Document And Entity Information	6 Months Ended
	Apr. 13, 2014	May 09, 2014
Document And Entity Information [Abstract]
Entity Registrant Name	JACK IN THE BOX INC /NEW/
Entity Central Index Key	0000807882
Current Fiscal Year End Date	--09-28
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	Apr. 13, 2014
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	Q2
Amendment Flag	false
Entity Common Stock, Shares Outstanding		40,037,523