Document And Entity Information	3 Months Ended
	Jan. 31, 2012	Mar. 01, 2012
Document And Entity Information [Abstract]
Entity Registrant Name	PIEDMONT NATURAL GAS CO INC
Entity Central Index Key	0000078460
Document Type	10-Q
Document Period End Date	Jan. 31, 2012
Document Fiscal Period Focus	Q1
Document Fiscal Year Focus	2012
Amendment Flag	false
Current Fiscal Year End Date	--10-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock Shares Outstanding		71,685,958