Cover - USD ($)	12 Months Ended
	Sep. 30, 2023	Oct. 31, 2023	Mar. 31, 2023
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Current Fiscal Year End Date	--09-30
Document Period End Date	Sep. 30, 2023
Document Transition Report	false
Entity File Number	1-3880
Entity Registrant Name	National Fuel Gas Company
Entity Incorporation, State or Country Code	NJ
Entity Tax Identification Number	13-1086010
Entity Address, Address Line One	6363 Main Street
Entity Address, Postal Zip Code	14221
Entity Address, State or Province	NY
Entity Address, City or Town	Williamsville,
City Area Code	716
Local Phone Number	857-7000
Title of 12(b) Security	Common Stock, par value $1.00 per share
Trading Symbol	NFG
Security Exchange Name	NYSE
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
Document Financial Statement Error Correction [Flag]	false
Entity Shell Company	false
Entity Public Float			$ 5,187,493,000
Entity Listing, Par Value Per Share	$ 1.00
Entity Common Stock, Shares Outstanding		91,829,588
Documents Incorporated by Reference	Portions of the registrant’s definitive Proxy Statement for its 2024 Annual Meeting of Stockholders, to be filed with the Securities and Exchange Commission within 120 days of September 30, 2023, are incorporated by reference into Part III of this report.
Entity Central Index Key	0000070145
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	FY
Amendment Flag	false