Basis of Financial Statements	9 Months Ended
Sep. 30, 2013
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Financial Statements	Basis of Financial Statements The accompanying unaudited consolidated interim financial statements were prepared in accordance with the rules and regulations of the Securities and Exchange Commission (the "SEC") for interim periods. Accordingly, certain information and footnotes required for complete financial statements under generally accepted accounting principles in the United States ("U.S. GAAP") have not been included. These interim consolidated financial statements should be read in conjunction with the December 31, 2012 financial statements and notes thereto of Westlake Chemical Corporation (the "Company") included in the annual report on Form 10-K for the fiscal year ended December 31, 2012 (the "2012 Form 10-K"), filed with the SEC on February 22, 2013. These financial statements have been prepared in conformity with the accounting principles and practices as disclosed in the notes to the consolidated financial statements of the Company for the fiscal year ended December 31, 2012. In the opinion of the Company's management, the accompanying unaudited consolidated interim financial statements reflect all adjustments (consisting only of normal recurring adjustments) that are necessary for a fair statement of the Company's financial position as of September 30, 2013, its results of operations for the three and nine months ended September 30, 2013 and 2012 and the changes in its cash position for the nine months ended September 30, 2013 and 2012. Results of operations and changes in cash position for the interim periods presented are not necessarily indicative of the results that will be realized for the fiscal year ending December 31, 2013 or any other interim period. The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses and the disclosure of contingent assets and liabilities. Actual results could differ from those estimates. Revisions The consolidated statement of cash flows for the nine months ended September 30, 2012 has been revised to correct the presentation of windfall tax benefits from share-based compensation of $7,792 in financing activities, instead of operating activities. The Company has determined that this revision was immaterial to the Company's previously issued financial statements. Recent Accounting Pronouncements Disclosures about Offsetting Assets and Liabilities In December 2011, the Financial Accounting Standards Board ("FASB") issued an accounting standards update on disclosures for offsetting assets and liabilities. The new accounting guidance requires companies to disclose both gross and net information about (1) instruments and transactions eligible for offset in the statement of financial position, and (2) instruments and transactions subject to an agreement similar to a master netting arrangement. The FASB issued another accounting standards update clarifying the scope of the assets and liabilities offset disclosure requirements in January 2013. The effective date of the disclosure requirements remains unchanged. The Company adopted the new guidance as of January 1, 2013, and the adoption did not have an impact on the Company's consolidated financial position, results of operations or cash flows. Testing Indefinite-Lived Intangible Assets for Impairment In July 2012, the FASB issued an accounting standards update to simplify how entities test indefinite-lived intangible assets for impairment and to improve consistency in impairment testing guidance among long-lived asset categories. The new accounting guidance provides an entity with an option to first assess qualitative factors to determine whether it is more likely than not that an indefinite-lived intangible asset is impaired as a basis for determining whether it is necessary to perform the quantitative impairment test under current accounting guidance. If an entity concludes that it is not more likely than not that the indefinite-lived intangible asset is impaired, then the entity is not required to take further action. However, if an entity concludes otherwise, then it is required to determine the fair value of the indefinite-lived intangible asset and perform the quantitative impairment test by comparing the fair value with the carrying amount in accordance with current accounting guidance. Also under this new accounting guidance, an entity has the option to bypass the qualitative assessment for any indefinite-lived intangible asset in any period and proceed directly to performing the quantitative impairment test, but may resume performing the qualitative assessment in any subsequent period. The Company adopted the new indefinite-lived intangible assets test guidance as of January 1, 2013, and the adoption did not have a material impact on the Company's consolidated financial position, results of operations or cash flows. Reclassifications Out of Accumulated Other Comprehensive Income In February 2013, the FASB issued an accounting standards update on reporting items reclassified out of accumulated other comprehensive income. The new accounting guidance requires companies to present either parenthetically on the face of the financial statements or in the notes, significant amounts reclassified from each component of accumulated other comprehensive income and the income statement line items affected by the reclassification, with certain exceptions. The Company adopted the new guidance as of January 1, 2013, and the adoption did not have an impact on the Company's consolidated financial position, results of operations or cash flows.

Basis of Financial Statements

The accompanying unaudited consolidated interim financial statements were prepared in accordance with the rules and regulations of the Securities and Exchange Commission (the "SEC") for interim periods. Accordingly, certain information and footnotes required for complete financial statements under generally accepted accounting principles in the United States ("U.S. GAAP") have not been included. These interim consolidated financial statements should be read in conjunction with the December 31, 2012 financial statements and notes thereto of Westlake Chemical Corporation (the "Company") included in the annual report on Form 10-K for the fiscal year ended December 31, 2012 (the "2012 Form 10-K"), filed with the SEC on February 22, 2013. These financial statements have been prepared in conformity with the accounting principles and practices as disclosed in the notes to the consolidated financial statements of the Company for the fiscal year ended December 31, 2012.

In the opinion of the Company's management, the accompanying unaudited consolidated interim financial statements reflect all adjustments (consisting only of normal recurring adjustments) that are necessary for a fair statement of the Company's financial position as of September 30, 2013, its results of operations for the three and nine months ended September 30, 2013 and 2012 and the changes in its cash position for the nine months ended September 30, 2013 and 2012.

Results of operations and changes in cash position for the interim periods presented are not necessarily indicative of the results that will be realized for the fiscal year ending December 31, 2013 or any other interim period. The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses and the disclosure of contingent assets and liabilities. Actual results could differ from those estimates.

Revisions

The consolidated statement of cash flows for the nine months ended September 30, 2012 has been revised to correct the presentation of windfall tax benefits from share-based compensation of $7,792 in financing activities, instead of operating activities. The Company has determined that this revision was immaterial to the Company's previously issued financial statements.

Recent Accounting Pronouncements

Disclosures about Offsetting Assets and Liabilities

In December 2011, the Financial Accounting Standards Board ("FASB") issued an accounting standards update on disclosures for offsetting assets and liabilities. The new accounting guidance requires companies to disclose both gross and net information about (1) instruments and transactions eligible for offset in the statement of financial position, and (2) instruments and transactions subject to an agreement similar to a master netting arrangement. The FASB issued another accounting standards update clarifying the scope of the assets and liabilities offset disclosure requirements in January 2013. The effective date of the disclosure requirements remains unchanged. The Company adopted the new guidance as of January 1, 2013, and the adoption did not have an impact on the Company's consolidated financial position, results of operations or cash flows.

Testing Indefinite-Lived Intangible Assets for Impairment

In July 2012, the FASB issued an accounting standards update to simplify how entities test indefinite-lived intangible assets for impairment and to improve consistency in impairment testing guidance among long-lived asset categories. The new accounting guidance provides an entity with an option to first assess qualitative factors to determine whether it is more likely than not that an indefinite-lived intangible asset is impaired as a basis for determining whether it is necessary to perform the quantitative impairment test under current accounting guidance. If an entity concludes that it is not more likely than not that the indefinite-lived intangible asset is impaired, then the entity is not required to take further action. However, if an entity concludes otherwise, then it is required to determine the fair value of the indefinite-lived intangible asset and perform the quantitative impairment test by comparing the fair value with the carrying amount in accordance with current accounting guidance. Also under this new accounting guidance, an entity has the option to bypass the qualitative assessment for any indefinite-lived intangible asset in any period and proceed directly to performing the quantitative impairment test, but may resume performing the qualitative assessment in any subsequent period. The Company adopted the new indefinite-lived intangible assets test guidance as of January 1, 2013, and the adoption did not have a material impact on the Company's consolidated financial position, results of operations or cash flows.

Reclassifications Out of Accumulated Other Comprehensive Income

In February 2013, the FASB issued an accounting standards update on reporting items reclassified out of accumulated other comprehensive income. The new accounting guidance requires companies to present either parenthetically on the face of the financial statements or in the notes, significant amounts reclassified from each component of accumulated other comprehensive income and the income statement line items affected by the reclassification, with certain exceptions. The Company adopted the new guidance as of January 1, 2013, and the adoption did not have an impact on the Company's consolidated financial position, results of operations or cash flows.