Variable Interest Entities - Carrying Amounts and Classification of Consolidated VIE Assets and Liabilities (Details) - USD ($) $ in Millions		Mar. 31, 2016		Dec. 31, 2015
Variable Interest Entity [Line Items]
Current Assets	[2]	$ 928	[1]	$ 909
Non Current Assets	[2]	8,047	[1]	8,009
Total Assets	[2]	8,975	[1]	8,918
Current Liabilities	[2]	544	[1]	473
Non Current Liabilities	[2]	3,050	[1]	2,927
Total Liabilities	[2]	3,594	[1]	3,400
Assets		111,742		95,384
Total liabilities	[3]	84,537		68,062
Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Assets		8,310		8,268
Total liabilities		3,421		3,264
Exelon Generation Co L L C [Member]
Variable Interest Entity [Line Items]
Current Assets		860	[1]	881
Non Current Assets		7,996	[1]	8,004
Total Assets		8,856	[1]	8,885
Current Liabilities		400	[1]	387
Non Current Liabilities		2,865	[1]	2,884
Total Liabilities		3,265	[1]	3,271
Assets		47,002		46,529
Total liabilities	[4]	33,649		33,559
Exelon Generation Co L L C [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Assets		8,190		8,235
Total liabilities		3,094		3,135
Baltimore Gas and Electric Company [Member]
Variable Interest Entity [Line Items]
Current Assets		44		23
Non Current Assets		3		3
Total Assets		47		26
Current Liabilities		83		81
Non Current Liabilities		41		41
Total Liabilities		124		122
Assets		8,361		8,295
Total liabilities	[5]	5,417		5,418
Baltimore Gas and Electric Company [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Assets		47		26
Total liabilities		124		122
Pepco Holdings, LLC [Member] | Predecessor [Member]
Variable Interest Entity [Line Items]
Assets				16,184
Total liabilities				11,588
Pepco Holdings, LLC [Member] | Successor [Member]
Variable Interest Entity [Line Items]
Assets		20,932
Total liabilities		14,260
PEPCO Holdings Inc [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
PEPCO Holdings Inc [Member] | Successor [Member]
Variable Interest Entity [Line Items]
Current Assets		22
Non Current Assets		46
Total Assets		68
Current Liabilities		58
Non Current Liabilities		142
Total Liabilities		200
PEPCO Holdings Inc [Member] | Variable Interest Entity, Primary Beneficiary [Member] | Predecessor [Member]
Variable Interest Entity [Line Items]
Assets				30
Total liabilities				172
PEPCO Holdings Inc [Member] | Variable Interest Entity, Primary Beneficiary [Member] | Successor [Member]
Variable Interest Entity [Line Items]
Assets		68
Total liabilities		200
Atlantic City Electric Company [Member]
Variable Interest Entity [Line Items]
Current Assets		11		12
Non Current Assets		18		18
Total Assets		29		30
Current Liabilities		47		48
Non Current Liabilities		114		124
Total Liabilities		161		172
Assets		3,393		3,387
Total liabilities		2,504		2,387
Atlantic City Electric Company [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Assets		29		30
Total liabilities		$ 161		$ 172

[1] .

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

[3] Exelon’s consolidated assets include $8,310 million and $8,268 million at March 31, 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 $3,421 million and $3,264 million at March 31, 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 $8,190 million and $8,235 million at March 31, 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 $3,094 million and $3,135 million at March 31, 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 $47 million and $26 million at March 31, 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 $41 million and $41 million at March 31, 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.