Regulatory Matters - Annual Electric Transmission Fillings (Details) - Baltimore Gas and Electric Company [Member] $ in Millions	Apr. 25, 2023 USD ($)	May 27, 2022
2023 Transmission Formula Rate Annual Update [Domain]
Public Utilities, General Disclosures [Line Items]
Public Utilities, Requested Rate Increase (Decrease), Amount	$ 19
Annual Reconciliation Increase	(12)
Public Utilities, Requested Rate Increase (Decrease), Amended, Amount	$ 4
Public Utilities, Approved Equity Capital Structure, Percentage	7.34%
Public Utilities, Approved Return on Equity, Percentage	10.50%
Basis points for Transmission Formula Rate		50
2023 Transmission Formula Rate Revenue Reduction
Public Utilities, General Disclosures [Line Items]
Public Utilities, Requested Rate Increase (Decrease), Amended, Amount	$ 3

Basis points for Transmission Formula Rate

No definition available.

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

- Definition

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

+ References

No definition available.

+ Details

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

- Definition

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

+ References

No definition available.

+ Details

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

- Definition

Percentage of public utility's approved return on equity.

+ References

No definition available.

+ Details

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

- Definition

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.

+ References

No definition available.

+ Details

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

- Definition

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

+ References

No definition available.

+ Details

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

- Definition

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

+ References

No definition available.

+ Details

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

- Details

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

- Details

Name:	us-gaap_PublicUtilitiesRegulatoryProceedingAxis=exc_A2023TransmissionFormulaRateAnnualUpdateDomain
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PublicUtilitiesRegulatoryProceedingAxis=exc_A2023TransmissionFormulaRateRevenueReductionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: