XML 12 R1.htm IDEA: XBRL DOCUMENT v3.23.2
Document and Entity Information - shares
 9 Months Ended
Jun. 30, 2023
Aug. 04, 2023
Document and Entity Information    
Document Type 10-Q  
Document Period End Date Jun. 30, 2023  
Document Quarterly Report true  
Document Transition Report false  
Entity File Number 000-52423  
Entity Registrant Name AECOM  
Entity Incorporation, State or Country Code DE  
Entity Tax Identification Number 61-1088522  
Entity Address, Address Line One 13355 Noel Road  
Entity Address, City or Town Dallas  
Entity Address, State or Province TX  
Entity Address, Postal Zip Code 75240  
City Area Code 972  
Local Phone Number 788-1000  
Title of 12(b) Security Common Stock, $0.01 par value  
Trading Symbol ACM  
Security Exchange Name NYSE  
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   138,726,792
Entity Central Index Key 0000868857  
Current Fiscal Year End Date --09-30  
Document Fiscal Year Focus 2023  
Document Fiscal Period Focus Q3  
Amendment Flag false