The number of issuer's shares to which the forward contract is indexed.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 40
-Section 50
-Paragraph 5
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=6445032&loc=d3e90205-114008

+ Details

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Namespace Prefix:	us-gaap_
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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The cash inflow from the issuance of common stock, preferred stock, treasury stock, stock options, and other types of equity.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Financing Activities
-URI http://asc.fasb.org/extlink&oid=6513228

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3255-108585

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

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Namespace Prefix:
Data Type:	na
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- Details

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Common Stock Common Stock (Equity Securities Offering) (Details) - Piedmont Natural Gas [Member] - USD ($) shares in Millions, $ in Millions	Oct. 05, 2016	Sep. 30, 2016
Forward Contract Indexed to Issuer's Equity [Line Items]
Shares offered		10.6
Subsequent Event [Member]
Forward Contract Indexed to Issuer's Equity [Line Items]
Proceeds from Issuance or Sale of Equity	$ 723