Segment Information Segment Information - Electric and Gas Revenue by Customer Class (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2018		Jun. 30, 2017		Jun. 30, 2018		Jun. 30, 2017
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues			$ 0				$ 0
Rate-regulated natural gas revenues			0				0
Revenues from alternative revenue programs	$ (26)		58		$ (16)		137
Revenues	8,076		7,665		17,769		16,413
Revenue from Related Parties	0	[1]	0	[1]	0	[2]	0	[2]
Operating Segments [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	3,542	[3]	3,511	[3]	7,496	[4]	7,156	[4]
Rate-regulated natural gas revenues	230	[3]	204	[3]	855	[4]	757	[4]
Revenues	8,076	[3]	7,665	[3]	17,769	[4]	16,413	[4]
Commonwealth Edison Co [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	1,410		1,336		2,903		2,615
Rate-regulated natural gas revenues			0				0
Revenues from alternative revenue programs	(17)		18		(12)		32
Revenues	1,398		1,357		2,910		2,656
Revenue from Related Parties	5		3		19		9
Commonwealth Edison Co [Member] | Operating Segments [Member]
Revenue, Major Customer [Line Items]
Revenues from alternative revenue programs	(17)		18		(12)		32
Revenues			0				0
Commonwealth Edison Co [Member] | Rate-Regulated Electric Revenues [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	1,408	[5]	1,331	[5]	2,906	[6]	2,608	[6]
Commonwealth Edison Co [Member] | Rate-Regulated Electric Revenues [Member] | Operating Segments [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	7	[7]	8	[7]	16	[8]	16	[8]
Commonwealth Edison Co [Member] | Rate-Regulated Electric Revenues [Member] | Residential [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	699		644		1,416		1,255
Commonwealth Edison Co [Member] | Rate-Regulated Electric Revenues [Member] | Small Commercial & Industrial [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	357		340		741		668
Commonwealth Edison Co [Member] | Rate-Regulated Electric Revenues [Member] | Large Commercial & Industrial [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	127		119		280		226
Commonwealth Edison Co [Member] | Rate-Regulated Electric Revenues [Member] | Public Authorities & Electric Railroads [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	12		11		25		22
Commonwealth Edison Co [Member] | Rate-Regulated Electric Revenues [Member] | Other [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	213	[9]	217	[9]	444	[10]	437	[10]
Commonwealth Edison Co [Member] | Rate-Regulated Natural Gas Revenues [Member]
Revenue, Major Customer [Line Items]
Rate-regulated natural gas revenues	0	[11]	0	[11]	0	[12]	0	[12]
Commonwealth Edison Co [Member] | Rate-Regulated Natural Gas Revenues [Member] | Operating Segments [Member]
Revenue, Major Customer [Line Items]
Rate-regulated natural gas revenues	0	[7]	0	[7]	0	[8]	0	[8]
Commonwealth Edison Co [Member] | Rate-Regulated Natural Gas Revenues [Member] | Residential [Member]
Revenue, Major Customer [Line Items]
Rate-regulated natural gas revenues	0		0		0		0
Commonwealth Edison Co [Member] | Rate-Regulated Natural Gas Revenues [Member] | Small Commercial & Industrial [Member]
Revenue, Major Customer [Line Items]
Rate-regulated natural gas revenues	0		0		0		0
Commonwealth Edison Co [Member] | Rate-Regulated Natural Gas Revenues [Member] | Large Commercial & Industrial [Member]
Revenue, Major Customer [Line Items]
Rate-regulated natural gas revenues					0		0
Commonwealth Edison Co [Member] | Rate-Regulated Natural Gas Revenues [Member] | Transportation [Member]
Revenue, Major Customer [Line Items]
Rate-regulated natural gas revenues	0		0		0		0
Commonwealth Edison Co [Member] | Rate-Regulated Natural Gas Revenues [Member] | Other [Member]
Revenue, Major Customer [Line Items]
Rate-regulated natural gas revenues	0	[13]	0	[13]	0	[14]	0	[14]
Commonwealth Edison Co [Member] | Regulated Operation [Member]
Revenue, Major Customer [Line Items]
Revenues	1,408		1,331		2,906		2,608
Commonwealth Edison Co [Member] | Other Regulated Revenue [Member]
Revenue, Major Customer [Line Items]
Revenues	(10)		26		4		48
PECO Energy Co [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	556		548		1,189		1,138
Rate-regulated natural gas revenues	93		80		325		285
Revenues from alternative revenue programs	2		0		1		0
Revenues	653		630		1,518		1,426
Revenue from Related Parties	2		2		3		3
PECO Energy Co [Member] | Operating Segments [Member]
Revenue, Major Customer [Line Items]
Revenues from alternative revenue programs	2		0		1		0
Revenues			0				0
PECO Energy Co [Member] | Rate-Regulated Electric Revenues [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	553	[5]	547	[5]	1,185	[6]	1,134	[6]
Revenue from Related Parties	2		2		3		3
PECO Energy Co [Member] | Rate-Regulated Electric Revenues [Member] | Operating Segments [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	5	[7]	3	[7]	7	[8]	6	[8]
PECO Energy Co [Member] | Rate-Regulated Electric Revenues [Member] | Residential [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	338		331		741		713
PECO Energy Co [Member] | Rate-Regulated Electric Revenues [Member] | Small Commercial & Industrial [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	97		100		198		197
PECO Energy Co [Member] | Rate-Regulated Electric Revenues [Member] | Large Commercial & Industrial [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	52		57		110		109
PECO Energy Co [Member] | Rate-Regulated Electric Revenues [Member] | Public Authorities & Electric Railroads [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	6		8		14		16
PECO Energy Co [Member] | Rate-Regulated Electric Revenues [Member] | Other [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	60	[9]	51	[9]	122	[10]	99	[10]
PECO Energy Co [Member] | Rate-Regulated Natural Gas Revenues [Member]
Revenue, Major Customer [Line Items]
Rate-regulated natural gas revenues	93	[11]	80	[11]	325	[12]	286	[12]
Revenue from Related Parties					0		0
PECO Energy Co [Member] | Rate-Regulated Natural Gas Revenues [Member] | Operating Segments [Member]
Revenue, Major Customer [Line Items]
Rate-regulated natural gas revenues	0	[7]	0	[7]	0	[8]	0	[8]
PECO Energy Co [Member] | Rate-Regulated Natural Gas Revenues [Member] | Residential [Member]
Revenue, Major Customer [Line Items]
Rate-regulated natural gas revenues	62		50		223		192
PECO Energy Co [Member] | Rate-Regulated Natural Gas Revenues [Member] | Small Commercial & Industrial [Member]
Revenue, Major Customer [Line Items]
Rate-regulated natural gas revenues	25		22		87		77
PECO Energy Co [Member] | Rate-Regulated Natural Gas Revenues [Member] | Large Commercial & Industrial [Member]
Revenue, Major Customer [Line Items]
Rate-regulated natural gas revenues	0		0		1		0
PECO Energy Co [Member] | Rate-Regulated Natural Gas Revenues [Member] | Transportation [Member]
Revenue, Major Customer [Line Items]
Rate-regulated natural gas revenues	5		5		11		11
PECO Energy Co [Member] | Rate-Regulated Natural Gas Revenues [Member] | Other [Member]
Revenue, Major Customer [Line Items]
Rate-regulated natural gas revenues	1	[13]	3	[13]	3	[14]	6	[14]
PECO Energy Co [Member] | Regulated Operation [Member]
Revenue, Major Customer [Line Items]
Revenues	646		627		1,510		1,420
PECO Energy Co [Member] | Other Regulated Revenue [Member]
Revenue, Major Customer [Line Items]
Revenues	7		3		8		6
Baltimore Gas and Electric Company [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	542		545		1,196		1,186
Rate-regulated natural gas revenues	118		94		448		365
Revenues from alternative revenue programs	(4)		32		(17)		66
Revenues	662		674		1,639		1,625
Revenue from Related Parties	6		3		12		8
Baltimore Gas and Electric Company [Member] | Operating Segments [Member]
Revenue, Major Customer [Line Items]
Revenues from alternative revenue programs	(4)		32		(17)		66
Revenues			0				0
Baltimore Gas and Electric Company [Member] | Rate-Regulated Electric Revenues [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	541	[5]	544	[5]	1,193	[6]	1,182	[6]
Revenue from Related Parties	2		1		3		3
Baltimore Gas and Electric Company [Member] | Rate-Regulated Electric Revenues [Member] | Operating Segments [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	3	[7]	2	[7]	6	[8]	7	[8]
Baltimore Gas and Electric Company [Member] | Rate-Regulated Electric Revenues [Member] | Residential [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	295		300		688		686
Baltimore Gas and Electric Company [Member] | Rate-Regulated Electric Revenues [Member] | Small Commercial & Industrial [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	60		58		128		128
Baltimore Gas and Electric Company [Member] | Rate-Regulated Electric Revenues [Member] | Large Commercial & Industrial [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	101		107		207		215
Baltimore Gas and Electric Company [Member] | Rate-Regulated Electric Revenues [Member] | Public Authorities & Electric Railroads [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	7		8		14		15
Baltimore Gas and Electric Company [Member] | Rate-Regulated Electric Revenues [Member] | Other [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	78	[9]	71	[9]	156	[10]	138	[10]
Baltimore Gas and Electric Company [Member] | Rate-Regulated Natural Gas Revenues [Member]
Revenue, Major Customer [Line Items]
Rate-regulated natural gas revenues	122	[11]	95	[11]	455	[12]	368	[12]
Revenue from Related Parties	4		2		9		5
Baltimore Gas and Electric Company [Member] | Rate-Regulated Natural Gas Revenues [Member] | Operating Segments [Member]
Revenue, Major Customer [Line Items]
Rate-regulated natural gas revenues	0	[7]	1	[7]	2	[8]	2	[8]
Baltimore Gas and Electric Company [Member] | Rate-Regulated Natural Gas Revenues [Member] | Residential [Member]
Revenue, Major Customer [Line Items]
Rate-regulated natural gas revenues	74		60		298		245
Baltimore Gas and Electric Company [Member] | Rate-Regulated Natural Gas Revenues [Member] | Small Commercial & Industrial [Member]
Revenue, Major Customer [Line Items]
Rate-regulated natural gas revenues	13		12		47		42
Baltimore Gas and Electric Company [Member] | Rate-Regulated Natural Gas Revenues [Member] | Large Commercial & Industrial [Member]
Revenue, Major Customer [Line Items]
Rate-regulated natural gas revenues	23		19		70		64
Baltimore Gas and Electric Company [Member] | Rate-Regulated Natural Gas Revenues [Member] | Transportation [Member]
Revenue, Major Customer [Line Items]
Rate-regulated natural gas revenues	0		0		0		0
Baltimore Gas and Electric Company [Member] | Rate-Regulated Natural Gas Revenues [Member] | Other [Member]
Revenue, Major Customer [Line Items]
Rate-regulated natural gas revenues	12	[13]	4	[13]	40	[14]	17	[14]
Baltimore Gas and Electric Company [Member] | Regulated Operation [Member]
Revenue, Major Customer [Line Items]
Revenues	663		639		1,648		1,550
Baltimore Gas and Electric Company [Member] | Other Regulated Revenue [Member]
Revenue, Major Customer [Line Items]
Revenues	(1)		35		(9)		75
Pepco Holdings LLC [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	1,052		1,032		2,202		2,100
Rate-regulated natural gas revenues	28		22		106		87
Revenues from alternative revenue programs	(7)		8		12		38
Revenues	1,076		1,074		2,327		2,248
Revenue from Related Parties	3		12		7		23
Pepco Holdings LLC [Member] | Operating Segments [Member]
Revenue, Major Customer [Line Items]
Revenues from alternative revenue programs	(7)		8		12		38
Pepco Holdings LLC [Member] | Rate-Regulated Electric Revenues [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	1,051	[5]	1,030	[5]	2,204	[6]	2,096	[6]
Revenue from Related Parties			1				1
Pepco Holdings LLC [Member] | Rate-Regulated Electric Revenues [Member] | Operating Segments [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	4	[7]	3	[7]	5	[8]	5	[8]
Pepco Holdings LLC [Member] | Rate-Regulated Electric Revenues [Member] | Residential [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	505		498		1,114		1,053
Pepco Holdings LLC [Member] | Rate-Regulated Electric Revenues [Member] | Small Commercial & Industrial [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	115		119		230		233
Pepco Holdings LLC [Member] | Rate-Regulated Electric Revenues [Member] | Large Commercial & Industrial [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	282		268		541		526
Pepco Holdings LLC [Member] | Rate-Regulated Electric Revenues [Member] | Public Authorities & Electric Railroads [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	16		16		30		31
Pepco Holdings LLC [Member] | Rate-Regulated Electric Revenues [Member] | Other [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	133	[9]	129	[9]	289	[10]	253	[10]
Pepco Holdings LLC [Member] | Rate-Regulated Natural Gas Revenues [Member]
Revenue, Major Customer [Line Items]
Rate-regulated natural gas revenues	28	[11]	22	[11]	106	[12]	87	[12]
Pepco Holdings LLC [Member] | Rate-Regulated Natural Gas Revenues [Member] | Operating Segments [Member]
Revenue, Major Customer [Line Items]
Rate-regulated natural gas revenues	0	[7]	0	[7]	0	[8]	0	[8]
Pepco Holdings LLC [Member] | Rate-Regulated Natural Gas Revenues [Member] | Residential [Member]
Revenue, Major Customer [Line Items]
Rate-regulated natural gas revenues	13		10		60		50
Pepco Holdings LLC [Member] | Rate-Regulated Natural Gas Revenues [Member] | Small Commercial & Industrial [Member]
Revenue, Major Customer [Line Items]
Rate-regulated natural gas revenues	8		5		26		22
Pepco Holdings LLC [Member] | Rate-Regulated Natural Gas Revenues [Member] | Large Commercial & Industrial [Member]
Revenue, Major Customer [Line Items]
Rate-regulated natural gas revenues	1		2		5		4
Pepco Holdings LLC [Member] | Rate-Regulated Natural Gas Revenues [Member] | Transportation [Member]
Revenue, Major Customer [Line Items]
Rate-regulated natural gas revenues	4		2		9		7
Pepco Holdings LLC [Member] | Rate-Regulated Natural Gas Revenues [Member] | Other [Member]
Revenue, Major Customer [Line Items]
Rate-regulated natural gas revenues	2	[13]	3	[13]	6	[14]	4	[14]
Pepco Holdings LLC [Member] | Regulated Operation [Member]
Revenue, Major Customer [Line Items]
Revenues	1,079		1,052		2,310		2,183
Pepco Holdings LLC [Member] | Other Regulated Revenue [Member]
Revenue, Major Customer [Line Items]
Revenues	(3)		22		17		65
Revenue from Related Parties			11	[15]			22	[16]
Potomac Electric Power Company [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	531		508		1,067		1,022
Rate-regulated natural gas revenues			0				0
Revenues from alternative revenue programs	(10)		5		10		20
Revenues	523		514		1,080		1,045
Revenue from Related Parties	2		1		3		3
Potomac Electric Power Company [Member] | Operating Segments [Member]
Revenue, Major Customer [Line Items]
Revenues from alternative revenue programs	(10)		5		10		20
Revenues			0				0
Potomac Electric Power Company [Member] | Rate-Regulated Electric Revenues [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	531	[5]	507	[5]	1,067	[6]	1,022	[6]
Potomac Electric Power Company [Member] | Rate-Regulated Electric Revenues [Member] | Operating Segments [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	2	[7]	2	[7]	3	[8]	3	[8]
Potomac Electric Power Company [Member] | Rate-Regulated Electric Revenues [Member] | Residential [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	228		223		486		460
Potomac Electric Power Company [Member] | Rate-Regulated Electric Revenues [Member] | Small Commercial & Industrial [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	33		34		65		68
Potomac Electric Power Company [Member] | Rate-Regulated Electric Revenues [Member] | Large Commercial & Industrial [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	212		193		402		382
Potomac Electric Power Company [Member] | Rate-Regulated Electric Revenues [Member] | Public Authorities & Electric Railroads [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	9		8		16		16
Potomac Electric Power Company [Member] | Rate-Regulated Electric Revenues [Member] | Other [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	49	[9]	49	[9]	98	[10]	96	[10]
Potomac Electric Power Company [Member] | Rate-Regulated Natural Gas Revenues [Member]
Revenue, Major Customer [Line Items]
Rate-regulated natural gas revenues	0	[11]	0	[11]	0	[12]	0	[12]
Potomac Electric Power Company [Member] | Rate-Regulated Natural Gas Revenues [Member] | Operating Segments [Member]
Revenue, Major Customer [Line Items]
Rate-regulated natural gas revenues	0	[7]	0	[7]	0	[8]	0	[8]
Potomac Electric Power Company [Member] | Rate-Regulated Natural Gas Revenues [Member] | Residential [Member]
Revenue, Major Customer [Line Items]
Rate-regulated natural gas revenues	0		0		0		0
Potomac Electric Power Company [Member] | Rate-Regulated Natural Gas Revenues [Member] | Small Commercial & Industrial [Member]
Revenue, Major Customer [Line Items]
Rate-regulated natural gas revenues	0		0		0		0
Potomac Electric Power Company [Member] | Rate-Regulated Natural Gas Revenues [Member] | Large Commercial & Industrial [Member]
Revenue, Major Customer [Line Items]
Rate-regulated natural gas revenues	0		0		0		0
Potomac Electric Power Company [Member] | Rate-Regulated Natural Gas Revenues [Member] | Transportation [Member]
Revenue, Major Customer [Line Items]
Rate-regulated natural gas revenues	0		0		0		0
Potomac Electric Power Company [Member] | Rate-Regulated Natural Gas Revenues [Member] | Other [Member]
Revenue, Major Customer [Line Items]
Rate-regulated natural gas revenues	0	[13]	0	[13]	0	[14]	0	[14]
Potomac Electric Power Company [Member] | Regulated Operation [Member]
Revenue, Major Customer [Line Items]
Revenues	531		507		1,067		1,022
Potomac Electric Power Company [Member] | Other Regulated Revenue [Member]
Revenue, Major Customer [Line Items]
Revenues	(8)		7		13		23
Delmarva Power and Light Company [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	255		258		558		544
Rate-regulated natural gas revenues	28		22		106		87
Revenues from alternative revenue programs	4		0		5		9
Revenues	289		282		673		644
Revenue from Related Parties	2		2		4		4
Delmarva Power and Light Company [Member] | Operating Segments [Member]
Revenue, Major Customer [Line Items]
Revenues from alternative revenue programs	4		0		5		9
Revenues			0				0
Delmarva Power and Light Company [Member] | Rate-Regulated Electric Revenues [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	255	[5]	259	[5]	560	[6]	546	[6]
Delmarva Power and Light Company [Member] | Rate-Regulated Electric Revenues [Member] | Operating Segments [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	2	[7]	1	[7]	2	[8]	2	[8]
Delmarva Power and Light Company [Member] | Rate-Regulated Electric Revenues [Member] | Residential [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	142		145		333		321
Delmarva Power and Light Company [Member] | Rate-Regulated Electric Revenues [Member] | Small Commercial & Industrial [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	44		45		90		89
Delmarva Power and Light Company [Member] | Rate-Regulated Electric Revenues [Member] | Large Commercial & Industrial [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	25		26		48		50
Delmarva Power and Light Company [Member] | Rate-Regulated Electric Revenues [Member] | Public Authorities & Electric Railroads [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	3		4		7		8
Delmarva Power and Light Company [Member] | Rate-Regulated Electric Revenues [Member] | Other [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	41	[9]	39	[9]	82	[10]	78	[10]
Delmarva Power and Light Company [Member] | Rate-Regulated Natural Gas Revenues [Member]
Revenue, Major Customer [Line Items]
Rate-regulated natural gas revenues	28	[11]	22	[11]	106	[12]	87	[12]
Delmarva Power and Light Company [Member] | Rate-Regulated Natural Gas Revenues [Member] | Operating Segments [Member]
Revenue, Major Customer [Line Items]
Rate-regulated natural gas revenues	0	[7]	0	[7]	0	[8]	0	[8]
Delmarva Power and Light Company [Member] | Rate-Regulated Natural Gas Revenues [Member] | Residential [Member]
Revenue, Major Customer [Line Items]
Rate-regulated natural gas revenues	13		10		60		50
Delmarva Power and Light Company [Member] | Rate-Regulated Natural Gas Revenues [Member] | Small Commercial & Industrial [Member]
Revenue, Major Customer [Line Items]
Rate-regulated natural gas revenues	8		5		26		22
Delmarva Power and Light Company [Member] | Rate-Regulated Natural Gas Revenues [Member] | Large Commercial & Industrial [Member]
Revenue, Major Customer [Line Items]
Rate-regulated natural gas revenues	1		2		5		4
Delmarva Power and Light Company [Member] | Rate-Regulated Natural Gas Revenues [Member] | Transportation [Member]
Revenue, Major Customer [Line Items]
Rate-regulated natural gas revenues	4		2		9		7
Delmarva Power and Light Company [Member] | Rate-Regulated Natural Gas Revenues [Member] | Other [Member]
Revenue, Major Customer [Line Items]
Rate-regulated natural gas revenues	2	[13]	3	[13]	6	[14]	4	[14]
Delmarva Power and Light Company [Member] | Regulated Operation [Member]
Revenue, Major Customer [Line Items]
Revenues	283		281		666		633
Delmarva Power and Light Company [Member] | Other Regulated Revenue [Member]
Revenue, Major Customer [Line Items]
Revenues	6		1		7		11
Atlantic City Electric Company [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	265		266		576		534
Rate-regulated natural gas revenues			0				0
Revenues from alternative revenue programs	(1)		3		(3)		9
Revenues	265		270		575		544
Revenue from Related Parties	1		1		2		1
Atlantic City Electric Company [Member] | Operating Segments [Member]
Revenue, Major Customer [Line Items]
Revenues from alternative revenue programs	(1)		3		(3)		9
Revenues			0				0
Atlantic City Electric Company [Member] | Rate-Regulated Electric Revenues [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	266	[5]	267	[5]	578	[6]	535	[6]
Atlantic City Electric Company [Member] | Rate-Regulated Electric Revenues [Member] | Operating Segments [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	0	[7]	0	[7]	0	[8]	0	[8]
Atlantic City Electric Company [Member] | Rate-Regulated Electric Revenues [Member] | Residential [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	135		130		295		272
Atlantic City Electric Company [Member] | Rate-Regulated Electric Revenues [Member] | Small Commercial & Industrial [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	38		40		75		76
Atlantic City Electric Company [Member] | Rate-Regulated Electric Revenues [Member] | Large Commercial & Industrial [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	45		49		91		94
Atlantic City Electric Company [Member] | Rate-Regulated Electric Revenues [Member] | Public Authorities & Electric Railroads [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	4		4		7		7
Atlantic City Electric Company [Member] | Rate-Regulated Electric Revenues [Member] | Other [Member]
Revenue, Major Customer [Line Items]
Rate-regulated electric revenues	44	[9]	44	[9]	110	[10]	86	[10]
Atlantic City Electric Company [Member] | Rate-Regulated Natural Gas Revenues [Member]
Revenue, Major Customer [Line Items]
Rate-regulated natural gas revenues	0	[11]	0	[11]	0	[12]	0	[12]
Atlantic City Electric Company [Member] | Rate-Regulated Natural Gas Revenues [Member] | Operating Segments [Member]
Revenue, Major Customer [Line Items]
Rate-regulated natural gas revenues	0	[7]	0	[7]	0	[8]	0	[8]
Atlantic City Electric Company [Member] | Rate-Regulated Natural Gas Revenues [Member] | Residential [Member]
Revenue, Major Customer [Line Items]
Rate-regulated natural gas revenues	0		0		0		0
Atlantic City Electric Company [Member] | Rate-Regulated Natural Gas Revenues [Member] | Small Commercial & Industrial [Member]
Revenue, Major Customer [Line Items]
Rate-regulated natural gas revenues	0		0		0		0
Atlantic City Electric Company [Member] | Rate-Regulated Natural Gas Revenues [Member] | Large Commercial & Industrial [Member]
Revenue, Major Customer [Line Items]
Rate-regulated natural gas revenues	0		0		0		0
Atlantic City Electric Company [Member] | Rate-Regulated Natural Gas Revenues [Member] | Transportation [Member]
Revenue, Major Customer [Line Items]
Rate-regulated natural gas revenues	0		0		0		0
Atlantic City Electric Company [Member] | Rate-Regulated Natural Gas Revenues [Member] | Other [Member]
Revenue, Major Customer [Line Items]
Rate-regulated natural gas revenues	0	[13]	0	[13]	0	[14]	0	[14]
Atlantic City Electric Company [Member] | Regulated Operation [Member]
Revenue, Major Customer [Line Items]
Revenues	266		267		578		535
Atlantic City Electric Company [Member] | Other Regulated Revenue [Member]
Revenue, Major Customer [Line Items]
Revenues	$ (1)		$ 3		$ (3)		$ 9

[1] Intersegment revenues exclude sales to unconsolidated affiliates. The intersegment profit associated with Generation’s sale of certain products and services by and between Exelon’s segments is not eliminated in consolidation due to the recognition of intersegment profit in accordance with regulatory accounting guidance. For Exelon, these amounts are included in Operating revenues in the Consolidated Statements of Operations and Comprehensive Income.

[2] Intersegment revenues exclude sales to unconsolidated affiliates. The intersegment profit associated with Generation’s sale of certain products and services by and between Exelon’s segments is not eliminated in consolidation due to the recognition of intersegment profit in accordance with regulatory accounting guidance. For Exelon, these amounts are included in Operating revenues in the Consolidated Statements of Operations and Comprehensive Income.

[3] Includes gross utility tax receipts from customers. The offsetting remittance of utility taxes to the governing bodies is recorded in expenses on the Registrants’ Consolidated Statements of Operations and Comprehensive Income. See Note 18 — Supplemental Financial Information for total utility taxes for the three months ended June 30, 2018 and 2017.

[4] Includes gross utility tax receipts from customers. The offsetting remittance of utility taxes to the governing bodies is recorded in expenses on the Registrants’ Consolidated Statements of Operations and Comprehensive Income. See Note 18 — Supplemental Financial Information for total utility taxes for the six months ended June 30, 2018 and 2017.

[5] Includes operating revenues from affiliates of $5 million, $2 million, $2 million, $3 million, $2 million, $2 million and $1 million at ComEd, PECO, BGE, PHI, Pepco, DPL and ACE, respectively, for the three months ended June 30, 2018 and $3 million, $2 million, $1 million, $1 million $1 million, $2 million and $1 million at ComEd, PECO, BGE, PHI, Pepco, DPL and ACE, respectively, for the three months ended June 30, 2017.

[6] Includes operating revenues from affiliates of $19 million, $3 million, $3 million, $7 million, $3 million, $4 million and $2 million at ComEd, PECO, BGE, PHI, Pepco, DPL and ACE, respectively, for the six months ended June 30, 2018 and $9 million, $3 million, $3 million, $1 million, $3 million, $4 million and $1 million at ComEd, PECO, BGE, PHI, Pepco, DPL and ACE, respectively, for the six months ended June 30, 2017.

[7] Includes late payment charge revenues.

[8] Includes late payment charge revenues.

[9] Includes revenues from transmission revenue from PJM, wholesale electric revenue and mutual assistance revenue.

[10] Includes revenues from transmission revenue from PJM, wholesale electric revenue and mutual assistance revenue.

[11] Includes operating revenues from affiliates of less than $1 million and $4 million at PECO and BGE, respectively, for the three months ended June 30, 2018 and less than $1 million and $2 million at PECO and BGE, respectively, for the three months ended June 30, 2017.

[12] Includes operating revenues from affiliates of less than $1 million and $9 million at PECO and BGE, respectively, for the six months ended June 30, 2018 and less than $1 million and $5 million at PECO and BGE, respectively, for the six months ended June 30, 2017.

[13] Includes revenues from off-system natural gas sales.

[14] Includes revenues from off-system natural gas sales.

[15] Includes operating revenues from affiliates of $11 million at PHI for the three months ended June 30, 2017.

[16] Includes operating revenues from affiliates of $22 million at PHI for the six months ended June 30, 2017.