, gross amount Other Comprehensive Income (Loss), Derivative, Excluded Component, Increase (Decrease), after Adjustments, before Tax Estimates and Assumptions Use of Estimates, Policy [Policy Text Block] Current Other liabilities Liability, Defined Benefit Plan, Current Exchange rate changes Finite-Lived Intangible Assets, Foreign Currency Translation Gain (Loss) Schedule of Goodwill Schedule of Goodwill [Table Text Block] Trading Arrangement: Trading Arrangement [Axis] Total Shareholder Return Amount Total Shareholder Return Amount Loss Contingencies [Line Items] Loss Contingencies [Line Items] Gross amount offset in the consolidated balance sheets Derivative Asset, Subject to Master Netting Arrangement, Liability Offset Subsequent Events Subsequent Events [Text Block] Foreign currency translation gain (loss) Foreign currency translation gain (loss) Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax Insider Trading Arrangements [Line Items] Segment Reporting, Reconciling Item, Corporate Nonsegment Segment Reporting, Reconciling Item, Corporate Nonsegment [Member] Security Exchange Name Security Exchange Name Foreign Currency Contracts, Liability, Fair Value Disclosure Foreign Currency Contracts, Liability, Fair Value Disclosure Antidilutive Securities, Name [Domain] Antidilutive Securities, Name [Domain] Currency [Axis] Currency [Axis] Plant Closures [Abstract] Plant Closures [Abstract] Plant Closures [Abstract] Line of credit facility, maximum borrowing capacity Line of Credit Facility, Maximum Borrowing Capacity China Factoring Agreements China Factoring Agreements [Member] China Factoring Agreements Pension Adjustments Prior Service Cost Pension Adjustments Prior Service Cost [Member] Loss contingency accrual, carrying value, payments Loss Contingency Accrual, Payments Debt Instrument, Repurchased Face Amount Debt Instrument, Repurchased Face Amount Indefinite-lived Intangible Assets, Major Class Name [Domain] Indefinite-Lived Intangible Assets, Major Class Name [Domain] Material Terms of Trading Arrangement Material Terms of Trading Arrangement [Text Block] Other liabilities Total Other Liabilities, Current Trademarks and Trade Names Trademarks and Trade Names [Member] Other Other Sundry Liabilities, Current Benefit obligations Liability, Defined Benefit Plan, Noncurrent Statement [Line Items] Statement [Line Items] Consolidation Items [Axis] Consolidation Items [Axis] Variable Rate [Axis] Variable Rate [Axis] Schedule of Restructuring Reserve by Type of Cost Schedule of Restructuring Reserve by Type of Cost [Table Text Block] Rule 10b5-1 Arrangement Adopted Rule 10b5-1 Arrangement Adopted [Flag] Deferred income taxes, net Increase (Decrease) in Deferred Income Taxes Common Stock Common Stock [Member] Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code 2.125% Senior Notes due 2027 Senior unsecured notes due 2027, interest rate of 2.125% EUR Senior Unsecured Notes Due 2027 [Member] EUR Senior Unsecured Notes Due 2027 [Member] Non-NEOs Non-NEOs [Member] December 2025 Offering of Senior Unsecured Notes December 2025 Offering of Senior Unsecured Notes [Member] The December 2025 Offering of senior unsecured notes by Celanese completed on December 2025. This offering consisted of: USD 600 Million 7.000% Senior Unsecured Notes Due 2031 and USD 800 Million 7.375% Senior Unsecured Notes Due 2034. Short-term borrowings, including amounts due to affiliates(1) Other Short-Term Borrowings Net increase (decrease) in cash and cash equivalents Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Period Increase (Decrease), Including Exchange Rate Effect and Discontinued Operation