Consolidated Statements of Operations and Comprehensive Income (Unaudited) - USD ($) shares in Millions, $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Operating revenues
Revenues from alternative revenue programs		$ (122)	$ (13)	$ (55)	$ (19)
Operating revenues from affiliates		1	0	2	0
Total operating revenues		7,322	7,689	16,069	17,166
Operating expenses
Operating and maintenance		2,433	2,159	4,637	4,347
Depreciation and amortization		1,001	1,079	2,023	2,154
Taxes other than income taxes		411	418	847	863
Total operating expenses		6,769	6,881	14,298	15,142
Gain on sales of assets and businesses		12	33	13	36
Operating income		565	841	1,784	2,060
Other income and (deductions)
Interest expense, net		(421)	(403)	(824)	(800)
Interest expense to affiliates		(6)	(6)	(13)	(13)
Other, net		656	212	(68)	679
Total other income and (deductions)		229	(197)	(905)	(134)
Income before income taxes		794	644	879	1,926
Income taxes		219	144	(75)	454
Equity in losses of unconsolidated affiliates		(1)	(6)	(4)	(12)
Net income (loss)		574	494	950	1,460
Net income (loss) attributable to noncontrolling interests		53	10	(153)	69
Net income (loss) attributable to common shareholders		521	484	1,103	1,391
Other comprehensive income (loss), net of income taxes
Prior service benefit reclassified to periodic benefit cost		(10)	(16)	(20)	(32)
Actuarial loss reclassified to periodic benefit cost		47	36	94	74
Pension and non-pension postretirement benefit plan valuation adjustment		2	0	(5)	(39)
Unrealized (loss) gain on cash flow hedges		0	0	(1)	0
Unrealized (loss) gain on investments in unconsolidated affiliates		0	(2)	0	(4)
Unrealized gain (loss) on foreign currency translation		2	3	(6)	4
Other comprehensive income		41	21	62	3
Comprehensive income		615	515	1,012	1,463
Comprehensive income (loss) attributable to noncontrolling interests		53	9	(153)	67
Comprehensive income attributable to common shareholders/membership interest		$ 562	$ 506	$ 1,165	$ 1,396
Average shares of common stock outstanding:
Basic average shares of common stock outstanding		976	972	975	972
Assumed exercise and/or distributions of stock-based awards		0	2	1	1
Diluted average shares of common stock outstanding	[1]	976	974	976	973
Earnings per average common share:
Basic earnings per average common share		$ 0.53	$ 0.50	$ 1.13	$ 1.43
Diluted earnings per average common share		$ 0.53	$ 0.50	$ 1.13	$ 1.43
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount		1	0	0	0
Exelon Generation Co L L C [Member]
Operating revenues
Operating revenues from affiliates		$ 271	$ 252	$ 601	$ 569
Total operating revenues		3,880	4,210	8,613	9,506
Operating expenses
Purchased power and/or fuel from affiliates		(3)	3	(9)	4
Operating and maintenance		1,053	1,117	2,174	2,185
Operating and maintenance from affiliates		136	149	277	299
Depreciation and amortization		300	409	604	814
Taxes other than income taxes		116	129	246	264
Total operating expenses		3,547	4,096	7,947	9,059
Gain on sales of assets and businesses		12	33	12	33
Operating income		345	147	678	480
Other income and (deductions)
Interest expense, net		(78)	(107)	(179)	(209)
Interest expense to affiliates		(9)	(9)	(18)	(18)
Other, net		602	171	(168)	601
Total other income and (deductions)		515	55	(365)	374
Income before income taxes		860	202	313	854
Income taxes		329	78	(59)	301
Equity in losses of unconsolidated affiliates		(2)	(6)	(4)	(13)
Net income (loss)		529	118	368	540
Net income (loss) attributable to noncontrolling interests		53	10	(153)	68
Net income attributable to membership interest		476	108	521	472
Other comprehensive income (loss), net of income taxes
Unrealized (loss) gain on cash flow hedges		0	(1)	(1)	0
Unrealized (loss) gain on investments in unconsolidated affiliates		0	(2)	0	(4)
Unrealized gain (loss) on foreign currency translation		2	2	(6)	4
Other comprehensive income		2	(1)	(7)	0
Comprehensive income		531	117	361	540
Comprehensive income (loss) attributable to noncontrolling interests		53	9	(153)	66
Comprehensive income attributable to common shareholders/membership interest		478	108	514	474
Commonwealth Edison Co [Member]
Operating revenues
Revenues from alternative revenue programs		(25)	(14)	(13)	(42)
Operating revenues from affiliates		11	5	16	9
Total operating revenues		1,417	1,351	2,856	2,759
Operating expenses
Purchased power and/or fuel from affiliates		84	91	181	187
Operating and maintenance		469	245	713	504
Operating and maintenance from affiliates		67	60	140	122
Depreciation and amortization		274	257	547	508
Taxes other than income taxes		71	71	146	148
Total operating expenses		1,345	1,040	2,497	2,174
Gain on sales of assets and businesses		0	0	0	3
Operating income		72	311	359	588
Other income and (deductions)
Interest expense, net		(95)	(86)	(186)	(171)
Interest expense to affiliates		(3)	(3)	(6)	(7)
Other, net		11	10	22	19
Total other income and (deductions)		(87)	(79)	(170)	(159)
Income before income taxes		(15)	232	189	429
Income taxes		46	46	82	85
Net income (loss)		(61)	186	107	344
Other comprehensive income (loss), net of income taxes
Comprehensive income		(61)	186	107	344
PECO Energy Co [Member]
Operating revenues
Revenues from alternative revenue programs		4	(3)	5	(6)
Operating revenues from affiliates		2	2	4	3
Total operating revenues		681	655	1,493	1,554
Operating expenses
Purchased power and/or fuel from affiliates		40	35	76	79
Operating and maintenance		235	162	414	349
Operating and maintenance from affiliates		40	37	78	75
Depreciation and amortization		88	83	173	164
Taxes other than income taxes		39	37	78	79
Total operating expenses		618	510	1,242	1,187
Operating income		63	145	251	367
Other income and (deductions)
Interest expense, net		(33)	(30)	(65)	(61)
Interest expense to affiliates		(3)	(3)	(6)	(6)
Other, net		5	3	7	7
Total other income and (deductions)		(31)	(30)	(64)	(60)
Income before income taxes		32	115	187	307
Income taxes		(7)	13	9	37
Net income (loss)		39	102	178	270
Other comprehensive income (loss), net of income taxes
Comprehensive income		39	102	178	270
Baltimore Gas and Electric Company [Member]
Operating revenues
Revenues from alternative revenue programs		(37)	6	0	17
Operating revenues from affiliates		4	6	10	12
Total operating revenues		616	649	1,554	1,625
Operating expenses
Purchased power and/or fuel from affiliates		69	56	167	132
Operating and maintenance		146	142	293	294
Operating and maintenance from affiliates		41	40	83	78
Depreciation and amortization		129	117	272	252
Taxes other than income taxes		63	62	132	131
Total operating expenses		573	569	1,263	1,325
Operating income		43	80	291	300
Other income and (deductions)
Interest expense, net		(32)	(29)	(64)	(58)
Other, net		6	5	10	11
Total other income and (deductions)		(26)	(24)	(54)	(47)
Income before income taxes		17	56	237	253
Income taxes		(22)	11	18	47
Net income (loss)		39	45	219	206
Other comprehensive income (loss), net of income taxes
Comprehensive income		39	45	219	206
Pepco Holdings LLC [Member]
Operating revenues
Revenues from alternative revenue programs		(64)	(3)	(47)	12
Operating revenues from affiliates		3	3	7	7
Total operating revenues		1,016	1,091	2,187	2,319
Operating expenses
Purchased power and/or fuel from affiliates		78	70	182	171
Operating and maintenance		245	213	464	452
Operating and maintenance from affiliates		36	35	74	68
Depreciation and amortization		191	188	385	369
Taxes other than income taxes		109	108	222	220
Total operating expenses		956	926	1,955	1,981
Gain on sales of assets and businesses		0	0	2	0
Operating income		60	165	234	338
Other income and (deductions)
Interest expense, net		(67)	(67)	(134)	(131)
Other, net		14	14	26	27
Total other income and (deductions)		(53)	(53)	(108)	(104)
Income before income taxes		7	112	126	234
Income taxes		(87)	6	(76)	11
Net income (loss)		94	106	202	223
Other comprehensive income (loss), net of income taxes
Comprehensive income attributable to common shareholders/membership interest		94	106	202	223
Potomac Electric Power Company [Member]
Operating revenues
Revenues from alternative revenue programs		(13)	(1)	2	13
Operating revenues from affiliates		1	1	3	3
Total operating revenues		494	531	1,039	1,106
Operating expenses
Purchased power and/or fuel from affiliates		60	52	139	122
Operating and maintenance		67	59	128	123
Operating and maintenance from affiliates		52	52	103	107
Depreciation and amortization		92	93	186	186
Taxes other than income taxes		87	90	179	182
Total operating expenses		436	438	899	929
Operating income		58	93	140	177
Other income and (deductions)
Interest expense, net		(34)	(34)	(68)	(68)
Other, net		9	7	18	14
Total other income and (deductions)		(25)	(27)	(50)	(54)
Income before income taxes		33	66	90	123
Income taxes		(24)	2	(19)	4
Net income (loss)		57	64	109	119
Other comprehensive income (loss), net of income taxes
Comprehensive income		57	64	109	119
Delmarva Power and Light Company [Member]
Operating revenues
Revenues from alternative revenue programs		(25)	0	(24)	1
Operating revenues from affiliates		2	2	4	3
Total operating revenues		267	287	617	667
Operating expenses
Purchased power and/or fuel from affiliates		16	12	38	35
Operating and maintenance		54	39	97	84
Operating and maintenance from affiliates		38	38	75	76
Depreciation and amortization		47	45	94	91
Taxes other than income taxes		17	14	32	28
Total operating expenses		263	243	547	550
Operating income		4	44	70	117
Other income and (deductions)
Interest expense, net		(15)	(15)	(31)	(30)
Other, net		2	5	5	7
Total other income and (deductions)		(13)	(10)	(26)	(23)
Income before income taxes		(9)	34	44	94
Income taxes		(28)	4	(20)	11
Net income (loss)		19	30	64	83
Other comprehensive income (loss), net of income taxes
Comprehensive income		19	30	64	83
Atlantic City Electric Company [Member]
Operating revenues
Revenues from alternative revenue programs		(26)	(2)	(25)	(1)
Operating revenues from affiliates		1	1	1	1
Total operating revenues		256	274	532	547
Operating expenses
Purchased power and/or fuel from affiliates		2	6	5	13
Operating and maintenance		48	41	94	88
Operating and maintenance from affiliates		34	33	66	67
Depreciation and amortization		44	40	86	71
Taxes other than income taxes		2	1	4	2
Total operating expenses		258	246	509	498
Gain on sales of assets and businesses		0	0	2	0
Operating income		(2)	28	25	49
Other income and (deductions)
Interest expense, net		(15)	(15)	(29)	(28)
Other, net		2	1	3	4
Total other income and (deductions)		(13)	(14)	(26)	(24)
Income before income taxes		(15)	14	(1)	25
Income taxes		(33)	0	(32)	1
Net income (loss)		18	14	31	24
Other comprehensive income (loss), net of income taxes
Comprehensive income		18	14	31	24
Generation commodities and services
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		3,611	3,959	8,014	8,938
Operating expenses
Purchased power and/or fuel		1,945	2,289	4,655	5,493
Generation commodities and services | Exelon Generation Co L L C [Member]
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		3,609	3,958	8,012	8,937
Operating expenses
Purchased power and/or fuel		1,945	2,289	4,655	5,493
Rate-regulated utility revenues
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		3,832	3,743	8,108	8,247
Operating expenses
Purchased power and/or fuel		979	936	2,136	2,285
Electricity, US Regulated
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		3,475	3,512	7,222	7,343
Electricity, US Regulated | Commonwealth Edison Co [Member]
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		1,431	1,360	2,853	2,792
Operating expenses
Purchased power and/or fuel		380	316	770	705
Electricity, US Regulated | PECO Energy Co [Member]
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		580	567	1,180	1,188
Operating expenses
Purchased power and/or fuel		142	124	306	275
Electricity, US Regulated | Baltimore Gas and Electric Company [Member]
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		530	540	1,125	1,191
Operating expenses
Purchased power and/or fuel		107	131	221	322
Electricity, US Regulated | Pepco Holdings LLC [Member]
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		1,047	1,067	2,133	2,205
Operating expenses
Purchased power and/or fuel		286	303	586	658
Electricity, US Regulated | Potomac Electric Power Company [Member]
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		506	531	1,034	1,090
Operating expenses
Purchased power and/or fuel		78	92	164	209
Electricity, US Regulated | Delmarva Power and Light Company [Member]
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		260	261	543	568
Operating expenses
Purchased power and/or fuel		80	86	169	193
Electricity, US Regulated | Atlantic City Electric Company [Member]
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		281	275	556	547
Operating expenses
Purchased power and/or fuel		128	125	254	257
Natural Gas, US Regulated
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		236	218	832	883
Natural Gas, US Regulated | PECO Energy Co [Member]
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		95	89	304	369
Operating expenses
Purchased power and/or fuel		34	32	117	166
Natural Gas, US Regulated | Baltimore Gas and Electric Company [Member]
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		119	97	419	405
Operating expenses
Purchased power and/or fuel		18	21	95	116
Natural Gas, US Regulated | Pepco Holdings LLC [Member]
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		30	24	94	95
Operating expenses
Purchased power and/or fuel		11	9	42	43
Natural Gas, US Regulated | Delmarva Power and Light Company [Member]
Operating revenues
Revenue from Contract with Customer, Including Assessed Tax		30	24	94	95
Operating expenses
Purchased power and/or fuel		$ 11	$ 9	$ 42	$ 43

[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 and immaterial for the three and six months ended June 30, 2020, respectively, and immaterial for the three and six months ended June 30, 2019.