Variable Interest Entities - Carrying Amounts and Classification of Consolidated VIE Assets and Liabilities (Details) - USD ($) $ in Millions		Jun. 30, 2016		Dec. 31, 2015
Variable Interest Entity [Line Items]
Current Assets	[2]	$ 818	[1]	$ 909
Non Current Assets	[2]	8,083	[1]	8,009
Total Assets	[2]	8,901	[1]	8,918
Current Liabilities	[2]	597	[1]	473
Non Current Liabilities	[2]	3,070	[1]	2,927
Total Liabilities	[2]	3,667	[1]	3,400
Assets		112,778		95,384
Total liabilities	[3]	85,456		68,062
Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Assets		8,240		8,268
Total liabilities		3,461		3,264
Exelon Generation Co L L C [Member]
Variable Interest Entity [Line Items]
Current Assets		784	[1]	881
Non Current Assets		8,048	[1]	8,004
Total Assets		8,832	[1]	8,885
Current Liabilities		464	[1]	387
Non Current Liabilities		2,951	[1]	2,884
Total Liabilities		3,415	[1]	3,271
Assets		46,897		46,529
Total liabilities	[4]	33,530		33,559
Exelon Generation Co L L C [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Assets		8,172		8,235
Total liabilities		3,211		3,135
Baltimore Gas and Electric Company [Member]
Variable Interest Entity [Line Items]
Current Assets		17		23
Non Current Assets		3		3
Total Assets		20		26
Current Liabilities		82		81
Non Current Liabilities		0		41
Total Liabilities		82		122
Assets		8,325		8,295
Total liabilities	[5]	5,395		5,418
Baltimore Gas and Electric Company [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Assets		20		26
Total liabilities		82		122
Pepco Holdings LLC [Member] | Predecessor [Member]
Variable Interest Entity [Line Items]
Current Assets				12
Non Current Assets				18
Total Assets				30
Current Liabilities				48
Non Current Liabilities				124
Total Liabilities				172
Assets				16,188
Total liabilities				11,592
Pepco Holdings LLC [Member] | Successor [Member]
Variable Interest Entity [Line Items]
Current Assets		14
Non Current Assets		31
Total Assets		45
Current Liabilities		48
Non Current Liabilities		118
Total Liabilities		166
Assets		20,921
Total liabilities		13,150
Pepco Holdings LLC [Member] | Variable Interest Entity, Primary Beneficiary [Member] | Predecessor [Member]
Variable Interest Entity [Line Items]
Assets				30
Total liabilities				172
Pepco Holdings LLC [Member] | Variable Interest Entity, Primary Beneficiary [Member] | Successor [Member]
Variable Interest Entity [Line Items]
Assets		45
Total liabilities		166
Atlantic City Electric Company [Member]
Variable Interest Entity [Line Items]
Current Assets		10		12
Non Current Assets		19		18
Total Assets		29		30
Current Liabilities		44		48
Non Current Liabilities		106		124
Total Liabilities		150		172
Assets		3,461		3,387
Total liabilities		2,430		2,387
Atlantic City Electric Company [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Assets		29		30
Total liabilities		$ 150		$ 172

[1] .

[2] Includes certain purchase accounting adjustments not pushed down to the BGE standalone entity.

[3] Exelon’s consolidated assets include $8,240 million and $8,268 million at June 30, 2016 and December 31, 2015, respectively, of certain VIEs that can only be used to settle the liabilities of the VIE. Exelon’s consolidated liabilities include $3,461 million and $3,264 million at June 30, 2016 and December 31, 2015, respectively, of certain VIEs for which the VIE creditors do not have recourse to Exelon. See Note 3 - Variable Interest Entities.

[4] Generation’s consolidated assets include $8,172 million and $8,235 million at June 30, 2016 and December 31, 2015, respectively, of certain VIEs that can only be used to settle the liabilities of the VIE. Generation’s consolidated liabilities include $3,211 million and $3,135 million at June 30, 2016 and December 31, 2015, respectively, of certain VIEs for which the VIE creditors do not have recourse to Generation. See Note 3 - Variable Interest Entities.

[5] BGE’s consolidated assets include $20 million and $26 million at June 30, 2016 and December 31, 2015, respectively, of BGE’s consolidated VIE that can only be used to settle the liabilities of the VIE. BGE’s consolidated liabilities include $82 million and $122 million at June 30, 2016 and December 31, 2015, respectively, of BGE’s consolidated VIE for which the VIE creditors do not have recourse to BGE. See Note 3 - Variable Interest Entities.