Cover Page - USD ($) $ in Billions	12 Months Ended
	Oct. 03, 2021	Nov. 17, 2021	Apr. 09, 2021
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Oct. 03, 2021
Current Fiscal Year End Date	--10-03
Document Transition Report	false
Entity File Number	1-9390
Entity Registrant Name	JACK IN THE BOX INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	95-2698708
Entity Address, Address Line One	9357 Spectrum Center Blvd.
Entity Address, City or Town	San Diego
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	92123
City Area Code	858
Local Phone Number	571-2121
Title of 12(b) Security	Common Stock, $0.01 par value
Trading Symbol	JACK
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
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
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 2.5
Entity Common Stock, Shares Outstanding		21,013,361
Documents Incorporated by Reference	Portions of the Proxy Statement to be filed with the Securities and Exchange Commission in connection with the 2022 Annual Meeting of Stockholders are incorporated by reference into Part III hereof.
Entity Central Index Key	0000807882
Amendment Flag	false
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY