Asset Retirement Obligations - Non-Nuclear Asset Retirement Obligations Rollforward (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Accretion expense		$ 44	$ 514
Commonwealth Edison Co
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Accretion expense		0	0
PECO Energy Co
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Accretion expense		0	0
Baltimore Gas and Electric Company
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Accretion expense		0	0
Pepco Holdings LLC
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Accretion expense		0	0
Potomac Electric Power Company
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Accretion expense		0	0
Delmarva Power & Light Company
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Accretion expense		0	0
Atlantic City Electric Company
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Accretion expense		0	0
Nonnuclear Decommissioning Asset Retirement Obligation [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
ARO beginning balance	$ 271	274
Asset Retirement Obligation, Revision of Estimate	(9)	(8)
Accretion expense	11	8
Payments	(4)	(3)
ARO ending balance	269	271	274
Nonnuclear Decommissioning Asset Retirement Obligation [Member] \| Commonwealth Edison Co
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
ARO beginning balance	150	146
Asset Retirement Obligation, Revision of Estimate	(3)	2
Accretion expense	6	4
Payments	(3)	(2)
ARO ending balance	150	150	146
Nonnuclear Decommissioning Asset Retirement Obligation [Member] \| PECO Energy Co
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
ARO beginning balance	28	29
Asset Retirement Obligation, Revision of Estimate	(1)	(1)
Accretion expense	1	1
Payments	(1)	(1)
ARO ending balance	27	28	29
Nonnuclear Decommissioning Asset Retirement Obligation [Member] \| Baltimore Gas and Electric Company
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
ARO beginning balance	30	26
Asset Retirement Obligation, Revision of Estimate	1	3
Accretion expense	1	1
Payments	0	0
ARO ending balance	32	30	26
Nonnuclear Decommissioning Asset Retirement Obligation [Member] \| Pepco Holdings LLC
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
ARO beginning balance	59	70
Asset Retirement Obligation, Revision of Estimate	(6)	(13)
Accretion expense	3	2
Payments	0	0
ARO ending balance	56	59	70
Nonnuclear Decommissioning Asset Retirement Obligation [Member] \| Potomac Electric Power Company
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
ARO beginning balance	39	45
Asset Retirement Obligation, Revision of Estimate	(4)	(8)
Accretion expense	2	2
Payments	0	0
ARO ending balance	37	39	45
Nonnuclear Decommissioning Asset Retirement Obligation [Member] \| Delmarva Power & Light Company
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
ARO beginning balance	13	16
Asset Retirement Obligation, Revision of Estimate	(1)	(3)
Accretion expense	1	0
Payments	0	0
ARO ending balance	13	13	16
Nonnuclear Decommissioning Asset Retirement Obligation [Member] \| Atlantic City Electric Company
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
ARO beginning balance	7	9
Asset Retirement Obligation, Revision of Estimate	(1)	(2)
Accretion expense	0	0
Payments	0	0
ARO ending balance	$ 6	$ 7	$ 9

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
-Topic 410
-SubTopic 20
-Name Accounting Standards Codification
-Section 25
-Paragraph 4
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481999/410-20-25-4

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 410
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481850/410-20-50-1

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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
-Topic 410
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481879/410-20-45-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 410
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (c)(3)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481850/410-20-50-1

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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
-Topic 410
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481879/410-20-45-3

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 17
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482740/230-10-45-17

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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
-Topic 410
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (c)(4)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481850/410-20-50-1

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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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