Additional Federal And State Income Tax On Lease Investments

No definition available.

Name:	pom_AdditionalFederalAndStateIncomeTaxOnLeaseInvestments
Namespace Prefix:	pom_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Annual Tax-benefits From Lease Investments

+ References

No definition available.

+ Details

Name:	pom_AnnualTaxBenefitsFromLeaseInvestments
Namespace Prefix:	pom_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	pom_CommitmentsAndContingenciesLineItems
Namespace Prefix:	pom_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Federal And State Income Tax Benefits On Lease Investments

+ References

No definition available.

+ Details

Name:	pom_FederalAndStateIncomeTaxBenefitsOnLeaseInvestments
Namespace Prefix:	pom_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Percentage Of Penalty On The Amount Of Additional Taxes Due

+ References

No definition available.

+ Details

Name:	pom_PercentageOfPenaltyOnAmountOfAdditionalTaxesDue
Namespace Prefix:	pom_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Potential interest on potential tax liability related to disallowed tax benefits

+ References

No definition available.

+ Details

Name:	pom_PotentialInterestOnPotentialTaxLiabilityRelatedToDisallowedTaxBenefits
Namespace Prefix:	pom_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Tax Payment Made

+ References

No definition available.

+ Details

Name:	pom_TaxPaymentMade
Namespace Prefix:	pom_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The amount of cash, securities, or other assets held by a third-party trustee pursuant to the terms of an agreement which assets are available to be used by beneficiaries to that agreement only within the specific terms thereof and which agreement is expected to terminate more than one year from the balance sheet date (or operating cycle, if longer) at which time the assets held-in-trust will be released or forfeited.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.4-08.(b))

-URI http://asc.fasb.org/extlink&oid=6881521&loc=d3e23780-122690

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 140

-Paragraph 17

-Subparagraph c

-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.

+ Details

Name:	us-gaap_AssetsHeldInTrustNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The amount of estimated interest recognized in the period arising from income tax examinations.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 15

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32718-109319

+ Details

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

- Definition

The amount of the additional liability or refund received or expected based on a final settlement with a taxing authority.

+ References

+ Details

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

- Definition

The amount of estimated penalties recognized in the period arising from income tax examinations.

+ References

+ Details

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

Commitments And Contingencies (PHI's Cross-Border Energy Lease Investments) (Detail) (USD $) In Millions, unless otherwise specified	1 Months Ended		6 Months Ended
	Jun. 30, 2012	Jan. 31, 2011	Jun. 30, 2012	Dec. 31, 2011
Commitments And Contingencies [Line Items]
Estimated current annual tax benefits			$ 48
Investment in finance leases held in trust	1,375		1,375	1,349
Federal and state income tax benefits			534
Tax payment made		74
Income tax penalties		1
Interest expense associated with the disallowed deductions		28
Additional federal and state taxes	806		674
Potential interest on potential tax liability related to disallowed tax benefits	132		132
Maximum tax penalty percentage
Potential tax liability in the event of a total disallowance	806		806
Pepco Holdings Inc [Member]
Commitments And Contingencies [Line Items]
Investment in finance leases held in trust	$ 1,400		$ 1,400