Commitments and Contingencies - Other Purchase Obligations (Details) $ in Millions		Jun. 30, 2015 USD ($)
Other Purchase Obligations [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Total		$ 1,422
2015		342
2016		421
2017		220
2018		77
2019		80
Thereafter		282
Exelon Generation Co L L C [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Total		1,893
2015		283
2016		583
2017		410
2018		185
2019		130
Thereafter		302
Exelon Generation Co L L C [Member] | Other Purchase Obligations [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Total	[1],[2]	339
2015	[1],[2]	79
2016	[1],[2]	95
2017	[1],[2]	46
2018	[1],[2]	33
2019	[1],[2]	24
Thereafter	[1],[2]	62
Commonwealth Edison Co [Member] | Other Purchase Obligations [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Total	[3]	356
2015	[3]	153
2016	[3]	166
2017	[3]	8
2018	[3]	7
2019	[3]	7
Thereafter	[3]	15
PECO Energy Co [Member] | Other Purchase Obligations [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Total	[3]	21
2015	[3]	5
2016	[3]	5
2017	[3]	2
2018	[3]	2
2019	[3]	2
Thereafter	[3]	5
Baltimore Gas and Electric Company [Member] | Other Purchase Obligations [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Total	[3]	302
2015	[3]	75
2016	[3]	116
2017	[3]	111
2018	[3]	0
2019	[3]	0
Thereafter	[3]	$ 0

[1] Purchase obligations do not include commitments related to construction contracts. See Construction Commitments section below for additional information.

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[3] Purchase obligations include commitments related to smart meter installation. See Note 5 — Regulatory Matters for additional information.