Document And Entity Information	6 Months Ended
	Mar. 30, 2012	Apr. 23, 2012
Entity Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 30, 2012
Document Fiscal Year Focus	2012
Document Fiscal Period Focus	Q2
Trading Symbol	jec
Entity Registrant Name	JACOBS ENGINEERING GROUP INC /DE/
Entity Central Index Key	0000052988
Current Fiscal Year End Date	--09-28
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		129,027,558