Carbon mitigation credit (CMC)

No definition available.

Name:	exc_CarbonMitigationCredit
Namespace Prefix:	exc_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- 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://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 20
-Section 35
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=6392603&loc=d3e7123-110846

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (c)(4)
-URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849

+ Details

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Balance Type:	credit
Period Type:	duration

- Definition

Amount of expense for allocation of cost of tangible and intangible assets over their useful lives directly used in production of good and rendering of service.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(b)(2))
-URI http://asc.fasb.org/extlink&oid=123367319&loc=SL114868664-224227

+ Details

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Balance Type:	debit
Period Type:	duration

- Definition

Generally recurring costs associated with normal operations except for the portion of these expenses which can be clearly related to production and included in cost of sales or services. Includes selling, general and administrative expense.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Amount of expenses for special or contractual termination benefits provided to current employees involuntarily terminated under a benefit arrangement associated exit or disposal activities pursuant to an authorized plan. Excludes expenses related to one-time termination benefits, a discontinued operation or an asset retirement obligation.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3602-108585

+ Details

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Balance Type:	debit
Period Type:	duration

- Details

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- Details

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- Details

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Early Plant Retirements - Narrative (Details) $ in Millions	3 Months Ended	12 Months Ended
Early Plant Retirements - Narrative (Details) $ in Millions	Sep. 30, 2021 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Property, Plant and Equipment [Line Items]
Carbon mitigation credit		54,500,000
Operating Expenses		$ 33,825	$ 30,240	$ 30,096
Depreciation and Amortization		6,036	5,014	$ 4,252
Byron Dresden [Member] \| Facility Closing [Member]
Property, Plant and Equipment [Line Items]
Severance Costs	$ (81)
Asset Retirement Obligation, Revision of Estimate	$ (13)	9	34
Generation New England [Member]
Property, Plant and Equipment [Line Items]
Operating Expenses			22
Depreciation and Amortization		$ 41	$ 26