The amount added to the accrual for environmental loss contingencies. These additions include remediation expense and interest accretion.

Name:	pgn_AmountAccruedDuringPeriodForEnvironmentalLossContingencies
Namespace Prefix:	pgn
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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:	pgn_DisclosureEnvironmentalMattersDetailsLineItems
Namespace Prefix:	pgn
Data Type:	xbrli:stringItemType
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:	pgn_EmissionAllowancesInventoryLineItems
Namespace Prefix:	pgn
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Disclosure of carrying amount as of the balance sheet date of current and long term emission allowances inventories.

+ Details

Name:	pgn_EmissionAllowancesInventoryTotal
Namespace Prefix:	pgn
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

EPA's estimate of cost to remediate an individual site for which no accrual has been recorded because allocation among potentially responsible parties has not been determined.

+ Details

Name:	pgn_SiteContingencyLossExposureNotAccruedSite
Namespace Prefix:	pgn
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of reimbursement request from the EPA for EPA's past expenditures to address conditions at an individual site for which no accrual has been recorded because allocation among potentially responsible parties has not been determined.

+ Details

Name:	pgn_SiteContingencyLossExposureNotAccruedSiteReimbursement
Namespace Prefix:	pgn
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Total costs accrued as of the balance sheet date for environmental loss contingencies.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Statement of Position (SOP)
-Number 96-1
-Paragraph 161
-Subparagraph a

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 5
-Paragraph 9

+ Details

Name:	us-gaap_AccrualForEnvironmentalLossContingencies
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The aggregate amount disbursed during the reporting period to settle environmental loss contingencies.

+ Details

Name:	us-gaap_AccrualForEnvironmentalLossContingenciesPayments
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Estimated undiscounted amount of the accrual for the environmental loss contingencies at an individual site as of the balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Statement of Position (SOP)
-Number 96-1
-Paragraph 132, 161, 163

+ Details

Name:	us-gaap_SiteContingencyAccrualUndiscountedAmount
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Environmental Matters (Details) (USD $) In Millions	6 Months Ended		3 Months Ended	6 Months Ended		3 Months Ended	6 Months Ended
Environmental Matters (Details) (USD $) In Millions	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2010 MGP And Other Sites	Jun. 30, 2011 MGP And Other Sites	Jun. 30, 2010 MGP And Other Sites	Jun. 30, 2010 Remediation Of Distribution And Substation Transformers	Jun. 30, 2011 Remediation Of Distribution And Substation Transformers	Jun. 30, 2010 Remediation Of Distribution And Substation Transformers	Jun. 30, 2011 PEC	Dec. 31, 2010 PEC	Jun. 30, 2011 PEC Sulfur Dioxide	Dec. 31, 2010 PEC Sulfur Dioxide	Jun. 30, 2011 PEF Nitrogen Oxides	Dec. 31, 2010 PEF Nitrogen Oxides	Jun. 30, 2011 PEF Sulfur Dioxide	Dec. 31, 2010 PEF Sulfur Dioxide
Disclosure Environmental Matters Details [Line Items]
Beginning Balance	$ 35	$ 42		$ 20	$ 22		$ 15	$ 20
Amount accrued for environmental loss contingencies	3	14	2	0	4	8	3	10
Expenditures for environmental loss contingencies	(11)	(16)	(5)	(2)	(7)	(5)	(9)	(9)
Ending Balance	27	40	19	18	19	21	9	21
(Ward) site recorded liability									5	5
Site contingency, loss exposure not accrued									6
Site contingency, loss exposure not accrued, reimbursement									1
Emission Allowances Inventory [Line Items]
Emission allowances inventory											$ 5	$ 8	$ 25	$ 28	$ 5	$ 5