Maximum basis points that can be added to the average rate on 30-year treasury notes, to determine the allowed ROE for ComEd's revenue requirement.

No definition available.

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

[Line Items] for Schedule of Energy Efficiency Formula Rate Updates [Table]

No definition available.

Name:	exc_ScheduleofEnergyEfficiencyFormulaRateUpdatesLineItems
Namespace Prefix:	exc_
Data Type:	xbrli:stringItemType
Balance Type:	na
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:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Amount of public utility's approved rate increase (decrease) by regulatory agency.

No definition available.

Name:	us-gaap_PublicUtilitiesApprovedRateIncreaseDecreaseAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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:	dtr-types:percentItemType
Balance Type:	na
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:	us-gaap_PublicUtilitiesRegulatoryProceedingAxis=exc_ComEd2023EnergyEfficiencyFormulaRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Regulatory Matters - Energy Efficiency Formula Rate (Details) - Commonwealth Edison Co - ComEd 2023 Energy Efficiency Formula Rate [Member] $ in Millions	Nov. 30, 2023 USD ($)	May 26, 2023 USD ($)	Oct. 27, 2022
Schedule of Energy Efficiency Formula Rate Updates [Line Items]
Public Utilities, Requested Rate Increase (Decrease), Amount		$ 118
Public Utilities, Approved Rate Increase (Decrease), Amount	$ 118
Public Utilities, Approved Return on Equity, Percentage	8.91%
Public Utilities, Approved Equity Capital Structure, Percentage	6.48%
Basis points for ComEd's Revenue Requirement			580
2022
Schedule of Energy Efficiency Formula Rate Updates [Line Items]
Public Utilities, Approved Rate Increase (Decrease), Amount	$ 47
Public Utilities, Approved Return on Equity, Percentage			10.89%
Public Utilities, Approved Equity Capital Structure, Percentage	7.47%
2024
Schedule of Energy Efficiency Formula Rate Updates [Line Items]
Public Utilities, Approved Rate Increase (Decrease), Amount	$ 71