Consolidated Statements of Operations and Comprehensive Income (Unaudited) - USD ($) shares in Millions, $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Operating revenues
Revenues from alternative revenue programs		$ (47)	$ (11)	$ 129	$ (66)
Operating revenues from affiliates		0	1	0	4
Total operating revenues		8,910	8,853	26,715	24,925
Operating expenses
Operating and maintenance		1,992	2,732	6,416	7,370
Depreciation and amortization		1,624	1,289	4,988	3,312
Taxes other than income taxes		468	452	1,337	1,299
Total operating expenses		7,117	8,087	24,758	22,387
Gain on sales of assets and businesses		65	3	147	16
Operating income (loss)		1,858	769	2,104	2,554
Other income and (deductions)
Interest expense, net		(391)	(398)	(1,161)	(1,222)
Interest expense to affiliates		(6)	(6)	(19)	(19)
Other, net		(55)	421	751	352
Total other income and (deductions)		(452)	17	(429)	(889)
Income before income taxes		1,406	786	1,675	1,665
Income taxes		174	216	229	141
Equity in losses of unconsolidated affiliates		(3)	(1)	(5)	(5)
Net income (loss)		1,229	569	1,441	1,519
Net income (loss) attributable to noncontrolling interests		26	68	126	(85)
Net Income (Loss) Available to Common Stockholders, Basic		1,203	501	1,315	1,604
Other comprehensive income (loss), net of income taxes
Prior service benefit reclassified to periodic benefit cost		(1)	(10)	(4)	(30)
Actuarial loss reclassified to periodic benefit cost		56	49	167	142
Pension and non-pension postretirement benefit plan valuation adjustment		14	(13)	15	(17)
Unrealized (loss) gain on cash flow hedges		0	(1)	(1)	(2)
Unrealized gain (loss) on foreign currency translation		(3)	3	0	(3)
Other comprehensive income		66	28	177	90
Comprehensive income		1,295	597	1,618	1,609
Comprehensive income (loss) attributable to noncontrolling interests		26	68	126	(85)
Comprehensive income attributable to common shareholders/membership interest		$ 1,269	$ 529	$ 1,492	$ 1,694
Average shares of common stock outstanding:
Basic average shares of common stock outstanding		979	976	978	976
Assumed exercise and/or distributions of stock-based awards		1	1	1	0
Diluted average shares of common stock outstanding	[1]	980	977	979	976
Earnings per average common share
Basic earnings per average common share		$ 1.23	$ 0.51	$ 1.34	$ 1.64
Diluted earnings per average common share		$ 1.23	$ 0.51	$ 1.34	$ 1.64
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount		0	1	0	1
Exelon Generation Co L L C [Member]
Operating revenues
Operating revenues from affiliates		$ 324	$ 331	$ 872	$ 932
Total operating revenues		4,406	4,659	14,117	13,272
Operating expenses
Purchased power and fuel from affiliates		4	3	0	(6)
Operating and maintenance		761	1,605	2,955	3,779
Operating and maintenance from affiliates		177	132	458	409
Depreciation and amortization		866	558	2,735	1,161
Taxes other than income taxes		115	118	354	364
Total operating expenses		3,465	4,727	14,605	12,674
Gain on sales of assets and businesses		65	0	144	12
Operating income (loss)		1,006	(68)	(344)	610
Other income and (deductions)
Interest expense, net		(73)	(72)	(214)	(251)
Interest expense to affiliates		(4)	(8)	(11)	(26)
Other, net		(115)	367	561	199
Total other income and (deductions)		(192)	287	336	(78)
Income before income taxes		814	219	(8)	532
Income taxes		177	100	108	41
Equity in losses of unconsolidated affiliates		(4)	(2)	(6)	(6)
Net income (loss)		633	117	(122)	485
Net income (loss) attributable to noncontrolling interests		26	68	125	(85)
Net income attributable to membership interest		607	49	(247)	570
Other comprehensive income (loss), net of income taxes
Unrealized (loss) gain on cash flow hedges		0	0	(1)	(1)
Unrealized gain (loss) on foreign currency translation		(4)	3	0	(3)
Other comprehensive income		(4)	3	(1)	(4)
Comprehensive income		629	120	(123)	481
Comprehensive income (loss) attributable to noncontrolling interests		26	68	125	(85)
Comprehensive income attributable to common shareholders/membership interest		603	52	(248)	566
Commonwealth Edison Co [Member]
Operating revenues
Revenues from alternative revenue programs		(32)	(38)	32	(51)
Operating revenues from affiliates		9	15	19	31
Total operating revenues		1,789	1,643	4,840	4,499
Operating expenses
Purchased power and/or fuel from affiliates		93	71	256	252
Operating and maintenance		257	252	752	964
Operating and maintenance from affiliates		73	69	217	209
Depreciation and amortization		304	294	893	841
Taxes other than income taxes		91	81	243	227
Total operating expenses		1,428	1,302	3,833	3,798
Operating income (loss)		361	341	1,007	701
Other income and (deductions)
Interest expense, net		(95)	(92)	(282)	(277)
Interest expense to affiliates		(3)	(3)	(10)	(10)
Other, net		13	10	35	32
Total other income and (deductions)		(85)	(85)	(257)	(255)
Income before income taxes		276	256	750	446
Income taxes		56	60	141	142
Net income (loss)		220	196	609	304
Other comprehensive income (loss), net of income taxes
Comprehensive income		220	196	609	304
PECO Energy Co [Member]
Operating revenues
Revenues from alternative revenue programs		3	5	20	10
Operating revenues from affiliates		2	3	6	7
Total operating revenues		818	813	2,399	2,306
Operating expenses
Purchased power and/or fuel from affiliates		60	67	141	144
Operating and maintenance		220	214	580	628
Operating and maintenance from affiliates		43	37	126	114
Depreciation and amortization		86	85	259	259
Taxes other than income taxes		51	53	143	131
Total operating expenses		677	658	1,908	1,900
Operating income (loss)		141	155	491	406
Other income and (deductions)
Interest expense, net		(37)	(36)	(110)	(100)
Interest expense to affiliates		(3)	(3)	(9)	(8)
Other, net		7	6	20	12
Total other income and (deductions)		(33)	(33)	(99)	(96)
Income before income taxes		108	122	392	310
Income taxes		(3)	(16)	9	(7)
Net income (loss)		111	138	383	317
Other comprehensive income (loss), net of income taxes
Comprehensive income		111	138	383	317
Baltimore Gas and Electric Company [Member]
Operating revenues
Revenues from alternative revenue programs		(24)	(9)	(17)	(10)
Operating revenues from affiliates		7	6	20	16
Total operating revenues		770	731	2,426	2,284
Operating expenses
Purchased power and/or fuel from affiliates		64	83	193	249
Operating and maintenance		159	152	458	445
Operating and maintenance from affiliates		46	39	137	122
Depreciation and amortization		142	133	434	405
Taxes other than income taxes		72	68	211	200
Total operating expenses		709	642	2,080	1,903
Operating income (loss)		61	89	346	381
Other income and (deductions)
Interest expense, net		(36)	(34)	(103)	(99)
Other, net		7	6	23	17
Total other income and (deductions)		(29)	(28)	(80)	(82)
Income before income taxes		32	61	266	299
Income taxes		(4)	8	(24)	26
Net income (loss)		36	53	290	273
Other comprehensive income (loss), net of income taxes
Comprehensive income		36	53	290	273
Pepco Holdings LLC [Member]
Operating revenues
Revenues from alternative revenue programs		6	31	94	(15)
Operating revenues from affiliates		3	6	10	13
Total operating revenues		1,470	1,368	3,854	3,554
Operating expenses
Purchased power and/or fuel from affiliates		100	106	277	288
Operating and maintenance		235	237	668	702
Operating and maintenance from affiliates		43	38	122	111
Depreciation and amortization		210	200	614	585
Taxes other than income taxes		127	121	349	343
Total operating expenses		1,155	1,102	3,167	3,057
Gain on sales of assets and businesses		0	0	0	2
Operating income (loss)		315	266	687	499
Other income and (deductions)
Interest expense, net		(67)	(67)	(201)	(201)
Other, net		16	16	52	42
Total other income and (deductions)		(51)	(51)	(149)	(159)
Income before income taxes		264	215	538	340
Income taxes		(2)	(1)	3	(77)
Equity in losses of unconsolidated affiliates		0	0	0	1
Net income (loss)		266	216	535	418
Other comprehensive income (loss), net of income taxes
Comprehensive income attributable to common shareholders/membership interest		266	216	535	418
Potomac Electric Power Company [Member]
Operating revenues
Revenues from alternative revenue programs		9	18	54	20
Operating revenues from affiliates		2	3	4	6
Total operating revenues		660	611	1,736	1,650
Operating expenses
Purchased power and/or fuel from affiliates		69	80	200	219
Operating and maintenance		68	57	186	184
Operating and maintenance from affiliates		52	49	155	152
Depreciation and amortization		104	96	302	282
Taxes other than income taxes		105	100	282	279
Total operating expenses		501	465	1,396	1,364
Operating income (loss)		159	146	340	286
Other income and (deductions)
Interest expense, net		(35)	(35)	(104)	(103)
Other, net		12	10	37	28
Total other income and (deductions)		(23)	(25)	(67)	(75)
Income before income taxes		136	121	273	211
Income taxes		6	3	9	(16)
Net income (loss)		130	118	264	227
Other comprehensive income (loss), net of income taxes
Comprehensive income		130	118	264	227
Delmarva Power and Light Company [Member]
Operating revenues
Revenues from alternative revenue programs		(2)	8	17	(15)
Operating revenues from affiliates		2	3	6	7
Total operating revenues		360	337	1,040	954
Operating expenses
Purchased power and/or fuel from affiliates		26	21	63	60
Operating and maintenance		47	64	132	160
Operating and maintenance from affiliates		40	37	117	112
Depreciation and amortization		53	48	157	143
Taxes other than income taxes		17	16	50	49
Total operating expenses		295	296	858	843
Operating income (loss)		65	41	182	111
Other income and (deductions)
Interest expense, net		(15)	(15)	(47)	(47)
Other, net		3	2	9	7
Total other income and (deductions)		(12)	(13)	(38)	(40)
Income before income taxes		53	28	144	71
Income taxes		3	1	9	(20)
Net income (loss)		50	27	135	91
Other comprehensive income (loss), net of income taxes
Comprehensive income		50	27	135	91
Atlantic City Electric Company [Member]
Operating revenues
Revenues from alternative revenue programs		0	5	23	(20)
Operating revenues from affiliates		1	1	2	3
Total operating revenues		451	420	1,080	952
Operating expenses
Purchased power and/or fuel from affiliates		5	4	14	9
Operating and maintenance		46	45	128	140
Operating and maintenance from affiliates		35	32	103	98
Depreciation and amortization		46	48	133	134
Taxes other than income taxes		2	2	6	6
Total operating expenses		359	338	911	847
Gain on sales of assets and businesses		0	0	0	2
Operating income (loss)		92	82	169	107
Other income and (deductions)
Interest expense, net		(14)	(15)	(43)	(45)
Other, net		1	1	3	5
Total other income and (deductions)		(13)	(14)	(40)	(40)
Income before income taxes		79	68	129	67
Income taxes		(11)	(7)	(12)	(39)
Net income (loss)		90	75	141	106
Other comprehensive income (loss), net of income taxes
Comprehensive income		90	75	141	106
Generation commodities and services [Member]
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		4,084	4,331	13,250	12,348
Operating expenses
Purchased power and/or fuel		1,541	2,311	8,103	6,967
Generation commodities and services [Member] | Exelon Generation Co L L C [Member]
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		4,082	4,328	13,245	12,340
Operating expenses
Purchased power and/or fuel		1,542	2,311	8,103	6,967
Rate-regulated utility revenues [Member]
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		4,873	4,533	13,336	12,643
Operating expenses
Purchased power and/or fuel		1,492	1,303	3,914	3,439
Electricity, US Regulated [Member]
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		4,657	4,365	12,432	11,585
Electricity, US Regulated [Member] | Commonwealth Edison Co [Member]
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		1,812	1,666	4,789	4,519
Operating expenses
Purchased power and/or fuel		610	535	1,472	1,305
Electricity, US Regulated [Member] | PECO Energy Co [Member]
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		757	751	2,008	1,931
Operating expenses
Purchased power and/or fuel		206	190	540	495
Electricity, US Regulated [Member] | Baltimore Gas and Electric Company [Member]
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		694	649	1,874	1,775
Operating expenses
Purchased power and/or fuel		206	155	501	376
Electricity, US Regulated [Member] | Pepco Holdings LLC [Member]
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		1,438	1,308	3,632	3,440
Operating expenses
Purchased power and/or fuel		431	393	1,087	979
Electricity, US Regulated [Member] | Potomac Electric Power Company [Member]
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		649	590	1,678	1,624
Operating expenses
Purchased power and/or fuel		103	83	271	248
Electricity, US Regulated [Member] | Delmarva Power and Light Company [Member]
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		337	303	899	846
Operating expenses
Purchased power and/or fuel		103	103	289	270
Electricity, US Regulated [Member] | Atlantic City Electric Company [Member]
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		450	414	1,055	969
Operating expenses
Purchased power and/or fuel		225	207	527	460
Natural Gas, US Regulated [Member]
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		169	159	1,035	990
Natural Gas, US Regulated [Member] | PECO Energy Co [Member]
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		56	54	365	358
Operating expenses
Purchased power and/or fuel		11	12	119	129
Natural Gas, US Regulated [Member] | Baltimore Gas and Electric Company [Member]
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		93	85	549	503
Operating expenses
Purchased power and/or fuel		20	12	146	106
Natural Gas, US Regulated [Member] | Pepco Holdings LLC [Member]
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		23	23	118	116
Operating expenses
Purchased power and/or fuel		9	7	50	49
Natural Gas, US Regulated [Member] | Delmarva Power and Light Company [Member]
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		23	23	118	116
Operating expenses
Purchased power and/or fuel		$ 9	$ 7	$ 50	$ 49

[1] The number of stock options not included in the calculation of diluted common shares outstanding due to their antidilutive effect was zero for the three and nine months ended September 30, 2021 and approximately 1 million for the three and nine months ended September 30, 2020, respectively.