Consolidated Statements of Operations and Comprehensive Income (Unaudited) - USD ($) shares in Millions, $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Operating revenues
Revenues from alternative revenue programs		$ (80)	$ (25)	$ (98)	$ (41)
Operating revenues from affiliates		0	0	0	0
Total operating revenues		8,929	9,403	26,096	27,170
Operating expenses
Operating and maintenance		2,072	2,346	6,419	7,036
Depreciation and amortization		1,083	1,105	3,237	3,284
Taxes other than income		452	469	1,316	1,342
Total operating expenses		7,559	8,252	22,703	24,036
Gain on sales of assets and businesses		(17)	(5)	19	55
Operating income		1,353	1,146	3,412	3,189
Other income and (deductions)
Interest expense, net		(403)	(387)	(1,202)	(1,119)
Interest expense to affiliates		(6)	(6)	(19)	(19)
Other, net		158	194	837	212
Total other income and (deductions)		(251)	(199)	(384)	(926)
Income before income taxes		1,102	947	3,028	2,263
Income taxes		172	137	626	262
Equity in losses of unconsolidated affiliates		(170)	(10)	(182)	(22)
Net income		760	800	2,220	1,979
Net income attributable to noncontrolling interests		(12)	67	56	121
Net income (loss) attributable to common shareholders		772	733	2,164	1,858
Other comprehensive income (loss), net of income taxes
Prior service benefit reclassified to periodic benefit cost		(16)	(17)	(49)	(50)
Actuarial loss reclassified to periodic benefit cost		37	62	111	186
Pension and non-pension postretirement benefit plan valuation adjustment		6	5	(32)	22
Unrealized (loss) gain on cash flow hedges		0	0	0	12
Unrealized (loss) gain on investments in unconsolidated affiliates		5	0	1	3
Unrealized gain (loss) on foreign currency translation		(2)	2	2	(4)
Other comprehensive income		30	52	33	169
Comprehensive income		790	852	2,253	2,148
Comprehensive (loss) income attributable to noncontrolling interests		(9)	67	57	123
Comprehensive income attributable to common shareholders/membership interest		$ 799	$ 785	$ 2,196	$ 2,025
Average shares of common stock outstanding:
Basic average shares of common stock outstanding		973	968	972	967
Assumed exercise and/or distributions of stock-based awards		1	2	1	2
Diluted average shares of common stock outstanding	[1]	974	970	973	969
Earnings per average common share:
Basic earnings per average common share		$ 0.79	$ 0.76	$ 2.23	$ 1.92
Diluted earnings per average common share		$ 0.79	$ 0.76	$ 2.22	$ 1.92
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount			2		3
Exelon Generation Co L L C [Member]
Operating revenues
Operating revenues from affiliates		$ 275	$ 308	$ 844	$ 979
Total operating revenues		4,774	5,278	14,280	15,368
Operating expenses
Purchased power and/or fuel from affiliates		3	3	7	10
Operating and maintenance		947	1,218	3,131	3,643
Operating and maintenance from affiliates		140	152	439	483
Depreciation and amortization		407	468	1,221	1,383
Taxes other than income		129	143	394	414
Total operating expenses		4,274	4,961	13,333	14,475
Gain on sales of assets and businesses		(18)	(6)	15	48
Operating income		482	311	962	941
Other income and (deductions)
Interest expense, net		(101)	(93)	(310)	(278)
Interest expense to affiliates		(8)	(8)	(26)	(27)
Other, net		128	179	729	164
Total other income and (deductions)		19	78	393	(141)
Income before income taxes		501	389	1,355	800
Income taxes		87	78	388	110
Equity in losses of unconsolidated affiliates		(170)	(11)	(183)	(23)
Net income		244	300	784	667
Net income attributable to noncontrolling interests		(13)	66	56	120
Net income attributable to membership interest		257	234	728	547
Other comprehensive income (loss), net of income taxes
Unrealized (loss) gain on cash flow hedges		0	0	0	12
Unrealized (loss) gain on investments in unconsolidated affiliates		5	0	1	3
Unrealized gain (loss) on foreign currency translation		(2)	2	2	(4)
Other comprehensive income		3	2	3	11
Comprehensive income		247	302	787	678
Comprehensive (loss) income attributable to noncontrolling interests		(10)	66	57	122
Comprehensive income attributable to common shareholders/membership interest		257	236	730	556
Commonwealth Edison Co [Member]
Operating revenues
Revenues from alternative revenue programs		(56)	(15)	(98)	(27)
Operating revenues from affiliates		4	4	13	23
Total operating revenues		1,583	1,598	4,342	4,508
Operating expenses
Purchased power and/or fuel from affiliates		83	123	270	421
Operating and maintenance		267	276	771	785
Operating and maintenance from affiliates		73	61	196	189
Depreciation and amortization		259	237	767	696
Taxes other than income		80	82	228	238
Total operating expenses		1,256	1,275	3,431	3,610
Gain on sales of assets and businesses		1	0	4	5
Operating income		328	323	915	903
Other income and (deductions)
Interest expense, net		(87)	(82)	(258)	(251)
Interest expense to affiliates		(4)	(3)	(10)	(10)
Other, net		8	7	27	21
Total other income and (deductions)		(83)	(78)	(241)	(240)
Income before income taxes		245	245	674	663
Income taxes		45	52	130	140
Net income		200	193	544	523
Other comprehensive income (loss), net of income taxes
Comprehensive income		200	193	544	523
PECO Energy Co [Member]
Operating revenues
Revenues from alternative revenue programs		(11)	1	(16)	2
Operating revenues from affiliates		1	2	4	5
Total operating revenues		778	757	2,333	2,275
Operating expenses
Purchased power and/or fuel from affiliates		43	34	122	94
Operating and maintenance		182	184	531	572
Operating and maintenance from affiliates		37	35	112	114
Depreciation and amortization		83	75	247	224
Taxes other than income		47	46	126	125
Total operating expenses		595	603	1,783	1,853
Gain on sales of assets and businesses		0	0	0	1
Operating income		183	154	550	423
Other income and (deductions)
Interest expense, net		(30)	(28)	(91)	(85)
Interest expense to affiliates		(3)	(4)	(9)	(11)
Other, net		4	2	11	4
Total other income and (deductions)		(29)	(30)	(89)	(92)
Income before income taxes		154	124	461	331
Income taxes		14	(2)	51	(5)
Net income		140	126	410	336
Other comprehensive income (loss), net of income taxes
Comprehensive income		140	126	410	336
Baltimore Gas and Electric Company [Member]
Operating revenues
Revenues from alternative revenue programs		(5)	(6)	11	(23)
Operating revenues from affiliates		6	6	18	18
Total operating revenues		703	731	2,327	2,369
Operating expenses
Purchased power and/or fuel from affiliates		64	68	196	195
Operating and maintenance		157	144	451	462
Operating and maintenance from affiliates		39	38	118	116
Depreciation and amortization		116	110	368	358
Taxes other than income		65	64	195	188
Total operating expenses		612	628	1,936	2,005
Gain on sales of assets and businesses		0	0	0	1
Operating income		91	103	391	365
Other income and (deductions)
Interest expense, net		(31)	(27)	(89)	(78)
Other, net		7	5	18	14
Total other income and (deductions)		(24)	(22)	(71)	(64)
Income before income taxes		67	81	320	301
Income taxes		12	18	59	59
Net income		55	63	261	242
Other comprehensive income (loss), net of income taxes
Comprehensive income		55	63	261	242
Pepco Holdings LLC [Member]
Operating revenues
Revenues from alternative revenue programs		(9)	(5)	4	7
Operating revenues from affiliates		4	3	11	11
Total operating revenues		1,380	1,361	3,700	3,688
Operating expenses
Purchased power and/or fuel from affiliates		83	82	254	268
Operating and maintenance		254	261	706	751
Operating and maintenance from affiliates		36	31	105	106
Depreciation and amortization		193	192	562	555
Taxes other than income		122	123	342	343
Total operating expenses		1,124	1,116	3,106	3,165
Operating income		256	245	594	523
Other income and (deductions)
Interest expense, net		(66)	(65)	(197)	(193)
Other, net		13	11	39	33
Total other income and (deductions)		(53)	(54)	(158)	(160)
Income before income taxes		203	191	436	363
Income taxes		14	4	25	28
Equity in losses of unconsolidated affiliates		0	0	1	1
Net income		189	187	412	336
Other comprehensive income (loss), net of income taxes
Comprehensive income attributable to common shareholders/membership interest		189	187	412	336
Potomac Electric Power Company [Member]
Operating revenues
Revenues from alternative revenue programs		(3)	(4)	10	6
Operating revenues from affiliates		2	2	5	5
Total operating revenues		642	628	1,748	1,708
Operating expenses
Purchased power and/or fuel from affiliates		65	46	188	143
Operating and maintenance		85	84	208	216
Operating and maintenance from affiliates		50	52	156	167
Depreciation and amortization		95	99	281	286
Taxes other than income		104	104	286	288
Total operating expenses		515	516	1,444	1,454
Operating income		127	112	304	254
Other income and (deductions)
Interest expense, net		(33)	(32)	(100)	(96)
Other, net		9	7	22	23
Total other income and (deductions)		(24)	(25)	(78)	(73)
Income before income taxes		103	87	226	181
Income taxes		5	(2)	9	7
Net income		98	89	217	174
Other comprehensive income (loss), net of income taxes
Comprehensive income		98	89	217	174
Delmarva Power and Light Company [Member]
Operating revenues
Revenues from alternative revenue programs		(6)	0	(6)	5
Operating revenues from affiliates		1	2	5	6
Total operating revenues		319	328	987	1,001
Operating expenses
Purchased power and/or fuel from affiliates		14	26	50	103
Operating and maintenance		43	44	127	137
Operating and maintenance from affiliates		37	38	113	119
Depreciation and amortization		46	47	138	135
Taxes other than income		15	15	43	43
Total operating expenses		268	277	820	859
Operating income		51	51	167	142
Other income and (deductions)
Interest expense, net		(15)	(15)	(45)	(42)
Other, net		2	2	10	7
Total other income and (deductions)		(13)	(13)	(35)	(35)
Income before income taxes		38	38	132	107
Income taxes		5	5	16	17
Net income		33	33	116	90
Other comprehensive income (loss), net of income taxes
Comprehensive income		33	33	116	90
Atlantic City Electric Company [Member]
Operating revenues
Revenues from alternative revenue programs		1	(1)	0	(4)
Operating revenues from affiliates		1	1	2	2
Total operating revenues		419	406	966	981
Operating expenses
Purchased power and/or fuel from affiliates		3	10	16	21
Operating and maintenance		54	52	142	146
Operating and maintenance from affiliates		32	33	99	104
Depreciation and amortization		43	38	114	107
Taxes other than income		1	1	4	4
Total operating expenses		340	322	838	847
Operating income		79	84	128	134
Other income and (deductions)
Interest expense, net		(15)	(16)	(44)	(48)
Other, net		1	1	5	2
Total other income and (deductions)		(14)	(15)	(39)	(46)
Income before income taxes		65	69	89	88
Income taxes		2	8	2	12
Net income		63	61	87	76
Other comprehensive income (loss), net of income taxes
Comprehensive income		63	61	87	76
Generation commodities and services
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		4,499	4,971	13,436	14,387
Operating expenses
Purchased power and/or fuel		2,648	2,977	8,142	8,542
Generation commodities and services | Exelon Generation Co L L C [Member]
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		4,499	4,970	13,436	14,389
Operating expenses
Purchased power and/or fuel		2,648	2,977	8,141	8,542
Rate-regulated utility revenues
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		4,510	4,457	12,758	12,824
Operating expenses
Purchased power and/or fuel		1,304	1,355	3,589	3,832
Electricity, US Regulated | Commonwealth Edison Co [Member]
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		1,635	1,609	4,427	4,512
Operating expenses
Purchased power and/or fuel		494	496	1,199	1,281
Electricity, US Regulated | PECO Energy Co [Member]
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		726	697	1,914	1,886
Operating expenses
Purchased power and/or fuel		185	215	461	576
Electricity, US Regulated | Baltimore Gas and Electric Company [Member]
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		623	652	1,814	1,847
Operating expenses
Purchased power and/or fuel		159	183	480	510
Electricity, US Regulated | Pepco Holdings LLC [Member]
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		1,365	1,340	3,570	3,541
Operating expenses
Purchased power and/or fuel		428	415	1,086	1,077
Electricity, US Regulated | Potomac Electric Power Company [Member]
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		643	630	1,733	1,697
Operating expenses
Purchased power and/or fuel		116	131	325	354
Electricity, US Regulated | Delmarva Power and Light Company [Member]
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		304	302	872	861
Operating expenses
Purchased power and/or fuel		105	96	298	258
Electricity, US Regulated | Atlantic City Electric Company [Member]
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		417	406	964	983
Operating expenses
Purchased power and/or fuel		207	188	463	465
Natural Gas, US Regulated | PECO Energy Co [Member]
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		62	57	431	382
Operating expenses
Purchased power and/or fuel		18	14	184	148
Natural Gas, US Regulated | Baltimore Gas and Electric Company [Member]
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		79	79	484	527
Operating expenses
Purchased power and/or fuel		12	21	128	176
Natural Gas, US Regulated | Pepco Holdings LLC [Member]
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		20	23	115	129
Operating expenses
Purchased power and/or fuel		8	12	51	65
Natural Gas, US Regulated | Delmarva Power and Light Company [Member]
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		20	24	116	129
Operating expenses
Purchased power and/or fuel		$ 8	$ 11	$ 51	$ 64

[1] The number of stock options not included in the calculation of diluted common shares outstanding due to their antidilutive effect was immaterial for the three and nine months ended September 30, 2019 and approximately 2 million and 3 million for the three and nine months ended September 30, 2018, respectively.