v3.26.3
Cover Page - shares
 9 Months Ended
Sep. 30, 2026
Oct. 28, 2026
Document Information [Line Items]    
Document Type 10-Q  
Document Quarterly Report true  
Document Period End Date Sep. 30, 2026  
Document Transition Report false  
Entity File Number 001-32260  
Entity Registrant Name Westlake Corporation  
Entity Incorporation, State or Country Code DE  
Entity Tax Identification Number 76-0346924  
Entity Address, Address Line One 5444 Westheimer  
Entity Address, Address Line Two Suite 101  
Entity Address, City or Town Houston  
Entity Address, State or Province TX  
Entity Address, Postal Zip Code 77056  
City Area Code 713  
Local Phone Number 960-9111  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Filer Category Large Accelerated Filer  
Entity Small Business false  
Entity Emerging Growth Company false  
Entity Shell Company false  
Entity Common Stock, Shares Outstanding   127,886,945
Amendment Flag false  
Document Fiscal Year Focus 2026  
Document Fiscal Period Focus Q3  
Entity Central Index Key 0001262823  
Current Fiscal Year End Date --12-31  
Common Stock | NEW YORK STOCK EXCHANGE, INC.    
Document Information [Line Items]    
Title of 12(b) Security Common Stock, $0.01 par value  
Trading Symbol WLK  
Security Exchange Name NYSE  
Common Stock | NYSE TEXAS, INC.    
Document Information [Line Items]    
Title of 12(b) Security Common Stock, $0.01 par value  
Trading Symbol WLK  
Security Exchange Name NYSETX  
1.625% Senior Notes Due 2029    
Document Information [Line Items]    
Title of 12(b) Security 1.625% Senior Notes due 2029  
Trading Symbol WLK29  
Security Exchange Name NYSE