Consolidated Statements of Operations and Comprehensive Income (Unaudited) - USD ($) shares in Millions, $ in Millions		3 Months Ended			6 Months Ended	9 Months Ended
		Sep. 30, 2016	Mar. 23, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2016	Sep. 30, 2015
Gain (Loss) on Disposition of Assets	[1]						$ (26)
Operating revenues [Abstract]
Electrical Generation Revenue		$ 4,535		$ 4,564		$ 12,243	14,278
Gas Domestic Regulated Revenue		137		116		781	904
Operating revenues from affiliates		1		2
Regulated Operating Revenue		4,467		2,837		11,243	8,468
Electric Revenue		4,330		2,721		10,461	7,564
Revenues		9,002		7,401		23,486	22,746
Operating expenses
Purchased power		2,584		2,515		6,599	7,789
Cost of Purchased Power		1,170		776		2,863	2,421
Operating and maintenance		2,338		1,996		7,677	6,119
Depreciation and amortization		1,195		606		2,821	1,818
Taxes other than income		449		310		1,168	908
Total operating expenses		7,736		6,203		21,128	19,055
Gain (Loss) on Sale of Assets and Asset Impairment Charges		1		2		41	10
Operating income		1,267		1,200		2,399	3,701
Other income and (deductions)
Interest expense, net		(506)		(243)		(1,148)	(724)
Interest expense to affiliates		(10)		(10)		(31)	(31)
Other, net		120		(244)		377	(179)
Total other income and (deductions)		(396)		(497)		(802)	(934)
Income before income taxes		871		703		1,597	2,767
Income taxes		340		115		625	805
Income (Loss) from Equity Method Investments, Net of Dividends or Distributions		(5)		(1)		(16)	(3)
Net income		526		587		956	1,959
Net income (loss) attributable to noncontrolling interests and preference stock dividends		36		(42)		26	0
Net income attributable to common shareholders		490		629		930	1,959
Other comprehensive income (loss), net of income taxes
Prior service benefit reclassified to periodic benefit cost		(12)		(11)		(35)	(35)
Actuarial loss reclassified to periodic benefit cost		47		55		140	165
Other Comprehensive Income Pension And Non Pension Postretirement Benefit Plan Valuation Adjustment Net Of Tax		0		0		3	29
Unrealized gain (loss) on cash flow hedges		3		(3)		(4)	4
Other Comprehensive Income Unrealized Income Loss On Equity Investments Arising During Period Net Of Tax		(4)		0		(10)	0
Unrealized loss on marketable securities		0		(1)		0	0
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax		2		(8)		8	(17)
Other comprehensive income		36		32		96	88	[2]
Comprehensive income		562		619		1,052	2,047
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest		31		(42)		21	0
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest		$ 531		$ 661		$ 1,031	$ 2,047
Average shares of common stock outstanding:
Weighted average common shares outstanding — basic		925		913		924	879
Average common shares outstanding — diluted		927		915		926	883
Earnings per average common share:
Earnings per share - basic (in usd per share)		$ 0.53		$ 0.69		$ 1.01	$ 2.23
Earnings per average common share - diluted
Earnings per share - diluted (in usd per share)		0.53		0.69		1.00	2.22
Dividends per common share (in usd per share)		$ 0.318		$ 0.31		$ 0.946	$ 0.93
PECO Energy Co [Member]
Operating revenues [Abstract]
Gas Domestic Regulated Revenue		$ 48		$ 48		$ 322	$ 435
Operating revenues from affiliates		2		1		5	1
Electric Revenue		738		691		1,966	1,950
Revenues		788		740		2,293	2,386
Operating expenses
Utilities Operating Expense, Purchased Power		171		207		466	584
Purchased power and fuel from affiliates		91		61		233	171
Utilities Operating Expense, Fuel Used		10		10		110	198
Operating and maintenance		168		166		501	529
Operating and maintenance from affiliates		31		30		103	80
Depreciation and amortization		67		68		201	198
Taxes other than income		46		44		126	125
Total operating expenses		584		586		1,740	1,885
Gain (Loss) on Disposition of Other Assets						0	1
Operating income		204		154		553	502
Other income and (deductions)
Interest expense, net		(27)		(25)		(83)	(75)
Interest expense to affiliates		(3)		(3)		(9)	(9)
Other, net		2		1		6	3
Total other income and (deductions)		(28)		(27)		(86)	(81)
Income before income taxes		176		127		467	421
Income taxes		54		37		121	122
Net income		122		90		346	299
Other comprehensive income (loss), net of income taxes
Other comprehensive income	[2]						0
Comprehensive income		122		90		346	299
Exelon Generation Co L L C [Member]
Gain (Loss) on Disposition of Assets							0
Operating revenues [Abstract]
Electrical Generation Revenue		4,533		4,562		12,234	14,270
Operating revenues from affiliates		502		206		1,129	571
Revenues		5,035		4,768		13,363	14,841
Operating expenses
Cost of Purchased Power		2,584		2,516		6,599	7,789
Purchased power and fuel from affiliates		5		3		10	11
Operating and maintenance		1,189		1,088		3,855	3,399
Operating and maintenance from affiliates		147		153		478	461
Depreciation and amortization		632		264		1,329	774
Taxes other than income		136		123		380	369
Total operating expenses		4,693		4,147		12,651	12,803
Gain (Loss) on Sale of Assets and Asset Impairment Charges		0		1		31	7
Operating income		342		622		743	2,045
Other income and (deductions)
Interest expense, net		(67)		(56)		(243)	(236)
Interest expense to affiliates		(10)		(12)		(30)	(33)
Other, net		185		(257)		395	(193)
Total other income and (deductions)		108		(325)		122	(462)
Income before income taxes		450		297		865	1,583
Income taxes		173		(36)		293	371
Income (Loss) from Equity Method Investments, Net of Dividends or Distributions		(6)		(1)		(16)	(4)
Net income		271		332		556	1,208
Net income (loss) attributable to noncontrolling interests		35		(45)		18	(10)
Net income attributable to membership interest		236		377		538	1,218
Other comprehensive income (loss), net of income taxes
Unrealized gain (loss) on cash flow hedges		1		(3)		(3)	(7)
Other Comprehensive Income Unrealized Income Loss On Equity Investments Arising During Period Net Of Tax		0		0		(4)	0
Unrealized loss on marketable securities		1		(2)		1	0
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax		2		(8)		8	(17)
Other comprehensive income		4		(13)		2	(24)	[2]
Comprehensive income		275		319		558	1,184
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest		245		364		545	1,194
Commonwealth Edison Co [Member]
Operating revenues [Abstract]
Operating revenues		1,493		1,375		4,019	3,706
Operating revenues from affiliates		4		1		12	3
Revenues		1,497		1,376		4,031	3,709
Operating expenses
Cost of Purchased Power		435		388		1,104	974
Purchased power and fuel from affiliates		19		2		37	17
Operating and maintenance		327		353		950	1,023
Operating and maintenance from affiliates		50		51		163	143
Depreciation and amortization		196		176		574	528
Taxes other than income		82		79		222	225
Total operating expenses		1,109		1,049		3,050	2,910
Gain (Loss) on Sale of Assets and Asset Impairment Charges		1		0		6	0
Operating income		389		327		987	799
Other income and (deductions)
Interest expense, net		(194)		(80)		(364)	(238)
Interest expense to affiliates		(3)		(3)		(10)	(10)
Other, net		(80)		4		(72)	14
Total other income and (deductions)		(277)		(79)		(446)	(234)
Income before income taxes		112		248		541	565
Income taxes		75		99		244	226
Net income		37		149		297	339
Other comprehensive income (loss), net of income taxes
Comprehensive income		37		149		297	339
Baltimore Gas and Electric Company [Member]
Operating revenues [Abstract]
Gas Domestic Regulated Revenue		72		66		412	468
Operating revenues from affiliates		7		3		16	10
Electric Revenue		733		656		1,993	1,910
Revenues		812		725		2,421	2,388
Operating expenses
Utilities Operating Expense, Purchased Power		164		159		399	497
Purchased power and fuel from affiliates		182		141		486	373
Utilities Operating Expense, Fuel Used		14		11		109	167
Operating and maintenance		150		138		494	412
Operating and maintenance from affiliates		28		31		94	87
Depreciation and amortization		101		79		307	271
Taxes other than income		58		57		172	169
Total operating expenses		697		616		2,061	1,976
Gain (Loss) on Sale of Assets and Asset Impairment Charges				1			1
Operating income		115		110		360	413
Other income and (deductions)
Interest expense, net		(24)		(21)		(64)	(62)
Interest expense to affiliates		(4)		(4)		(12)	(11)
Other, net		5		4		16	13
Total other income and (deductions)		(23)		(21)		(60)	(60)
Income before income taxes		92		89		300	353
Income taxes		36		35		109	141
Net income		56		54		191	212
Preferred security dividends and redemption		2		3		8	10
Net income attributable to common shareholders		54		51		183	202
Other comprehensive income (loss), net of income taxes
Comprehensive income		56		54		191	212
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest		2		3		8	10
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest		54		51		183	202
Pepco Holdings LLC [Member] | Predecessor [Member]
Operating revenues [Abstract]
Gas Domestic Regulated Revenue			$ 57	19			129
Operating revenues from affiliates			0	0			0
Electric Revenue			1,096	1,317			3,680
Revenues			1,153	1,336			3,809
Operating expenses
Cost of Purchased Power			471	570			1,575
Purchased power and fuel from affiliates			0	0			0
Utilities Operating Expense, Fuel Used			26	9			71
Operating and maintenance			294	287			875
Operating and maintenance from affiliates			0	0			0
Depreciation and amortization			152	166			474
Taxes other than income			105	120			349
Total operating expenses			1,048	1,152			3,344
Operating income			105	184			465
Other income and (deductions)
Interest expense, net			(65)	(71)			(211)
Other, net			(4)	27			48
Total other income and (deductions)			(69)	(44)			(163)
Income before income taxes			36	140			302
Income taxes			17	49			105
Net income			19	91			197
Other comprehensive income (loss), net of income taxes
Actuarial loss reclassified to periodic benefit cost			1	0			4
Unrealized gain (loss) on cash flow hedges				1			1
Other comprehensive income			1	1			5
Comprehensive income			$ 20	92			202
Pepco Holdings LLC [Member] | Successor [Member]
Operating revenues [Abstract]
Gas Domestic Regulated Revenue		17			$ 46
Operating revenues from affiliates		11			34
Electric Revenue		1,366			2,485
Revenues		1,394			2,565
Operating expenses
Cost of Purchased Power		370			658
Purchased power and fuel from affiliates		207			362
Utilities Operating Expense, Fuel Used		6			17
Operating and maintenance		200			870
Operating and maintenance from affiliates		26			51
Depreciation and amortization		182			355
Taxes other than income		124			248
Total operating expenses		1,115			2,561
Operating income		279			4
Other income and (deductions)
Interest expense, net		(64)			(135)
Other, net		19			31
Total other income and (deductions)		(45)			(104)
Income before income taxes		234			(100)
Income taxes		68			(9)
Net income		166			(91)
Other comprehensive income (loss), net of income taxes
Actuarial loss reclassified to periodic benefit cost		0			0
Other comprehensive income		0			0
Comprehensive income		166			$ (91)
Potomac Electric Power Company [Member]
Gain (Loss) on Disposition of Assets		0				8
Operating revenues [Abstract]
Operating revenues from affiliates		1		1		3	4
Electric Revenue		634		591		1,692	1,637
Revenues		635		592		1,695	1,641
Operating expenses
Cost of Purchased Power		84		200		340	573
Purchased power and fuel from affiliates		129		0		223	0
Operating and maintenance		100		110		488	324
Operating and maintenance from affiliates		9		1		20	3
Depreciation and amortization		76		66		221	191
Taxes other than income		105		100		287	289
Total operating expenses		503		477		1,579	1,380
Operating income		132		115		124	261
Other income and (deductions)
Interest expense, net		(30)		(31)		(98)	(92)
Other, net		12		8		28	21
Total other income and (deductions)		(18)		(23)		(70)	(71)
Income before income taxes		114		92		54	190
Income taxes		35		32		34	62
Net income		79		60		20	128
Other comprehensive income (loss), net of income taxes
Comprehensive income		79		60		20	128
Delmarva Power and Light Company [Member]
Gain (Loss) on Disposition of Assets		4		0		4	0
Operating revenues [Abstract]
Gas Domestic Regulated Revenue		17		19		102	129
Operating revenues from affiliates		2		1		6	4
Electric Revenue		312		294		866	871
Revenues		331		314		974	1,004
Operating expenses
Utilities Operating Expense, Purchased Power		81		143		297	435
Purchased power and fuel from affiliates		63		0		110	0
Utilities Operating Expense, Fuel Used		6		8		41	65
Operating and maintenance		50		77		327	233
Operating and maintenance from affiliates		5		0		11	1
Depreciation and amortization		44		40		120	113
Taxes other than income		14		14		42	39
Total operating expenses		263		282		948	886
Operating income		72		32		30	118
Other income and (deductions)
Interest expense, net		(12)		(12)		(37)	(37)
Other, net		3		4		9	8
Total other income and (deductions)		(9)		(8)		(28)	(29)
Income before income taxes		63		24		2	89
Income taxes		19		9		18	34
Net income		44		15		(16)	55
Other comprehensive income (loss), net of income taxes
Comprehensive income		44		15		(16)	55
Atlantic City Electric Company [Member]
Gain (Loss) on Disposition of Assets		0				1
Operating revenues [Abstract]
Operating revenues from affiliates		1		1		3	2
Electric Revenue		420		385		979	1,001
Revenues		421		386		982	1,003
Operating expenses
Cost of Purchased Power		206		214		491	552
Purchased power and fuel from affiliates		15		0		29	0
Operating and maintenance		62		69		336	205
Operating and maintenance from affiliates		5		1		10	2
Depreciation and amortization		49		49		130	135
Taxes other than income		1		2		6	5
Total operating expenses		338		335		1,002	899
Operating income		83		51		(19)	104
Other income and (deductions)
Interest expense, net		(15)		(16)		(47)	(48)
Other, net		2		1		8	4
Total other income and (deductions)		(13)		(15)		(39)	(44)
Income before income taxes		70		36		(58)	60
Income taxes		23		14		(8)	23
Net income		47		22		(50)	37
Other comprehensive income (loss), net of income taxes
Comprehensive income		$ 47		$ 22		$ (50)	$ 37

[1] In January 2015, in connection with Generation's $750 million issuance of five-year Senior Unsecured Notes, Exelon terminated certain floating-to-fixed interest rate swaps. As the original forecasted transactions were a series of future interest payments over a ten year period, a portion of the anticipated interest payments were probable not to occur. As a result, $26 million of anticipated payments were reclassified from AOCI to Other, net in Exelon's Consolidated Statement of Operations and Comprehensive Income.

[2] All amounts are net of tax and noncontrolling interest. Amounts in parenthesis represent a decrease in AOCI.