Document and Entity Information	3 Months Ended
Apr. 30, 2011	May 31, 2011
Document And Entity Information
Entity registrant name	PIEDMONT NATURAL GAS CO INC
Entity central index key	0000078460
Document type	10-Q
Document period end date	Apr. 30, 2011
Amendment flag	false
Document fiscal year focus	2011
Document Fiscal Period Focus	Q2
Current fiscal year end date	--10-31
Entity filer category	Large Accelerated Filer
Entity common stock shares outstanding		71,977,343

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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