Description of the Company and Basis of Presentation	3 Months Ended
Description of the Company and Basis of Presentation	Mar. 31, 2018
Schedule of Equity Method Investments [Line Items]
Description of the Company and Basis of Presentation	Description of the Company and Basis of Presentation Description of the Company Celanese Corporation and its subsidiaries (collectively, the "Company") is a global technology and specialty materials company. The Company's business involves processing chemical raw materials, such as methanol, carbon monoxide and ethylene, and natural products, including wood pulp, into value-added chemicals, thermoplastic polymers and other chemical-based products. Definitions In this Quarterly Report on Form 10-Q ("Quarterly Report"), the term "Celanese" refers to Celanese Corporation, a Delaware corporation, and not its subsidiaries. The term "Celanese US" refers to the Company's subsidiary, Celanese US Holdings LLC, a Delaware limited liability company, and not its subsidiaries. Basis of Presentation The unaudited interim consolidated financial statements for the three months ended March 31, 2018 and 2017 contained in this Quarterly Report were prepared in accordance with accounting principles generally accepted in the United States of America ("US GAAP") for all periods presented and include the accounts of the Company, its majority owned subsidiaries over which the Company exercises control and, when applicable, variable interest entities in which the Company is the primary beneficiary. The unaudited interim consolidated financial statements and other financial information included in this Quarterly Report, unless otherwise specified, have been presented to separately show the effects of discontinued operations. In the opinion of management, the accompanying unaudited consolidated balance sheets and related unaudited interim consolidated statements of operations, comprehensive income (loss), cash flows and equity include all adjustments, consisting only of normal recurring items necessary for their fair presentation in conformity with US GAAP. Certain information and footnote disclosures normally included in financial statements prepared in accordance with US GAAP have been condensed or omitted in accordance with rules and regulations of the Securities and Exchange Commission ("SEC"). These unaudited interim consolidated financial statements should be read in conjunction with the Company's consolidated financial statements as of and for the year ended December 31, 2017, filed on February 9, 2018 with the SEC as part of the Company's Annual Report on Form 10-K. Operating results for the three months ended March 31, 2018 are not necessarily indicative of the results to be expected for the entire year. In the ordinary course of business, the Company enters into contracts and agreements relative to a number of topics, including acquisitions, dispositions, joint ventures, supply agreements, product sales and other arrangements. The Company endeavors to describe those contracts or agreements that are material to its business, results of operations or financial position. The Company may also describe some arrangements that are not material but in which the Company believes investors may have an interest or which may have been included in a Form 8-K filing. Investors should not assume the Company has described all contracts and agreements relative to the Company's business in this Quarterly Report. For those consolidated ventures in which the Company owns or is exposed to less than 100% of the economics, the outside stockholders' interests are shown as noncontrolling interests. During the three months ended March 31, 2018, the Company settled its dispute concerning the exercise of an option right by a partner in two of the Company's InfraServ equity affiliate investments. As a result of the settlement, the Company's ownership in InfraServ GmbH & Co. Gendorf KG and InfraServ GmbH & Co. Knapsack KG was reduced from 39% and 27%, to 30% and 22%, respectively. The Company has reclassified certain prior period amounts due to (1) the adoption of ASU 2017-07 (defined below in Note 2) and (2) to conform to the presentation of the Company's current reportable segments (Note 19). Estimates and Assumptions The preparation of unaudited interim consolidated financial statements in conformity with US GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the unaudited interim consolidated financial statements and the reported amounts of Net sales, expenses and allocated charges during the reporting period. Significant estimates pertain to impairments of goodwill, intangible assets and other long-lived assets, purchase price allocations, restructuring costs and other (charges) gains, net, income taxes, pension and other postretirement benefits, asset retirement obligations, environmental liabilities and loss contingencies, among others. Actual results could differ from those estimates.
InfraServ GmbH & Co. Gendorf KG [Member] \| Maximum [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	39.00%
InfraServ GmbH & Co. Gendorf KG [Member] \| Minimum [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	30.00%
InfraServ GmbH & Co. Knapsack KG [Member] \| Maximum [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	27.00%
InfraServ GmbH & Co. Knapsack KG [Member] \| Minimum [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	22.00%