Consolidated Balance Sheets - USD ($) $ in Millions		Dec. 31, 2019		Dec. 31, 2018
Current assets
Cash and cash equivalents		$ 587		$ 1,349
Restricted cash and cash equivalents		358		247
Accounts receivable, net
Customer		4,592		4,607
Other		1,583		1,256
Mark-to-market derivative assets, current		679		804
Unamortized energy contract assets, current		47		48
Inventories, net
Fossil fuel		312		334
Materials and supplies		1,456		1,351
Regulatory assets, current		1,170		1,190
Assets held for sale		0		904
Other		1,253		1,238
Total current assets		12,037		13,328
Property, plant and equipment, net		80,233		76,707
Deferred debits and other assets
Regulatory assets, noncurrent		8,335		8,237
Nuclear decommissioning trust funds		13,190		11,661
Investments		464		625
Goodwill		6,677		6,677
Mark-to-market derivative assets, noncurrent		508		452
Unamortized energy contract assets, noncurrent		336		372
Other		3,197		1,575
Total deferred debits and other assets		32,707		29,599
Total assets	[1]	124,977		119,634
Current liabilities
Short-term borrowings		1,370		714
Long-term debt due within one year		4,710		1,349
Accounts payable		3,560		3,800
Accrued expenses		1,981		2,112
Payables to affiliates, current		5		5
Regulatory Liability, Current		406		644
Mark-to-market derivative liabilities, current		247		475
Unamortized energy contract liabilities, current		132		149
Renewable energy credit obligation		443		344
Liabilities held for sale		0		777
Other		1,331		1,035
Total current liabilities		14,185		11,404
Long-term debt		31,329		34,075
Long-term debt to financing trusts		390		390
Deferred credits and other liabilities
Deferred income taxes and unamortized investment tax credits		12,351		11,321
Asset retirement obligations, noncurrent		10,846		9,679
Pension obligations		4,247		3,988
Non-pension postretirement benefit obligations		2,076		1,928
Spent nuclear fuel obligation		1,199		1,171
Regulatory liabilities, noncurrent		9,986		9,559
Mark-to-market derivative liabilities, noncurrent		393		479
Unamortized energy contract liabilities, noncurrent		338		463
Other		3,064		2,130
Total deferred credits and other liabilities		44,500		40,718
Total liabilities		90,404		86,587	[1]
Commitments and Contingencies
Shareholders’ equity
Common stock		19,274		19,116
Treasury stock, at cost		(123)		(123)
Retained earnings/Undistributed earnings		16,267		14,743
Accumulated other comprehensive income (loss), net		(3,194)		(2,995)
Total shareholders’ equity		32,224		30,741
Member’s equity
Noncontrolling interests		2,349		2,306
Total equity		34,573		33,047
Total liabilities and equity		$ 124,977		$ 119,634
Common Stock, Shares Authorized		2,000,000,000		2,000,000,000
Common Stock, Shares, Outstanding		973,000,000		968,000,000
Variable Interest Entity, Consolidated, Assets, Pledged		$ 9,532		$ 9,667
Variable Interest Entity, Consolidated, Liabilities, No Recourse		3,473		3,548
Exelon Generation Co L L C [Member]
Current assets
Cash and cash equivalents		303		750
Restricted cash and cash equivalents		146		153
Accounts receivable, net
Customer		2,893		2,941
Other		619		562
Mark-to-market derivative assets, current		675		804
Receivables from affiliates, current		190		173
Unamortized energy contract assets, current		47		49
Inventories, net
Fossil fuel and emission allowances		236		251
Materials and supplies		1,026		963
Assets held for sale		0		904
Other		941		883
Total current assets		7,076		8,433
Property, plant and equipment, net		24,193		23,981
Deferred debits and other assets
Nuclear decommissioning trust funds		13,190		11,661
Investments		235		414
Goodwill		47		47
Mark-to-market derivative assets, noncurrent		508		452
Prepaid pension asset		1,438		1,421
Unamortized energy contract assets, noncurrent		336		371
Deferred income taxes		12		21
Other		1,960		755
Total deferred debits and other assets		17,726		15,142
Total assets	[2]	48,995		47,556
Current liabilities
Short-term borrowings		320		0
Long-term debt due within one year		2,624		906
Long-term debt to affiliates due within one year		558		0
Accounts payable		1,692		1,847
Accrued expenses		786		898
Payables to affiliates, current		117		139
Borrowings from Exelon intercompany money pool		0		100
Mark-to-market derivative liabilities, current		215		449
Unamortized energy contract liabilities, current		17		31
Renewable energy credit obligation		443		343
Liabilities held for sale		0		777
Other		517		279
Total current liabilities		7,289		5,769
Long-term debt		4,464		6,989
Long-term debt to affiliates		328		898
Deferred credits and other liabilities
Deferred income taxes and unamortized investment tax credits		3,752		3,383
Asset retirement obligations, noncurrent		10,603		9,450
Non-pension postretirement benefit obligations		878		900
Spent nuclear fuel obligation		1,199		1,171
Payables to affiliates, noncurrent		3,103		2,606
Mark-to-market derivative liabilities, noncurrent		123		252
Unamortized energy contract liabilities, noncurrent		11		20
Other		1,415		610
Total deferred credits and other liabilities		21,084		18,392
Total liabilities	[2]	33,165		32,048
Commitments and Contingencies
Shareholders’ equity
Retained earnings/Undistributed earnings		3,950		3,724
Accumulated other comprehensive income (loss), net		(32)		(38)
Member’s equity
Membership interest		9,566		9,518
Total member’s equity		13,484		13,204
Noncontrolling interests		2,346		2,304
Total equity		15,830		15,508
Total liabilities and equity		48,995		47,556
Variable Interest Entity, Consolidated, Assets, Pledged		9,512		9,634
Variable Interest Entity, Consolidated, Liabilities, No Recourse		3,429		3,480
Commonwealth Edison Co [Member]
Current assets
Cash and cash equivalents		90		135
Restricted cash and cash equivalents		150		29
Accounts receivable, net
Customer		545		539
Other		286		320
Receivables from affiliates, current		28		20
Inventories, net
Inventories, net		159		148
Regulatory assets, current		281		293
Other		44		86
Total current assets		1,583		1,570
Property, plant and equipment, net		23,107		22,058
Deferred debits and other assets
Regulatory assets, noncurrent		1,480		1,307
Investments		6		6
Goodwill		2,625		2,625
Receivable from affiliates, noncurrent		2,622		2,217
Prepaid pension asset		995		1,035
Other		347		395
Total deferred debits and other assets		8,075		7,585
Total assets		32,765		31,213
Current liabilities
Short-term borrowings		130		0
Long-term debt due within one year		500		300
Accounts payable		527		607
Accrued expenses		385		373
Payables to affiliates, current		103		119
Customer deposits		118		111
Regulatory Liability, Current		200		293
Mark-to-market derivative liabilities, current		32		26
Other		122		96
Total current liabilities		2,117		1,925
Long-term debt		7,991		7,801
Long-term debt to financing trusts		205		205
Deferred credits and other liabilities
Deferred income taxes and unamortized investment tax credits		4,021		3,813
Asset retirement obligations, noncurrent		128		118
Non-pension postretirement benefit obligations		180		201
Regulatory liabilities, noncurrent		6,542		6,050
Mark-to-market derivative liabilities, noncurrent		269		223
Other		635		630
Total deferred credits and other liabilities		11,775		11,035
Total liabilities		22,088		20,966
Commitments and Contingencies
Shareholders’ equity
Common stock		1,588		1,588
Other paid-in capital		7,572		7,322
Retained earnings (deficit) unappropriated		(1,639)		(1,639)
Retained earnings (deficit) appropriated		3,156		2,976
Total shareholders’ equity		10,677		10,247
Member’s equity
Total liabilities and equity		32,765		31,213
PECO Energy Co [Member]
Current assets
Cash and cash equivalents		21		130
Restricted cash and cash equivalents		6		5
Accounts receivable, net
Customer		357		321
Other		138		151
Receivables from affiliates, current		1		0
Due from Affiliates		68		0
Inventories, net
Fossil fuel		36		38
Materials and supplies		35		37
Regulatory assets, current		41		81
Other		19		19
Total current assets		722		782
Property, plant and equipment, net		9,292		8,610
Deferred debits and other assets
Regulatory assets, noncurrent		554		460
Investments		27		25
Receivable from affiliates, noncurrent		480		389
Prepaid pension asset		365		349
Other		29		27
Total deferred debits and other assets		1,455		1,250
Total assets		11,469		10,642
Current liabilities
Accounts payable		387		370
Accrued expenses		101		113
Payables to affiliates, current		55		59
Customer deposits		69		68
Regulatory Liability, Current		91		175
Other		19		24
Total current liabilities		722		809
Long-term debt		3,405		3,084
Long-term debt to financing trusts		184		184
Deferred credits and other liabilities
Deferred income taxes and unamortized investment tax credits		2,080		1,933
Asset retirement obligations, noncurrent		28		27
Non-pension postretirement benefit obligations		288		288
Regulatory liabilities, noncurrent		510		421
Other		74		76
Total deferred credits and other liabilities		2,980		2,745
Total liabilities		7,291		6,822
Commitments and Contingencies
Shareholders’ equity
Common stock		2,766		2,578
Retained earnings/Undistributed earnings		1,412		1,242
Total shareholders’ equity		4,178		3,820
Member’s equity
Total liabilities and equity		11,469		10,642
Baltimore Gas and Electric Company [Member]
Current assets
Cash and cash equivalents		24		7
Restricted cash and cash equivalents		1		6
Accounts receivable, net
Customer		317		353
Other		147		90
Receivables from affiliates, current		1		1
Inventories, net
Fossil fuel and emission allowances		30		36
Materials and supplies		46		39
Prepaid utility taxes		78		74
Regulatory assets, current		183		177
Other		6		3
Total current assets		833		786
Property, plant and equipment, net		8,990		8,243
Deferred debits and other assets
Regulatory assets, noncurrent		454		398
Investments		7		5
Prepaid pension asset		264		279
Other		86		5
Total deferred debits and other assets		811		687
Total assets		10,634		9,716
Current liabilities
Short-term borrowings		76		35
Accounts payable		243		295
Accrued expenses		152		155
Payables to affiliates, current		66		65
Customer deposits		120		120
Regulatory Liability, Current		33		77
Other		63		27
Total current liabilities		753		774
Long-term debt		3,270		2,876
Deferred credits and other liabilities
Deferred income taxes and unamortized investment tax credits		1,396		1,222
Asset retirement obligations, noncurrent		22		24
Non-pension postretirement benefit obligations		199		201
Regulatory liabilities, noncurrent		1,195		1,192
Other		116		73
Total deferred credits and other liabilities		2,928		2,712
Total liabilities		6,951		6,362
Commitments and Contingencies
Shareholders’ equity
Common stock		1,907	[3]	1,714
Retained earnings/Undistributed earnings		1,776		1,640
Total shareholders’ equity		3,683		3,354
Member’s equity
Total liabilities and equity		10,634		9,716
Pepco Holdings LLC [Member]
Current assets
Cash and cash equivalents		131		124
Restricted cash and cash equivalents		36		43
Accounts receivable, net
Customer		479		453
Other		174		177
Receivables from affiliates, current		1		0
Inventories, net
Fossil fuel and emission allowances		8		9
Materials and supplies		190		163
Regulatory assets, current		412		457
Other		49		75
Total current assets		1,480		1,501
Property, plant and equipment, net		14,296		13,446
Deferred debits and other assets
Regulatory assets, noncurrent		2,061		2,312
Investments		135		130
Goodwill		4,005		4,005
Prepaid pension asset		406		486
Deferred income taxes		13		12
Other		323		60
Total deferred debits and other assets		6,943		7,005
Total assets		22,719		21,952
Current liabilities
Short-term borrowings		208		179
Long-term debt due within one year		103		125
Accounts payable		462		496
Accrued expenses		296		256
Payables to affiliates, current		98		94
Other Short-term Borrowings		12		0
Customer deposits		117		116
Regulatory Liability, Current		70		84
Unamortized energy contract liabilities, current		115		119
Other		131		123
Total current liabilities		1,612		1,592
Long-term debt		6,460		6,134
Deferred credits and other liabilities
Deferred income taxes and unamortized investment tax credits		2,278		2,137
Asset retirement obligations, noncurrent		57		52
Non-pension postretirement benefit obligations		93		103
Regulatory liabilities, noncurrent		1,707		1,864
Unamortized energy contract liabilities, noncurrent		327		442
Other		577		369
Total deferred credits and other liabilities		5,039		4,967
Total liabilities		13,111	[4]	12,693
Commitments and Contingencies
Shareholders’ equity
Retained earnings/Undistributed earnings		(10)		39
Member’s equity
Membership interest		9,618		9,220
Total member’s equity		9,608		9,259
Total equity		9,608		9,259
Total liabilities and equity		22,719		21,952
Variable Interest Entity, Consolidated, Assets, Pledged		20		33
Variable Interest Entity, Consolidated, Liabilities, No Recourse		44		69
Potomac Electric Power Company [Member]
Current assets
Cash and cash equivalents		30		16
Restricted cash and cash equivalents		33		37
Accounts receivable, net
Customer		231		225
Other		91		81
Receivables from affiliates, current		0		1
Inventories, net
Inventories, net		112		93
Regulatory assets, current		188		238
Other		11		37
Total current assets		696		728
Property, plant and equipment, net		6,909		6,460
Deferred debits and other assets
Regulatory assets, noncurrent		584		643
Investments		110		105
Prepaid pension asset		296		316
Other		66		15
Total deferred debits and other assets		1,056		1,079
Total assets		8,661		8,267
Current liabilities
Short-term borrowings		82		40
Long-term debt due within one year		2		15
Accounts payable		195		214
Accrued expenses		156		126
Payables to affiliates, current		66		62
Customer deposits		57		54
Regulatory Liability, Current		8		7
Merger related obligation		39		38
Current portion of DC PLUG obligation		30		30
Other		22		42
Total current liabilities		657		628
Long-term debt		2,862		2,704
Deferred credits and other liabilities
Deferred income taxes and unamortized investment tax credits		1,131		1,055
Asset retirement obligations, noncurrent		41		37
Non-pension postretirement benefit obligations		20		29
Regulatory liabilities, noncurrent		746		822
Other		297		275
Total deferred credits and other liabilities		2,235		2,218
Total liabilities		5,754		5,550
Commitments and Contingencies
Shareholders’ equity
Common stock		1,796	[5]	1,636
Retained earnings/Undistributed earnings		1,111		1,081
Total shareholders’ equity		2,907		2,717
Member’s equity
Total liabilities and equity		8,661		8,267
Delmarva Power & Light Company [Member]
Current assets
Cash and cash equivalents		13		23
Restricted cash and cash equivalents		0		1
Accounts receivable, net
Customer		141		134
Other		38		46
Inventories, net
Fossil fuel and emission allowances		8		9
Materials and supplies		44		37
Prepaid utility taxes		18		17
Regulatory assets, current		52		59
Other		11		10
Total current assets		325		336
Property, plant and equipment, net		4,035		3,821
Deferred debits and other assets
Regulatory assets, noncurrent		222		231
Investments		0		0
Goodwill		8		8
Prepaid pension asset		171		186
Other		69		6
Total deferred debits and other assets		470		431
Total assets		4,830		4,588
Current liabilities
Short-term borrowings		56		0
Long-term debt due within one year		80		91
Accounts payable		112		111
Accrued expenses		46		39
Payables to affiliates, current		32		33
Customer deposits		36		35
Regulatory Liability, Current		37		59
Other		15		7
Total current liabilities		414		375
Long-term debt		1,487		1,403
Deferred credits and other liabilities
Deferred income taxes and unamortized investment tax credits		655		628
Non-pension postretirement benefit obligations		16		17
Regulatory liabilities, noncurrent		574		606
Other		104		50
Total deferred credits and other liabilities		1,349		1,301
Total liabilities		3,250		3,079
Commitments and Contingencies
Shareholders’ equity
Common stock		977	[6]	914
Retained earnings/Undistributed earnings		603		595
Total shareholders’ equity		1,580		1,509
Member’s equity
Total liabilities and equity		4,830		4,588
Atlantic City Electric Company [Member]
Current assets
Cash and cash equivalents		12		7
Restricted cash and cash equivalents		2		4
Accounts receivable, net
Customer		108		95
Other		48		55
Receivables from affiliates, current		4		1
Inventories, net
Inventories, net		34		33
Regulatory assets, current		57		40
Other		5		5
Total current assets		270		240
Property, plant and equipment, net		3,190		2,966
Deferred debits and other assets
Regulatory assets, noncurrent		368		386
Investments		0		0
Prepaid pension asset		52		67
Other		53		40
Total deferred debits and other assets		473		493
Total assets	[7]	3,933		3,699
Current liabilities
Short-term borrowings		70		139
Long-term debt due within one year		20		18
Accounts payable		144		154
Accrued expenses		42		35
Payables to affiliates, current		25		28
Customer deposits		25		26
Regulatory Liability, Current		25		18
Other		9		4
Total current liabilities		360		422
Long-term debt		1,307		1,170
Deferred credits and other liabilities
Deferred income taxes and unamortized investment tax credits		577		535
Non-pension postretirement benefit obligations		17		17
Regulatory liabilities, noncurrent		357		402
Other		39		27
Total deferred credits and other liabilities		990		981
Total liabilities		2,657		2,573
Commitments and Contingencies
Shareholders’ equity
Common stock		1,154		979
Retained earnings/Undistributed earnings		122		147
Total shareholders’ equity		1,276		1,126
Member’s equity
Total liabilities and equity		3,933		3,699
Variable Interest Entity, Consolidated, Assets, Pledged		17		23
Variable Interest Entity, Consolidated, Liabilities, No Recourse		$ 41		$ 59
Common Stock [Member] | Commonwealth Edison Co [Member]
Member’s equity
Common Stock, Shares Authorized		250,000,000		250,000,000
Common Stock, Shares, Outstanding		127,000,000		127,000,000
Common Stock [Member] | PECO Energy Co [Member]
Member’s equity
Common Stock, Shares Authorized		500,000,000		500,000,000
Common Stock, Shares, Outstanding		170,000,000		170,000,000
Common Stock [Member] | Baltimore Gas and Electric Company [Member]
Member’s equity
Common Stock, Shares Authorized		1,500		0
Common Stock, Shares, Outstanding		1,000
Common Stock [Member] | Potomac Electric Power Company [Member]
Member’s equity
Common Stock, Shares Authorized		200,000,000		200,000,000
Common Stock, Shares, Outstanding		100		100
Common Stock [Member] | Delmarva Power & Light Company [Member]
Member’s equity
Common Stock, Shares Authorized		1,000		1,000
Common Stock, Shares, Outstanding		1,000		1,000
Common Stock [Member] | Atlantic City Electric Company [Member]
Member’s equity
Common Stock, Shares Authorized		25,000,000		25,000,000
Common Stock, Shares, Outstanding		9,000,000		9,000,000

[1] Exelon’s consolidated assets include $9,532 million and $9,667 million at December 31, 2019 and 2018, respectively, of certain VIEs that can only be used to settle the liabilities of the VIE. Exelon’s consolidated liabilities include $3,473 million and $3,548 million at December 31, 2019 and 2018, respectively, of certain VIEs for which the VIE creditors do not have recourse to Exelon. See Note 22–Variable Interest Entities for additional information.

[2] Generation’s consolidated assets include $9,512 million and $9,634 million at December 31, 2019 and 2018, respectively, of certain VIEs that can only be used to settle the liabilities of the VIE. Generation’s consolidated liabilities include $3,429 million and $3,480 million at December 31, 2019 and 2018, respectively, of certain VIEs for which the VIE creditors do not have recourse to Generation. See Note 22–Variable Interest Entities for additional information.

[3] In millions, shares round to zero. Number of shares is 1,500 authorized and 1,000 outstanding at December 31, 2019 and 2018.

[4] PHI’s consolidated total assets include $20 million and $33 million at December 31, 2019 and 2018, respectively, of PHI's consolidated VIE that can only be used to settle the liabilities of the VIE. PHI’s consolidated total liabilities include $44 million and $69 million at December 31, 2019 and 2018, respectively, of PHI's consolidated VIE for which the VIE creditors do not have recourse to PHI. See Note 22 - Variable Interest Entities for additional information.

[5] In millions, shares round to zero. Number of shares is 100 outstanding at December 31, 2019 and 2018.

[6] In millions, shares round to zero. Number of shares is 1,000 authorized and 1,000 outstanding at December 31, 2019 and 2018.

[7] ACE’s consolidated assets include $17 million and $23 million at December 31, 2019 and 2018, respectively, of ACE’s consolidated VIE that can only be used to settle the liabilities of the VIE. ACE’s consolidated liabilities include $41 million and $59 million at December 31, 2019 and 2018, respectively, of ACE’s consolidated VIE for which the VIE creditors do not have recourse to ACE. See Note 22 - Variable Interest Entities for additional information.