Commitments and Contingencies - Schedule of Fuel Purchase Obligations (Details) (Public Utilities, Inventory, Fuel [Member], USD $) In Millions, unless otherwise specified	Dec. 31, 2014
Exelon Generation Co L L C [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Total	$ 8,981
2015	1,404
2016	1,119
2017	1,124
2018	1,001
2019	888
Thereafter	3,445
PECO Energy Co [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Total	428
2015	146
2016	103
2017	60
2018	34
2019	14
Thereafter	71
Baltimore Gas and Electric Company [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Total	611
2015	111
2016	82
2017	67
2018	57
2019	54
Thereafter	$ 240

Amount of the fixed and determinable portion of the unrecorded unconditional purchase obligation maturing in the fifth fiscal year following the latest fiscal year.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 440

-SubTopic 10

-Section 50

-Paragraph 4

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6394976&loc=d3e25336-109308

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- Definition

Amount of the fixed and determinable portion of the unrecorded unconditional purchase obligation maturing in the next fiscal year following the latest fiscal year.

+ References

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- Definition

Amount of the fixed and determinable portion of the unrecorded unconditional purchase obligation maturing in the four fiscal year following the latest fiscal year.

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- Definition

Amount of the fixed and determinable portion of the unrecorded unconditional purchase obligation maturing in the second fiscal year following the latest fiscal year.

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- Definition

Amount of the fixed and determinable portion of the unrecorded unconditional purchase obligation maturing in the third fiscal year following the latest fiscal year.

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- Definition

Amount of the unrecorded obligation to transfer funds in the future for fixed or minimum amounts or quantities of goods or services at fixed or minimum prices (for example, as in take-or-pay contracts or throughput contracts).

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- Definition

Amount of the fixed and determinable portion of the unrecorded unconditional purchase obligation maturing after the fifth fiscal year following the latest fiscal year.

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