Name:	exc_CaponEquityComponentofRateofReturnonCommonEquityinFederalEnergyRegulatoryCommitteeComplaint
Namespace Prefix:	exc_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Proposed Capital Expenditure

No definition available.

Name:	exc_ProposedCapitalExpenditure
Namespace Prefix:	exc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Exepected adjustment to revenue to be recorded in the prior year.

No definition available.

Name:	exc_Revenue
Namespace Prefix:	exc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

The total amount of other operating income, the components of which are not separately disclosed on the income statement, from items that are associated with the entity's normal revenue producing operation.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1)
-URI http://asc.fasb.org/extlink&oid=116634182&loc=SL114868664-224227

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

Percentage of public utility's approved equity to capital, including debt and equity.

No definition available.

Name:	us-gaap_PublicUtilitiesApprovedEquityCapitalStructurePercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Percentage of public utility's approved return on equity.

No definition available.

Name:	us-gaap_PublicUtilitiesApprovedReturnOnEquityPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

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.

No definition available.

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

Amount of public utility's amended requested rate increase (decrease) with regulatory agency.

No definition available.

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

Amount of public utility's requested rate increase (decrease) with regulatory agency.

No definition available.

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

Name:	dei_LegalEntityAxis=exc_CommonwealthEdisonCoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	dei_LegalEntityAxis=exc_BaltimoreGasAndElectricCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	dei_LegalEntityAxis=exc_PotomacElectricPowerCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	dei_LegalEntityAxis=exc_DelmarvaPowerandLightCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	dei_LegalEntityAxis=exc_AtlanticCityElectricCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RegulatoryLiabilityAxis=exc_CleanEnergyLegislationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: