XML 14 R1.htm IDEA: XBRL DOCUMENT v3.5.0.2
Document And Entity Information - shares
9 Months Ended
Jul. 01, 2016
Aug. 05, 2016
Document And Entity Information [Abstract]    
Entity Registrant Name JACOBS ENGINEERING GROUP INC /DE/  
Trading Symbol jec  
Entity Central Index Key 0000052988  
Current Fiscal Year End Date --09-30  
Entity Filer Category Large Accelerated Filer  
Document Type 10-Q  
Document Period End Date Jul. 01, 2016  
Document Fiscal Year Focus 2016  
Document Fiscal Period Focus Q3  
Amendment Flag false  
Entity Common Stock, Shares Outstanding   121,428,197