Early Plant Retirements - Pretax Expense (Details) - Facility Closing [Member] - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2019	Jun. 30, 2019
Three Mile Island [Member]
Accelerated depreciation		$ 145
Accelerated nuclear fuel amortization		9
Operating and maintenance		(83)
Restructuring and Related Cost, Incurred Cost		71
TMOysterCreek [Member]
Accelerated depreciation	$ 71
Accelerated nuclear fuel amortization	4
Operating and maintenance	0
Restructuring and Related Cost, Incurred Cost	75
Exelon Generation Co L L C [Member] \| Three Mile Island [Member]
Accelerated depreciation	71	145
Accelerated nuclear fuel amortization	4	9
Operating and maintenance	0	(83)
Restructuring and Related Cost, Incurred Cost	$ 75	$ 71

The amount of capitalized nuclear fuel costs that are charged to fuel expense during the period using the unit-of-production method.

No definition available.

+ Details

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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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Balance Type:	debit
Period Type:	duration

- Definition

Discloses the amount charged against the accrued restructuring reserves, or earnings if not previously accrued, during the period for the specified type of restructuring cost.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=6394359&loc=d3e17939-110869

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 5.P.4(b)(1))
-URI http://asc.fasb.org/extlink&oid=115931487&loc=d3e140904-122747

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=6394359&loc=d3e17939-110869

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 5.P.4(d))
-URI http://asc.fasb.org/extlink&oid=115931487&loc=d3e140904-122747

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- Definition

Amount of accelerated depreciation charged against earnings associated with exit from or disposal of business activities or restructuring plan.

+ References

No definition available.

+ Details

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- Details

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- Details

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- Details

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- Details

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