Cover Page - shares	9 Months Ended
	Sep. 30, 2022	Oct. 25, 2022
Document Information [Line Items]
Document Type	10-Q
Document Period End Date	Sep. 30, 2022
Entity Registrant Name	ONE Gas, Inc.
Entity Central Index Key	0001587732
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q3
Amendment Flag	false
Entity Information [Line Items]
Document Quarterly Report	true
Document Transition Report	false
Entity File Number	001-36108
Entity Incorporation, State or Country Code	OK
Entity Tax Identification Number	46-3561936
Entity Address, Address Line One	15 East Fifth Street
Entity Address, City or Town	Tulsa,
Entity Address, State or Province	OK
Entity Address, Postal Zip Code	74103
City Area Code	(918)
Local Phone Number	947-7000
Title of 12(b) Security	Common Stock, par value $0.01 per share
Trading Symbol	OGS
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		54,141,036