Market Payment Shortfall in Collections

No definition available.

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Namespace Prefix:	exc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Market-wide Limit Recovery of Default

+ References

No definition available.

+ Details

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Balance Type:	debit
Period Type:	duration

- Definition

Regulatory Matters Additional Narrative Information [Line Items]

+ References

No definition available.

+ Details

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- Definition

The increase (decrease) during the reporting period in the value of other assets that are created when regulatory agencies permits public utilities to defer costs to the balance sheet.

+ 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 (a)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3602-108585

+ Details

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Balance Type:	credit
Period Type:	duration

- Definition

The increase (decrease) during the reporting period in regulated liabilities. Regulated liabilities are created when regulatory agency permits an entity to defer revenues to the balance sheet.

+ References

+ Details

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

- Definition

The total amount of other operating cost and expense items that are associated with the entity's normal revenue producing operation.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.3)
-URI http://asc.fasb.org/extlink&oid=120395209&loc=SL114868664-224227

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

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

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
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Balance Type:	credit
Period Type:	duration

- Details

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- Details

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- Details

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- Details

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Regulatory Matters - Narrative (Details) - USD ($)		3 Months Ended
Regulatory Matters - Narrative (Details) - USD ($)	Feb. 15, 2021	Mar. 31, 2021
Texas-based generating assets
Regulatory Matters Additional Narrative Information [Line Items]
Operating and maintenance		$ 880,000,000
Market Payment Shortfall in Collections		28,000,000
Exelon Generation Co L L C [Member] \| ERCOT
Regulatory Matters Additional Narrative Information [Line Items]
Public Utilities, Requested Rate Increase (Decrease), Amount	$ 9,000
Market Payment Shortfall in Collections		2,900,000,000
Market-wide Limit Recovery of Default		2,500,000
Exelon Generation Co L L C [Member] \| Texas-based generating assets
Regulatory Matters Additional Narrative Information [Line Items]
Operating and maintenance		880,000,000
Market Payment Shortfall in Collections		28,000,000
Commonwealth Edison Co [Member]
Regulatory Matters Additional Narrative Information [Line Items]
Increase (Decrease) in Regulatory Assets		106,000,000
Commonwealth Edison Co [Member] \| Electric Distribution Formula Rate Annual Reconciliations [Member]
Regulatory Matters Additional Narrative Information [Line Items]
Increase (Decrease) in Regulatory Assets		55,000,000
Commonwealth Edison Co [Member] \| Energy Efficiency Costs [Member]
Regulatory Matters Additional Narrative Information [Line Items]
Increase (Decrease) in Regulatory Assets		38,000,000
PECO Energy Co [Member]
Regulatory Matters Additional Narrative Information [Line Items]
Increase (Decrease) in Regulatory Assets		56,000,000
PECO Energy Co [Member] \| Deferred Income Tax Charge [Member]
Regulatory Matters Additional Narrative Information [Line Items]
Increase (Decrease) in Regulatory Assets		48,000,000
PECO Energy Co [Member] \| Vacation Accrual
Regulatory Matters Additional Narrative Information [Line Items]
Increase (Decrease) in Regulatory Assets		9,000,000
Baltimore Gas and Electric Company [Member]
Regulatory Matters Additional Narrative Information [Line Items]
Increase (Decrease) in Regulatory Assets
Increase (Decrease) in Regulatory Liabilities		(82,000,000)
Baltimore Gas and Electric Company [Member] \| Deferred Income Tax Charge [Member]
Regulatory Matters Additional Narrative Information [Line Items]
Increase (Decrease) in Regulatory Liabilities		(93,000,000)
Baltimore Gas and Electric Company [Member] \| electric energy and natural gas cost [Member]
Regulatory Matters Additional Narrative Information [Line Items]
Increase (Decrease) in Regulatory Liabilities		$ 9,000,000