Segment Information - Reconciliation to Consolidated Financial Statements (Details) - USD ($) $ in Millions		3 Months Ended						9 Months Ended
		Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Segment Reporting Information [Line Items]
Revenues		$ 8,929			$ 9,403			$ 26,096	$ 27,170
Operating revenues from affiliates		0			0			0	0
Depreciation, Depletion and Amortization		1,083			1,105			3,237	3,284
Operating Expenses		7,559			8,252			22,703	24,036
Interest Revenue (Expense), Net		409			393			1,221	1,138
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest		1,102			947			3,028	2,263
Income taxes		172			137			626	262
Net income (loss)		760	$ 494	$ 966	800	$ 542	$ 636	2,220	1,979
Payments to Acquire Property, Plant, and Equipment		1,687			1,690			5,259	5,497
Assets	[1]	122,738						122,738		$ 119,666
Pepco Holdings LLC [Member]
Segment Reporting Information [Line Items]
Revenues		1,380			1,361			3,700	3,688
Operating revenues from affiliates		4			3			11	11
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest		203			191			436	363
Income taxes		14			4			25	28
Net income (loss)		189	106	117	187	84	65	412	336
Payments to Acquire Property, Plant, and Equipment								1,006	988
Assets	[2]	22,576						22,576		21,984
Exelon Generation Co L L C [Member]
Segment Reporting Information [Line Items]
Revenues		4,774			5,278			14,280	15,368
Operating revenues from affiliates		275			308			844	979
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest		501			389			1,355	800
Income taxes		87			78			388	110
Net income (loss)		244	$ 118	$ 422	300	$ 181	$ 186	784	667
Payments to Acquire Property, Plant, and Equipment								1,282	1,660
Assets	[3]	47,984						47,984		47,556
Operating Segments [Member]
Segment Reporting Information [Line Items]
Competitive businesses other revenues		194			139			432	335
Revenues		8,929			9,403			26,096	27,170
Net income (loss)		760			800			2,220	1,979
Assets		122,738						122,738		119,666
Operating Segments [Member] | Pepco Holdings LLC [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		(9)			(5)			4	7
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Competitive businesses other revenues		(1)			(1)			(4)	(4)
Revenues		(763)			(780)			(2,296)	(2,436)
Operating revenues from affiliates		(764)			(779)			(2,300)	(2,430)
Depreciation, Depletion and Amortization		0			0			0	0
Operating Expenses		(759)			(790)			(2,291)	(2,467)
Interest Revenue (Expense), Net		0			0			0	0
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest		0			0			0	0
Income taxes		0			0			0	0
Net income (loss)		0			0			0	0
Payments to Acquire Property, Plant, and Equipment		0			0			0	0
Assets		(10,085)						(10,085)		(9,800)
Intersegment Eliminations [Member] | Pepco Holdings LLC [Member]
Segment Reporting Information [Line Items]
Revenues		(92)			(104)			(298)	(328)
Operating revenues from affiliates		(93)			(105)			(298)	(327)
Depreciation, Depletion and Amortization		0			0			0	0
Operating Expenses		(94)			(104)			(298)	(324)
Interest Revenue (Expense), Net		0			0			0	0
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest		(195)			(182)			(422)	(339)
Income taxes		(1)			1			(1)	0
Net income (loss)		4			3			11	11
Payments to Acquire Property, Plant, and Equipment		0			0			0	0
Assets		(5,738)						(5,738)		(5,421)
Exelon Generation Co L L C [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Competitive businesses other revenues		195			140			436	339
Revenues		4,774			5,278			14,280	15,368
Depreciation, Depletion and Amortization		407			468			1,221	1,383
Operating Expenses		4,274			4,961			13,333	14,475
Interest Revenue (Expense), Net		109			101			336	305
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest		501			389			1,355	800
Income taxes		87			78			388	110
Net income (loss)		244			300			784	667
Payments to Acquire Property, Plant, and Equipment		392			362			1,282	1,660
Assets		47,984						47,984		47,556
Exelon Generation Co L L C [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Operating revenues from affiliates		275			308			844	981
Commonwealth Edison Co [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Competitive businesses other revenues		0			0			0	0
Revenues		1,583			1,598			4,342	4,508
Depreciation, Depletion and Amortization		259			237			767	696
Operating Expenses		1,256			1,275			3,431	3,610
Interest Revenue (Expense), Net		91			85			268	261
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest		245			245			674	663
Income taxes		45			52			130	140
Net income (loss)		200			193			544	523
Payments to Acquire Property, Plant, and Equipment		452			514			1,413	1,540
Assets		32,326						32,326		31,213
Commonwealth Edison Co [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Operating revenues from affiliates		4			4			13	23
PECO Energy Co [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Competitive businesses other revenues		0			0			0	0
Revenues		778			757			2,333	2,275
Depreciation, Depletion and Amortization		83			75			247	224
Operating Expenses		595			603			1,783	1,853
Interest Revenue (Expense), Net		33			32			100	96
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest		154			124			461	331
Income taxes		14			(2)			51	(5)
Net income (loss)		140			126			410	336
Payments to Acquire Property, Plant, and Equipment		228			204			675	615
Assets		11,379						11,379		10,642
PECO Energy Co [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Operating revenues from affiliates		1			2			4	5
Baltimore Gas and Electric Company [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Competitive businesses other revenues		0			0			0	0
Revenues		703			731			2,327	2,369
Depreciation, Depletion and Amortization		116			110			368	358
Operating Expenses		612			628			1,936	2,005
Interest Revenue (Expense), Net		31			27			89	78
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest		67			81			320	301
Income taxes		12			18			59	59
Net income (loss)		55			63			261	242
Payments to Acquire Property, Plant, and Equipment		300			233			842	667
Assets		10,304						10,304		9,716
Baltimore Gas and Electric Company [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Operating revenues from affiliates		6			6			18	18
Pepco Holdings LLC [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Competitive businesses other revenues		0			0			0	0
Revenues		1,380			1,361			3,700	3,688
Depreciation, Depletion and Amortization		193			192			562	555
Operating Expenses		1,124			1,116			3,106	3,165
Interest Revenue (Expense), Net		66			65			197	193
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest		203			191			436	363
Income taxes		14			4			25	28
Net income (loss)		189			187			412	336
Payments to Acquire Property, Plant, and Equipment		308			359			1,006	988
Assets		22,576						22,576		21,984
Pepco Holdings LLC [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Operating revenues from affiliates		4			3			11	11
Potomac Electric Power Company [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues		642			628			1,748	1,708
Depreciation, Depletion and Amortization		95			99			281	286
Operating Expenses		515			516			1,444	1,454
Interest Revenue (Expense), Net		33			32			100	96
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest		103			87			226	181
Income taxes		5			(2)			9	7
Net income (loss)		98			89			217	174
Payments to Acquire Property, Plant, and Equipment		157			188			455	475
Assets		8,603						8,603		8,299
Potomac Electric Power Company [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Operating revenues from affiliates		2			2			5	5
Delmarva Power and Light Company [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues		319			328			987	1,001
Depreciation, Depletion and Amortization		46			47			138	135
Operating Expenses		268			277			820	859
Interest Revenue (Expense), Net		15			15			45	42
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest		38			38			132	107
Income taxes		5			5			16	17
Net income (loss)		33			33			116	90
Payments to Acquire Property, Plant, and Equipment		85			88			245	254
Assets		4,724						4,724		4,588
Delmarva Power and Light Company [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Operating revenues from affiliates		1			2			5	6
Atlantic City Electric Company [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues		419			406			966	981
Depreciation, Depletion and Amortization		43			38			114	107
Operating Expenses		340			322			838	847
Interest Revenue (Expense), Net		15			16			44	48
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest		65			69			89	88
Income taxes		2			8			2	12
Net income (loss)		63			61			87	76
Payments to Acquire Property, Plant, and Equipment		73			77			300	247
Assets		3,916						3,916		3,699
Atlantic City Electric Company [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Operating revenues from affiliates		1			1			2	2
Corporate and Other [Member] | Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Competitive businesses other revenues		0			0			0	0
Revenues		474			458			1,410	1,398
Depreciation, Depletion and Amortization		25			23			72	68
Operating Expenses		457			459			1,405	1,395
Interest Revenue (Expense), Net		79			83			231	205
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest		(68)			(83)			(218)	(195)
Income taxes		0			(13)			(27)	(70)
Net income (loss)		(68)			(69)			(191)	(125)
Payments to Acquire Property, Plant, and Equipment		7			18			41	27
Assets		8,254						8,254		8,355
Corporate and Other [Member] | Corporate, Non-Segment [Member] | Pepco Holdings LLC [Member]
Segment Reporting Information [Line Items]
Revenues		92			103			297	326
Depreciation, Depletion and Amortization		9			8			29	27
Operating Expenses		95			105			302	329
Interest Revenue (Expense), Net		3			2			8	7
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest		192			179			411	326
Income taxes		3			(8)			(1)	(8)
Net income (loss)		(9)			1			(19)	(15)
Payments to Acquire Property, Plant, and Equipment		(7)			6			6	12
Assets		11,071						11,071		$ 10,819
Corporate and Other [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Operating revenues from affiliates		474			456			1,410	1,392
Corporate and Other [Member] | Intersegment Eliminations [Member] | Pepco Holdings LLC [Member]
Segment Reporting Information [Line Items]
Operating revenues from affiliates		93			103			297	325
Generation Mid Atlantic [Member]
Segment Reporting Information [Line Items]
Revenues		1,364			1,456			3,809	4,179
Generation Mid Atlantic [Member] | PECO Energy Co Affiliate [Member] | Exelon Generation Co L L C [Member]
Segment Reporting Information [Line Items]
Operating revenues from affiliates		43			35			123	97
Generation Mid Atlantic [Member] | Baltimore Gas And Electric Company Affiliate [Member] | Exelon Generation Co L L C [Member]
Segment Reporting Information [Line Items]
Operating revenues from affiliates		65			69			199	198
Generation Mid Atlantic [Member] | PotomacElectricPowerCompanyAffiliate [Member] | Exelon Generation Co L L C [Member]
Segment Reporting Information [Line Items]
Operating revenues from affiliates		65			46			188	143
Generation Mid Atlantic [Member] | DelmarvaPowerandLightCompanyAffiliate [Member] | Exelon Generation Co L L C [Member]
Segment Reporting Information [Line Items]
Operating revenues from affiliates		14			26			50	103
Generation Mid Atlantic [Member] | AtlanticCityElectricCompanyAffiliate [Member] | Exelon Generation Co L L C [Member]
Segment Reporting Information [Line Items]
Operating revenues from affiliates		3			10			16	21
Generation Mid Atlantic [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues		1,361			1,449			3,807	4,162
Generation Mid Atlantic [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Operating revenues from affiliates		3			7			2	17
Generation Midwest [Member]
Segment Reporting Information [Line Items]
Revenues		1,082			1,117			3,224	3,593
Generation Midwest [Member] | Commonwealth Edison Co Affiliate [Member] | Exelon Generation Co L L C [Member]
Segment Reporting Information [Line Items]
Operating revenues from affiliates		83			122			266	419
Generation Midwest [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues		1,099			1,121			3,255	3,601
Generation Midwest [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Operating revenues from affiliates		(17)			(4)			(31)	(8)
Oil and Gas, Purchased [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		266			397			1,479	1,831
Oil and Gas, Purchased [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		1			0			0	(8)
Oil and Gas, Purchased [Member] | Exelon Generation Co L L C [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		265			397			1,479	1,839
Oil and Gas, Purchased [Member] | Commonwealth Edison Co [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		0			0			0	0
Oil and Gas, Purchased [Member] | PECO Energy Co [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		0			0			0	0
Oil and Gas, Purchased [Member] | Baltimore Gas and Electric Company [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		0			0			0	0
Oil and Gas, Purchased [Member] | Pepco Holdings LLC [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		0			0			0	0
Oil and Gas, Purchased [Member] | Corporate and Other [Member] | Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		0			0			0	0
Electricity, US Regulated | Pepco Holdings LLC [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		1,365			1,340			3,570	3,541
Electricity, US Regulated | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		4,268			4,270			11,609	11,766
Electricity, US Regulated | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		(7)			(7)			(25)	(34)
Electricity, US Regulated | Intersegment Eliminations [Member] | Pepco Holdings LLC [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		(3)			(4)			(10)	(12)
Electricity, US Regulated | Exelon Generation Co L L C [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		0			0			0	0
Electricity, US Regulated | Commonwealth Edison Co [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		1,583			1,598			4,342	4,508
Electricity, US Regulated | PECO Energy Co [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		716			700			1,901	1,893
Electricity, US Regulated | Baltimore Gas and Electric Company [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		619			645			1,817	1,850
Electricity, US Regulated | Pepco Holdings LLC [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		1,357			1,334			3,574	3,549
Electricity, US Regulated | Potomac Electric Power Company [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		642			628			1,748	1,708
Electricity, US Regulated | Delmarva Power and Light Company [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		299			304			871	872
Electricity, US Regulated | Atlantic City Electric Company [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		419			406			966	981
Electricity, US Regulated | Corporate and Other [Member] | Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		0			0			0	0
Electricity, US Regulated | Corporate and Other [Member] | Corporate, Non-Segment [Member] | Pepco Holdings LLC [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		0			0			(1)	0
Electricity, Generation [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		4,039			4,435			11,525	12,221
Electricity, Generation [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		(275)			(306)			(840)	(969)
Electricity, Generation [Member] | Exelon Generation Co L L C [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		4,314			4,741			12,365	13,190
Electricity, Generation [Member] | Commonwealth Edison Co [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		0			0			0	0
Electricity, Generation [Member] | PECO Energy Co [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		0			0			0	0
Electricity, Generation [Member] | Baltimore Gas and Electric Company [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		0			0			0	0
Electricity, Generation [Member] | Pepco Holdings LLC [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		0			0			0	0
Electricity, Generation [Member] | Corporate and Other [Member] | Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		0			0			0	0
Natural Gas, US Regulated | Pepco Holdings LLC [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		20			23			115	129
Natural Gas, US Regulated | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		163			162			1,046	1,017
Natural Gas, US Regulated | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		(3)			(5)			(12)	(13)
Natural Gas, US Regulated | Intersegment Eliminations [Member] | Pepco Holdings LLC [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		0			0			0	0
Natural Gas, US Regulated | Exelon Generation Co L L C [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		0			0			0	0
Natural Gas, US Regulated | Commonwealth Edison Co [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		0			0			0	0
Natural Gas, US Regulated | PECO Energy Co [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		62			57			432	382
Natural Gas, US Regulated | Baltimore Gas and Electric Company [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		84			86			510	519
Natural Gas, US Regulated | Pepco Holdings LLC [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		20			24			116	129
Natural Gas, US Regulated | Potomac Electric Power Company [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		0			0			0	0
Natural Gas, US Regulated | Delmarva Power and Light Company [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		20			24			116	129
Natural Gas, US Regulated | Atlantic City Electric Company [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		0			0			0	0
Natural Gas, US Regulated | Corporate and Other [Member] | Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		0			0			0	0
Natural Gas, US Regulated | Corporate and Other [Member] | Corporate, Non-Segment [Member] | Pepco Holdings LLC [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		0			0			0	0
Service, Other [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		(1)			0			5	0
Service, Other [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		(478)			(461)			(1,415)	(1,408)
Service, Other [Member] | Intersegment Eliminations [Member] | Pepco Holdings LLC [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		(89)			(100)			(288)	(316)
Service, Other [Member] | Exelon Generation Co L L C [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		0			0			0	0
Service, Other [Member] | Commonwealth Edison Co [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		0			0			0	0
Service, Other [Member] | PECO Energy Co [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		0			0			0	0
Service, Other [Member] | Baltimore Gas and Electric Company [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		0			0			0	0
Service, Other [Member] | Pepco Holdings LLC [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		3			3			10	10
Service, Other [Member] | Potomac Electric Power Company [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		0			0			0	0
Service, Other [Member] | Delmarva Power and Light Company [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		0			0			0	0
Service, Other [Member] | Atlantic City Electric Company [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		0			0			0	0
Service, Other [Member] | Corporate and Other [Member] | Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		474			458			1,410	1,398
Service, Other [Member] | Corporate and Other [Member] | Corporate, Non-Segment [Member] | Pepco Holdings LLC [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Including Assessed Tax		$ 92			$ 103			$ 298	$ 326

[1] Exelon’s consolidated assets include $9,465 million and $9,667 million at September 30, 2019 and December 31, 2018, respectively, of certain VIEs that can only be used to settle the liabilities of the VIE. Exelon’s consolidated liabilities include $3,517 million and $3,548 million at September 30, 2019 and December 31, 2018, respectively, of certain VIEs for which the VIE creditors do not have recourse to Exelon. See Note 2 — Variable Interest Entities for additional information.

[2] PHI’s consolidated total assets include $22 million and $33 million at September 30, 2019 and December 31, 2018, respectively, of PHI's consolidated VIE that can only be used to settle the liabilities of the VIE. PHI’s consolidated total liabilities include $50 million and $69 million at September 30, 2019 and December 31, 2018, respectively, of PHI's consolidated VIE for which the VIE creditors do not have recourse to PHI. See Note 2 — Variable Interest Entities for additional information.

[3] Generation’s consolidated assets include $9,443 million and $9,634 million at September 30, 2019 and December 31, 2018, respectively, of certain VIEs that can only be used to settle the liabilities of the VIE. Generation’s consolidated liabilities include $3,467 million and $3,480 million at September 30, 2019 and December 31, 2018, respectively, of certain VIEs for which the VIE creditors do not have recourse to Generation. See Note 2 — Variable Interest Entities for additional information.