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Description of Business and Significant Accounting Policies (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2022 USD ($) plant	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Oct. 31, 2022
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Capitalized interest	$ 4	$ 3	$ 4
Asset Retirement Obligation, Current	0	1
Asset Retirement Obligations, Noncurrent	$ 31	$ 23
Minimum
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Deferred Cost, Amortization Period	3 years
Maximum
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Deferred Cost, Amortization Period	6 years
RS Cogen
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Ownership interest acquired				50.00%
Westlake Chemical OpCo LP \| Limited Partner \| IPO \| Subsidiary of Common Parent
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Limited partner interest (percent)	77.20%
Westlake Chemical OpCo LP \| Subsidiaries [Member] \| Louisiana
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Number of production facilities \| plant	2
Westlake Chemical OpCo LP \| Subsidiaries [Member] \| Kentucky
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Number of production facilities \| plant	1