Consolidated Statements of Operations and Comprehensive Income (Unaudited) - USD ($) shares in Millions, $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Operating revenues
Revenues from alternative revenue programs		$ (11)	$ (80)	$ (66)	$ (98)
Operating revenues from affiliates		1	0	4	0
Total operating revenues		8,853	8,929	24,925	26,096
Operating expenses
Operating and maintenance		2,732	2,072	7,370	6,419
Depreciation and amortization		1,289	1,083	3,312	3,237
Taxes other than income taxes		452	452	1,299	1,316
Total operating expenses		8,087	7,559	22,387	22,703
Gain on sales of assets and businesses		3	(17)	16	19
Operating income		769	1,353	2,554	3,412
Other income and (deductions)
Interest expense, net		(398)	(403)	(1,222)	(1,202)
Interest expense to affiliates		(6)	(6)	(19)	(19)
Other, net		421	158	352	837
Total other income and (deductions)		17	(251)	(889)	(384)
Income before income taxes		786	1,102	1,665	3,028
Income taxes		216	172	141	626
Equity in losses of unconsolidated affiliates		(1)	(170)	(5)	(182)
Net income (loss)		569	760	1,519	2,220
Net income (loss) attributable to noncontrolling interests		68	(12)	(85)	56
Net Income (Loss) Available to Common Stockholders, Basic		501	772	1,604	2,164
Other comprehensive income (loss), net of income taxes
Prior service benefit reclassified to periodic benefit cost		(10)	(16)	(30)	(49)
Actuarial loss reclassified to periodic benefit cost		49	37	142	111
Pension and non-pension postretirement benefit plan valuation adjustment		(13)	6	(17)	(32)
Unrealized (loss) gain on cash flow hedges		(1)	0	(2)	0
Unrealized (loss) gain on investments in unconsolidated affiliates		0	5	0	1
Unrealized gain (loss) on foreign currency translation		3	(2)	(3)	2
Other comprehensive income		28	30	90	33
Comprehensive income		597	790	1,609	2,253
Comprehensive income (loss) attributable to noncontrolling interests		68	(9)	(85)	57
Comprehensive income attributable to common shareholders/membership interest		$ 529	$ 799	$ 1,694	$ 2,196
Average shares of common stock outstanding:
Basic average shares of common stock outstanding		976	973	976	972
Assumed exercise and/or distributions of stock-based awards		1	1	0	1
Diluted average shares of common stock outstanding	[1]	977	974	976	973
Earnings per average common share:
Basic earnings per average common share		$ 0.51	$ 0.79	$ 1.64	$ 2.23
Diluted earnings per average common share		$ 0.51	$ 0.79	$ 1.64	$ 2.22
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount		1		1
Retained Earnings [Member]
Other income and (deductions)
Net income (loss)		$ 501	$ 772
Exelon Generation Co L L C [Member]
Operating revenues
Operating revenues from affiliates		331	275	$ 932	$ 844
Total operating revenues		4,659	4,774	13,272	14,280
Operating expenses
Purchased power and/or fuel from affiliates		3	3	(6)	7
Operating and maintenance		1,605	947	3,779	3,131
Operating and maintenance from affiliates		132	140	409	439
Depreciation and amortization		558	407	1,161	1,221
Taxes other than income taxes		118	129	364	394
Total operating expenses		4,727	4,274	12,674	13,333
Gain on sales of assets and businesses		0	(18)	12	15
Operating income		(68)	482	610	962
Other income and (deductions)
Interest expense, net		(72)	(101)	(251)	(310)
Interest expense to affiliates		(8)	(8)	(26)	(26)
Other, net		367	128	199	729
Total other income and (deductions)		287	19	(78)	393
Income before income taxes		219	501	532	1,355
Income taxes		100	87	41	388
Equity in losses of unconsolidated affiliates		(2)	(170)	(6)	(183)
Net income (loss)		117	244	485	784
Net income (loss) attributable to noncontrolling interests		68	(13)	(85)	56
Net income attributable to membership interest		49	257	570	728
Other comprehensive income (loss), net of income taxes
Unrealized (loss) gain on cash flow hedges		0	0	(1)	0
Unrealized (loss) gain on investments in unconsolidated affiliates		0	5	0	1
Unrealized gain (loss) on foreign currency translation		3	(2)	(3)	2
Other comprehensive income		3	3	(4)	3
Comprehensive income		120	247	481	787
Comprehensive income (loss) attributable to noncontrolling interests		68	(10)	(85)	57
Comprehensive income attributable to common shareholders/membership interest		52	257	566	730
Commonwealth Edison Co [Member]
Operating revenues
Revenues from alternative revenue programs		(38)	(56)	(51)	(98)
Operating revenues from affiliates		15	4	31	13
Total operating revenues		1,643	1,583	4,499	4,342
Operating expenses
Purchased power and/or fuel from affiliates		71	83	252	270
Operating and maintenance		252	267	964	771
Operating and maintenance from affiliates		69	73	209	196
Depreciation and amortization		294	259	841	767
Taxes other than income taxes		81	80	227	228
Total operating expenses		1,302	1,256	3,798	3,431
Gain on sales of assets and businesses		0	1	0	4
Operating income		341	328	701	915
Other income and (deductions)
Interest expense, net		(92)	(87)	(277)	(258)
Interest expense to affiliates		(3)	(4)	(10)	(10)
Other, net		10	8	32	27
Total other income and (deductions)		(85)	(83)	(255)	(241)
Income before income taxes		256	245	446	674
Income taxes		60	45	142	130
Net income (loss)		196	200	304	544
Other comprehensive income (loss), net of income taxes
Comprehensive income		196	200	304	544
PECO Energy Co [Member]
Operating revenues
Revenues from alternative revenue programs		5	(11)	10	(16)
Operating revenues from affiliates		3	1	7	4
Total operating revenues		813	778	2,306	2,333
Operating expenses
Purchased power and/or fuel from affiliates		67	43	144	122
Operating and maintenance		214	182	628	531
Operating and maintenance from affiliates		37	37	114	112
Depreciation and amortization		85	83	259	247
Taxes other than income taxes		53	47	131	126
Total operating expenses		658	595	1,900	1,783
Operating income		155	183	406	550
Other income and (deductions)
Interest expense, net		(36)	(30)	(100)	(91)
Interest expense to affiliates		(3)	(3)	(8)	(9)
Other, net		6	4	12	11
Total other income and (deductions)		(33)	(29)	(96)	(89)
Income before income taxes		122	154	310	461
Income taxes		(16)	14	(7)	51
Net income (loss)		138	140	317	410
Other comprehensive income (loss), net of income taxes
Comprehensive income		138	140	317	410
PECO Energy Co [Member] | Retained Earnings [Member]
Other income and (deductions)
Net income (loss)		138	140
Baltimore Gas and Electric Company [Member]
Operating revenues
Revenues from alternative revenue programs		(9)	(5)	(10)	11
Operating revenues from affiliates		6	6	16	18
Total operating revenues		731	703	2,284	2,327
Operating expenses
Purchased power and/or fuel from affiliates		83	64	249	196
Operating and maintenance		152	157	445	451
Operating and maintenance from affiliates		39	39	122	118
Depreciation and amortization		133	116	405	368
Taxes other than income taxes		68	65	200	195
Total operating expenses		642	612	1,903	1,936
Operating income		89	91	381	391
Other income and (deductions)
Interest expense, net		(34)	(31)	(99)	(89)
Other, net		6	7	17	18
Total other income and (deductions)		(28)	(24)	(82)	(71)
Income before income taxes		61	67	299	320
Income taxes		8	12	26	59
Net income (loss)		53	55	273	261
Other comprehensive income (loss), net of income taxes
Comprehensive income		53	55	273	261
Baltimore Gas and Electric Company [Member] | Retained Earnings [Member]
Other income and (deductions)
Net income (loss)		53	55
Pepco Holdings LLC [Member]
Operating revenues
Revenues from alternative revenue programs		31	(9)	(15)	4
Operating revenues from affiliates		6	4	13	11
Total operating revenues		1,368	1,380	3,554	3,700
Operating expenses
Purchased power and/or fuel from affiliates		106	83	288	254
Operating and maintenance		237	254	702	706
Operating and maintenance from affiliates		38	36	111	105
Depreciation and amortization		200	193	585	562
Taxes other than income taxes		121	122	343	342
Total operating expenses		1,102	1,124	3,057	3,106
Gain on sales of assets and businesses		0	0	2	0
Operating income		266	256	499	594
Other income and (deductions)
Interest expense, net		(67)	(66)	(201)	(197)
Other, net		16	13	42	39
Total other income and (deductions)		(51)	(53)	(159)	(158)
Income before income taxes		215	203	340	436
Income taxes		(1)	14	(77)	25
Equity in losses of unconsolidated affiliates		0	0	1	1
Net income (loss)		216	189	418	412
Other comprehensive income (loss), net of income taxes
Comprehensive income attributable to common shareholders/membership interest		216	189	418	412
Potomac Electric Power Company [Member]
Operating revenues
Revenues from alternative revenue programs		18	(3)	20	10
Operating revenues from affiliates		3	2	6	5
Total operating revenues		611	642	1,650	1,748
Operating expenses
Purchased power and/or fuel from affiliates		80	65	219	188
Operating and maintenance		57	85	184	208
Operating and maintenance from affiliates		49	50	152	156
Depreciation and amortization		96	95	282	281
Taxes other than income taxes		100	104	279	286
Total operating expenses		465	515	1,364	1,444
Operating income		146	127	286	304
Other income and (deductions)
Interest expense, net		(35)	(33)	(103)	(100)
Other, net		10	9	28	22
Total other income and (deductions)		(25)	(24)	(75)	(78)
Income before income taxes		121	103	211	226
Income taxes		3	5	(16)	9
Net income (loss)		118	98	227	217
Other comprehensive income (loss), net of income taxes
Comprehensive income		118	98	227	217
Potomac Electric Power Company [Member] | Retained Earnings [Member]
Other income and (deductions)
Net income (loss)		118	98
Delmarva Power and Light Company [Member]
Operating revenues
Revenues from alternative revenue programs		8	(6)	(15)	(6)
Operating revenues from affiliates		3	1	7	5
Total operating revenues		337	319	954	987
Operating expenses
Purchased power and/or fuel from affiliates		21	14	60	50
Operating and maintenance		64	43	160	127
Operating and maintenance from affiliates		37	37	112	113
Depreciation and amortization		48	46	143	138
Taxes other than income taxes		16	15	49	43
Total operating expenses		296	268	843	820
Operating income		41	51	111	167
Other income and (deductions)
Interest expense, net		(15)	(15)	(47)	(45)
Other, net		2	2	7	10
Total other income and (deductions)		(13)	(13)	(40)	(35)
Income before income taxes		28	38	71	132
Income taxes		1	5	(20)	16
Net income (loss)		27	33	91	116
Other comprehensive income (loss), net of income taxes
Comprehensive income		27	33	91	116
Delmarva Power and Light Company [Member] | Retained Earnings [Member]
Other income and (deductions)
Net income (loss)		27	33
Atlantic City Electric Company [Member]
Operating revenues
Revenues from alternative revenue programs		5	1	(20)	0
Operating revenues from affiliates		1	1	3	2
Total operating revenues		420	419	952	966
Operating expenses
Purchased power and/or fuel from affiliates		4	3	9	16
Operating and maintenance		45	54	140	142
Operating and maintenance from affiliates		32	32	98	99
Depreciation and amortization		48	43	134	114
Taxes other than income taxes		2	1	6	4
Total operating expenses		338	340	847	838
Gain on sales of assets and businesses		0	0	2	0
Operating income		82	79	107	128
Other income and (deductions)
Interest expense, net		(15)	(15)	(45)	(44)
Other, net		1	1	5	5
Total other income and (deductions)		(14)	(14)	(40)	(39)
Income before income taxes		68	65	67	89
Income taxes		(7)	2	(39)	2
Net income (loss)		75	63	106	87
Other comprehensive income (loss), net of income taxes
Comprehensive income		75	63	106	87
Atlantic City Electric Company [Member] | Retained Earnings [Member]
Other income and (deductions)
Net income (loss)		75	63
Generation commodities and services
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		4,330	4,499	12,344	13,436
Operating expenses
Purchased power and/or fuel		2,311	2,648	6,967	8,142
Generation commodities and services | Exelon Generation Co L L C [Member]
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		4,328	4,499	12,340	13,436
Operating expenses
Purchased power and/or fuel		2,311	2,648	6,967	8,141
Rate-regulated utility revenues
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		4,533	4,510	12,643	12,758
Operating expenses
Purchased power and/or fuel		1,303	1,304	3,439	3,589
Electricity, US Regulated
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		4,365	4,268	11,585	11,609
Electricity, US Regulated | Commonwealth Edison Co [Member]
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		1,666	1,635	4,519	4,427
Operating expenses
Purchased power and/or fuel		535	494	1,305	1,199
Electricity, US Regulated | PECO Energy Co [Member]
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		751	726	1,931	1,914
Operating expenses
Purchased power and/or fuel		190	185	495	461
Electricity, US Regulated | Baltimore Gas and Electric Company [Member]
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		649	623	1,775	1,814
Operating expenses
Purchased power and/or fuel		155	159	376	480
Electricity, US Regulated | Pepco Holdings LLC [Member]
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		1,308	1,365	3,440	3,570
Operating expenses
Purchased power and/or fuel		393	428	979	1,086
Electricity, US Regulated | Potomac Electric Power Company [Member]
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		590	643	1,624	1,733
Operating expenses
Purchased power and/or fuel		83	116	248	325
Electricity, US Regulated | Delmarva Power and Light Company [Member]
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		303	304	846	872
Operating expenses
Purchased power and/or fuel		103	105	270	298
Electricity, US Regulated | Atlantic City Electric Company [Member]
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		414	417	969	964
Operating expenses
Purchased power and/or fuel		207	207	460	463
Natural Gas, US Regulated
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		159	163	990	1,046
Natural Gas, US Regulated | PECO Energy Co [Member]
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		54	62	358	431
Operating expenses
Purchased power and/or fuel		12	18	129	184
Natural Gas, US Regulated | Baltimore Gas and Electric Company [Member]
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		85	79	503	484
Operating expenses
Purchased power and/or fuel		12	12	106	128
Natural Gas, US Regulated | Pepco Holdings LLC [Member]
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		23	20	116	115
Operating expenses
Purchased power and/or fuel		7	8	49	51
Natural Gas, US Regulated | Delmarva Power and Light Company [Member]
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		23	20	116	116
Operating expenses
Purchased power and/or fuel		$ 7	$ 8	$ 49	$ 51

[1] The number of stock options not included in the calculation of diluted common shares outstanding due to their antidilutive effect was approximately 1 million for the three and nine months ended September 30, 2020, and less than 1 million for the three and nine months ended September 30, 2019.