Acquisitions and Divestitures Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustments (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
Dec. 31, 2013
Business Combinations, Provisional Information [Abstract]
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Property, Plant, and Equipment	$ 14
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Financial Assets	46
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Financial Liabilities	$ 32

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Namespace Prefix:	pva_
Data Type:	xbrli:stringItemType
Balance Type:	na
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This element represents the amount of any measurement period adjustment (as defined) realized during the reporting period to financial assets acquired in connection with a business combination for which the initial accounting was incomplete.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 10

-Section 50

-Paragraph 6

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=25497992&loc=d3e1500-128463

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

This element represents the amount of any measurement period adjustment (as defined) realized during the reporting period to financial liabilities assumed in connection with a business combination for which the initial accounting was incomplete.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

This element represents the amount of any measurement period adjustment (as defined) realized during the reporting period to property, plant, and equipment acquired in connection with a business combination for which the initial accounting was incomplete.

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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