Regulatory Matters - Schedule of Completed Rate Cases (Details) (Details) - Illinois 2019 Electric Distribution Base Rate Case [Member] - Commonwealth Edison Co [Member] - USD ($) $ in Millions	Dec. 04, 2019	Apr. 08, 2019
Regulatory Matters Completed Rate Cases [Line Items]
Requested Revenue Requirement Increase (Decrease)		$ (6)
Approved Revenue Requirement Increase (Decrease)	$ (17)
Public Utilities, Interim Rate Increase (Decrease), Amount	51
Public Utilities Requested Rate Increase (Decrease), Prior Year Annual Reconciliation	$ (68)
Public Utilities, Approved Equity Capital Structure, Percentage	6.51%
Approved Return on Equity, Percentage	8.91%
Basis points for ComEd's Revenue Requirement	580

- 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.

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No definition available.

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- Definition

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

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No definition available.

+ Details

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- Definition

[Line Items] for Regulatory Matters Completed Rate Cases [Table]

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No definition available.

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- Definition

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

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No definition available.

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- Definition

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

+ References

No definition available.

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- Definition

Percentage of public utility's approved return on equity.

+ References

No definition available.

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- Definition

Amount of public utility's interim rate increase (decrease) allowed while waiting final decision of regulatory agency.

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No definition available.

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- Definition

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

+ References

No definition available.

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