v3.26.1
Cover Page - shares
6 Months Ended
Jun. 30, 2026
Jul. 24, 2026
Cover [Abstract]    
Document Type 10-Q  
Document Quarterly Report true  
Document Period End Date Jun. 30, 2026  
Document Transition Report false  
Entity File Number 1-1463  
Entity Registrant Name Union Carbide Corporation  
Entity Incorporation, State or Country Code NY  
Entity Tax Identification Number 13-1421730  
Entity Address, Address Line One 7501 STATE HIGHWAY 185 NORTH  
Entity Address, City or Town SEADRIFT  
Entity Address, State or Province TX  
Entity Address, Postal Zip Code 77983  
City Area Code 361  
Local Phone Number 553-2769  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Filer Category Non-accelerated Filer  
Entity Small Business false  
Entity Emerging Growth Company false  
Entity Shell Company false  
Entity Common Stock, Shares Outstanding   935.51
Entity Central Index Key 0000100790  
Current Fiscal Year End Date --12-31  
Document Fiscal Year Focus 2026  
Document Fiscal Period Focus Q2  
Amendment Flag false  
Title of 12(b) Security None  
Document Information [Line Items]    
Entity Central Index Key 0000100790  
Amendment Flag false