Merger Agreement (Details) (USD $) In Millions, except Share data	3 Months Ended	6 Months Ended
Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Business Combinations Abstract
Business Acquisition, Date Of Acquisition Agreement			January 8, 2011
Merger, Description			Pursuant to the Merger Agreement, Progress Energy will be acquired by Duke Energy in a stock-for-stock transaction (the Merger) and continue as a wholly owned subsidiary of Duke Energy.
Merger share exchange ratio	2.6125		2.6125
Merger Share Exchange Ratio, Adjusted	0.87083		0.87083
Merger and integration costs, net of tax	$ 7	$ 0	$ 21	$ 0
Employee Rentention Member
Loss Contingencies [Line Items]
Loss Contingency Estimate Of Possible Loss	$ 13		$ 13

This element represents acquisition-related and integration-related costs incurred to effect a business combination which costs have been expensed during the period. Acquisition-related costs include finder's fees; advisory, legal, accounting, valuation, and other professional or consulting fees; general administrative costs, including the costs of maintaining an internal acquisitions department; and may include costs of registering and issuing debt and equity securities. Integration-related costs could include business integration costs, systems integration and conversion costs, and severance and other employee-related costs.

Name:	pgn_BusinessCombinationAcquisitionAndIntegrationRelatedCosts
Namespace Prefix:	pgn
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	pgn_BusinessCombinationsAbstract
Namespace Prefix:	pgn
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Description of the planned business combination.

+ Details

Name:	pgn_Mergerdescription
Namespace Prefix:	pgn
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Discloses the number of shares of the acquirer's stock that each share of the acquiree's stock will be converted into in conjuction with a merger.

+ Details

Name:	pgn_MergerShareExchangeRatio
Namespace Prefix:	pgn
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Discloses the number of shares of the acquirer's stock that each share of the acquiree's stock will be converted into in conjuction with a merger after the acquiring company's planned reverse stock split.

+ Details

Name:	pgn_MergerShareExchangeRatioAdjusted
Namespace Prefix:	pgn
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Month, day and year when the business acquisition agreement was executed.

+ Details

Name:	us-gaap_BusinessAcquisitionDateOfAcquisitionAgreement
Namespace Prefix:	us-gaap
Data Type:	us-types:dateStringItemType
Balance Type:	na
Period Type:	duration

- 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.

+ Details

Name:	us-gaap_LossContingenciesLineItems
Namespace Prefix:	us-gaap
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Reflects the estimated amount of loss from the specified contingency as of the balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 5
-Paragraph 9, 10, 11, 12

+ Details

Name:	us-gaap_LossContingencyEstimateOfPossibleLoss
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant