Document And Entity Information - USD ($)
12 Months Ended
Sep. 30, 2018
Oct. 31, 2018
Mar. 31, 2018
Document And Entity Information [Abstract]      
Entity Registrant Name ASHLAND GLOBAL HOLDINGS INC.    
Entity Central Index Key 0001674862    
Current Fiscal Year End Date --09-30    
Entity Well-known Seasoned Issuer Yes    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Filer Category Large Accelerated Filer    
Entity Small Business false    
Entity Emerging Growth Company false    
Entity Shell Company false    
Entity Public Float     $ 4,338,042,000
Entity Common Stock, Shares Outstanding   62,487,188  
Document Fiscal Year Focus 2018    
Document Fiscal Period Focus FY    
Trading Symbol ASH    
Document Type 10-K    
Amendment Flag false    
Document Period End Date Sep. 30, 2018