Line Items for Regulatory Matters Pending Rate Cases [Table]

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

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

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

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

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Percentage of public utility's requested return on equity.

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Regulatory Matters Schedule of Pending Rate Cases (Details) (Details) - USD ($) $ in Millions												9 Months Ended	12 Months Ended
	Oct. 25, 2019	Aug. 12, 2019	May 30, 2019	May 24, 2019	May 23, 2019	Apr. 08, 2019	Jan. 15, 2019	Jan. 04, 2019	Dec. 04, 2018	Jun. 08, 2018	Apr. 16, 2018	Sep. 30, 2019	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2018
Potomac Electric Power Company [Member]
Regulatory Matters Pending Rate Cases [Line Items]
Requested Revenue Requirement Increase (Decrease), Amended												$ 26
Requested Revenue Requirement Increase (Decrease)												15
Commonwealth Edison Co [Member]
Regulatory Matters Pending Rate Cases [Line Items]
Requested Revenue Requirement Increase (Decrease), Amended					$ 51							5
Requested Revenue Requirement Increase (Decrease)					$ 53							21
Requested Return on Equity, Percentage					8.91%
Baltimore Gas and Electric Company [Member]
Regulatory Matters Pending Rate Cases [Line Items]
Requested Revenue Requirement Increase (Decrease), Amended												(19)
Requested Revenue Requirement Increase (Decrease)												(10)
Electric Distribution [Member] \| Commonwealth Edison Co [Member]
Regulatory Matters Pending Rate Cases [Line Items]
Requested Revenue Requirement Increase (Decrease)						$ (6)					$ (23)	$ 57
Requested Return on Equity, Percentage						8.91%
Approved Revenue Requirement Increase (Decrease)									$ (24)							$ (63)
Requested Return on Distribution Rate Base, Percentage					6.53%											6.53%
Electric Distribution [Member] \| Baltimore Gas and Electric Company [Member]
Regulatory Matters Pending Rate Cases [Line Items]
Requested Revenue Requirement Increase (Decrease)				$ 74
Requested Return on Equity, Percentage				10.30%
Electric Distribution [Member] \| Baltimore Gas and Electric Company [Member] \| Subsequent Event [Member]
Regulatory Matters Pending Rate Cases [Line Items]
Requested Revenue Requirement Increase (Decrease)	$ 18
Requested Return on Equity, Percentage	4500000000.00%
Gas Distribution [Member] \| Baltimore Gas and Electric Company [Member]
Regulatory Matters Pending Rate Cases [Line Items]
Requested Revenue Requirement Increase (Decrease)				$ 59						$ 61
Requested Return on Equity, Percentage				10.30%
Approved Revenue Requirement Increase (Decrease)								$ 43
MARYLAND \| Electric Distribution [Member] \| Potomac Electric Power Company [Member]
Regulatory Matters Pending Rate Cases [Line Items]
Requested Revenue Requirement Increase (Decrease)							$ 27
Approved Revenue Requirement Increase (Decrease)		$ 10
DISTRICT OF COLUMBIA \| Electric Distribution [Member] \| Potomac Electric Power Company [Member]
Regulatory Matters Pending Rate Cases [Line Items]
Requested Revenue Requirement Increase (Decrease)			$ 160
Requested Return on Equity, Percentage			10.30%
DISTRICT OF COLUMBIA \| Forecast [Member] \| Electric Distribution [Member] \| Potomac Electric Power Company [Member]
Regulatory Matters Pending Rate Cases [Line Items]
Requested Revenue Requirement Increase (Decrease)													$ 36	$ 40	$ 84