Asset Retirement Obligations - Non-Nuclear Asset Retirement Obligations Rollforward (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Accretion expense	$ 44	$ 514	$ 500
Commonwealth Edison Co [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Accretion expense	0	0	0
PECO Energy Co [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Accretion expense	0	0	0
Baltimore Gas and Electric Company [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Accretion expense	0	0	0
Pepco Holdings LLC [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Accretion expense	0	0	0
Potomac Electric Power Company [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Accretion expense	0	0	0
Delmarva Power & Light Company [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Accretion expense	0	0	0
Atlantic City Electric Company [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Accretion expense	0	0	0
Nonnuclear Decommissioning Asset Retirement Obligation [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
ARO beginning balance	274	249
Asset Retirement Obligation, Revision of Estimate	(8)	26
Accretion expense	8	7
Payments	(3)	(8)
ARO ending balance	271	274	249
Nonnuclear Decommissioning Asset Retirement Obligation [Member] \| Commonwealth Edison Co [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
ARO beginning balance	146	129
Asset Retirement Obligation, Revision of Estimate	2	15
Accretion expense	4	4
Payments	(2)	(2)
ARO ending balance	150	146	129
Nonnuclear Decommissioning Asset Retirement Obligation [Member] \| PECO Energy Co [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
ARO beginning balance	29	29
Asset Retirement Obligation, Revision of Estimate	(1)	0
Accretion expense	1	1
Payments	(1)	(1)
ARO ending balance	28	29	29
Nonnuclear Decommissioning Asset Retirement Obligation [Member] \| Baltimore Gas and Electric Company [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
ARO beginning balance	26	23
Asset Retirement Obligation, Revision of Estimate	3	2
Accretion expense	1	1
Payments	0	0
ARO ending balance	30	26	23
Nonnuclear Decommissioning Asset Retirement Obligation [Member] \| Pepco Holdings LLC [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
ARO beginning balance	70	59
Asset Retirement Obligation, Revision of Estimate	(13)	10
Accretion expense	2	1
Payments	0	0
ARO ending balance	59	70	59
Nonnuclear Decommissioning Asset Retirement Obligation [Member] \| Potomac Electric Power Company [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
ARO beginning balance	45	39
Asset Retirement Obligation, Revision of Estimate	(8)	5
Accretion expense	2	1
Payments	0	0
ARO ending balance	39	45	39
Nonnuclear Decommissioning Asset Retirement Obligation [Member] \| Delmarva Power & Light Company [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
ARO beginning balance	16	14
Asset Retirement Obligation, Revision of Estimate	(3)	2
Accretion expense	0	0
Payments	0	0
ARO ending balance	13	16	14
Nonnuclear Decommissioning Asset Retirement Obligation [Member] \| Atlantic City Electric Company [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
ARO beginning balance	9	6
Asset Retirement Obligation, Revision of Estimate	(2)	3
Accretion expense	0	0
Payments	0	0
ARO ending balance	$ 7	$ 9	$ 6

The carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 20
-Section 25
-Paragraph 4
-URI https://asc.fasb.org/extlink&oid=116646717&loc=d3e6290-110844

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI https://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849

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- Definition

Amount of accretion expense recognized during the period that is associated with an asset retirement obligation. Accretion expense measures and incorporates changes due to the passage of time into the carrying amount of the liability.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 20
-Section 45
-Paragraph 1
-URI https://asc.fasb.org/extlink&oid=6392676&loc=d3e7480-110848

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (c)(3)
-URI https://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849

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- Definition

Amount of cash paid during the period to settle an asset retirement obligation. Amounts paid to settle an asset retirement obligation are generally included in the operating section of the Statement of Cash Flows.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 17
-Subparagraph (e)
-URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3367-108585

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 20
-Section 45
-Paragraph 3
-URI https://asc.fasb.org/extlink&oid=6392676&loc=SL5974666-110848

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- Definition

Amount of increase (decrease) in the asset retirement obligation from changes in the amount or timing of the estimated cash flows associated with the settlement of the obligation.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (c)(4)
-URI https://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

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