Consolidated Balance Sheets - USD ($) $ in Millions		Dec. 31, 2018	Dec. 31, 2017
Current assets
Cash and cash equivalents		$ 1,349	$ 898
Restricted cash and cash equivalents		247	207
Accounts receivable, net
Customer		4,607	4,445
Other		1,256	1,132
Mark-to-market derivative assets, current		804	976
Unamortized energy contract assets, current		48	60
Inventories, net
Energy Related Inventory, Other Fossil Fuel		334	340
Materials and supplies		1,351	1,311
Regulatory assets, current		1,222	1,267
Assets held for sale		904	0
Other		1,238	1,260
Total current assets		13,360	11,896
Property, plant and equipment, net		76,707	74,202
Deferred debits and other assets
Regulatory assets, noncurrent		8,237	8,021
Nuclear decommissioning trust funds		11,661	13,272
Investments		625	640
Goodwill		6,677	6,677
Mark-to-market derivative assets, noncurrent		452	337
Unamortized energy contract assets, noncurrent		372	395
Other		1,575	1,330
Total deferred debits and other assets		29,599	30,672
Total assets	[1]	119,666	116,770
Current liabilities
Short-term borrowings		714	929
Long-term debt due within one year		1,349	2,088
Accounts payable		3,800	3,532
Accrued expenses		2,112	1,837
Payables to affiliates, current		5	5
Regulatory Liability, Current		644	523
Mark-to-market derivative liabilities, current		475	232
Unamortized energy contract liabilities, current		149	231
Renewable energy credit obligation		344	352
Liabilities held for sale		777	0
Other		1,035	1,069
Total current liabilities		11,404	10,798
Long-term debt		34,075	32,176
Long-term debt to financing trusts		390	389
Deferred credits and other liabilities
Deferred income taxes and unamortized investment tax credits		11,330	11,235
Asset retirement obligations, noncurrent		9,679	10,029
Pension obligations		3,988	3,736
Non-pension postretirement benefit obligations		1,928	2,093
Spent nuclear fuel obligation		1,171	1,147
Regulatory liabilities, noncurrent		9,559	9,865
Mark-to-market derivative liabilities, noncurrent		479	409
Unamortized energy contract liabilities, noncurrent		463	609
Other		2,130	2,097
Total deferred credits and other liabilities		40,727	41,220
Total liabilities	[1]	86,596	84,583
Commitments and Contingencies
Shareholders’ equity
Common stock		19,116	18,964
Treasury stock, at cost		(123)	(123)
Retained earnings		14,766	14,081
Accumulated other comprehensive income (loss), net		(2,995)	(3,026)
Total shareholders’ equity		30,764	29,896
Member’s equity
Noncontrolling interests		2,306	2,291
Total equity		33,070	32,187
Total liabilities and equity		119,666	116,770
Variable Interest Entity, Consolidated, Assets, Not Pledged		9,667	9,597
Variable Interest Entity, Consolidated, Liabilities, No Recourse		3,548	3,618
Exelon Generation Co L L C [Member]
Current assets
Cash and cash equivalents		750	416
Restricted cash and cash equivalents		153	138
Accounts receivable, net
Customer		2,941	2,697
Other		562	321
Mark-to-market derivative assets, current		804	976
Receivables from affiliates, current		173	140
Unamortized energy contract assets, current		49	60
Inventories, net
Energy Related Inventory, Other Fossil Fuel		251	264
Materials and supplies		963	937
Assets held for sale		904	0
Other		883	933
Total current assets		8,433	6,882
Property, plant and equipment, net		23,981	24,906
Deferred debits and other assets
Nuclear decommissioning trust funds		11,661	13,272
Investments		414	433
Goodwill		47	47
Mark-to-market derivative assets, noncurrent		452	334
Prepaid pension asset		1,421	1,502
Unamortized energy contract assets, noncurrent		371	395
Deferred income taxes		21	16
Other		755	670
Total deferred debits and other assets		15,142	16,669
Total assets	[2]	47,556	48,457
Current liabilities
Short-term borrowings		0	2
Long-term debt due within one year		906	346
Accounts payable		1,847	1,773
Accrued expenses		898	1,022
Payables to affiliates, current		139	123
Borrowings from Exelon intercompany money pool		100	54
Mark-to-market derivative liabilities, current		449	211
Unamortized energy contract liabilities, current		31	43
Renewable energy credit obligation		343	352
Liabilities held for sale		777	0
Other		279	265
Total current liabilities		5,769	4,191
Long-term debt		6,989	7,734
Long-term debt to affiliates		898	910
Deferred credits and other liabilities
Deferred income taxes and unamortized investment tax credits		3,383	3,811
Asset retirement obligations, noncurrent		9,450	9,844
Non-pension postretirement benefit obligations		900	916
Spent nuclear fuel obligation		1,171	1,147
Payables to affiliates, noncurrent		2,606	3,065
Mark-to-market derivative liabilities, noncurrent		252	174
Unamortized energy contract liabilities, noncurrent		20	48
Other		610	658
Total deferred credits and other liabilities		18,392	19,663
Total liabilities	[2]	32,048	32,498
Commitments and Contingencies
Shareholders’ equity
Retained earnings		3,724	4,349
Accumulated other comprehensive income (loss), net		(38)	(37)
Member’s equity
Membership interest		9,518	9,357
Total member’s equity		13,204	13,669
Noncontrolling interests		2,304	2,290
Total equity		15,508	15,959
Total liabilities and equity		47,556	48,457
Variable Interest Entity, Consolidated, Assets, Not Pledged		9,634	9,556
Variable Interest Entity, Consolidated, Liabilities, No Recourse		3,480	3,516
Commonwealth Edison Co [Member]
Current assets
Cash and cash equivalents		135	76
Restricted cash and cash equivalents		29	5
Accounts receivable, net
Customer		539	559
Other		320	266
Receivables from affiliates, current		20	13
Inventories, net
Inventories, net		148	152
Regulatory assets, current		293	225
Other		86	68
Total current assets		1,570	1,364
Property, plant and equipment, net		22,058	20,723
Deferred debits and other assets
Regulatory assets, noncurrent		1,307	1,054
Investments		6	6
Goodwill		2,625	2,625
Receivable from affiliates, noncurrent		2,217	2,528
Prepaid pension asset		1,035	1,188
Other		395	238
Total deferred debits and other assets		7,585	7,639
Total assets		31,213	29,726
Current liabilities
Long-term debt due within one year		300	840
Accounts payable		607	568
Accrued expenses		373	327
Payables to affiliates, current		119	74
Regulatory Liability, Current		293	249
Mark-to-market derivative liabilities, current		26	21
Customer deposits		111	112
Other		96	103
Total current liabilities		1,925	2,294
Long-term debt		7,801	6,761
Long-term debt to financing trusts		205	205
Deferred credits and other liabilities
Deferred income taxes and unamortized investment tax credits		3,813	3,469
Asset retirement obligations, noncurrent		118	111
Non-pension postretirement benefit obligations		201	219
Regulatory liabilities, noncurrent		6,050	6,328
Mark-to-market derivative liabilities, noncurrent		223	235
Other		630	562
Total deferred credits and other liabilities		11,035	10,924
Total liabilities		20,966	20,184
Commitments and Contingencies
Shareholders’ equity
Common stock		1,588	1,588
Other paid-in capital		7,322	6,822
Retained earnings (deficit) unappropriated		(1,639)	(1,639)
Retained earnings (deficit) appropriated		2,976	2,771
Total shareholders’ equity		10,247	9,542
Member’s equity
Total liabilities and equity		31,213	29,726
PECO Energy Co [Member]
Current assets
Cash and cash equivalents		130	271
Restricted cash and cash equivalents		5	4
Accounts receivable, net
Customer		321	327
Other		151	105
Inventories, net
Energy Related Inventory, Other Fossil Fuel		38	31
Materials and supplies		37	30
Regulatory assets, current		81	29
Prepaid utility taxes		0	8
Other		19	17
Total current assets		782	822
Property, plant and equipment, net		8,610	8,053
Deferred debits and other assets
Regulatory assets, noncurrent		460	381
Investments		25	25
Receivable from affiliates, noncurrent		389	537
Prepaid pension asset		349	340
Other		27	12
Total deferred debits and other assets		1,250	1,295
Total assets		10,642	10,170
Current liabilities
Long-term debt due within one year		0	500
Accounts payable		370	370
Accrued expenses		113	114
Payables to affiliates, current		59	53
Regulatory Liability, Current		175	141
Customer deposits		68	66
Other		24	23
Total current liabilities		809	1,267
Long-term debt		3,084	2,403
Long-term debt to financing trusts	[3]	184	184
Deferred credits and other liabilities
Deferred income taxes and unamortized investment tax credits		1,933	1,789
Asset retirement obligations, noncurrent		27	27
Non-pension postretirement benefit obligations		288	288
Regulatory liabilities, noncurrent		421	549
Other		76	86
Total deferred credits and other liabilities		2,745	2,739
Total liabilities		6,822	6,593
Commitments and Contingencies
Shareholders’ equity
Common stock		2,578	2,489
Retained earnings		1,242	1,087
Accumulated other comprehensive income (loss), net		0	1
Total shareholders’ equity		3,820	3,577
Member’s equity
Total liabilities and equity		10,642	10,170
Baltimore Gas and Electric Company [Member]
Current assets
Cash and cash equivalents		7	17
Restricted cash and cash equivalents		6	1
Accounts receivable, net
Customer		353	375
Other		90	94
Receivables from affiliates, current		1	1
Inventories, net
Materials and supplies		39	40
Gas Held in Storage		36	37
Regulatory assets, current		177	174
Prepaid utility taxes		74	69
Other		3	3
Total current assets		786	811
Property, plant and equipment, net		8,243	7,602
Deferred debits and other assets
Regulatory assets, noncurrent		398	397
Investments		5	5
Prepaid pension asset		279	285
Other		5	4
Total deferred debits and other assets		687	691
Total assets		9,716	9,104
Current liabilities
Short-term borrowings		35	77
Accounts payable		295	265
Accrued expenses		155	164
Payables to affiliates, current		65	52
Regulatory Liability, Current		77	62
Customer deposits		120	116
Other		27	24
Total current liabilities		774	760
Long-term debt		2,876	2,577
Deferred credits and other liabilities
Deferred income taxes and unamortized investment tax credits		1,222	1,244
Asset retirement obligations, noncurrent		24	23
Non-pension postretirement benefit obligations		201	202
Regulatory liabilities, noncurrent		1,192	1,101
Other		73	56
Total deferred credits and other liabilities		2,712	2,626
Total liabilities		6,362	5,963
Commitments and Contingencies
Shareholders’ equity
Common stock		1,714	1,605
Retained earnings		1,640	1,536
Total shareholders’ equity		3,354	3,141
Member’s equity
Total liabilities and equity		9,716	9,104
Pepco Holdings LLC [Member]
Current assets
Cash and cash equivalents		124	30
Restricted cash and cash equivalents		43	42
Accounts receivable, net
Customer		453	486
Other		177	206
Inventories, net
Materials and supplies		163	151
Gas Held in Storage		9	7
Regulatory assets, current		489	554
Other		75	75
Total current assets		1,533	1,551
Property, plant and equipment, net		13,446	12,498
Deferred debits and other assets
Regulatory assets, noncurrent		2,312	2,493
Investments		130	132
Goodwill		4,005	4,005
Prepaid pension asset		486	490
Deferred income taxes		12	4
Long-term note receivable		0	4
Other		60	70
Total deferred debits and other assets		7,005	7,198
Total assets	[4]	21,984	21,247
Current liabilities
Short-term borrowings		179	350
Long-term debt due within one year		125	396
Accounts payable		496	348
Accrued expenses		256	261
Payables to affiliates, current		94	90
Regulatory Liability, Current		84	56
Unamortized energy contract liabilities, current		119	188
Customer deposits		116	119
Other		123	123
Total current liabilities		1,592	1,931
Long-term debt		6,134	5,478
Deferred credits and other liabilities
Deferred income taxes and unamortized investment tax credits		2,146	2,070
Asset retirement obligations, noncurrent		52	16
Non-pension postretirement benefit obligations		103	105
Regulatory liabilities, noncurrent		1,864	1,872
Unamortized energy contract liabilities, noncurrent		442	561
Other		369	389
Total deferred credits and other liabilities		4,976	5,013
Total liabilities	[4]	12,702	12,422
Commitments and Contingencies
Shareholders’ equity
Retained earnings		62	(10)
Member’s equity
Membership interest		9,220	8,835
Total member’s equity		9,282	8,825
Total equity		9,282	8,825
Total liabilities and equity		21,984	21,247
Variable Interest Entity, Consolidated, Assets, Not Pledged		33	41
Variable Interest Entity, Consolidated, Liabilities, No Recourse		69	102
Potomac Electric Power Company [Member]
Current assets
Cash and cash equivalents		16	5
Restricted cash and cash equivalents		37	35
Accounts receivable, net
Customer		225	250
Other		81	87
Receivables from affiliates, current		1	0
Inventories, net
Inventories, net		93	87
Regulatory assets, current		270	213
Other		37	33
Total current assets		760	710
Property, plant and equipment, net		6,460	6,001
Deferred debits and other assets
Regulatory assets, noncurrent		643	678
Investments		105	102
Prepaid pension asset		316	322
Other		15	19
Total deferred debits and other assets		1,079	1,121
Total assets		8,299	7,832
Current liabilities
Short-term borrowings		40	26
Long-term debt due within one year		15	19
Accounts payable		214	139
Accrued expenses		126	137
Payables to affiliates, current		62	74
Regulatory Liability, Current		7	3
Customer deposits		54	54
Merger related obligation		38	42
Current portion of DC PLUG obligation		30	28
Other		42	28
Total current liabilities		628	550
Long-term debt		2,704	2,521
Deferred credits and other liabilities
Deferred income taxes and unamortized investment tax credits		1,064	1,063
Non-pension postretirement benefit obligations		29	36
Regulatory liabilities, noncurrent		822	829
Other		312	300
Total deferred credits and other liabilities		2,227	2,228
Total liabilities		5,559	5,299
Commitments and Contingencies
Shareholders’ equity
Common stock		1,636	1,470
Retained earnings		1,104	1,063
Total shareholders’ equity		2,740	2,533
Member’s equity
Total liabilities and equity		8,299	7,832
Delmarva Power & Light Company [Member]
Current assets
Cash and cash equivalents		23	2
Restricted cash and cash equivalents		1	0
Accounts receivable, net
Customer		134	146
Other		46	38
Inventories, net
Materials and supplies		37	36
Gas Held in Storage		9	7
Regulatory assets, current		59	69
Other		27	27
Total current assets		336	325
Property, plant and equipment, net		3,821	3,579
Deferred debits and other assets
Regulatory assets, noncurrent		231	245
Investments		0	0
Goodwill		8	8
Prepaid pension asset		186	193
Other		6	7
Total deferred debits and other assets		431	453
Total assets		4,588	4,357
Current liabilities
Short-term borrowings		0	216
Long-term debt due within one year		91	83
Accounts payable		111	82
Accrued expenses		39	35
Payables to affiliates, current		33	46
Regulatory Liability, Current		59	42
Customer deposits		35	35
Other		7	8
Total current liabilities		375	547
Long-term debt		1,403	1,217
Deferred credits and other liabilities
Deferred income taxes and unamortized investment tax credits		628	603
Non-pension postretirement benefit obligations		17	14
Regulatory liabilities, noncurrent		606	593
Other		50	48
Total deferred credits and other liabilities		1,301	1,258
Total liabilities		3,079	3,022
Commitments and Contingencies
Shareholders’ equity
Common stock		914	764
Retained earnings		595	571
Total shareholders’ equity		1,509	1,335
Member’s equity
Total liabilities and equity		4,588	4,357
Atlantic City Electric Company [Member]
Current assets
Cash and cash equivalents		7	2
Restricted cash and cash equivalents		4	6
Accounts receivable, net
Customer		95	92
Other		55	56
Receivables from affiliates, current		1	0
Inventories, net
Inventories, net		33	29
Regulatory assets, current		40	71
Other		5	2
Total current assets		240	258
Property, plant and equipment, net		2,966	2,706
Deferred debits and other assets
Regulatory assets, noncurrent		386	359
Investments		0	0
Prepaid pension asset		67	73
Long-term note receivable		0	4
Other		40	45
Total deferred debits and other assets		493	481
Total assets	[5]	3,699	3,445
Current liabilities
Short-term borrowings		139	108
Long-term debt due within one year		18	281
Accounts payable		154	118
Accrued expenses		35	33
Payables to affiliates, current		28	29
Regulatory Liability, Current		18	11
Customer deposits		26	31
Other		4	8
Total current liabilities		422	619
Long-term debt		1,170	840
Deferred credits and other liabilities
Deferred income taxes and unamortized investment tax credits		535	493
Non-pension postretirement benefit obligations		17	14
Regulatory liabilities, noncurrent		402	411
Other		27	25
Total deferred credits and other liabilities		981	943
Total liabilities	[5]	2,573	2,402
Commitments and Contingencies
Shareholders’ equity
Common stock		979	912
Retained earnings		147	131
Total shareholders’ equity		1,126	1,043
Member’s equity
Total liabilities and equity		3,699	3,445
Variable Interest Entity, Consolidated, Assets, Not Pledged		23	29
Variable Interest Entity, Consolidated, Liabilities, No Recourse		$ 59	$ 90

[1] Exelon’s consolidated assets include $9,667 million and $9,597 million at December 31, 2018 and 2017, respectively, of certain VIEs that can only be used to settle the liabilities of the VIE. Exelon’s consolidated liabilities include $3,548 million and $3,618 million at December 31, 2018 and 2017, respectively, of certain VIEs for which the VIE creditors do not have recourse to Exelon. See Note 2–Variable Interest Entities for additional information.

[2] Generation’s consolidated assets include $9,634 million and $9,556 million at December 31, 2018 and 2017, respectively, of certain VIEs that can only be used to settle the liabilities of the VIE. Generation’s consolidated liabilities include $3,480 million and $3,516 million at December 31, 2018 and 2017, respectively, of certain VIEs for which the VIE creditors do not have recourse to Generation. See Note 2–Variable Interest Entities for additional information.

[3] Amounts owed to this financing trust are recorded as Long-term debt to financing trusts within PECO’s Consolidated Balance Sheets.

[4] PHI’s consolidated total assets include $33 million and $41 million at December 31, 2018 and 2017, respectively, of PHI's consolidated VIE that can only be used to settle the liabilities of the VIE. PHI’s consolidated total liabilities include $69 million and $102 million at December 31, 2018 and 2017, respectively, of PHI's consolidated VIE for which the VIE creditors do not have recourse to PHI. See Note 2 - Variable Interest Entities for additional information.

[5] ACE’s consolidated assets include $23 million and $29 million at December 31, 2018 and 2017, respectively, of ACE’s consolidated VIE that can only be used to settle the liabilities of the VIE. ACE’s consolidated liabilities include $59 million and $90 million at December 31, 2018 and 2017, respectively, of ACE’s consolidated VIE for which the VIE creditors do not have recourse to ACE. See Note 2 - Variable Interest Entities for additional information.