Consolidated Statements of Operations and Comprehensive Income (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended						6 Months Ended
	Jun. 30, 2017		Jun. 30, 2016		Jun. 30, 2016	Mar. 23, 2016	Jun. 30, 2017		Jun. 30, 2016
Operating revenues [Abstract]
Operating Revenue	$ 3,908		$ 3,234				$ 8,468		$ 7,708
Regulated Operating Revenue	3,715		3,676				7,913		6,777
Electric operating revenues	3,511	[1]	3,480	[1]			7,156	[2]	6,136	[2]
Natural gas operating revenues	204	[1]	197	[1]			757	[2]	641	[2]
Operating revenues from affiliates	0	[3]	1	[3]			0	[4]	2	[4]
Revenues	7,623		6,910				16,381		14,485
Operating expenses
Competitive businesses purchased power and fuel	2,158		1,576				4,952		4,016
Cost of Purchased Power	928		878				2,033		1,692
Operating and maintenance	2,971		2,505				5,431		5,341
Depreciation and amortization	915		941				1,811		1,626
Taxes other than income	420		394				857		720
Total operating expenses	7,392		6,294				15,084		13,395
Gain (Loss) on Disposition of Other Assets	1		31				5		40
Bargain purchase gain	0		0				226		0
Operating income	232		647				1,528		1,130
Other income and (deductions)
Interest expense, net	(426)		(366)				(789)		(643)
Interest expense to affiliates	(10)		(10)				(20)		(20)
Other, net	205		144				488		258
Total other income and (deductions)	(231)		(232)				(321)		(405)
Income before income taxes	1		415				1,207		725
Income taxes	(72)		102				143		285
Equity in losses of unconsolidated affiliates	(9)		(7)				(18)		(10)
Net income	64		306				1,046		430
Net (loss) income attributable to noncontrolling interests and preference stock dividends	(16)		39				(30)		(10)
Net income attributable to common shareholders	80		267				1,076		440
Other comprehensive income (loss), net of income taxes
Prior service benefit reclassified to periodic benefit cost	(14)		(12)				(28)		(23)
Actuarial loss reclassified to periodic benefit cost	49		46				98		93
Pension and non-pension postretirement benefit plan valuation adjustment	(2)		(1)				(58)		(3)
Unrealized (loss) gain on cash flow hedges	1		0				(5)		7
Other Comprehensive Income Unrealized Income Loss On Equity Investments Arising During Period Net Of Tax	0		(4)				3		(7)
Unrealized gain on foreign currency translation	2		0				3		6
Unrealized gain on marketable securities	1		2				2		0
Other comprehensive income	35		31				25		59
Comprehensive income	99		337				1,071		489
Comprehensive (loss) income attributable to noncontrolling interests and preference stock dividends	(16)		39				(32)		(10)
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	$ 115		$ 298				$ 1,103		$ 499
Average shares of common stock outstanding:
Weighted average common shares outstanding — basic	934		924				931		923
Weighted average common shares outstanding — diluted	936		926				932		926
Earnings per average common share:
Basic	$ 0.09		$ 0.29				$ 1.16		$ 0.48
Diluted	0.09		0.29				1.15		0.48
Dividends declared per common share	$ 0.33		$ 0.32				$ 0.66		$ 0.63
Exelon Generation Co L L C [Member]
Operating revenues [Abstract]
Operating Revenue	$ 3,906		$ 3,231				$ 8,463		$ 7,702
Operating revenues from affiliates	268		358				598		627
Revenues	4,174		3,589				9,061		8,329
Operating expenses
Cost of Purchased Power	2,156		1,575				4,952		4,015
Purchased power from affiliate	1		2				3		5
Operating and maintenance	1,824		1,369				3,132		2,665
Operating and maintenance from affiliates	186		161				365		332
Depreciation and amortization	334		408				637		697
Taxes other than income	140		118				282		244
Total operating expenses	4,641		3,633				9,371		7,958
Gain (Loss) on Disposition of Other Assets	0		31				4		31
Bargain purchase gain	0		0				226		0
Operating income	(467)		(13)				(80)		402
Other income and (deductions)
Interest expense, net	(120)		(89)				(209)		(176)
Interest expense to affiliates	(9)		(10)				(19)		(20)
Other, net	181		117				440		210
Total other income and (deductions)	52		18				212		14
Income before income taxes	(415)		5				132		416
Income taxes	(158)		(31)				(31)		120
Equity in losses of unconsolidated affiliates	(9)		(8)				(19)		(11)
Net income	(266)		28				144		285
Net (loss) income attributable to noncontrolling interests	(16)		36				(30)		(17)
Net (loss) income attributable to membership interest	(250)		(8)				174		302
Other comprehensive income (loss), net of income taxes
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Net of Tax	0		1				0		0
Unrealized (loss) gain on cash flow hedges	1		(1)				(5)		4
Other Comprehensive Income Unrealized Income Loss On Equity Investments Arising During Period Net Of Tax	0		(2)				4		(4)
Unrealized gain on foreign currency translation	2		0				3		6
Other comprehensive income	1		0				12		(2)
Comprehensive income	(265)		28				156		283
Comprehensive (loss) income attributable to noncontrolling interests and preference stock dividends	(16)		36				(32)		(17)
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	(249)		(8)				188		300
Commonwealth Edison Co [Member]
Operating revenues [Abstract]
Electric operating revenues	1,354		1,283				2,647		2,527
Operating revenues from affiliates	3		3				9		8
Revenues	1,357		1,286				2,656		2,535
Operating expenses
Purchased power	360		326				689		668
Purchased power from affiliate	18		13				24		18
Operating and maintenance	312		318				620		623
Operating and maintenance from affiliates	65		50				127		113
Depreciation and amortization	211		190				419		379
Taxes other than income	72		65				144		141
Total operating expenses	1,038		962				2,023		1,942
Gain (Loss) on Disposition of Other Assets	0		0				0		5
Operating income	319		324				633		598
Other income and (deductions)
Interest expense, net	(98)		(88)				(179)		(170)
Interest expense to affiliates	(3)		(3)				(6)		(7)
Other, net	4		3				8		7
Total other income and (deductions)	(97)		(88)				(177)		(170)
Income before income taxes	222		236				456		428
Income taxes	104		91				197		168
Net income	118		145				259		260
Other comprehensive income (loss), net of income taxes
Comprehensive income	118		145				259		260
PECO Energy Co [Member]
Operating revenues [Abstract]
Electric operating revenues	548		585				1,138		1,228
Natural gas operating revenues	80		77				285		273
Operating revenues from affiliates	2		2				3		4
Revenues	630		664				1,426		1,505
Operating expenses
Purchased power	136		130				292		295
Purchased fuel	27		23				113		100
Purchased power from affiliate	34		64				79		142
Operating and maintenance	153		157				326		333
Operating and maintenance from affiliates	37		33				72		72
Depreciation and amortization	71		67				141		134
Taxes other than income	35		38				74		80
Total operating expenses	493		512				1,097		1,156
Operating income	137		152				329		349
Other income and (deductions)
Interest expense, net	(28)		(28)				(56)		(56)
Interest expense to affiliates	(3)		(3)				(6)		(6)
Other, net	2		2				3		4
Total other income and (deductions)	(29)		(29)				(59)		(58)
Income before income taxes	108		123				270		291
Income taxes	20		23				55		67
Net income	88		100				215		224
Other comprehensive income (loss), net of income taxes
Comprehensive income	88		100				215		224
Baltimore Gas and Electric Company [Member]
Operating revenues [Abstract]
Electric operating revenues	569		582				1,234		1,260
Natural gas operating revenues	102		94				383		340
Operating revenues from affiliates	3		4				8		9
Revenues	674		680				1,625		1,609
Operating expenses
Purchased power	115		108				248		235
Purchased fuel	22		20				105		95
Purchased power from affiliate	97		133				231		304
Operating and maintenance	135		177				284		345
Operating and maintenance from affiliates	39		31				73		65
Depreciation and amortization	112		97				239		206
Taxes other than income	56		55				119		114
Total operating expenses	576		621				1,299		1,364
Operating income	98		59				326		245
Other income and (deductions)
Interest expense, net	(22)		(20)				(46)		(40)
Interest expense to affiliates	(4)		(4)				(8)		(8)
Other, net	4		5				8		11
Total other income and (deductions)	(22)		(19)				(46)		(37)
Income before income taxes	76		40				280		208
Income taxes	31		6				111		73
Net income	45		34				169		135
Preference stock dividends	0		3				0		6
Net income attributable to common shareholders	45		31				169		129
Other comprehensive income (loss), net of income taxes
Comprehensive income	45		34				169		135
Comprehensive (loss) income attributable to noncontrolling interests and preference stock dividends	0		3				0		6
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	45		31				169		129
Pepco Holdings LLC [Member] | Predecessor [Member]
Operating revenues [Abstract]
Electric operating revenues						$ 1,096
Natural gas operating revenues						57
Operating revenues from affiliates						0
Revenues						1,153
Operating expenses
Purchased power						471
Purchased fuel						26
Purchased power from affiliate						0
Operating and maintenance						294
Operating and maintenance from affiliates						0
Depreciation and amortization						152
Taxes other than income						105
Total operating expenses						1,048
Operating income						105
Other income and (deductions)
Interest expense, net						(65)
Other, net						(4)
Total other income and (deductions)						(69)
Income before income taxes						36
Income taxes						17
Net income						19
Other comprehensive income (loss), net of income taxes
Actuarial loss reclassified to periodic benefit cost						1
Other comprehensive income						1
Comprehensive income						$ 20
Pepco Holdings LLC [Member] | Successor [Member]
Operating revenues [Abstract]
Electric operating revenues	1,040		1,030		$ 1,120		2,138
Natural gas operating revenues	22		26		28		87
Operating revenues from affiliates	12		10		23		23
Revenues	1,074		1,066		1,171		2,248
Operating expenses
Purchased power	259		263		288		547
Purchased fuel	9		9		11		39
Purchased power from affiliate	115		144		155		259
Operating and maintenance	231		223		670		454
Operating and maintenance from affiliates	38		23		25		70
Depreciation and amortization	165		160		174		332
Taxes other than income	110		108		123		221
Total operating expenses	927		930		1,446		1,922
Gain (Loss) on Disposition of Other Assets	1						1
Operating income	148		136		(275)		327
Other income and (deductions)
Interest expense, net	(59)		(66)		(71)		(122)
Other, net	13		11		12		26
Total other income and (deductions)	(46)		(55)		(59)		(96)
Income before income taxes	102		81		(334)		231
Income taxes	36		29		(77)		26
Net income	66		52		(257)		205
Other comprehensive income (loss), net of income taxes
Actuarial loss reclassified to periodic benefit cost	0		0		0		0
Other comprehensive income	0		0		0		0
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	66		52		$ (257)		205
Potomac Electric Power Company [Member]
Operating revenues [Abstract]
Electric operating revenues	513		508				1,042		1,058
Operating revenues from affiliates	1		1				3		3
Revenues	514		509				1,045		1,061
Operating expenses
Purchased power	74		64				157		256
Purchased power from affiliate	69		88				152		95
Operating and maintenance	106		100				208		389
Operating and maintenance from affiliates	14		9				26		10
Depreciation and amortization	78		70				160		144
Taxes other than income	90		89				180		182
Total operating expenses	431		420				883		1,076
Gain (Loss) on Disposition of Other Assets	1		8				1		8
Operating income	84		97				163		(7)
Other income and (deductions)
Interest expense, net	(28)		(31)				(58)		(68)
Other, net	7		6				15		14
Total other income and (deductions)	(21)		(25)				(43)		(54)
Income before income taxes	63		72				120		(61)
Income taxes	20		23				19		(1)
Net income	43		49				101		(60)
Other comprehensive income (loss), net of income taxes
Comprehensive income	43		49				101		(60)
Delmarva Power and Light Company [Member]
Operating revenues [Abstract]
Electric operating revenues	258		253				553		554
Natural gas operating revenues	22		26				87		85
Operating revenues from affiliates	2		2				4		4
Revenues	282		281				644		643
Operating expenses
Purchased power	64		70				141		216
Purchased fuel	9		9				38		35
Purchased power from affiliate	40		43				91		47
Operating and maintenance	66		73				133		277
Operating and maintenance from affiliates	8		5				15		6
Depreciation and amortization	40		38				79		76
Taxes other than income	14		13				28		28
Total operating expenses	241		251				525		685
Operating income	41		30				119		(42)
Other income and (deductions)
Interest expense, net	(13)		(13)				(25)		(25)
Other, net	3		3				6		6
Total other income and (deductions)	(10)		(10)				(19)		(19)
Income before income taxes	31		20				100		(61)
Income taxes	12		8				24		(1)
Net income	19		12				76		(60)
Other comprehensive income (loss), net of income taxes
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	19		12				76		(60)
Atlantic City Electric Company [Member]
Operating revenues [Abstract]
Electric operating revenues	269		269				543		559
Operating revenues from affiliates	1		1				1		2
Revenues	270		270				544		561
Operating expenses
Purchased power	121		129				250		285
Purchased power from affiliate	7		12				16		13
Operating and maintenance	71		63				139		275
Operating and maintenance from affiliates	7		5				13		5
Depreciation and amortization	37		41				72		81
Taxes other than income	2		2				4		4
Total operating expenses	245		252				494		663
Gain (Loss) on Disposition of Other Assets	0		1				0		1
Operating income	25		19				50		(101)
Other income and (deductions)
Interest expense, net	(15)		(16)				(30)		(32)
Other, net	2		2				4		5
Total other income and (deductions)	(13)		(14)				(26)		(27)
Income before income taxes	12		5				24		(128)
Income taxes	4		2				(12)		(31)
Net income	8		3				36		(97)
Other comprehensive income (loss), net of income taxes
Comprehensive income							$ 36		$ (97)
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	$ 8		$ 3

[1] 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, 2017 and 2016.

[2] 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, 2017 and 2016.

[3] 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.

[4] 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.