Document and Entity Information Document (USD $)
 12 Months Ended
Dec. 31, 2014
Mar. 01, 2015
Document Information [Line Items]    
Entity Registrant Name HEXION INC.  
Entity Central Index Key 0000013239  
Current Fiscal Year End Date --12-31  
Entity Filer Category Non-accelerated Filer  
Document Type 10-K  
Document Period End Date Dec. 31, 2014  
Document Fiscal Year Focus 2014  
Document Fiscal Period Focus Q4  
Amendment Flag false  
Entity Common Stock, Shares Outstanding   82,556,847
Entity Well-known Seasoned Issuer No  
Entity Voluntary Filers No  
Entity Current Reporting Status Yes  
Entity Public Float $ 0