Purchase Obligations (Details) (PEC [Member], USD $) In Millions, unless otherwise specified	Dec. 31, 2011
Purchase Obligations [Line Items]
2012	$ 20
Contractual obligations one to three years	103
Contractual obligations three to five years	103
Thereafter	804
Unrecorded unconditional purchase obligation, total	1,030
Conditional Agreement [Member]
Purchase Obligations [Line Items]
Unrecorded unconditional purchase obligation, total	1,510
Long term contract amount, classified as capital lease	$ 380

The total contract amount under a long-term contract classified as capital lease.

No definition available.

Name:	pgn_LongTermContractAmountClassifiedAsCapitalLease
Namespace Prefix:	pgn_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The minimum amount the entity agreed to spend under the long-term purchase commitment from one to three years.

+ References

No definition available.

+ Details

Name:	pgn_UnrecordedUnconditionalPurchaseObligationDueOneToThreeYears
Namespace Prefix:	pgn_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The minimum amount the entity agreed to spend under the long-term purchase commitment from three to five years.

+ References

No definition available.

+ Details

Name:	pgn_UnrecordedUnconditionalPurchaseObligationDueThreeToFiveYears
Namespace Prefix:	pgn_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The remaining amount of the fixed and determinable portion of an unrecorded unconditional purchase obligation to be paid within one year 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 47

-Paragraph 7

-Subparagraph b

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 440

-SubTopic 10

-Section 50

-Paragraph 4

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6394976&loc=d3e25336-109308

+ Details

Name:	us-gaap_UnrecordedUnconditionalPurchaseObligationBalanceOnFirstAnniversary
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The amount of the fixed and determinable portion of an unrecorded unconditional purchase obligation as of the balance sheet date.

+ References

+ Details

Name:	us-gaap_UnrecordedUnconditionalPurchaseObligationBalanceSheetAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The remaining amount of the fixed and determinable portion of an unrecorded unconditional purchase obligation to be paid after five years from the balance sheet date.

+ References

No definition available.

+ Details

Name:	us-gaap_UnrecordedUnconditionalPurchaseObligationDueAfterFiveYears
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

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