Jointly Owned Electric Utility Plant - Ownership Interests in Jointly Owned Electric Plants and Transmission Facilities (Details) $ in Millions	12 Months Ended
Dec. 31, 2023 USD ($) V mi	Dec. 31, 2022 USD ($)
Schedule Of Jointly Owned Utility Plant Net Ownership [Abstract]
Ownership interest	10000.00%
Delaware And New Jersey [Member]
Schedule Of Jointly Owned Utility Plant Net Ownership [Abstract]
Miles of transmission voltage lines \| mi	151.3
Transmission line capacity \| V	500
Delaware River Crossing [Member]
Schedule Of Jointly Owned Utility Plant Net Ownership [Abstract]
Miles of transmission voltage lines \| mi	2.5
Transmission line capacity \| V	500
New Freedom Switching [Member]
Schedule Of Jointly Owned Utility Plant Net Ownership [Abstract]
Transmission line capacity \| V	500
Electric Transmission [Member] \| Delaware And New Jersey [Member]
Schedule Of Jointly Owned Utility Plant Net Ownership [Abstract]
Plant	$ 103	$ 103
Accumulated depreciation	56	56
Jointly Owned Utility Plant, Ownership Amount of Other Assets	2	0
Electric Transmission [Member] \| PECO Energy Co
Schedule Of Jointly Owned Utility Plant Net Ownership [Abstract]
Plant	7	7
Accumulated depreciation	0	0
Jointly Owned Utility Plant, Ownership Amount of Other Assets	70	41
Electric Transmission [Member] \| PHI Service Company [Member]
Schedule Of Jointly Owned Utility Plant Net Ownership [Abstract]
Plant	6	6
Accumulated depreciation	0	0
Jointly Owned Utility Plant, Ownership Amount of Other Assets	58	36
Electric Transmission [Member] \| Delmarva Power & Light Company
Schedule Of Jointly Owned Utility Plant Net Ownership [Abstract]
Plant	4	4
Accumulated depreciation	0	0
Jointly Owned Utility Plant, Ownership Amount of Other Assets	36	22
Electric Transmission [Member] \| Atlantic City Electric Company
Schedule Of Jointly Owned Utility Plant Net Ownership [Abstract]
Plant	2	2
Accumulated depreciation	0	0
Jointly Owned Utility Plant, Ownership Amount of Other Assets	$ 22	$ 14
PECO Energy Co
Schedule Of Jointly Owned Utility Plant Net Ownership [Abstract]
Ownership interest	56.00%
PECO Energy Co \| Delaware And New Jersey [Member]
Schedule Of Jointly Owned Utility Plant Net Ownership [Abstract]
Ownership interest	42.55%
PECO Energy Co \| Delaware River Crossing [Member]
Schedule Of Jointly Owned Utility Plant Net Ownership [Abstract]
Ownership interest	42.55%
Delmarva Power & Light Company
Schedule Of Jointly Owned Utility Plant Net Ownership [Abstract]
Ownership interest	27.00%
Delmarva Power & Light Company \| Delaware And New Jersey [Member]
Schedule Of Jointly Owned Utility Plant Net Ownership [Abstract]
Ownership interest	1.00%
Delmarva Power & Light Company \| Delaware River Crossing [Member]
Schedule Of Jointly Owned Utility Plant Net Ownership [Abstract]
Ownership interest	7.45%
Atlantic City Electric Company
Schedule Of Jointly Owned Utility Plant Net Ownership [Abstract]
Ownership interest	17.00%
Atlantic City Electric Company \| Delaware And New Jersey [Member]
Schedule Of Jointly Owned Utility Plant Net Ownership [Abstract]
Ownership interest	13.90%
Atlantic City Electric Company \| Delaware River Crossing [Member]
Schedule Of Jointly Owned Utility Plant Net Ownership [Abstract]
Ownership interest	7.45%
Atlantic City Electric Company \| New Freedom Switching [Member]
Schedule Of Jointly Owned Utility Plant Net Ownership [Abstract]
Ownership interest	21.78%
Pepco Holdings LLC
Schedule Of Jointly Owned Utility Plant Net Ownership [Abstract]
Ownership interest	44.00%

Total number of miles of 500,000 voltage transmission lines

No definition available.

Name:	exc_MilesOfTransmissionVoltageLines
Namespace Prefix:	exc_
Data Type:	dtr-types1:lengthItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of voltage capacity in transmission lines

+ References

No definition available.

+ Details

Name:	exc_VoltageOfTransmissionLines
Namespace Prefix:	exc_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	duration

- Definition

The period end amount owned by the reporting utility of a jointly owned utility plant in service.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 980
-SubTopic 360
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 10.C)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479960/980-360-S99-1

+ Details

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

- References

No definition available.

+ Details

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

- Definition

The period end amount of construction work in progress at a jointly owned electricity generation plant.

+ References

+ Details

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

- Definition

The period end amount of accumulated depreciation in a jointly owned electricity generation plant.

+ References

+ Details

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

- Definition

The proportionate share of interest (percent) in a jointly owned utility plant.

+ References

+ Details

Name:	us-gaap_JointlyOwnedUtilityPlantProportionateOwnershipShare
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	us-gaap_PublicUtilityAxis=exc_DelawareAndNewJerseyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PublicUtilityAxis=exc_DelawareRiverCrossingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PublicUtilityAxis=exc_NewFreedomSwitchingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_JointlyOwnedUtilityPlantAxis=us-gaap_ElectricTransmissionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PublicUtilityAxis=exc_PecoEnergyCoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PublicUtilityAxis=exc_PHIServiceCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PublicUtilityAxis=exc_DelmarvaPowerandLightCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PublicUtilityAxis=exc_AtlanticCityElectricCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

- Details

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

- Details

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