Name:	exc_DueFromAffiliateCurrentElectricUtility
Namespace Prefix:	exc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Represents the pre-tax mark-to-market gains or losses of certain purchase and sale contracts due to the change in fair value of the derivative contracts held at the reporting date. These contracts are entered into purely to profit from market prices changes as opposed to hedging an exposure.

No definition available.

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

Net pre-tax mark-to-market gain or loss on derivative contracts that were entered into purely to profit from market prices changes as opposed to hedging an exposure.

No definition available.

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

Represents the pre-tax mark-to-market gains or losses of certain purchase and sale contracts due to the recognized change in fair value that was reclassified to realized due to settlement of the derivative during the period. These contracts are entered into purely to profit from market prices changes as opposed to hedging an exposure.

No definition available.

Name:	exc_ProprietaryTradingActivitiesReclassificationToRealizedAtSettlement
Namespace Prefix:	exc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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_DerivativeLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Name:	exc_ProprietaryTradingActivitiesGainLossByIncomeStatementLocationAxis=exc_OperatingRevenueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_StatementEquityComponentsAxis=us-gaap_InterestRateSwapMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=exc_PHIPEPCOMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: