Document And Entity Information	6 Months Ended
	Mar. 31, 2013	Apr. 30, 2013
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2013
Document Fiscal Year Focus	2013
Document Fiscal Period Focus	Q2
Entity Registrant Name	NATIONAL FUEL GAS CO
Entity Central Index Key	0000070145
Current Fiscal Year End Date	--09-30
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		83,550,403
Trading Symbol	nfg