Regulatory Matters - Energy Efficiency Formula Rate (Details) - ComEd 2022 Energy Efficiency Formula Rate [Domain] - Commonwealth Edison Co [Member] - USD ($) $ in Millions		12 Months Ended
Jun. 01, 2022	Dec. 31, 2021
Schedule of Energy Efficiency Formula Rate Updates [Line Items]
Public Utilities, Requested Rate Increase (Decrease), Amount	$ 66
Public Utilities Requested Rate Increase (Decrease), Prior Year Annual Reconciliation	(16)
Public Utilities, Requested Rate Increase (Decrease), Amended, Amount	$ 50
Public Utilities, Requested Equity Capital Structure, Percentage	5.94%
Requested Return on Equity, Percentage	7.85%
Basis points for ComEd's Revenue Requirement	580
Public Utilities, Approved Equity Capital Structure, Percentage		5.52%
Public Utilities, Approved Return on Equity, Percentage		6.99%

- Definition

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.

+ References

No definition available.

+ Details

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- Definition

Amount of public utility's requested rate increase (decrease) with regulatory agency, prior year annual reconciliation.

+ References

No definition available.

+ Details

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

- Definition

Schedule of Energy Efficiency Formula Rate Updates [Line Items]

+ References

No definition available.

+ Details

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- Definition

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

+ References

No definition available.

+ Details

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- Definition

Percentage of public utility's approved return on equity.

+ References

No definition available.

+ Details

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Data Type:	dtr-types:percentItemType
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- Definition

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

+ References

No definition available.

+ Details

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- Definition

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

+ References

No definition available.

+ Details

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- Definition

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

+ References

No definition available.

+ Details

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- Definition

Percentage of public utility's requested return on equity.

+ References

No definition available.

+ Details

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- Details

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- Details

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