Consolidated Balance Sheets (Unaudited) - USD ($) $ in Millions		Mar. 31, 2018	Dec. 31, 2017
Current Assets
Cash and cash equivalents		$ 787	$ 898
Restricted cash and cash equivalents		209	207
Accounts receivable, net
Customer		4,190	4,445
Other		1,103	1,132
Mark-to-market derivative assets, current		978	976
Unamortized energy contract assets		55	60
Inventories, net
Energy Related Inventory, Other Fossil Fuel		180	340
Inventory, Raw Materials and Supplies, Gross		1,291	1,311
Regulatory Assets, Current		1,245	1,267
Other		1,495	1,260
Total current assets		11,533	11,896
Property, plant and equipment, net		74,711	74,202
Deferred debits and other assets
Regulatory Assets, Noncurrent		8,063	8,021
Nuclear decommissioning trust funds		13,149	13,272
Investments		640	640
Goodwill		6,677	6,677
Mark-to-market derivative assets, noncurrent		527	337
Unamortized energy contract assets		385	395
Other		1,333	1,330
Total deferred debits and other assets		30,774	30,672
Total assets	[1]	117,018	116,770
Current Liabilities
Short-term borrowings		1,654	929
Long-term debt due within one year		1,203	2,088
Accounts payable		3,207	3,532
Accrued expenses		1,569	1,837
Payable to affiliates, current		5	5
Regulatory Liability, Current		522	523
Mark-to-market derivative liabilities		415	232
Unamortized energy contract liabilities		202	231
Energy Marketing Accounts Payable		333	352
Accounts Payable and Accrued Liabilities, Current		87	87
Other		956	982
Total current liabilities		10,153	10,798
Long-term debt		32,905	32,176
Long-term debt to financing trust		389	389
Deferred credits and other liabilities
Deferred Income Taxes and Other Tax Liabilities, Noncurrent		11,344	11,235
Asset Retirement Obligations, Noncurrent		10,126	10,029
Pension obligations		3,433	3,736
Non-pension postretirement benefit obligations		2,114	2,093
Spent nuclear fuel obligation		1,151	1,147
Regulatory Liability, Noncurrent		9,724	9,865
Mark-to-market derivative liabilities, noncurrent		468	409
Unamortized energy contract liabilities		579	609
Other		2,067	2,097
Total deferred credits and other liabilities		41,006	41,220
Total liabilities	[1]	84,453	84,583
Commitments and contingencies
Stockholders' Equity Attributable to Parent
Common stock		18,973	18,964
Treasury stock, at cost (2 shares at March 31, 2018 and December 31, 2017)		(123)	(123)
Retained Earnings		14,346	14,081
Accumulated other comprehensive loss, net		(2,965)	(3,026)
Total shareholders’ equity		30,231	29,896
Member’s equity
Noncontrolling Interests		2,334	2,291
Total equity		32,565	32,187
Total liabilities and shareholders’ equity		117,018	116,770
Variable Interest Entity, Consolidated, Liabilities, No Recourse		3,556	3,618
Variable Interest Entity, Consolidated, Assets, Not Pledged		9,727	9,597
Exelon Generation Co L L C [Member]
Current Assets
Cash and cash equivalents		610	416
Restricted cash and cash equivalents		127	138
Accounts receivable, net
Customer		2,478	2,697
Other		294	321
Mark-to-market derivative assets, current		978	976
Receivable from affiliates, current		153	140
Unamortized energy contract assets		55	60
Inventories, net
Energy Related Inventory, Other Fossil Fuel		151	264
Inventory, Raw Materials and Supplies, Gross		916	937
Other		1,122	933
Total current assets		6,884	6,882
Property, plant and equipment, net		24,714	24,906
Deferred debits and other assets
Nuclear decommissioning trust funds		13,149	13,272
Investments		431	433
Goodwill		47	47
Mark-to-market derivative assets, noncurrent		527	334
Prepaid pension asset		1,571	1,502
Unamortized energy contract assets		385	395
Deferred income taxes		10	16
Other		657	670
Total deferred debits and other assets		16,777	16,669
Total assets	[2]	48,375	48,457
Current Liabilities
Short-term borrowings		166	2
Long-term debt due within one year		373	346
Accounts payable		1,447	1,773
Accrued expenses		951	1,022
Payable to affiliates, current		114	123
Borrowings from Exelon intercompany money pool		54	54
Mark-to-market derivative liabilities		391	211
Unamortized energy contract liabilities		39	43
Energy Marketing Accounts Payable		333	352
Other		288	265
Total current liabilities		4,156	4,191
Long-term debt		7,685	7,734
Long-term debt to affiliate		907	910
Deferred credits and other liabilities
Deferred Income Taxes and Other Tax Liabilities, Noncurrent		3,749	3,811
Asset Retirement Obligations, Noncurrent		9,941	9,844
Non-pension postretirement benefit obligations		911	916
Spent nuclear fuel obligation		1,151	1,147
Payables to affiliates, noncurrent		2,970	3,065
Mark-to-market derivative liabilities, noncurrent		221	174
Unamortized energy contract liabilities		40	48
Other		686	658
Total deferred credits and other liabilities		19,669	19,663
Total liabilities	[2]	32,417	32,498
Commitments and contingencies
Stockholders' Equity Attributable to Parent
Retained Earnings		4,303	4,349
Accumulated other comprehensive loss, net		(34)	(37)
Member’s equity
Membership Interest		9,357	9,357
Total members' equity		13,626	13,669
Noncontrolling Interests		2,332	2,290
Total equity		15,958	15,959
Total liabilities and shareholders’ equity		48,375	48,457
Variable Interest Entity, Consolidated, Liabilities, No Recourse		3,461	3,516
Variable Interest Entity, Consolidated, Assets, Not Pledged		9,688	9,556
Commonwealth Edison Co [Member]
Current Assets
Cash and cash equivalents		70	76
Restricted cash and cash equivalents		9	5
Accounts receivable, net
Customer		485	559
Other		290	266
Receivable from affiliates, current		28	13
Inventories, net
Inventories, net		146	152
Regulatory Assets, Current		226	225
Other		82	68
Total current assets		1,336	1,364
Property, plant and equipment, net		21,010	20,723
Deferred debits and other assets
Regulatory Assets, Noncurrent		1,125	1,054
Investments		6	6
Goodwill		2,625	2,625
Receivable from affiliate, noncurrent		2,464	2,528
Prepaid pension asset		1,177	1,188
Other		259	238
Total deferred debits and other assets		7,656	7,639
Total assets		30,002	29,726
Current Liabilities
Short-term borrowings		317	0
Long-term debt due within one year		440	840
Accounts payable		491	568
Accrued expenses		198	327
Payable to affiliates, current		70	74
Regulatory Liability, Current		212	249
Mark-to-market derivative liabilities		24	21
Customer deposits		111	112
Other		82	103
Total current liabilities		1,945	2,294
Long-term debt		7,254	6,761
Long-term debt to financing trust		205	205
Deferred credits and other liabilities
Deferred Income Taxes and Other Tax Liabilities, Noncurrent		3,539	3,469
Asset Retirement Obligations, Noncurrent		111	111
Non-pension postretirement benefit obligations		215	219
Regulatory Liability, Noncurrent		6,212	6,328
Mark-to-market derivative liabilities, noncurrent		243	235
Other		572	562
Total deferred credits and other liabilities		10,892	10,924
Total liabilities		20,296	20,184
Stockholders' Equity Attributable to Parent
Common stock		1,588	1,588
Other paid-in capital		6,935	6,822
Retained Earnings, Unappropriated		(1,639)	(1,639)
Retained Earnings, Appropriated		2,822	2,771
Total shareholders’ equity		9,706	9,542
Member’s equity
Total liabilities and shareholders’ equity		30,002	29,726
PECO Energy Co [Member]
Current Assets
Cash and cash equivalents		21	271
Restricted cash and cash equivalents		5	4
Accounts receivable, net
Customer		349	327
Other		117	105
Inventories, net
Energy Related Inventory, Other Fossil Fuel		16	31
Inventory, Raw Materials and Supplies, Gross		33	30
Regulatory Assets, Current		78	29
Prepaid Taxes		97	8
Other		20	17
Total current assets		736	822
Property, plant and equipment, net		8,176	8,053
Deferred debits and other assets
Regulatory Assets, Noncurrent		408	381
Investments		25	25
Receivable from affiliate, noncurrent		505	537
Prepaid pension asset		359	340
Other		9	12
Total deferred debits and other assets		1,306	1,295
Total assets		10,218	10,170
Current Liabilities
Short-term borrowings		220	0
Long-term debt due within one year		0	500
Accounts payable		379	370
Accrued expenses		91	114
Payable to affiliates, current		59	53
Borrowings from Exelon intercompany money pool		194	0
Regulatory Liability, Current		117	141
Customer deposits		66	66
Other		29	23
Total current liabilities		1,155	1,267
Long-term debt		2,723	2,403
Long-term debt to financing trust		184	184
Deferred credits and other liabilities
Deferred Income Taxes and Other Tax Liabilities, Noncurrent		1,824	1,789
Asset Retirement Obligations, Noncurrent		27	27
Non-pension postretirement benefit obligations		288	288
Regulatory Liability, Noncurrent		529	549
Other		85	86
Total deferred credits and other liabilities		2,753	2,739
Total liabilities		6,815	6,593
Stockholders' Equity Attributable to Parent
Common stock		2,489	2,489
Retained Earnings		914	1,087
Accumulated other comprehensive loss, net		0	1
Total shareholders’ equity		3,403	3,577
Member’s equity
Total liabilities and shareholders’ equity		10,218	10,170
Baltimore Gas and Electric Company [Member]
Current Assets
Cash and cash equivalents		22	17
Restricted cash and cash equivalents		2	1
Accounts receivable, net
Customer		394	375
Other		91	94
Receivable from affiliates, current		0	1
Inventories, net
Energy Related Inventory, Natural Gas in Storage		12	37
Inventory, Raw Materials and Supplies, Gross		45	40
Regulatory Assets, Current		149	174
Prepaid Taxes		35	69
Other		5	3
Total current assets		755	811
Property, plant and equipment, net		7,725	7,602
Deferred debits and other assets
Regulatory Assets, Noncurrent		391	397
Investments		5	5
Prepaid pension asset		313	285
Other		6	4
Total deferred debits and other assets		715	691
Total assets		9,195	9,104
Current Liabilities
Short-term borrowings		45	77
Accounts payable		253	265
Accrued expenses		162	164
Payable to affiliates, current		51	52
Regulatory Liability, Current		102	62
Customer deposits		118	116
Other		26	24
Total current liabilities		757	760
Long-term debt		2,578	2,577
Deferred credits and other liabilities
Deferred Income Taxes and Other Tax Liabilities, Noncurrent		1,286	1,244
Asset Retirement Obligations, Noncurrent		22	23
Non-pension postretirement benefit obligations		199	202
Regulatory Liability, Noncurrent		1,083	1,101
Other		53	56
Total deferred credits and other liabilities		2,643	2,626
Total liabilities		5,978	5,963
Stockholders' Equity Attributable to Parent
Common stock		1,605	1,605
Retained Earnings		1,612	1,536
Total shareholders’ equity		3,217	3,141
Member’s equity
Total liabilities and shareholders’ equity		9,195	9,104
Pepco Holdings LLC [Member]
Current Assets
Cash and cash equivalents		43	30
Restricted cash and cash equivalents		40	42
Accounts receivable, net
Customer		484	486
Other		210	206
Inventories, net
Energy Related Inventory, Natural Gas in Storage		2	7
Inventory, Raw Materials and Supplies, Gross		152	151
Regulatory Assets, Current		507	554
Other		55	75
Total current assets		1,493	1,551
Property, plant and equipment, net		12,688	12,498
Deferred debits and other assets
Regulatory Assets, Noncurrent		2,453	2,493
Investments		132	132
Notes, Loans and Financing Receivable, Gross, Noncurrent		4	4
Goodwill		4,005	4,005
Prepaid pension asset		527	490
Deferred income taxes		4	4
Other		69	70
Total deferred debits and other assets		7,194	7,198
Total assets	[3]	21,375	21,247
Current Liabilities
Short-term borrowings		407	350
Long-term debt due within one year		385	396
Accounts payable		469	348
Accrued expenses		246	261
Payable to affiliates, current		100	90
Borrowings from Exelon intercompany money pool		13	0
Regulatory Liability, Current		77	56
Unamortized energy contract liabilities		162	188
Customer deposits		114	119
Merger related obligation		42	42
Other		52	81
Total current liabilities		2,067	1,931
Long-term debt		5,464	5,478
Deferred credits and other liabilities
Deferred Income Taxes and Other Tax Liabilities, Noncurrent		2,103	2,070
Asset Retirement Obligations, Noncurrent		16	16
Non-pension postretirement benefit obligations		102	105
Regulatory Liability, Noncurrent		1,888	1,872
Unamortized energy contract liabilities		539	561
Other		377	389
Total deferred credits and other liabilities		5,025	5,013
Total liabilities	[3]	12,556	12,422
Stockholders' Equity Attributable to Parent
Retained Earnings		(16)	(10)
Member’s equity
Membership Interest		8,835	8,835
Total members' equity		8,819	8,825
Total equity		8,819	8,825
Total liabilities and shareholders’ equity		21,375	21,247
Variable Interest Entity, Consolidated, Liabilities, No Recourse		95	102
Variable Interest Entity, Consolidated, Assets, Not Pledged			41
Potomac Electric Power Company [Member]
Current Assets
Cash and cash equivalents		15	5
Restricted cash and cash equivalents		33	35
Accounts receivable, net
Customer		246	250
Other		87	87
Inventories, net
Inventories, net		89	87
Regulatory Assets, Current		207	213
Other		19	33
Total current assets		696	710
Property, plant and equipment, net		6,095	6,001
Deferred debits and other assets
Regulatory Assets, Noncurrent		656	678
Investments		104	102
Prepaid pension asset		323	322
Other		22	19
Total deferred debits and other assets		1,105	1,121
Total assets		7,896	7,832
Current Liabilities
Short-term borrowings		60	26
Long-term debt due within one year		19	19
Accounts payable		181	139
Accrued expenses		145	137
Payable to affiliates, current		56	74
Regulatory Liability, Current		7	3
Customer deposits		52	54
Merger related obligation		42	42
Current portion of DC PLUG obligation		30	28
Other		8	28
Total current liabilities		600	550
Long-term debt		2,521	2,521
Deferred credits and other liabilities
Deferred Income Taxes and Other Tax Liabilities, Noncurrent		1,076	1,063
Non-pension postretirement benefit obligations		34	36
Regulatory Liability, Noncurrent		838	829
Other		288	300
Total deferred credits and other liabilities		2,236	2,228
Total liabilities		5,357	5,299
Stockholders' Equity Attributable to Parent
Common stock		1,470	1,470
Retained Earnings		1,069	1,063
Total shareholders’ equity		2,539	2,533
Member’s equity
Total liabilities and shareholders’ equity		7,896	7,832
Delmarva Power and Light Company [Member]
Current Assets
Cash and cash equivalents		7	2
Restricted cash and cash equivalents		0	0
Accounts receivable, net
Customer		141	146
Other		43	38
Receivable from affiliates, current		2	0
Inventories, net
Energy Related Inventory, Natural Gas in Storage		2	7
Inventory, Raw Materials and Supplies, Gross		34	36
Regulatory Assets, Current		63	69
Other		22	27
Total current assets		314	325
Property, plant and equipment, net		3,620	3,579
Deferred debits and other assets
Regulatory Assets, Noncurrent		242	245
Goodwill		8	8
Prepaid pension asset		192	193
Other		7	7
Total deferred debits and other assets		449	453
Total assets		4,383	4,357
Current Liabilities
Short-term borrowings		211	216
Long-term debt due within one year		79	83
Accounts payable		106	82
Accrued expenses		43	35
Payable to affiliates, current		32	46
Regulatory Liability, Current		48	42
Customer deposits		34	35
Other		5	8
Total current liabilities		558	547
Long-term debt		1,217	1,217
Deferred credits and other liabilities
Deferred Income Taxes and Other Tax Liabilities, Noncurrent		618	603
Non-pension postretirement benefit obligations		13	14
Regulatory Liability, Noncurrent		598	593
Other		49	48
Total deferred credits and other liabilities		1,278	1,258
Total liabilities		3,053	3,022
Stockholders' Equity Attributable to Parent
Common stock		764	764
Retained Earnings		566	571
Total shareholders’ equity		1,330	1,335
Member’s equity
Total liabilities and shareholders’ equity		4,383	4,357
Atlantic City Electric Company [Member]
Current Assets
Cash and cash equivalents		10	2
Restricted cash and cash equivalents		7	6
Accounts receivable, net
Customer		97	92
Other		51	56
Receivable from affiliates, current		1	0
Inventories, net
Inventories, net		29	29
Regulatory Assets, Current		64	71
Other		4	2
Total current assets		263	258
Property, plant and equipment, net		2,767	2,706
Deferred debits and other assets
Regulatory Assets, Noncurrent		377	359
Notes, Loans and Financing Receivable, Gross, Noncurrent		4	4
Prepaid pension asset		76	73
Other		43	45
Total deferred debits and other assets		500	481
Total assets	[4]	3,530	3,445
Current Liabilities
Short-term borrowings		136	108
Long-term debt due within one year		278	281
Accounts payable		166	118
Accrued expenses		41	33
Payable to affiliates, current		26	29
Regulatory Liability, Current		21	11
Customer deposits		28	31
Other		7	8
Total current liabilities		703	619
Long-term debt		836	840
Deferred credits and other liabilities
Deferred Income Taxes and Other Tax Liabilities, Noncurrent		496	493
Non-pension postretirement benefit obligations		14	14
Regulatory Liability, Noncurrent		416	411
Other		24	25
Total deferred credits and other liabilities		950	943
Total liabilities	[4]	2,489	2,402
Stockholders' Equity Attributable to Parent
Common stock		912	912
Retained Earnings		129	131
Total shareholders’ equity		1,041	1,043
Member’s equity
Total liabilities and shareholders’ equity		3,530	3,445
Variable Interest Entity, Consolidated, Liabilities, No Recourse		83	90
Variable Interest Entity, Consolidated, Assets, Not Pledged		$ 27	$ 29

[1] Exelon’s consolidated assets include $9,727 million and $9,597 million at March 31, 2018 and December 31, 2017, respectively, of certain VIEs that can only be used to settle the liabilities of the VIE. Exelon’s consolidated liabilities include $3,556 million and $3,618 million at March 31, 2018 and December 31, 2017, respectively, of certain VIEs for which the VIE creditors do not have recourse to Exelon. See Note 3 — Variable Interest Entities.

[2] Generation’s consolidated assets include $9,688 million and $9,556 million at March 31, 2018 and December 31, 2017, respectively, of certain VIEs that can only be used to settle the liabilities of the VIE. Generation’s consolidated liabilities include $3,461 million and $3,516 million at March 31, 2018 and December 31, 2017, respectively, of certain VIEs for which the VIE creditors do not have recourse to Generation. See Note 3 — Variable Interest Entities.

[3] PHI’s consolidated total assets include $39 million and $41 million at March 31, 2018 and December 31, 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 $95 million and $102 million at March 31, 2018 and December 31, 2017, respectively, of PHI's consolidated VIE for which the VIE creditors do not have recourse to PHI. See Note 3 — Variable Interest Entities.

[4] ACE’s consolidated total assets include $27 million and $29 million at March 31, 2018 and December 31, 2017, respectively, of ACE's consolidated VIE that can only be used to settle the liabilities of the VIE. ACE’s consolidated total liabilities include $83 million and $90 million at March 31, 2018 and December 31, 2017, respectively, of ACE's consolidated VIE for which the VIE creditors do not have recourse to ACE. See Note 3 — Variable Interest Entities.