v3.10.0.1
Document and Entity Information - shares
3 Months Ended
Dec. 31, 2018
Jan. 25, 2019
Document and Entity Information [Abstract]    
Entity Registrant Name AMERISOURCEBERGEN CORP  
Entity Central Index Key 0001140859  
Document Type 10-Q  
Document Period End Date Dec. 31, 2018  
Amendment Flag false  
Document Fiscal Year Focus 2019  
Document Fiscal Period Focus Q1  
Current Fiscal Year End Date --09-30  
Entity Current Reporting Status Yes  
Entity Filer Category Large Accelerated Filer  
Entity Small Business false  
Entity Emerging Growth Company false  
Entity Common Stock, Shares Outstanding   211,089,893
Trading Symbol abc