Income Tax Disclosure [Abstract] Components Of Income (Loss) Before Income Taxes Schedule of Income before Income Tax, Domestic and Foreign [Table Text Block] Schedule Of The Provision For (Benefit From) Income Taxes Schedule of Components of Income Tax Expense (Benefit) [Table Text Block] Reconciliation Of Taxes Computed At The Statutory Rate To Income Tax Expense Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] Schedule Of Deferred Tax Assets And Liabilities Schedule of Deferred Tax Assets and Liabilities [Table Text Block] Schedule Of Changes In Gross Unrecognized Tax Benefits Summary of Income Tax Contingencies [Table Text Block] Long-term Debt, Unclassified [Abstract] Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Range [Axis] Range [Axis] Range [Domain] Range [Domain] Minimum [Member] Minimum [Member] Maximum [Member] Maximum [Member] Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] Senior Secured Revolving Credit Facility [Member] Line of Credit [Member] 3.60% Senior Notes Due 2022 [Member] Three Point Six Zero Percentage Senior Notes Due Twenty Twenty Two [Member] Three Point Six Zero Percentage Senior Notes Due Twenty Twenty Two [Member] GO Zone 6 1/2% Senior Notes Due 2029 [Member] Go Zone Six And One Half Percent Senior Notes Due Twenty Twenty Nine [Member] GO Zone 6 1/2% Senior Notes Due 2029 [Member] GO Zone 6 3/4% Senior Notes Due 2032 [Member] Go Zone Six And Three Quarters Percent Senior Notes Due Twenty Thirty Two [Member] GO Zone 6 3/4% Senior Notes Due 2032 [Member] GO Zone 6 1/2% Tax-Exempt Revenue Bonds Due 2035 [Member] Go Zone Six Point Five Percent Tax Exempt Revenue Bonds Due Twenty Thirty Five [Member] Go Zone Six Point Five Percent Tax-Exempt Revenue Bonds Due Twenty Thirty Five [Member] Ike Zone Six Point Five Percent Tax Exempt Revenue Bonds Due Twenty Thirty Five [Member] Ike Zone Six Point Five Percent Tax Exempt Revenue Bonds Due Twenty Thirty Five [Member] IKE Zone six point five percent tax-exempt revenue bonds due twenty thirty five [Member] Waste Disposal Revenue Bonds Due 2027 [Member] Waste Disposal Revenue Bonds Due Twenty Twenty Seven [Member] Waste Disposal Revenue Bonds Due Twenty Twenty-Seven [Member] Debt Instrument [Line Items] Debt Instrument [Line Items] Line of Credit Facility, Covenant Terms, Acquisitions Restrictions, Borrowing Availability Threshold, Percent Of Commitments, Scenario One Line of Credit Facility, Covenant Terms, Acquisitions Restrictions, Borrowing Availability Threshold, Percent Of Commitments, Scenario One Line of Credit Facility, Covenant Terms, Acquisitions Restrictions, Borrowing Availability Threshold, Percent Of Commitments, Scenario One Senior notes Senior Notes Non-current loan payable Loans Payable Long-term debt Long-term Debt, Excluding Current Maturities Stated interest rate Debt Instrument, Interest Rate, Stated Percentage Maturity Debt Instrument Maturity Debt Instrument, Maturity Line of Credit Facility, Covenant Terms, Distributions Restrictions, Borrowing Availability Threshold, Scenario Two Line of Credit Facility, Covenant Terms, Acquisitions Restrictions, Borrowing Availability Threshold, Scenario One Line of Credit Facility, Covenant Terms, Acquisitions Restrictions, Borrowing Availability Threshold, Scenario One Debt Instrument, Redemption, Period [Axis] Debt Instrument, Redemption, Period [Axis] Debt Instrument, Redemption, Period [Domain] Debt Instrument, Redemption, Period [Domain] Prior to April Fifteenth Twenty Twenty Two Debt Instrument, Redemption, Period Three [Member] On or After April Fifteenth Twenty Twenty Two Debt Instrument, Redemption, Period Four [Member] Senior notes, principal amount issued Debt Instrument, Face Amount Senior notes, original discount issue Debt Instrument, Unamortized Discount Senior notes, redemption price as percentage of principal amount Debt Instrument, Redemption Price, Percentage Senior notes, repurchase price as percentage of principal amount upon change of control and below investment grade rating event Debt Instrument, Repurchase Price as Percentage of Principal Amount upon Change of Control and below Investment Grade Rating Event Represents repurchase price, of deb instrument, as percentage of principal amount upon change of control and below investment grade rating event Senior notes, maximum number of days from change of control for below investment grade rating event Maximum Number of Days from Change of Control for below Investment Grade Rating Event Maximum number of days from change of control for below investment grade rating event. Senior notes, minimum debt amount guaranteed by subsidiaries Debt Amount In Excess Of Guaranteed By Subsidiaries Debt amount in excess of guaranteed by subsidiaries. Document And Entity Information [Abstract] Document And Entity Information (Abstract) Document Type Amendment Flag Document Period End Date Document Fiscal Year Focus Document Fiscal Period Focus Entity Registrant Name Entity Central Index Key Current Fiscal Year End Date Entity Filer Category Entity Well-known Seasoned Issuer Entity Voluntary Filers Entity Current Reporting Status Entity Common Stock, Shares Outstanding Entity Public Float Segment Reporting [Abstract] Schedule of Revenues from External Customers and Long-Lived Assets [Table] Schedule of Revenues from External Customers and Long-Lived Assets [Table] Geographical [Axis] Geographical [Axis] Geographical [Domain] Geographical [Domain] United States [Member] UNITED STATES Canada [Member] CANADA GERMANY GERMANY Switzerland [Member] SWITZERLAND ITALY ITALY FRANCE FRANCE Other Foreign Countries [Member] Other Foreign Countries [Member] Other Foreign Countries [Member] Revenues from External Customers and Long-Lived Assets [Line Items] Revenues from External Customers and Long-Lived Assets [Line Items] Net external sales Revenue, Net Long-lived assets Property, Plant and Equipment, Net Organization, Consolidation and Presentation of Financial Statements [Abstract] Description Of Business And Significant Accounting Policies Organization, Consolidation, Basis of Presentation, Business Description and Accounting Policies [Text Block] Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract] Changes in Projected Benefit Obligations, Fair Value of Plan Assets, and Funded Status of Plan Changes in Projected Benefit Obligations, Fair Value of Plan Assets, and Funded Status of Plan [Table Text Block] Schedule of Amounts Recognized in Balance Sheet Schedule of Amounts Recognized in Balance Sheet [Table Text Block] Schedule of Amounts Recognized in Other Comprehensive Income (Loss) Schedule of Amounts Recognized in Other Comprehensive Income (Loss) [Table Text Block] Schedule Of Accumulated Benefit Obligations In Excess Of Plan Assets Schedule of Benefit Obligations in Excess of Fair Value of Plan Assets [Table Text Block] Schedule Of Net Benefit Costs And Amounts Recognized In Other Comprehensive Income Schedule Of Net Benefit Costs And Amounts Recognized In Other Comprehensive Income Loss [Table Text Block] Tabular disclosure of 1) the components of net benefit costs for pension plans and/or other employee benefit plans including service cost, interest cost, expected return on plan assets, gain (loss), prior service cost or credit, transition asset or obligation, and gain (loss) recognized due to settlements or curtailments, and 2) the net gain (loss) and net prior service cost or credit recognized in other comprehensive income (loss) for the period for pension plans and/or other employee benefit plans, and reclassification adjustments of other comprehensive income (loss) for the period, as those amounts, including amortization of the net transition asset or obligation, are recognized as components of net periodic benefit cost. Schedule Of Weighted Average Assumptions Used Schedule of Assumptions Used [Table Text Block] Schedule Of Fair Value Of Pension Plan Assets Schedule of Allocation of Plan Assets [Table Text Block] Schedule Of Estimated Future Benefit Payments Schedule of Expected Benefit Payments [Table Text Block] Share-based Compensation [Abstract] Options, Outstanding, beginning balance Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number Options, Granted Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures Options, Exercised Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Options, Cancelled Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period Options, Outstanding, ending balance Options, Exercisable, ending balance Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number Weighted Average Exercise Price, Outstanding, beginning balance Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price Weighted Average Exercise Price, Granted Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price Weighted Average Exercise Price, Exercised Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price Weighted Average Exercise Price, Cancelled Share-based Compensation Arrangements by Share-based Payment Award, Options, Forfeitures in Period, Weighted Average Exercise Price Weighted Average Exercise Price, Outstanding, ending balance Weighted Average Exercise Price, Exercisable, ending balance Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price Weighted Average Remaining Term (Years), Outstanding Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term Weighted Average Remaining Term (Years), Exercisable Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term Aggregate Intrinsic Value, Outstanding Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value Aggregate Intrinsic Value, Exercisable Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value Beginning balance Unrecognized Tax Benefits Reductions due to statutes of limitations expiring Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations Ending balance Business Combinations [Abstract] Schedule of Business Acquisitions, by Acquisition [Table] Schedule of Business Acquisitions, by Acquisition [Table] Business Acquisition [Axis] Business Acquisition [Axis] Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] Vinnolit [Member] Vinnolit [Member] Vinnolit [Member] Business Acquisition [Line Items] Business Acquisition [Line Items] Net sales Business Acquisition, Pro Forma Revenue Net income Business Acquisition, Pro Forma Net Income (Loss) Net income attributable to noncontrolling interests Business Acquisition, Pro Forma Net Income (Loss) Attributable to Noncontrolling Interest Business Acquisition, Pro Forma Net Income (Loss) Attributable to Noncontrolling Interest Net income attributable to Westlake Chemical Corporation Business Acquisition, Pro Forma Net Income (Loss) Attributable To Parent Business Acquisition, Pro Forma Net Income (Loss) Attributable To Parent Earnings per common share attributable to Westlake Chemical Corporation: Business Acquisition, ProForma Earnings Per Share [Abstract] Business Acquisition, ProForma Earnings Per Share [Abstract] Basic Business Acquisition, Pro Forma Earnings Per Share, Basic Diluted Business Acquisition, Pro Forma Earnings Per Share, Diluted Equity [Abstract] Stockholders' Equity Stockholders' Equity Note Disclosure [Text Block] Fair Value Disclosures [Abstract] Schedule Of Assets And Liabilities On A Recurring Basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Schedule Of Carrying And Fair Values Of Long-Term Debt Fair Value, by Balance Sheet Grouping [Table Text Block] Accounts Receivable, Net [Abstract] Schedule Of Accounts Receivable Schedule Of Accounts And Financing Receivables [Text Block] Tabular disclosure of the various categories of receivables, including trade and other receivables, and for each the gross carrying value, allowance (if appropriate), and net carrying value as of the balance sheet date. Investments, Debt and Equity Securities [Abstract] Financial Instruments Investment [Text Block] Commitments and Contingencies Disclosure [Abstract] Future Minimum Lease Commitments Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block] Related Party Transactions [Abstract] Related Party And Affiliate Transactions Related Party Transactions Disclosure [Text Block] Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [Table] Derivative Instrument Risk [Axis] Derivative Instrument [Axis] Derivative Contract Type [Domain] Derivative Contract [Domain] Commodity Forward Contracts [Member] Commodity Forward Contracts [Member] Commodity forward contracts [Member] Measurement Frequency [Axis] Measurement Frequency [Axis] Fair Value, Measurement Frequency [Domain] Fair Value, Measurement Frequency [Domain] Fair Value, Measurements, Recurring [Member] Fair Value, Measurements, Recurring [Member] Fair Value, Hierarchy [Axis] Fair Value, Hierarchy [Axis] Fair Value, Measurements, Fair Value Hierarchy [Domain] Fair Value Hierarchy [Domain] Level 1 [Member] Fair Value, Inputs, Level 1 [Member] Level 2 [Member] Fair Value, Inputs, Level 2 [Member] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Risk management assets Derivative Asset Risk management liabilities Derivative Liability Available-for-sale Securities Available-for-sale Securities Guarantor Disclosures [Abstract] Guarantor disclosures Schedule of Condensed Financial Statements [Table] Condensed Financial Statements [Table] Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] Westlake Chemical Corporation [Member] Parent Company [Member] Guarantor Subsidiaries [Member] Guarantor Subsidiaries [Member] Westlake Chemical OpCo LP [Member] Westlake Chemical OpCo LP [Member] Westlake Chemical OpCo LP [Member] Non-Guarantor Subsidiaries [Member] Non-Guarantor Subsidiaries [Member] Eliminations [Member] Consolidation, Eliminations [Member] Condensed Financial Statements, Captions [Line Items] Condensed Financial Statements, Captions [Line Items] Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Marketable securities Marketable Securities, Current Accounts receivable, net Receivables, Net, Current Inventories Inventory, Net Prepaid expenses and other current assets Prepaid Expense and Other Assets, Current Deferred income taxes Deferred Tax Assets, Net of Valuation Allowance, Current Total current assets Assets, Current Property, plant and equipment, net Equity investments Equity Method Investments Other assets, net Other Assets, Noncurrent Total assets Assets Accounts and notes payable Accounts Payable, Current Accrued liabilities Accrued Liabilities, Current Total current liabilities Liabilities, Current Long-term debt Deferred income taxes Deferred Tax Liabilities, Net, Noncurrent Other liabilities Other Liabilities, Noncurrent Liabilities Liabilities Stockholders' equity Stockholders' Equity Attributable to Parent Noncontrolling interests Stockholders' Equity Attributable to Noncontrolling Interest Total equity Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Total liabilities and equity Liabilities and Equity Schedule of Available-for-sale Securities [Table] Schedule of Available-for-sale Securities [Table] Debt Security [Axis] Debt Security [Axis] Major Types of Debt Securities [Domain] Major Types of Debt Securities [Domain] Corporate Bond Securities [Member] Corporate Bond Securities [Member] US Treasury and Government [Member] US Treasury and Government [Member] Asset-backed Securities [Member] Asset-backed Securities [Member] Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] Investment Type [Axis] Investment Type [Axis] Investments [Domain] Investments [Domain] Equity Securities [Member] Equity Securities [Member] Schedule of Available-for-sale Securities [Line Items] Schedule of Available-for-sale Securities [Line Items] Cost Available-for-sale Securities, Amortized Cost Basis Gross Unrealized Gains Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax Gross Unrealized Losses Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax Fair Value Net unrealized (losses) gains on AFS securities Accumulated Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax Income tax (benefit) expense on net unrealized (losses) gains on AFS securities Accumulated Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Tax Tax related to the accumulated appreciation or loss in value of the total of available-for-sale securities at the end of an accounting period. Maturity term of investments Investment Maturity, Term Investment Maturity, Term Proceeds from sales and maturities of securities Proceeds from Sale and Maturity of Available-for-sale Securities Gross realized gains Available-for-sale Securities, Gross Realized Gains Gross realized losses Available-for-sale Securities, Gross Realized Losses Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Weighted average fair value Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value Risk-free interest rate Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate Expected life in years Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term Expected volatility Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate Expected dividend yield Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Debt Covenant [Member] Debt Covenant [Member] Debt Covenant [Member] Senior Notes [Member] Senior Notes [Member] Line of Credit Facility, Covenant Terms, Acquisitions Restrictions, Borrowing Availability Threshold, Percent Of Commitments, Scenario Two Line of Credit Facility, Covenant Terms, Acquisitions Restrictions, Borrowing Availability Threshold, Percent Of Commitments, Scenario Two Line of Credit Facility, Covenant Terms, Acquisitions Restrictions, Borrowing Availability Threshold, Fixed Coverage Ratio, Scenario Two Number of credit rating agencies Number of Credit Rating Agencies Number of Credit Rating Agencies Fixed charge coverage ratio for debt covenant Fixed Charge Coverage Ratio The calculated fixed charge coverage ratio. Maximum unrestricted quarterly dividends allowable under debt covenants Maximum Unrestricted Quarterly Dividends Allowable Under Debt Covenants The maximum unrestricted payment per share allowed under debt covenants for the quarterly dividend. Maximum unrestricted distributions allowable Maximum Unrestricted Distributions Allowable Under Debt Covenants The maximum unrestricted distribution allowed under debt covenants. Distributions in excess of this amount are subject to certain restrictions. Maximum percentage of income distribution Maximum Percentage Of Income Distribution Maximum percentage of income distribution, subject to certain other distribution terms. Maximum distribution percentage of specified net cash proceeds Maximum Distribution Percentage Of Specified Net Cash Proceeds Maximum distribution percentage of specified net cash proceeds received after a stated period plus other adjustments, and subject to certain other distribution terms. Borrowing availability of bank commitments, minimum Line of Credit Facility, Covenant Terms, Acquisitions And Investments, Borrowing Availability Threshold, Scenario Two Line of Credit Facility, Covenant Terms, Acquisitions And Investments, Borrowing Availability Threshold, Scenario Two Line of Credit Facility, Covenant Terms, Acquisitions And Investments, Borrowing Availability Threshold, Percent Of Commitments, Scenario Two Line of Credit Facility, Covenant Terms, Acquisitions And Investments, Borrowing Availability Threshold, Percent Of Commitments, Scenario Two Line of Credit Facility, Covenant Terms, Acquisitions And Investments, Borrowing Availability Threshold, Percent Of Commitments, Scenario Two Line of Credit Facility, Covenant Terms, Specified Investments Permissible Line of Credit Facility, Covenant Terms, Specified Investments Permissible Line of Credit Facility, Covenant Terms, Specified Investments Permissible Line of Credit Facility, Covenant Terms, Specified Investments Permissible, Percentage Of Tangible Assets And Acquisitions Line of Credit Facility, Covenant Terms, Specified Investments Permissible, Percentage Of Tangible Assets And Acquisitions Line of Credit Facility, Covenant Terms, Specified Investments Permissible, Percentage Of Tangible Assets And Acquisitions Line of Credit Facility, Covenant Terms, Specified Acquisitions Permissible Line of Credit Facility, Covenant Terms, Specified Acquisitions Permissible Line of Credit Facility, Covenant Terms, Specified Acquisitions Permissible Line of Credit Facility, Covenant Terms, Specified Acquisitions Permissible, Percentage Of Tangible Assets Line of Credit Facility, Covenant Terms, Specified Acquisitions Permissible, Percentage Of Tangible Assets Line of Credit Facility, Covenant Terms, Specified Acquisitions Permissible, Percentage Of Tangible Assets Inventory, Net [Abstract] Finished products Inventory, Finished Goods, Net of Reserves Feedstock, additives, and chemicals Inventory, Work in Process and Raw Materials, Net of Reserves Materials and supplies Inventory, Supplies, Net of Reserves Inventories Earnings Per Share [Abstract] Weighted average common shares - basic Weighted Average Number of Shares Outstanding, Basic Plus incremental shares from: Assumed exercise of options Incremental Common Shares Attributable to Dilutive Effect of Call Options and Warrants Weighted average common shares - diluted Weighted Average Number of Shares Outstanding, Diluted Basic Earnings Per Share, Basic Diluted Earnings Per Share, Diluted Inventories Inventory Disclosure [Text Block] Accounts and Notes Payable [Abstract] Accounts and Notes Payable [Abstract] Accounts and Notes Payable Schedule of Accounts Payable and Accrued Liabilities [Table Text Block] Reconciliation Of Proceeds From Initial Public Offering Reconciliation Of Proceeds From Initial Public Offering [Table Text Block] Reconciliation Of Proceeds From Initial Public Offering [Table Text Block] Insurance Recovery [Abstract] Insurance Recovery [Abstract] Insurance Recovery Business Insurance Recoveries [Text Block] Provision for federal income tax at statutory rate Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount State income tax provision net of federal income tax effect Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount Foreign income tax rate differential Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential, Amount Manufacturing deduction Effective Income Tax Rate Reconciliation, Deduction, Qualified Production Activity, Amount Contingent tax liability Effective Income Tax Rate Reconciliation, Tax Contingency, Amount Noncontrolling interests Effective Income Tax Rate Reconciliation, Noncontrolling Interest Income (Loss), Amount Other, net Effective Income Tax Rate Reconciliation, Other Reconciling Items, Amount Provision for income taxes Income Tax Expense (Benefit) Schedule of Defined Benefit Plans Disclosures [Table] Schedule of Defined Benefit Plans Disclosures [Table] Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Axis] Defined Benefit Plans and Other Postretirement Benefit Plans [Axis] Defined Benefit Plans and Other Postretirement Benefit Plans [Domain] Defined Benefit Plan and Other Postretirement Benefit Plan [Domain] Pension Benefits [Member] Pension Plan [Member] U. S. Plans [Member] United States Pension Plan of US Entity [Member] Non-U. S. Plans [Member] Foreign Pension Plan [Member] Post-Retirement Healthcare Benefit Plans [Member] Other Postretirement Benefit Plan [Member] Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan Disclosure [Line Items] Fair value of plan assets, beginning of year Defined Benefit Plan, Fair Value of Plan Assets Actual return Defined Benefit Plan, Actual Return on Plan Assets Employer contribution Defined Benefit Plan, Contributions by Employer Benefits paid Defined Benefit Plan, Benefits Paid Fair value of plan assets, end of year Funded status, end of year Defined Benefit Plan, Funded Status of Plan Description Of Business Description Of Business [Policy Text Block] Description Of Business [Policy Text Block] Principles Of Consolidation Consolidation, Policy [Policy Text Block] Cash And Cash Equivalents Cash and Cash Equivalents, Policy [Policy Text Block] Investments Investment, Policy [Policy Text Block] Allowance For Doubtful Accounts Receivables, Trade and Other Accounts Receivable, Allowance for Doubtful Accounts, Policy [Policy Text Block] Inventories Inventory, Policy [Policy Text Block] Property, Plant and Equipment Property, Plant and Equipment, Policy [Policy Text Block] Fair Value Estimates Fair Value Estimate [Policy Text Block] Disclosure of accounting policy regarding the usage of fair value estimates. Impairment Of Long-Lived Assets and Intangible Assets Impairment or Disposal of Long-Lived Assets, Including Intangible Assets, Policy [Policy Text Block] Turnaround Costs Property, Plant and Equipment, Planned Major Maintenance Activities, Policy [Policy Text Block] Exchanges Inventory Exchange [Policy Text Block] Disclosure of accounting policy for the basis and manner that goods are exchanged and settled in like-kind quantities. This disclosure includes the nature of the cost elements included in inventory and how cost is determined (such as FIFO, LIFO, average). Income Taxes Income Tax, Policy [Policy Text Block] Foreign Currency Translation Foreign Currency Transactions and Translations Policy [Policy Text Block] Concentration Of Credit Risk Concentration Of Credit Risk [Policy Text Block] Disclosure of accounting policy for the concentration of credit risk. Revenue Recognition Revenue Recognition Accounting Policy, Gross and Net Revenue Disclosure [Policy Text Block] Earnings Per Share Earnings Per Share, Policy [Policy Text Block] Price Risk Management Derivatives, Policy [Policy Text Block] Environmental Costs Environmental Costs, Policy [Policy Text Block] Fair Value Of Financial Instruments Fair Value of Financial Instruments, Policy [Policy Text Block] Use Of Estimates Use of Estimates, Policy [Policy Text Block] Other Other [Policy Text Block] Disclosure of accounting policy for the method of amortizing debt issuance costs and certain other assets. New Accounting Pronouncements New Accounting Pronouncements, Policy [Policy Text Block] Federal, Current Current Federal Tax Expense (Benefit) State, Current Current State and Local Tax Expense (Benefit) Foreign, Current Current Foreign Tax Expense (Benefit) Total Current Current Income Tax Expense (Benefit) Federal, Deferred Deferred Federal Income Tax Expense (Benefit) State, Deferred Deferred State and Local Income Tax Expense (Benefit) Foreign, Deferred Deferred Foreign Income Tax Expense (Benefit) Total Deferred Deferred Income Tax Expense (Benefit) Foreign and state net operating loss carryforwards Operating Loss Carryforwards Net operating loss carryforwards, change in valuation allowance Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount Schedule Of Long-Term Debt Schedule of Long-term Debt Instruments [Table Text Block] Defined Benefit Plans and Other Postretirement Benefit Plans [Axis] Defined Benefit Plan and Other Postretirement Benefit Plan [Domain] Major Types of Debt and Equity Securities [Axis] Major Types of Debt and Equity Securities [Axis] Major Types of Debt and Equity Securities [Domain] Major Types of Debt and Equity Securities [Domain] Bank Collective Trust Funds - Equity Securities [Member] Bank Collective Trust Funds - Fixed Income [Member] Fixed Income Securities [Member] Defined Benefit Plan, Fair Value of Plan Assets by Measurement [Axis] Fair Value Plan Asset Measurement [Domain] Level 3 [Member] Fair Value, Inputs, Level 3 [Member] Defined Benefit Plan, Asset Categories [Axis] Defined Benefit Plan, Asset Categories [Axis] Plan Asset Categories [Domain] Plan Asset Categories [Domain] Large-Cap Index Funds [Member] Large Cap Index Funds [Member] Large-Cap Index Funds [Member] Small-Cap Index Funds [Member] Small Cap Index Funds [Member] Small-Cap Index Funds [Member] International Index Funds [Member] International Index Funds [Member] International Index Funds [Member] Bond Index Funds [Member] Bonds [Member] Short Term Investment Funds [Member] Short-term Investments [Member] Fair value of plan assets Earnings Per Share Earnings Per Share [Text Block] Schedule Of Inventory Schedule of Inventory, Current [Table Text Block] Quarterly Financial Information Disclosure [Abstract] Quarterly Financial Information Quarterly Financial Information [Text Block] Schedule Of Net Income Attributable To Common Stockholders Schedule Of Net Income Loss Attributable To Common Stockholders Table [Text Block] Schedule of net income (loss) attributable to common stockholders [Table Text Block] Reconciliation Of Denominator For Basic And Diluted Earnings (Loss) Per Share Schedule of Weighted Average Number of Shares [Table Text Block] Accumulated Other Comprehensive Income Comprehensive Income (Loss) Note [Text Block] Segment and Geographic Information Segment Reporting Disclosure [Text Block] Senior Notes, Carrying Value Senior Notes, Fair Value Notes Payable, Fair Value Disclosure Loans, Carrying Value Loans, Fair Value Loans Payable, Fair Value Disclosure Maturity date Compensation and Retirement Disclosure [Abstract] Defined Contribution Plan [Table] Defined Contribution Plan [Table] Defined Contribution Plan Name [Axis] Defined Contribution Plan Name [Axis] Defined Contribution Plan Name [Domain] Defined Contribution Plan Name [Domain] Defined Contribution Savings Plan [Member] Defined Contribution Savings Plan [Member] Defined Contribution Savings Plan [Member] Defined Contribution Retirement Plan [Member] Defined Contribution Retirement Plan [Member] Defined Contribution Retirement Plan [Member] Defined Contribution Plan Type [Axis] Defined Contribution Plan Type [Axis] Defined Contribution Plan Type [Domain] Defined Contribution Plan Type [Domain] U. S. Plans [Member] United States Postretirement Benefit Plan of US Entity [Member] Foreign Postretirement Benefit Plan [Member] Foreign Postretirement Benefit Plan [Member] Defined Contribution Plan [Line Items] Defined Contribution Plan Disclosure [Line Items] Maximum employee contribution as a percentage of annual compensation Maximum Employee Contribution As Percentage Of Annual Compensation Maximum Employee Contribution As Percentage Of Annual Compensation Matching percentage by company of first 4% of employee contribution Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay Percentage of employee contribution fully matched by company Percentage Of Employee Contribution Fully Matched By Company Percentage Of Employee Contribution Fully Matched By Company Employer contributions to plans Defined Contribution Plan, Employer Discretionary Contribution Amount Length of service required to be eligible for annual retirement contributions (in years) Eligibility Requirements Length Of Service Required For Annual Retirement Contribution Eligibility requirements, length of service required for annual retirement contribution Defined contribution savings plan expense Defined Contribution Plan, Cost Recognized Net operating loss carryforward Deferred Tax Assets, Operating Loss Carryforwards Credit carryforward Deferred Tax Assets, Tax Credit Carryforwards Accruals Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Accrued Liabilities Allowance for doubtful accounts Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Allowance for Doubtful Accounts Inventories Deferred Tax Assets, Inventory Other Deferred Tax Assets, Other Deferred taxes assets, total Deferred Tax Assets, Gross Property, plant and equipment Deferred Tax Liabilities, Property, Plant and Equipment Turnaround costs Deferred Tax Liabilities, Deferred Expense, Other Capitalized Costs Basis difference—consolidated partnerships Deferred Tax Liabilities, Parent's Basis In Consolidated Partnerships Deferred Tax Liabilities, Parent's Basis In Consolidated Partnerships Deferred tax liabilities—total Deferred Tax Liabilities, Gross Valuation allowance Deferred Tax Assets, Valuation Allowance Total net deferred tax liabilities Deferred Tax Liabilities, Net Balance sheet classifications Deferred Tax Assets, Net, Classification [Abstract] Current deferred tax asset Deferred Tax Assets, Net of Valuation Allowance Noncurrent deferred tax liability Property, Plant and Equipment, Net [Abstract] Property, Plant And Equipment Property, Plant and Equipment Disclosure [Text Block] Condensed Consolidating Financial Information Balance Sheet Condensed Balance Sheet [Table Text Block] Schedule of Guarantor Obligations Schedule of Guarantor Obligations [Table Text Block] Condensed Consolidating Financial Information Statement Of Operations Condensed Income Statement [Table Text Block] Condensed Consolidating Financial Information Statement Of Cash Flows Condensed Cash Flow Statement [Table Text Block] Schedule of Related Party Transactions, by Related Party [Table] Schedule of Related Party Transactions, by Related Party [Table] Related Party Transaction [Axis] Related Party Transaction [Axis] Related Party Transaction [Domain] Related Party Transaction [Domain] Pipeline Fees For Transport Of Natural Gas Liquid Feedstocks [Member] Pipeline Fees For Transport Of Natural Gas Liquid Feedstocks [Member] Pipeline Fees For Transport Of Natural Gas Liquid Feedstocks [Member] Electricity And Technical Services [Member] Electricity And Technical Services [Member] Electricity and Technical Services [Member] Pipeline Fees For Transport Of Ethylene Feedstocks [Member] Pipeline Fees For Transport Of Ethylene Feedstocks [Member] Pipeline Fees For Transport Of Ethylene Feedstocks [Member] Counterparty Name [Axis] Counterparty Name [Axis] Counterparty Name [Domain] Counterparty Name [Domain] InfraServ Knapsack GmbH & Co. KG [Member] InfraServ Knapsack GmbH & Co. KG [Member] InfraServ Knapsack GmbH & Co. KG [Member] InfraServ Gendorf GmbH & Co. KG [Member] InfraServ Gendorf GmbH & Co. KG [Member] InfraServ Gendorf GmbH & Co. KG [Member] InfraServ Knapsack & Gendorf GmbH & Co. KG [Member] InfraServ Knapsack & Gendorf GmbH & Co. KG [Member] InfraServ Knapsack & Gendorf GmbH & Co. KG [Member] EPS Ethylene Pipeline Süd GmbH & Co. KG [Member] EPS Ethylene Pipeline Süd GmbH & Co. KG [Member] EPS Ethylene Pipeline Süd GmbH & Co. KG [Member] American Air Liquide Holdings [Member] American Air Liquide Holdings [Member] American Air Liquide Holdings [Member] Equity Method Investee, Name [Axis] Investment, Name [Axis] Equity Method Investee, Name [Domain] Investment, Name [Domain] Cypress Interstate Pipeline L.L.C [Member] Cypress Interstate Pipeline L.L.C [Member] Cypress Interstate Pipeline L.L.C [Member] Related Party [Axis] Related Party [Axis] Related Party [Domain] Related Party [Domain] Affiliates [Member] Affiliated Entity [Member] Corporate Joint Venture [Member] Corporate Joint Venture [Member] American Air Liquide Holdings, Inc. [Member] Director [Member] Related Party Transaction [Line Items] Related Party Transaction [Line Items] Incurred and paid lease payments Office Lease Expense Lease expense incurred for office space. Accounts payable due to related parties Accounts Payable, Related Parties Ownership interest Equity Method Investment, Ownership Percentage Pipeline fees incurred for usage Pipeline Usage Fees Pipeline Usage Fees Accounts payable due to affiliate Due to Affiliate Noncontrolling Interest, Ownership Percentage by Parent Noncontrolling Interest, Ownership Percentage by Parent Purchases from related parties Related Party Transaction, Purchases from Related Party Dividends received from equity method investments Proceeds from Equity Method Investment, Dividends or Distributions Purchases and lease expense to related parties Purchases And Lease Expense Payments made for purchases and lease expenses. Insurance recoveries Insurance Recoveries Other Assets [Abstract] Suzhou Huasu Plastics Company Ltd [Member] Suzhou Huasu Plastics Company Ltd [Member] Suzhou Huasu Plastics Company, Ltd. Fair value of consideration transferred-cash Payments to Acquire Businesses, Gross Preexisting balances between the Company and Huasu, net Business Combination Net Preexisting Balances Between Acquirer And Acquiree Business Combination, Net Preexisting Balances Between the Acquirer And Acquiree Fair value of the Company's investment in Huasu before the business combination, net of preexisting balance Business Combination, Step Acquisition, Equity Interest in Acquiree, Fair Value Fair value of the noncontrolling interest in Huasu Business Combination, Acquisition of Less than 100 Percent, Noncontrolling Interest, Fair Value Cash consideration transferred, preexisting balances, fair value of existing interest and fair value of noncontrolling interest total Business Combination, Cash Consideration Transferred, Preexisting Balances, Fair Value of Existing Interest and Fair Value of Noncontrolling Interest Total Business Combination, Cash Consideration Transferred, Preexisting Balances, Fair Value of Existing Interest and Fair Value of Noncontrolling Interest Total. Cash Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents Working capital, excluding inventory and cash Business Combination, Recognized Identifiable Assets Acquired And Liabilities Assumed, Working Capital Excluding Inventory And Cash Business Combination, Recognized Identifiable Assets Acquired And Liabilities Assumed, Working Capital Excluding Inventory And Cash Inventories Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Inventory Property, plant and equipment Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment Other assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Noncurrent Assets Notes payable to banks Business Combination, Recognized Identifiable Assets Acquired And Liabilities Assumed, Notes Payable To Bank Business Combination, Recognized Identifiable Assets Acquired And Liabilities Assumed, Notes Payable To Bank Total identifiable net assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net Bargain purchase gain on acquisition Business Combination, Bargain Purchase, Gain Recognized, Amount Statement of Financial Position [Abstract] Preferred stock, par value Preferred Stock, Par or Stated Value Per Share Preferred stock, shares authorized Preferred Stock, Shares Authorized Preferred stock, shares issued Preferred Stock, Shares Issued Preferred stock, shares outstanding Preferred Stock, Shares Outstanding Common stock, par value per share Common Stock, Par or Stated Value Per Share Common Stock, shares authorized Common Stock, Shares Authorized Common stock, shares issued Common Stock, Shares, Issued Common stock, held in treasury Treasury Stock, Shares Net income (loss) Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Depreciation and amortization Depreciation And Amortization Including Amortization Of Debt Issuance Costs Depreciation and amortization expense, including amortization of debt issuance costs. Deferred income taxes Net changes in working capital and other Increase (Decrease) in Operating Capital Net cash provided by operating activities Net Cash Provided by (Used in) Operating Activities Acquisition of business, net of cash acquired Acquisition Of Business, Net Of Cash Acquired The cash inflow or outflow associated with the acquisition of a business, net of the cash acquired. Additions to property, plant and equipment Payments to Acquire Property, Plant, and Equipment Construction of assets pending sale-leaseback Payments for Construction of Assets Pending Sale Leaseback The cash outflow associated with the construction of long-lived assets pending financing through a sale-leaseback. Additions to equity investments Payments to Acquire Equity Method Investments Proceeds from disposition of assets Proceeds from Sale of Property, Plant, and Equipment Proceeds from sale of equity method investments Proceeds from Sale of Equity Method Investments Proceeds from repayment of loan acquired Proceeds From (Repayments of) Acquired Loan Proceeds From (Repayments of) Acquired Loan Proceeds from repayment of loan to affiliate Proceeds from (Repayments of) Related Party Debt Proceeds from sales and maturities of securities Proceeds from Sale and Maturity of Marketable Securities Purchase of securities Payments to Acquire Investments Settlements of derivative instruments Payments for (Proceeds from) Derivative Instrument, Investing Activities Net cash used for investing activities Net Cash Provided by (Used in) Investing Activities Intercompany financing Proceeds From Repayments Of Intercompany Financing Proceeds from (Repayments of) Intercompany Financing Proceeds from (Repayments of) Intercompany Financing, Subsidiary Proceeds from (Repayments of) Intercompany Financing, Subsidiary Proceeds from (Repayments of) Intercompany Financing, Subsidiary Net distributions prior to WLKP initial public offering Payments of Distributions to Affiliates Capitalized debt issuance costs Payments of Debt Issuance Costs Dividends paid Payments of Ordinary Dividends, Common Stock Distribution Made to Limited Partner, Cash Distributions Paid Distribution Made to Limited Partner, Cash Distributions Paid Net proceeds from issuance of Westlake Chemical Partners LP common units Proceeds from Issuance of Common Limited Partners Units Payments to Acquire Limited Partnership Interests Payments to Acquire Limited Partnership Interests Proceeds from exercise of stock options Proceeds from Stock Options Exercised Proceeds from issuance of notes payable Proceeds from Notes Payable Repayment of notes payable Repayments of Notes Payable Repurchase of common stock for treasury Payments for Repurchase of Common Stock Windfall tax benefits from share-based payment arrangements Excess Tax Benefit from Share-based Compensation, Financing Activities Net cash (used for) provided by financing activities Net Cash Provided by (Used in) Financing Activities Effect of exchange rate changes on cash and cash equivalents Effect of Exchange Rate on Cash and Cash Equivalents Net (decrease) increase in cash and cash equivalents Cash and Cash Equivalents, Period Increase (Decrease) Cash and cash equivalents at beginning of the year Cash and cash equivalents at end of the year Accounts Receivable Loans, Notes, Trade and Other Receivables Disclosure [Text Block] Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Products and Services [Axis] Products and Services [Axis] Products and Services [Domain] Products and Services [Domain] Polyethylene [Member] Polyethylene [Member] Polyethylene [Member] Ethylene, Styrene And Other [Member] Ethylene Styrene And Other [Member] Ethylene, Styrene And Other [Member] PVC, Caustic Soda And Other [Member] Pvc Caustic Soda And Other [Member] PVC, caustic soda and other [Member] Building Products [Member] Building Products [Member] Building Products [Member] Segments [Axis] Segments [Axis] Segment [Domain] Segments [Domain] Olefins [Member] Olefins [Member] Olefins [Member] Vinyls [Member] Vinyls [Member] Vinyls [Member] Corporate And Other [Member] Corporate and Other [Member] Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] Intersegment sales Revenues Income (loss) from operations Operating Income (Loss) Depreciation and amortization Depreciation, Depletion and Amortization Other income (expense), net Nonoperating Income (Expense) Provision for income taxes Property, Plant and Equipment, Additions Property, Plant and Equipment, Additions Net income attributable to Westlake Chemical Corporation Net Income (Loss) Attributable to Parent Less: Net income attributable to participating securities Net Income Loss Available To Participating Securities Net income (loss) available to participating securities Net income attributable to common shareholders Net Income Loss Available To Common Stockholders Net income available to common stockholders after adjustments for net income attributable to participating securities. Number of segments Number Of Segments Number of segments Number of major customers Concentration Risk, Number of Major Customers Concentration Risk, Number of Major Customers Number of plants Number Of Plants Represents the number of company plants that manufacture building products. Fair Value Measurements Fair Value Disclosures [Text Block] Net sales Gross profit Gross Profit Net income Basic earnings per common share Diluted earnings per common share Unconditional purchase obligations Purchase Obligation, Fiscal Year Maturity [Abstract] 2016 Unrecorded Unconditional Purchase Obligation, Due in Next Twelve Months 2017 Unrecorded Unconditional Purchase Obligation, Due within Two Years 2018 Unrecorded Unconditional Purchase Obligation, Due within Three Years 2019 Unrecorded Unconditional Purchase Obligation, Due within Four Years 2020 Unrecorded Unconditional Purchase Obligation, Due within Five Years Employee Benefits Pension and Other Postretirement Benefits Disclosure [Text Block] ASSETS Assets [Abstract] Current assets Assets, Current [Abstract] Other assets, net Intangible assets, net Intangible Assets, Net (Including Goodwill) Deferred charges and other assets, net Deferred Costs and Other Assets Total other assets, net LIABILITIES AND STOCKHOLDERS' EQUITY Liabilities and Equity [Abstract] Current liabilities Liabilities, Current [Abstract] Total liabilities Commitments and contingencies (Notes 8 and 22) Commitments and Contingencies Stockholders' equity Stockholders' Equity Attributable to Parent [Abstract] Preferred stock, $0.01 par value, 50,000,000 shares authorized; no shares issued and outstanding Preferred Stock, Value, Issued Common stock, $0.01 par value, 300,000,000 shares authorized; 134,663,244 and 134,679,064 shares issued at December 31, 2015 and 2014, respectively (Note 9) Common Stock, Value, Issued Common stock, held in treasury, at cost; 4,444,898 and 1,787,546 shares at December 31, 2015 and 2014, respectively (Note 9) Treasury Stock, Value Additional paid-in capital Additional Paid in Capital, Common Stock Retained earnings Retained Earnings (Accumulated Deficit) Accumulated other comprehensive loss Accumulated Other Comprehensive Income (Loss), Net of Tax Total Westlake Chemical Corporation stockholders' equity Gulf Opportunity Zone Act Of 2005 [Member] Gulf Opportunity Zone Act Of Two Thousand Five [Member] Gulf Opportunity Zone Act Of Two Thousand Five [Member] Redeemed Prior To November 1, 2017 [Member] Debt Instrument, Redemption, Period Seven [Member] Debt Instrument, Redemption, Period Seven [Member] Redeemed On Or After November 1, 2017 [Member] Debt Instrument, Redemption, Period Eight [Member] Debt Instrument, Redemption, Period Eight [Member] Maturity date Debt Instrument, Maturity Date Percentage of principal required if called Percentage Of Principal Required If Called Percentage of the principal required in the event bonds are redeemed Minimum debt amount guaranteed by subsidiaries Minimum Debt Amount Guaranteed By Subsidiaries Minimum Debt Amount Guaranteed By Subsidiaries Service cost Defined Benefit Plan, Service Cost Interest cost Defined Benefit Plan, Interest Cost Expected return on plan assets Defined Benefit Plan, Expected Return on Plan Assets Net amortization Defined Benefit Plan, Other Costs Settlement benefits Defined Benefit Plan, Recognized Net Gain (Loss) Due to Settlements Net periodic benefit cost Defined Benefit Plan, Net Periodic Benefit Cost Net loss (gain) emerging Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized Gain (Loss) Arising During Period, before Tax Amortization of net loss Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Gain (Loss), before Tax Amortization of prior service cost Other Comprehensive (Income) Loss, Amortization Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Prior Service Cost (Credit), before Tax Settlement benefits Other Comprehensive Income (Loss), Finalization of Pension and Other Postretirement Benefit Plan Valuation, before Tax Total recognized in OCI Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss), Net Actuarial Gain (Loss), before Tax Total net periodic benefit cost and OCI Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss) And Net Periodic Benefit Credit (Cost) The total amount of net periodic benefit cost and the aggregate net gain (loss) recognized in other comprehensive income for the period. Accounts payable Accounts Payable Notes payable to banks Notes Payable to Bank Accounts and notes payable Accounts Payable And Notes Payable, Current Accounts Payable and Notes Payable, Current Projected benefit obligation Defined Benefit Plan, Benefit Obligation Accumulated benefit obligation Defined Benefit Plan, Accumulated Benefit Obligation Organization, Consolidation, And Presentation Of Financial Statements [Table] Organization, Consolidation, And Presentation Of Financial Statements [Table] Organization, Consolidation, And Presentation Of Financial Statements [Table] Subsidiaries [Member] Subsidiaries [Member] Partner Type [Axis] Partner Type [Axis] Partner Type of Partners' Capital Account, Name [Domain] Partner Type of Partners' Capital Account, Name [Domain] Limited Partner [Member] Limited Partner [Member] Subsidiary, Sale of Stock [Axis] Sale of Stock [Axis] Sale of Stock, Name of Transaction [Domain] Sale of Stock [Domain] IPO [Member] IPO [Member] Westlake Chemical Partners LP [Member] Westlake Chemical Partners LP [Member] Westlake Chemical Partners LP [Member] Subsidiary of Common Parent [Member] Subsidiary of Common Parent [Member] Louisiana LOUISIANA Kentucky KENTUCKY Organization Consolidation And Presentation Of Financial Statements [Line Items] Organization consolidation and presentation of financial statements [Line Items]. Number of units sold in public offering Partners' Capital Account, Units, Sold in Public Offering Limited partner interest Limited Liability Company (LLC) or Limited Partnership (LP), Members or Limited Partners, Ownership Interest Undistributed earnings included in retained earnings Joint Ventures Retained Earnings Accumulated Deficit The cumulative amount of undistributed earnings or deficit from joint ventures included in the reporting entity's undistributed earnings or deficit. Number of production facilities Number Of Production Facilities Number Of Production Facilities Capitalized interest Interest Costs Capitalized Goodwill Amortization period, minimum (in years) Plant And Equipment Planned Major Maintenance Activities Amortization Period Minimum The minimum amortization period of planned major maintenance activities. Amortization period, maximum (in years) Plant And Equipment Planned Major Maintenance Activities Amortization Period Maximum The maximum amortization period of planned major maintenance activities. Other assets amortization period, minimum (in years) Finite Lived Intangible Assets Amortization Period Minimum The minimum amortization period of finite-lived intangible assets. Other assets amortization period, maximum (in years) Finite Lived Intangible Assets Amortization Period Maximum The maximum amortization period of finite-lived intangible assets. Trade customers Accounts Receivable, Gross, Current Affiliates Accounts Receivable, Related Parties, Current Allowance for doubtful accounts Allowance for Doubtful Accounts Receivable, Current Receivables from trade customers and affiliates, net Trade Customer And Affiliate Receivable, Net, Current The aggregate of amounts due from customers or clients, within one year of the balance sheet date (or one operating cycle, if longer), for goods or services that have been delivered or sold in the normal course of business, and amounts due from related parties (affiliates) payable within one year of the balance sheet, reduced to their estimated net realizable fair value by an allowance established by the entity of the amount it deems uncertain of collection. Federal and state taxes Income Taxes Receivable, Current Other Other Receivables, Net, Current Accounts receivable, net Schedule Of Other Assets [Table] Schedule Of Other Assets [Table] Schedule Of Other Assets [Table] Other Assets [Line Items] Other Assets [Line Items] Other Assets [Line Items] Amortization expense of other assets Amortization Of Other Assets Amortization of other assets Future amortization expense, 2016 Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months Future amortization expense, 2017 Finite-Lived Intangible Assets, Amortization Expense, Year Two Future amortization expense, 2018 Finite-Lived Intangible Assets, Amortization Expense, Year Three Future amortization expense, 2019 Finite-Lived Intangible Assets, Amortization Expense, Year Four Future amortization expense, 2020 Finite-Lived Intangible Assets, Amortization Expense, Year Five Impairment since goodwill was initially recorded Goodwill, Impaired, Accumulated Impairment Loss Number of years forecasted to test for impairment of goodwill Discounted Cash Flow Methodology, Asset Impairment, Number Of Years Forecasted The number of forecast years utilized in developing discounted cash flow projections in determining asset impairment. Discounted cash flow projections period Discounted Cash Flow Projections Period Discounted cash flow projections period Rate used to discount future cash flows for goodwill impairment test Discounted Cash Flow Methodology, Goodwill Impairment, Discount Rate The discount rate percentage utilized when developing discounted cash flow projections in determining projected future cash flows as they relate to goodwill impairment. Percentage future cash flows of segment could decrease by and not be impaired Discounted Cash Flow Methodology, Goodwill Impairment, Cash Flow Percentage Decrease Without Impairment Percentage used in the sensitivity analysis of future discounted cash flows analyzed for goodwill impairment under the discounted cash flow methodology. Income from operations for reportable segments Interest expense Interest Expense Other income, (expense), net Income (Loss) from Continuing Operations before Income Taxes Income (Loss) from Continuing Operations before Income Taxes Income (Loss) from continuing operations, including the portion attributable to noncontrolling interest, and income (loss) from equity method investments, but before extraordinary items, cumulative effects of changes in accounting principles and income taxes. Award Type [Axis] Award Type [Axis] Equity Award [Domain] Equity Award [Domain] Restricted Stock [Member] Restricted Stock [Member] Restricted Stock Units (RSUs) [Member] Restricted Stock Units (RSUs) [Member] Number of Shares, Non-vested, beginning balance Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Number of Shares, Granted Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Number of Shares, Vested Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Number of Shares, Forfeited Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period Number of Shares, Non-vested, ending balance Weighted Average Grant Date Fair Value, Non-vested, beginning balance Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Weighted Average Grant Date Fair Value, Granted Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Weighted Average Grant Date Fair Value, Vested Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value Weighted Average Grant Date Fair Value, Forfeited Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value Weighted Average Grant Date Fair Value, Non-vested, ending balance Unrecognized Stock-based Compensation Expense Related to Non-Vested RSU Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Fair Value Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value Segment Reporting Information Schedule of Segment Reporting Information, by Segment [Table Text Block] Total Assets Reconciliation of Assets from Segment to Consolidated [Table Text Block] Reconciliation Of Total Segment Income From Operations To Consolidated Income Before Income Taxes Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Table Text Block] Geographic Information For Sales To External Customers And Long-Lived Assets Schedule of Revenue from External Customers and Long-Lived Assets, by Geographical Areas [Table Text Block] Derivative Instruments and Hedges, Offsetting of Derivative Liabilities [Abstract] Derivative Instruments and Hedges, Offsetting of Derivative Liabilities [Abstract] Offsetting of Derivative Liabilities [Table] Offsetting Liabilities [Table] Type of Agreement [Axis] Type of Agreement [Axis] Type of Agreement [Axis] Type of Agreement [Domain] Type of Agreement [Domain] [Domain] for Type of Agreement [Axis] Subject to Master Netting [Member] Subject to Master Netting [Member] Subject to Master Netting [Member] Counterparty A [Member] Counterparty A [Member] Counterparty A [Member] Counterparty B [Member] Counterparty B [Member] Counterparty B [Member] Offsetting Liabilities [Line Items] Offsetting Liabilities [Line Items] Derivative liabilities subject to enforceable master netting arrangements Derivative Liability, Fair Value, Amount Not Offset Against Collateral Derivative liabilities not subject to enforceable master netting arrangements Derivative Liability, Not Subject to Master Netting Arrangement Total derivative liabilities Gross amounts of recognized liabilities Derivative Liability, Fair Value, Gross Liability Gross amounts offset in the consolidated balance sheet Derivative Liability, Fair Value, Gross Asset Gross amounts not offset in the consolidated balance sheet Derivative, Collateral, Right to Reclaim Cash Derivative liability, net amount offset against collateral Derivative Liability, Fair Value, Amount Offset Against Collateral Valuation and Qualifying Accounts [Abstract] Valuation and Qualifying Accounts Schedule of Valuation and Qualifying Accounts Disclosure [Text Block] Other Assets Other Assets Disclosure [Text Block] Subsequent Events [Abstract] Subsequent Events Subsequent Events [Text Block] Statement of Cash Flows [Abstract] Cash flows from operating activities Net Cash Provided by (Used in) Operating Activities [Abstract] Net income 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] Provision for doubtful accounts Provision for Doubtful Accounts Amortization of debt issuance costs Amortization of Financing Costs Stock-based compensation expense Share-based Compensation Loss from disposition of fixed assets Gain (Loss) on Disposition of Property Plant Equipment, Excluding Oil and Gas Property and Timber Property Gain from sales of equity securities Available-for-sale Securities, Gross Realized Gain (Loss) Gain on acquisition, net of loss on the fair value remeasurement of preexisting equity interest Business Combination, Bargain Purchase, Gain Net Business Combination, Bargain Purchase, Gain Recognized, Amount, Including Remeasurement Loss Impairment of equity method investment Equity Method Investment, Other than Temporary Impairment Windfall tax benefits from share-based payment arrangements Excess Tax Benefit from Share-based Compensation, Operating Activities (Income) loss from equity method investments, net of dividends Income (Loss) from Equity Method Investments, Net of Dividends or Distributions Other loss, net Other Operating Activities, Cash Flow Statement Changes in operating assets and liabilities Increase (Decrease) in Operating Capital [Abstract] Accounts receivable Increase (Decrease) in Accounts and Other Receivables Inventories Increase (Decrease) in Inventories Prepaid expenses and other current assets Increase Decrease In Prepaid Expenses And Other Current Assets The increase (decrease) during the reporting period in the aggregate value of prepaid expenses and other current assets. Accounts payable Increase (Decrease) in Accounts Payable Accrued liabilities Increase (Decrease) in Accrued Liabilities Other, net Increase (Decrease) in Other Operating Assets and Liabilities, Net Cash flows from investing activities Net Cash Provided by (Used in) Investing Activities [Abstract] Additions to property, plant and equipment Cash flows from financing activities Net Cash Provided by (Used in) Financing Activities [Abstract] Distributions to noncontrolling interests Payments to Noncontrolling Interests Domestic Income (Loss) from Continuing Operations before Income Taxes, Domestic Foreign Income (Loss) from Continuing Operations before Income Taxes, Foreign Income before income taxes Income Loss Before Income Taxes Income or loss from continuing operations, including the portion attributable to noncontrolling interest, and income or loss from equity method investments, but before extraordinary items, cumulative effects of changes in accounting principles and income taxes. Cost of sales Cost of Goods Sold Selling, general and administrative expenses Selling, General and Administrative Expense Income from operations (Loss) income before income taxes Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest (Benefit from) provision for income taxes Equity in net income of subsidiaries Income Loss From Equity Method Investments Subsidiaries Income loss from equity method investments and subsidiaries. Net income attributable to noncontrolling interests Net Income (Loss) Attributable to Noncontrolling Interest Comprehensive income Comprehensive Income (Loss), Net of Tax, Attributable to Parent Discount rate Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate Expected return on plan assets Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Expected Long-Term Return On Assets An assumption as to the rate of return on plan assets reflecting the average rate of earnings expected on the funds invested or to be invested to provide for the benefits included in the benefit obligation. Rate of compensation increase Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase Discount rate Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate Expected return on plan assets Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Return on Assets Rate of compensation increase Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Rate of Compensation Increase Number of multiemployer plans Number Of Multiemployer Plans Number Of Multiemployer Plans Contributions to multi-employer plans Multiemployer Plans, Plan Contributions Redeemed Prior To August First Twenty Twenty [Member] Debt Instrument, Redemption, Period Five [Member] Redeemed On Or After August First Twenty Twenty [Member] Debt Instrument, Redemption, Period Six [Member] Debt Instrument, Redemption, Period Six [Member] Benefit obligation, beginning of year Benefit obligation assumed with acquisition Defined Benefit Plan, Business Combinations and Acquisitions, Benefit Obligation Actuarial (gain) loss Defined Benefit Plan, Actuarial Gain (Loss) Benefits paid Foreign exchange effects Defined Benefit Plan, Foreign Currency Exchange Rate Gain (Loss) Benefit obligation, end of year Commitments And Contingencies Commitments and Contingencies Disclosure [Text Block] Effective interest rate Debt Instrument, Interest Rate, Effective Percentage Weighted average interest rate on all long-term debt Long-term Debt, Weighted Average Interest Rate PVC Resin Member [Member] PVC Resin [Member] PVC Resin [Member] PVC Film [Member] PVC Film [Member] PVC Film Vinyl Chloride Monomer [Member] Vinyl Chloride Monomer [Member] Vinyl Chloride Monomer [Member] Caustic Soda [Member] Caustic Soda [Member] Caustic Soda [Member] Percentage of interests acquired Business Acquisition, Percentage of Voting Interests Acquired Percentage of interest Business Combination, Step Acquisition, Equity Interest in Acquiree, Including Subsequent Acquisition, Percentage Combined annual capacity Business Combination, Annual Production Capacity Business Combination, Annual Production Capacity Ownership interest Net gains (loss) on fair value remeasurement Business Combination, Step Acquisition, Equity Interest in Acquiree, Remeasurement Gain (Loss), Net Fair value of accounts receivable Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Receivables Gross contractual amount of accounts receivable Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Receivables, Gross Contractual Amount Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Receivables, Gross Contractual Amount Uncollectible accounts receivable Business Combination, Acquired Receivables, Estimated Uncollectible Net sales contributed by acquired business since acquisition date Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual Net loss contributed by acquired business since acquisition date Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual Transaction related costs Business Combination, Acquisition Related Costs Total purchase consideration Schedule of Property, Plant and Equipment [Table] Property, Plant and Equipment [Table] Restructuring Type [Axis] Restructuring Type [Axis] Type of Restructuring [Domain] Type of Restructuring [Domain] Property, Plant and Equipment [Line Items] Property, Plant and Equipment [Line Items] Depreciation expense on property, plant and equipment Depreciation Land Land Building and improvements Buildings and Improvements, Gross Plant and equipment Machinery and Equipment, Gross Other Property, Plant and Equipment, Other, Gross Property, plant and equipment, gross Property, Plant and Equipment, Gross Excluding Construction In-Progress Gross amount, at the balance sheet date, of long-lived physical assets used in the normal conduct of business and not intended for resale. This can include land, buildings, machinery and equipment, and other types of furniture and equipment including, but not limited to, office equipment, furniture and fixtures, and computer equipment and software. Does not include construction in progress. Less: Accumulated depreciation Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Property, plant and equipment, net, before construction in progress Property, Plant and Equipment, Net Excluding Construction In-Progress Tangible assets that are held by an entity for use in the production or supply of goods and services, for rental to others, or for administrative purposes and that are expected to provide economic benefit for more than one year; net of accumulated depreciation. Examples include land, buildings, machinery and equipment, and other types of furniture and equipment including, but not limited to, office equipment, furniture and fixtures, and computer equipment and software. Does not include construction in progress. Construction in progress Construction in Progress, Gross Property, plant and equipment, net Accounts and Notes Payable Accounts Payable and Accrued Liabilities Disclosure [Text Block] Income Statement [Abstract] Gross profit Other income (expense) Nonoperating Income (Expense) [Abstract] Income before income taxes Earnings per common share attributable to Westlake Chemical Corporation (Note 9): Weighted average shares outstanding (Note 9): Weighted Average Number of Shares Outstanding, Diluted [Abstract] Basic Diluted Dividends per common share (Note 9) Common Stock, Dividends, Per Share, Declared Acquisitions Business Combination Disclosure [Text Block] Stock-Based Compensation Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Year one Defined Benefit Plan, Expected Future Benefit Payments, Next Twelve Months Year two Defined Benefit Plan, Expected Future Benefit Payments, Year Two Year three Defined Benefit Plan, Expected Future Benefit Payments, Year Three Year four Defined Benefit Plan, Expected Future Benefit Payments, Year Four Year five Defined Benefit Plan, Expected Future Benefit Payments, Year Five Years 6 to 10 Defined Benefit Plan, Expected Future Benefit Payments, Five Fiscal Years Thereafter Statement of Comprehensive Income [Abstract] Other comprehensive (loss) income, net of income taxes Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract] Pension and other post-retirement benefits liability Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax [Abstract] Pension and other post-retirement reserves adjustment (excluding amortization) Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, before Reclassification Adjustments and Tax Settlement benefits Amortization of benefits liability Income tax (provision) benefit on pension and other post-retirement benefits liability Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Tax, Portion Attributable to Parent Foreign currency translation adjustments Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax Available-for-sale investments Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax [Abstract] Unrealized holding gains on investments Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, before Reclassification Adjustments and Tax Reclassification of net realized loss (gains) to net income Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, before Tax Income tax (provision) benefit on available-for-sale investment Other Comprehensive Income (Loss) Income Tax (Provision) Benefit On Available For Sale Investment Amount of tax expense (benefit), including reclassification adjustments, of appreciation (loss) in value of available-for-sale securities. Excluded amounts related to other than temporary impairment (OTTI) loss. Other comprehensive (loss) income Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Comprehensive income Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Comprehensive income attributable to noncontrolling interests, net of tax Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest Comprehensive income attributable to Westlake Chemical Corporation Options excluded from computation of earnings per share, shares Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Vesting [Axis] Vesting [Axis] Vesting [Domain] Vesting [Domain] Ratably On Annual Basis [Member] Ratably On Annual Basis [Member] Ratably On An Annual Basis [Member] Cliff Vest [Member] Cliff Vest [Member] Cliff Vest [Member] First One Half Increment On Anniversary Of Award Date [Member] First One Half Increment On Anniversary Of Award Date [Member] First One-Half Increment On Anniversary Of The Award Date [Member] Second One Half Increment On Anniversary Of Award Date [Member] Second One Half Increment On Anniversary Of Award Date [Member] Second One-Half Increment On Anniversary Of The Award Date [Member] Stock Options [Member] Employee Stock Option [Member] Share-based Compensation, Shares Authorized under Stock Option Plans, by Exercise Price Range [Axis] Exercise Price Range [Axis] Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Domain] Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Domain] Range One [Member] Range One [Member] Range one [Member] Range Two [Member] Range Two [Member] Range two [Member] Range Three [Member] Range Three [Member] Range three [Member] Range Four [Member] Range Four [Member] Range four [Member] Range Five [Member] Range Five [Member] Range Five [Member] Stock option awards, term (in years) Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period Stock-based compensation, vesting period Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Stock-based compensation expense Allocated Share-based Compensation Expense Total intrinsic value of options exercised Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value Income tax benefit from the exercise of stock options Employee Service Share-based Compensation, Tax Benefit Realized from Exercise of Stock Options Unrecognized compensation expense Unrecognized compensation expense, weighted-average period of recognition (in years) Total fair value of shares of restricted stock that vested Weighted Average Remaining Contractual Life (Years) Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Remaining Contractual Term Operating Leases Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract] 2016 Operating Leases, Future Minimum Payments Due, Next Twelve Months 2017 Operating Leases, Future Minimum Payments, Due in Two Years 2018 Operating Leases, Future Minimum Payments, Due in Three Years 2019 Operating Leases, Future Minimum Payments, Due in Four Years 2020 Operating Leases, Future Minimum Payments, Due in Five Years Thereafter Operating Leases, Future Minimum Payments, Due Thereafter Total minimum lease payments Operating Leases, Future Minimum Payments Due Capital Leases Capital Leases, Future Minimum Payments, Net Minimum Payments, Fiscal Year Maturity [Abstract] 2016 Capital Leases, Future Minimum Payments Due, Next Twelve Months 2017 Capital Leases, Future Minimum Payments Due in Two Years 2018 Capital Leases, Future Minimum Payments Due in Three Years 2019 Capital Leases, Future Minimum Payments Due in Four Years 2020 Capital Leases, Future Minimum Payments Due in Five Years Thereafter Capital Leases, Future Minimum Payments Due Thereafter Total minimum lease payments Capital Leases, Future Minimum Payments Due Less: Imputed interest costs Capital Leases, Future Minimum Payments, Interest Included in Payments Present value of net minimum lease payments Capital Leases, Future Minimum Payments, Present Value of Net Minimum Payments Schedule Of Property, Plant And Equipment Property, Plant and Equipment [Table Text Block] Schedule of Goodwill [Table] Schedule of Goodwill [Table] Goodwill [Line Items] Goodwill [Line Items] Goodwill Goodwill, Other Changes Goodwill, Other Changes Goodwill, Acquired During Period Goodwill, Acquired During Period Guarantor Disclosures Guarantor Disclosures [Text Block] This element represents the Entity's financial schedules for guarantor and non guarantor subsidiary information. Accumulated Other Comprehensive Income (Loss) [Table] Accumulated Other Comprehensive Income (Loss) [Table] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Accumulated Defined Benefit Plans Adjustment, Net Prior Service Attributable to Parent [Member] Accumulated Defined Benefit Plans Adjustment, Net Prior Service Attributable to Parent [Member] Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Attributable to Parent [Member] Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Attributable to Parent [Member] Accumulated Defined Benefit Plan Adjustment, Settlement Benefits Attributable to Parent [Member] Accumulated Defined Benefit Plan Adjustment, Settlement Benefits Attributable to Parent [Member] Accumulated Defined Benefit Plan Adjustment, Settlement Benefits Attributable to Parent [Member] Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] Accumulated Net Investment Gain (Loss) Including Portion Attributable to Noncontrolling Interest [Member] Accumulated Net Investment Gain (Loss) Including Portion Attributable to Noncontrolling Interest [Member] Reclassification out of Accumulated Other Comprehensive Income [Axis] Reclassification out of Accumulated Other Comprehensive Income [Axis] Reclassification out of Accumulated Other Comprehensive Income [Domain] Reclassification out of Accumulated Other Comprehensive Income [Domain] Reclassification out of Accumulated Other Comprehensive Income [Member] Reclassification out of Accumulated Other Comprehensive Income [Member] Accumulated Other Comprehensive Income (Loss) [Line Items] Accumulated Other Comprehensive Income (Loss) [Line Items] Amortization of pension and other post-retirement items Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax Provision for income taxes, defined benefit plan Reclassification from AOCI, Current Period, Tax Provision for income taxes, investments Income (Loss) from Continuing Operations, including portion attributable to noncontrolling interest Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest Total reclassifications for the period Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax Derivative Instruments and Hedges, Assets [Abstract] Derivative Commodity Instruments Derivative Instruments and Hedging Activities Disclosure [Text Block] Valuation and Qualifying Accounts Disclosure [Table] Valuation and Qualifying Accounts Disclosure [Table] Valuation Allowances and Reserves Type [Axis] Valuation Allowances and Reserves Type [Axis] Valuation Allowances and Reserves [Domain] Valuation Allowances and Reserves [Domain] Allowance for Doubtful Accounts [Member] Allowance for Doubtful Accounts [Member] Valuation and Qualifying Accounts Disclosure [Line Items] Valuation and Qualifying Accounts Disclosure [Line Items] Valuation Allowances and Reserves, Balance Valuation Allowances and Reserves, Balance Valuation Allowances and Reserves, Charged to Cost and Expense Valuation Allowances and Reserves, Charged to Cost and Expense Valuation Allowances and Reserves, Adjustments Valuation Allowances and Reserves, Adjustments Statement [Table] Statement [Table] Range of Prices, Lower Limit Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Lower Range Limit Range of Prices, Upper Limit Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Upper Range Limit Options Outstanding Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Outstanding Options Fixed income securities Plan Name [Axis] Plan Name [Axis] Plan Name [Domain] Plan Name [Domain] Wage Pension Plan [Member] Wage Pension Plan [Member] Wage Pension Plan [Member] Salaried Pension Plan [Member] Salaried Pension Plan [Member] Salaried Pension Plan [Member] Funded status of pension plans Defined Benefit Plan, Funded Status, Percentage Defined Benefit Plan, Funded Status, Percentage Estimated prior service cost to be amortized from other comprehensive income into net periodic benefit cost during 2012 Defined Benefit Plan, Future Amortization of Prior Service Cost (Credit) Estimated net loss to be amortized from other comprehensive income into net periodic benefit cost during 2012 Defined Benefit Plan, Future Amortization of Gain (Loss) Percentage of investments for long-term growth included in investment strategy Defined Benefit Plan, Target Allocation Percentage of Assets, Long-Term Defined Benefit Plan, Target Allocation Percentage of Assets, Long-Term Percentage of investments for short-term growth included in investment strategy Defined Benefit Plan, Target Allocation Percentage of Assets, Short-Term Defined Benefit Plan, Target Allocation Percentage of Assets, Short-Term Discretionary range for pension fund trustee included in investment policy Defined Benefit Plan, Target Allocation Percentage of Assets, Discretionary Range Defined Benefit Plan, Target Allocation Percentage of Assets, Discretionary Range Fixed income, target allocation percentage Defined Benefit Plan, Target Plan Asset Allocations Expected contributions Defined Benefit Plans, Estimated Future Employer Contributions in Next Fiscal Year Number of subsidiaries company provides post-retirement healthcare benefits to Number Of Subsidiaries Company Provides Post Retirement Healthcare Benefit Number of subsidiaries, whose employees meet certain minimum age and service requirements, that are provided post-retirement healthcare benefits by the Company. Schedule Of Other Income, Net Schedule Of Other Nonoperating Income Expense By Component [Text Block] Tabular disclosure of the detailed components of other nonoperating income and expenses. Schedule of Cash Flow Information Schedule of Cash Flow, Supplemental Disclosures [Table Text Block] Capital expenditures Redeemed Prior To November 1, 2020 [Member] Debt Instrument, Redemption, Period One [Member] Redeemed On Or After November 1, 2020 [Member] Debt Instrument, Redemption, Period Two [Member] Minimum Debt Amount Guaranteed By Subsidiaries Derivative Instruments and Hedges, Offsetting of Derivative Assets [Abstract] Derivative Instruments and Hedges, Offsetting of Derivative Assets [Abstract] Offsetting of Derivative Assets [Table] Offsetting Assets [Table] Offsetting Assets [Line Items] Offsetting Assets [Line Items] Derivative assets subject to enforceable master netting arrangements Derivative Asset, Fair Value, Amount Not Offset Against Collateral Derivative assets not subject to enforceable master netting arrangements Derivative Asset, Not Subject to Master Netting Arrangement Total asset derivatives Gross amounts of recognized assets Derivative Asset, Fair Value, Gross Asset Gross amounts offset in the consolidated balance sheet Derivative Asset, Fair Value, Gross Liability Gross amounts not offset in the consolidated balance sheet Derivative, Collateral, Obligation to Return Cash Derivative Asset, net amount offset against collateral Derivative Asset, Fair Value, Amount Offset Against Collateral Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets, Major Class Name [Domain] Finite-Lived Intangible Assets, Major Class Name [Domain] Licenses and intellectual property [Member] Licensing Agreements [Member] Trademarks [Member] Trademarks [Member] Customer relationships [Member] Customer Relationships [Member] Other [Member] Other Intangible Assets [Member] Other Assets, Noncurrent [Axis] Other Assets, Noncurrent [Axis] Other Assets, Noncurrent [Axis] Other Assets, Noncurrent, By Type [Domain] Other Assets Noncurrent By Type [Domain] Other Assets, Noncurrent, By Type [Domain] Turnaround Costs [Member] Deferred Turnaround Costs [Member] Deferred Turnaround Costs [Member] Debt Issuance Costs [Member] Debt Issuance Cost [Member] Debt Issuance Cost [Member] Other, Net [Member] Other Amortizable Assets [Member] Other Amortizable Assets [Member] Goodwill and Intangible Assets Disclosure [Abstract] Goodwill and Intangible Assets Disclosure [Abstract] Intangible assets, Cost Finite-Lived Intangible Assets, Gross Intangible assets, Accumulated Amortization Finite-Lived Intangible Assets, Accumulated Amortization Intangible assets, Net Finite-Lived Intangible Assets, Net Goodwill, Cost Goodwill, Gross Goodwill, Net Total intangible assets Intangible Assets, Gross (Including Goodwill) Intangible Assets, Gross (Including Goodwill) Intangible assets, Accumulated Amortization Intangible Assets, Accumulated Amortization Intangible Assets, Accumulated Amortization Available-for-sale investments Available-for-sale Securities, Noncurrent Cost-method investments Cost Method Investments Turnaround costs Turnaround Costs, Gross Turnaround Costs, Gross Turnaround costs, Accumulated Amortization Accumulated Amortization, Turnaround Costs Accumulated Amortization, Turnaround Costs Turnaround costs, Net Turnaround Costs, Net Turnaround Costs, Net Debt issuance costs, Cost Deferred Finance Costs, Noncurrent, Gross Debt issuance costs, Accumulated Amortization Accumulated Amortization of Noncurrent Deferred Finance Costs Debt issuance costs, Net Deferred Finance Costs, Noncurrent, Net Other, Costs Noncurrent Assets, Other, Gross Noncurrent Assets, Other, Gross Other, Accumulated Amortization Accumulated Amortization, Noncurrent Assets, Other Accumulated Amortization, Noncurrent Assets, Other Other, Net Noncurrent Assets, Other, Net Noncurrent Assets, Other, Net Other assets, Cost Other Assets, Noncurrent, Gross Represents the gross amount (cost) of a specified group of non-current assets. Other assets, Accumulated Amortization Other Assets, Noncurrent, Accumulated Amortization Represents the accumulated amortization of a specified group of non-current assets. Other assets, net Total deferred charges and other assets, Cost Total Deferred Charges and Other Assets, Noncurrent, Gross Total Deferred Charges and Other Assets, Noncurrent, Gross Total deferred charges and other assets, Accumulated Amortization Accumulated Amortization, Total Deferred Charges and Other Assets, NonCurrent Accumulated Amortization, Total Deferred Charges and Other Assets, NonCurrent Total deferred charges and other assets, Net Total Deferred Charges and Other Assets, NonCurrent, Net Total Deferred Charges and Other Assets, NonCurrent, Net Weighted Average Life Finite-Lived Intangible Asset, Useful Life Reconciliation of Assets from Segment to Consolidated [Table] Reconciliation of Assets from Segment to Consolidated [Table] Total assets Net loss (gain) Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Net Gains (Losses), before Tax Foreign exchange effects Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Before Tax Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Before Tax Total before tax Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax Accumulated other comprehensive income, benefits, net of tax Accumulated Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net of Tax Business Acquisition, Pro Forma Information Business Acquisition, Pro Forma Information [Table Text Block] Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block] Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block] Cash Reserve Turnaround [Member] Cash Reserve Turnaround [Member] Cash Reserve Turnaround [Member] Preformation Capital Expenditure [Member] Preformation Capital Expenditure [Member] Preformation Capital Expenditure [Member] Intercompany Debt [Member] Intercompany Debt [Member] Intercompany Debt [Member] Over-Allotment Option [Member] Over-Allotment Option [Member] Price per unit Sale of Unit, Price Per Unit Per unit amount received by subsidiary or equity investee for each unit issued or sold in the unit transaction. Approximate proceeds from sale of units Estimated offering expenses from sale of partnership units Payments of Unit Issuance Costs The cash outflow for cost incurred directly with the issuance of an equity security. Percentage sold to public in IPO Other Ownership Interests, Percentage of Ownership After Transaction Other Ownership Interests, Percentage of Ownership After Transaction Amount used from proceeds Subsidiary Initial Public Offering, Use Of Proceeds Subsidiary Initial Public Offering, Use Of Proceeds Total proceeds from the initial public offering Gross Proceeds From Issuance Of Common Limited Partners Units Gross Proceeds From Issuance Of Common Limited Partners Units Net proceeds distributed to the Company from the initial public offering Net Proceeds Distributed To Parent Company From Initial Public Offering Net Proceeds Distributed To Parent Company From Initial Public Offering Schedule Of Other Assets Schedule of Other Assets, Noncurrent [Table Text Block] Schedule of Goodwill Schedule of Goodwill [Table Text Block] Current liabilities Pension and Other Postretirement Defined Benefit Plans, Current Liabilities Noncurrent liabilities Pension and Other Postretirement Defined Benefit Plans, Liabilities, Noncurrent Net amount recognized Pension and Other Postretirement Defined Benefit Plans, Liabilities Loss Contingencies [Table] Loss Contingencies [Table] PolyOne [Member] PolyOne Corporation [Member] PolyOne Corporation [Member] Litigation Status [Axis] Litigation Status [Axis] Litigation Status [Domain] Litigation Status [Domain] Pending Litigation [Member] Pending Litigation [Member] Threatened Litigation [Member] Settled Litigation [Member] Loss Contingencies [Line Items] Loss Contingencies [Line Items] Percentage of costs related to environmental issues to be paid by PolyOne Environmental Costs Percentage Net Of Recoveries From Third Parties Represents environmental costs percentage, net of recoveries or credits from third parties, to be paid by a counterparty. Minimum Time Between Arbitrations Loss Contingency, Arbitration Interval Period Represents the minimum number of years that must pass before another arbitration proceeding may be held to adjust the environmental costs percentage paid by a counterparty. Costs incurred environmental remediation services Environmental Remediation Expense Approximate value of damages sought Loss Contingency, Damages Sought, Value Loss Contingency, Claims Settled, Number Loss Contingency, Claims Settled, Number Operating lease rental expense Operating Leases, Rent Expense, Net Amount of settlement Litigation Settlement, Amount Schedule Of Estimated Useful Lives Of Assets Schedule Of Estimated Useful Lives Of Assets [Table Text Block] Table of estimated useful lives of long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale. Schedule of Cash Equivalents [Table] Schedule of Cash and Cash Equivalents [Table] Investments by Category [Axis] Investments by Category [Axis] Major Types of Debt Securities [Domain] Marketable Securities and Investments Held at Cost [Domain] Held-to-maturity Securities [Member] Held-to-maturity Securities [Member] Cash Equivalents [Line Items] Cash and Cash Equivalents [Line Items] Cash equivalents Cash Equivalents, at Carrying Value Schedule Of Option Activity And Changes Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding and Exercisable [Table Text Block] Schedule Of Range Of Exercise Prices For Outstanding Options Schedule of Share-based Compensation, Shares Authorized under Stock Option Plans, by Exercise Price Range [Table Text Block] Schedule Of Weighted Average Value And Assumptions For Fair Value Of Options Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block] Schedule Of Non-Vested Restricted Stock Award Activity And Changes Schedule of Nonvested Share Activity [Table Text Block] Trademarks and Trade Names [Member] Trademarks and Trade Names [Member] Developed Technology Rights [Member] Developed Technology Rights [Member] Cash paid to Sellers Cash deposited in escrow Business Combination, Cash Deposited In Escrow Business Combination, Cash Deposited In Escrow Retirement of long-term debt as of July 31, 2014, on behalf of the Sellers Business Combination, Retirement Of Debt Not Assumed In Acquisition Business Combination, Retirement Of Debt Not Assumed In Acquisition Total purchase consideration Business Combination, Consideration Transferred Cash Working capital, excluding inventory and cash Inventories Property, plant and equipment Investments Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Assets, Investments Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Assets, Investments Other assets Intangible assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles Deferred income tax asset - current Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Assets, Current Deferred income tax asset - non-current Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Assets Noncurrent Pension obligation Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Pension Obligation Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Pension Obligation Other long-term liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Other Power purchase agreement liability Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Power Purchase Agreement Liability Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Power Purchase Agreement Liability Deferred income tax liability - current Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Liabilities, Current Deferred income tax liability - non-current Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Liabilities Noncurrent Total identifiable net assets Consideration transferred Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net Fair value of accounts receivable Gross contractual amount of accounts receivable Uncollectable accounts receivable Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Uncollectable Receivables Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Uncollectable Receivables Adjustment to inventory fair value Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Inventory Adjustment Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Inventory Adjustment Weighted-average life of forward purchase contracts Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Power Purchase Agreement Liability, Weighted Average Life Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Power Purchase Agreement Liability, Weighted Average Life Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Reclassification out of Accumulated Other Comprehensive Income [Table Text Block] Reclassification out of Accumulated Other Comprehensive Income [Table Text Block] Statement of Stockholders' Equity [Abstract] Common Stock [Member] Common Stock [Member] Common Stock, Held In Treasury, At Cost [Member] Treasury Stock [Member] Additional Paid-In Capital [Member] Additional Paid-in Capital [Member] Retained Earnings [Member] Retained Earnings [Member] Benefits Liability Net Of Tax [Member] Benefits Liability Net Of Tax [Member] Benefits Liability Net Of Tax [Member] Cumulative Foreign Currency Exchange [Member] Cumulative Foreign Currency Exchange [Member] Cumulative Foreign Currency Exchange [Member] Net Unrealized Holding Gains On Investments, Net Of Tax [Member] Unrealized Holding Losses On Investments Net Of Tax [Member] Unrealized holding losses on investments, net of tax [Member] Noncontrolling Interest [Member] Noncontrolling Interest [Member] Statement [Line Items] Statement [Line Items] Number of shares, beginning balance Shares, Issued Total equity, beginning balance Other comprehensive (loss) income Other Comprehensive Income (Loss), Net of Tax Common stock repurchased, shares Treasury Stock, Shares, Acquired Common stock repurchased Treasury Stock, Value, Acquired, Cost Method Shares issued - stock based compensation, shares Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures Shares issued - stock based compensation Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures Stock-based compensation, net of tax on stock options exercised Adjustments To Additional Paid In Capital Share Based Compensation Requisite Service Period Recognition This element represents the amount of recognized equity-based compensation related to stock options and nonvested shares during the period, that is, the amount recognized as expense in the income statement (or as asset if compensation is capitalized). Dividends paid Dividends, Common Stock, Cash Distributions to noncontrolling interests Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders Issuance of Westlake Chemical Partners LP common units Noncontrolling Interest, Increase from Subsidiary Equity Issuance Number of shares, ending balance Total equity, ending balance Marketable Securities Marketable Securities [Table Text Block] Available-for-sale Securities Available-for-sale Securities [Table Text Block] Schedule of Realized Gain (Loss) Schedule of Realized Gain (Loss) [Table Text Block] Derivative Instruments, Gain (Loss) by Hedging Relationship, by Income Statement Location, by Derivative Instrument Risk [Table] Derivative Instruments, Gain (Loss) [Table] Derivative Instruments, Gain (Loss) by Hedging Relationship [Axis] Hedging Relationship [Axis] Hedging Relationship [Domain] Hedging Relationship [Domain] Firm Commitment Hedged Items [Member] Firm Commitment Derivative Items Designated As Hedges [Member] Firm commitment derivative items designated as hedges [member] Hedging Designation [Axis] Hedging Designation [Axis] Hedging Designation [Domain] Hedging Designation [Domain] Designated As Fair Value Hedges [Member] Designated as Hedging Instrument [Member] Derivative Instruments, Gain (Loss) by Income Statement Location [Axis] Income Statement Location [Axis] Income Statement and Other Comprehensive Income (Loss) Location [Domain] Income Statement Location [Domain] Cost of Sales [Member] Cost of Sales [Member] Derivative Instruments, Gain (Loss) [Line Items] Derivative Instruments, Gain (Loss) [Line Items] Gain (Loss) Recognized in Income on Derivative Derivative, Gain (Loss) on Derivative, Net Summary Of Quarterly Financial Information Schedule of Quarterly Financial Information [Table Text Block] Income Taxes Income Tax Disclosure [Text Block] Accrued Liabilities Accrued Liabilities [Abstract] Accrued rebates Accrued Rebates, Current Accrued Rebates, Current Accrued incentive compensation Accrued Incentive Compensation, Current Accrued Incentive Compensation, Current Other Liabilities [Abstract] Other Liabilities [Abstract] Non-current pension obligation Other Income, Net Other Income and Expenses [Abstract] Interest income Investment Income, Interest Dividend income Investment Income, Dividend Foreign exchange currency gains (losses), net Foreign Currency Transaction Gain (Loss), before Tax Income from equity method investees Income (Loss) from Equity Method Investments Impairment of equity method investment Gain on acquisition and related expenses, net BusinessCombinationBargainPurchaseGainNetOfRelatedExpenses Bargain purchase gain, net of related expenses. Gain (losses) from sales of securities, net Other Other Nonoperating Income (Expense) Other income (expense), net Cash Flow Information Supplemental Cash Flow Information [Abstract] Interest paid, net of interest capitalized Interest Paid, Net Income taxes paid Income Taxes Paid, Net Fair value of assets acquired Fair Value of Assets Acquired Fair value of investment before business combination, net of preexisting balances Fair Value Of Investment Before Business Combination, Net Of Preexisting Balances Fair value of investment before business combination, net of preexisting balances acquired in noncash investing or financing activities. Noncontrolling Interest Acquired Noncontrolling Interest Acquired Noncontrolling interest acquired, noncash investing activities Cash paid Fair Value Of Consideration Transferred Fair value of consideration transferred in noncash investing or financing activities. Liabilities assumed Liabilities Assumed Fair Values Of Derivative Instruments In Consolidated Balance Sheets Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block] Impact Of Derivative Instruments Designated As Fair Value Hedges Schedule of Derivatives Instruments Statements of Financial Performance and Financial Position, Location [Table Text Block] Impact Of Derivative Instruments Not Designated As Fair Value Hedges Schedule of Other Derivatives Not Designated as Hedging Instruments, Statements of Financial Performance and Financial Position, Location [Table Text Block] Offsetting of Derivative Assets Offsetting Assets [Table Text Block] Offsetting of Derivative Liabilities Offsetting Liabilities [Table Text Block] Westlake Chemical Partners LP Partners' Capital Notes Disclosure [Text Block] Derivative [Table] Derivative [Table] Derivatives Not Designated As Hedging Instrument [Member] Not Designated as Hedging Instrument [Member] Derivatives, Fair Value, by Balance Sheet Location [Axis] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Accounts Receivable, Net [Member] Accounts Receivable [Member] Other Assets [Member] Other Assets [Member] Accrued Liabilities [Member] Accrued Liabilities [Member] Other Liabilities [Member] Other Liabilities [Member] Derivative [Line Items] Derivative [Line Items] Total asset derivatives Derivative Asset, Fair Value, Gross Asset Including Not Subject to Master Netting Arrangement Total liability derivatives Derivative Liability, Fair Value, Gross Liability Including Not Subject to Master Netting Arrangement Emergency Economic Stabilization Act Of 2008 [Member] Emergency Economic Stabilization Act Of Two Thousand Eight [Member] Emergency Economic Stabilization Act Of Two Thousand Eight [Member] Schedule of Stock by Class [Table] Schedule of Stock by Class [Table] Share Repurchase Program [Axis] Share Repurchase Program [Axis] Share Repurchase Program [Domain] Share Repurchase Program [Domain] 2011 Program [Member] 2011 Program [Member] 2011 Program [Member] 2014 Program [Member] 2014 Program [Member] 2014 Program [Member] Dividends [Axis] Dividends [Axis] Dividends [Domain] Dividends [Domain] Ordinary Dividend [Member] Ordinary Dividend [Member] Ordinary Dividend [Member] Class of Stock [Line Items] Class of Stock [Line Items] Aggregated regular quarterly dividends on common stock Description of common stock voting rights Common Stock, Voting Rights Description of common stock subscription rights Common Stock Other Rights Description of other rights of common stock, including preemptive, conversion and other subscription rights. Common stock, redemption provision Common Stock, Redemption Provision Common Stock, Redemption Provision Stock split conversion ratio Stockholders' Equity Note, Stock Split, Conversion Ratio Stock repurchase program, authorized amount Stock Repurchase Program, Authorized Amount Stock repurchase 2011 program, shares repurchased Stock Repurchase Program, Shares Repurchased, Gross Stock Repurchase Program, Shares Repurchased, Gross Aggregate purchase price of common stock repurchased Treasury Stock, Value, Cost Method Equity impact of the cost of common stock that were repurchased by the entity. Recorded using the cost method. Stock repurchase 2014 program, shares repurchase Common stock, sinking fund Common Stock Sinking Fund Provision Sinking fund provision for common stock. Common stock, voting rights Common Stock, Voting Rights, Number of Votes Per Share Common Stock, Voting Rights, Number of Votes Per Share Benefits Liability, Net of Tax Cumulative Foreign Currency Exchange Accumulated Foreign Currency Adjustment Attributable to Parent [Member] Net Unrealized Holding Gains on Investments, Net of Tax Accumulated Net Investment Gain (Loss) Attributable to Parent [Member] AOCI Attributable to Parent [Member] AOCI Attributable to Parent [Member] Accumulated other comprehensive income, balance Other comprehensive income (loss) before reclassifications Other Comprehensive Income (Loss), before Reclassifications, Net of Tax Amounts reclassified from accumulated other comprehensive loss Net other comprehensive income (loss) for the year Number of derivative instruments designated as fair value hedges Derivative, Number of Instruments Held Long-Term Debt Long-term Debt [Text Block] Supplemental Information Other Income and Other Expense Disclosure [Text Block] Property, Plant and Equipment by Type [Axis] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Domain] Property, Plant and Equipment, Type [Domain] Buildings And Improvements [Member] Building and Building Improvements [Member] Plant And Equipment [Member] Plant And Equipment [Member] Plant And Equipment [Member] Ethylene Pipeline [Member] Ethylene Pipeline [Member] Ethylene Pipeline [Member] Other [Member] Other Capitalized Property Plant and Equipment [Member] Property, plant and equipment, useful life, minimum (in years) Property, Plant and Equipment, Useful Life Variable Rate [Axis] Variable Rate [Axis] Variable Rate [Domain] Variable Rate [Domain] LIBOR [Member] London Interbank Offered Rate (LIBOR) [Member] Base Rate [Member] Base Rate [Member] Maximum borrowing capacity Line of Credit Facility, Maximum Borrowing Capacity Increase in credit facility borrowings Line Of Credit Facility Permitted Increase The permitted amount the line of credit facility may be increased by, under certain circumstances if certain lenders agree to commit to such an increase. Amounts drawn under the facility limited to accounts receivable, percentage Line Of Credit Facility Limited To Accounts Receivable Percentage Represents a percentage, that when multiplied by the net amount of eligible accounts receivable, becomes a factor used in the calculation to determine the borrowing capacity of the revolving credit facility. Amounts drawn under the facility limited to eligible inventory, percentage Line Of Credit Facility Limited To Lesser Of Eligible Inventory Percentage Represents a percentage, that when multiplied by the value of the lower of cost or market of eligible inventory, becomes a factor used in the calculation to determine the borrowing capacity of the revolving credit facility. Amounts drawn under the facility limited to lesser of eligible inventory orderly liquidation, percentage Line Of Credit Facility Limited To Lesser Of Eligible Inventory Orderly Liquidation Value Percentage Represents a percentage, that when multiplied by the appraised net orderly liquidation value of eligible inventory, becomes a factor used in the calculation to determine the borrowing capacity of the revolving credit facility. Amounts drawn under the facility limited to cash held in an account with the agent Line Of Credit Facility Limited To Cash Held In Account With Agent Percentage Represents a percentage, that when multiplied by the cash held in account with an agent and subject to a control agreement with that agent, becomes a factor used in the calculation to determine the borrowing capacity of the revolving credit facility. Sub-limit for letters of credit facility Letter Of Credit Facility SubLimit Letter of credit sub-limit under the revolving credit facility. Long-term Line of Credit Long-term Line of Credit Percentage added to basis to find interest rate Debt Instrument, Basis Spread on Variable Rate Debt Instrument, Basis Spread on Variable Rate, Maximum, Provided Company Rated Investment Grade Debt Instrument, Basis Spread on Variable Rate, Maximum, Provided Company Rated Investment Grade Debt Instrument, Basis Spread on Variable Rate, Maximum, Provided Company Rated Investment Grade Percentage of commitment on borrowing availability Line of Credit Facility, Unused Capacity, Commitment Fee Percentage Letters of credit outstanding Letters of Credit Outstanding, Amount Remaining borrowing capacity Line of Credit Facility, Remaining Borrowing Capacity Borrowing availability compliance requirements for credit facility Line of Credit Facility, Covenant Terms, Distributions Restrictions, Borrowing Availability Threshold, Percent Of Commitments, Scenario One Line of Credit Facility, Covenant Terms, Distributions Restrictions, Borrowing Availability Threshold, Percent Of Commitments, Scenario One Borrowing availability compliance requirements for credit facility Line of Credit Facility, Covenant Terms, Distributions Restrictions, Borrowing Availability Threshold, Scenario One Line of Credit Facility, Covenant Terms, Distributions Restrictions, Borrowing Availability Threshold, Scenario One Covenant terms, specified distributions permissible Line of Credit Facility, Covenant Terms, Specified Distributions Permissible Line of Credit Facility, Covenant Terms, Specified Distributions Permissible Covenant Terms, specified distributions permissible, annual increase, percentage Line of Credit Facility, Covenant Terms, Specified Distributions Permissible, Annual Increase, Percentage Line of Credit Facility, Covenant Terms, Specified Distributions Permissible, Annual Increase, Percentage Current Available-for-sale Securities, Current Non-current Total Available-for-sale Securities