Consolidated Balance Sheets (Unaudited) - USD ($) $ in Millions		Dec. 31, 2016	Mar. 24, 2016		Dec. 31, 2015
Current assets
Cash and cash equivalents		$ 635			$ 6,502
Restricted cash and cash equivalents		253			205
Accounts receivable, net
Customer		4,158			3,187
Other		1,201			912
Mark-to-market derivative assets		917			1,365
Energy Marketing Contracts Assets, Current		88			86
Inventories, net
Fossil fuel		364			462
Materials and supplies		1,274			1,104
Prepaid utility taxes		1,250			0
Regulatory assets		1,342			759
Other		930			752
Total current assets		12,412			15,334
Property, plant and equipment, net		71,555			57,439
Deferred debits and other assets
Regulatory assets		10,046			6,065
Nuclear decommissioning trust funds		11,061			10,342
Investments		629			639
Goodwill		6,677			2,672
Mark-to-market derivative assets		492			758
Unamortized energy contract assets		447			484
Pledged assets for Zion Station decommissioning		113			206
Other		1,472			1,445
Deferred Costs and Other Assets		30,937			22,611
Total assets (a)	[1]	114,904			95,384
Current liabilities
Short-term borrowings		1,267			533
Long-term debt due within one year		2,430			1,500
Accounts payable		3,441			2,883
Accrued expenses		3,460			2,376
Payables to affiliates		706			0
Accounts Payable, Related Parties, Current		8			8
Mark-to-market derivative liabilities		282			205
Unamortized energy contract liabilities		407			100
Energy Marketing Accounts Payable		428			302
Payables to Customers		151			0
Regulatory liabilities		602			369
Other		981			842
Total current liabilities		13,457			9,118
Long-term debt		31,575			23,645
Long-term debt to financing trusts		641			641
Deferred credits and other liabilities
Deferred Income Taxes and Other Tax Liabilities, Noncurrent		18,138			13,776
Asset retirement obligations		9,111			8,585
Pension obligations		4,248			3,385
Non-pension postretirement benefit obligations		1,848			1,618
Spent nuclear fuel obligation		1,024			1,021
Regulatory liabilities		4,187			4,201
Mark-to-market derivative liabilities		392			374
Unamortized energy contract liabilities		830			117
Payable for Zion Station decommissioning		14			90
Other		1,827			1,491
Total deferred credits and other liabilities		41,619			34,658
Total liabilities	[1]	87,292			68,062
Redeemable Noncontrolling Interest, Equity, Common, Carrying Amount		0			28
Preferred stock(b)		0			193
Shareholders’ equity
Common stock		18,794			18,676
Treasury stock, at cost (35 shares at December 31, 2016 and 2015, respectively)		(2,327)			(2,327)
Accumulated other comprehensive loss, net		(2,660)			(2,624)
Total shareholders’ equity		25,837			25,793
BGE preference stock not subject to mandatory redemption		0			193
Noncontrolling interests		1,775			1,308
Total equity		27,612			27,294
Member’s equity
Retained earnings		12,030			12,068
Accumulated other comprehensive loss, net		(2,660)			(2,624)
Liabilities and Equity		114,904			95,384
Variable Interest Entity, Primary Beneficiary, Aggregated Disclosure [Member]
Deferred debits and other assets
Total assets (a)		8,893			8,268
Deferred credits and other liabilities
Total liabilities		3,356			3,264
Delmarva Power and Light Company [Member]
Current assets
Cash and cash equivalents		46			5
Accounts receivable, net
Customer		136			154
Other		63			96
Inventories, net
Fossil fuel		7			8
Materials and supplies		32			32
Regulatory assets		59			72
Other		24			21
Receivables from affiliates		3			0
Total current assets		370			388
Property, plant and equipment, net		3,273			3,070
Deferred debits and other assets
Regulatory assets		289			299
Investments		0			0
Goodwill		8			8
Prepaid pension asset		206			202
Other		7			2
Deferred Costs and Other Assets		510			511
Total assets (a)		4,153			3,969
Current liabilities
Short-term borrowings		0			105
Long-term debt due within one year		119			204
Accounts payable		88			109
Accrued expenses		36			31
Accounts Payable, Related Parties, Current		38			20
Customer deposits		36			31
Payables to Customers		13			0
Regulatory liabilities		43			49
Other		8			15
Total current liabilities		381			564
Long-term debt		1,221			1,061
Deferred credits and other liabilities
Deferred Income Taxes and Other Tax Liabilities, Noncurrent		1,056			945
Non-pension postretirement benefit obligations		19			19
Regulatory liabilities		97			111
Other		53			32
Total deferred credits and other liabilities		1,225			1,107
Total liabilities		2,827			2,732
Shareholders’ equity
Common stock		764			612
Total shareholders’ equity		1,326			1,237
Liabilities And Stockholders Equity Including Portion Attributable To Noncontrolling Interest		4,153			3,969
Member’s equity
Retained earnings		562			625
Commonwealth Edison Co [Member]
Current assets
Cash and cash equivalents		56			67
Restricted cash and cash equivalents		2			2
Accounts receivable, net
Customer		528			533
Other		218			272
Inventories, net
Inventories, net		159			164
Regulatory assets		190			218
Other		45			63
Receivables from affiliates		356			199
Total current assets		1,554			1,518
Property, plant and equipment, net		19,335			17,502
Deferred debits and other assets
Regulatory assets		977			895
Investments		6			6
Goodwill		2,625			2,625
Receivable from affiliates		2,170			2,172
Prepaid pension asset		1,343			1,490
Other		325			324
Deferred Costs and Other Assets		7,446			7,512
Total assets (a)		28,335			26,532
Current liabilities
Short-term borrowings		0			294
Long-term debt due within one year		425			665
Accounts payable		645			660
Accrued expenses		1,250			706
Accounts Payable, Related Parties, Current		65			62
Mark-to-market derivative liabilities		19			23
Customer deposits		121			131
Regulatory liabilities		329			155
Other		84			70
Total current liabilities		2,938			2,766
Long-term debt		6,608			5,844
Long-term debt to financing trusts		205			205
Deferred credits and other liabilities
Deferred Income Taxes and Other Tax Liabilities, Noncurrent		5,364			4,914
Asset retirement obligations		119			111
Non-pension postretirement benefit obligations		239			259
Regulatory liabilities		3,369			3,459
Mark-to-market derivative liabilities		(239)			224
Other		529			507
Total deferred credits and other liabilities		9,859			9,474
Total liabilities		19,610			18,289
Shareholders’ equity
Common stock		1,588			1,588
Other paid-in capital		6,150			5,677
Total shareholders’ equity		8,725			8,243
Member’s equity
Liabilities and Equity		28,335			26,532
Retained Earnings, Unappropriated		(1,639)			(1,639)
Retained Earnings, Appropriated		2,626			2,617
Exelon Generation Co L L C [Member]
Current assets
Cash and cash equivalents		290			431
Restricted cash and cash equivalents		158			123
Accounts receivable, net
Customer		2,433			2,095
Other		558			360
Mark-to-market derivative assets		917			1,365
Energy Marketing Contracts Assets, Current		88			86
Inventories, net
Fossil fuel		292			384
Materials and supplies		935			880
Other		701			535
Receivables from affiliates		156			83
Total current assets		6,528			6,342
Property, plant and equipment, net		25,585			25,843
Deferred debits and other assets
Nuclear decommissioning trust funds		11,061			10,342
Investments		418			210
Goodwill		47			47
Mark-to-market derivative assets		476			733
Prepaid pension asset		1,595			1,689
Unamortized energy contract assets		447			484
Deferred income taxes		16			6
Pledged assets for Zion Station decommissioning		113			206
Other		688			627
Deferred Costs and Other Assets		14,861			14,344
Total assets (a)	[2]	46,974			46,529
Current liabilities
Short-term borrowings		699			29
Long-term debt due within one year		1,117			90
Accounts payable		1,610			1,583
Accrued expenses		989			935
Accounts Payable, Related Parties, Current		137			104
Mark-to-market derivative liabilities		263			182
Unamortized energy contract liabilities		72			100
Energy Marketing Accounts Payable		428			302
Other		313			356
Notes Payable, Related Parties, Current		55			1,252
Total current liabilities		5,683			4,933
Long-term debt		7,202			7,936
Long-term debt to financing trusts		922			933
Deferred credits and other liabilities
Deferred Income Taxes and Other Tax Liabilities, Noncurrent		5,585			5,845
Asset retirement obligations		8,922			8,431
Non-pension postretirement benefit obligations		930			924
Spent nuclear fuel obligation		1,024			1,021
Mark-to-market derivative liabilities		153			150
Unamortized energy contract liabilities		80			117
Payable for Zion Station decommissioning		14			90
Other		595			602
Due to Affiliate, Noncurrent		2,608			2,577
Total deferred credits and other liabilities		19,911			19,757
Total liabilities	[2]	33,718			33,559
Redeemable Noncontrolling Interest, Equity, Common, Carrying Amount		0			28
Shareholders’ equity
Accumulated other comprehensive loss, net		(54)			(63)
Member’s equity
Membership interest/Common stock(c)		9,261			8,997
Retained earnings		2,275			2,701
Accumulated other comprehensive loss, net		(54)			(63)
Total member’s equity		11,482			11,635
Noncontrolling interests		1,774			1,307
Total equity		13,256			12,942
Liabilities and Equity		46,974			46,529
Exelon Generation Co L L C [Member] | Variable Interest Entity, Primary Beneficiary, Aggregated Disclosure [Member]
Deferred debits and other assets
Total assets (a)		8,817			8,235
Deferred credits and other liabilities
Total liabilities		3,170			3,135
PECO Energy Co [Member]
Current assets
Cash and cash equivalents		63			295
Restricted cash and cash equivalents		4			3
Accounts receivable, net
Customer		306			258
Other		131			146
Inventories, net
Fossil fuel		35			43
Materials and supplies		27			26
Prepaid utility taxes		9			11
Regulatory assets		29			34
Other		18			24
Due from Affiliates		131			0
Receivables from affiliates		4			2
Total current assets		757			842
Property, plant and equipment, net		7,565			7,141
Deferred debits and other assets
Regulatory assets		1,681			1,583
Investments		25			28
Receivable from affiliates		438			405
Prepaid pension asset		345			347
Other		20			21
Deferred Costs and Other Assets		2,509			2,384
Total assets (a)		10,831			10,367
Current liabilities
Long-term debt due within one year		0			300
Accounts payable		342			281
Accrued expenses		104			109
Accounts Payable, Related Parties, Current		63			55
Customer deposits		61			58
Regulatory liabilities		127			112
Other		30			29
Total current liabilities		727			944
Long-term debt		2,580			2,280
Long-term debt to financing trusts		184			184
Deferred credits and other liabilities
Deferred Income Taxes and Other Tax Liabilities, Noncurrent		3,006			2,792
Asset retirement obligations		28			27
Non-pension postretirement benefit obligations		289			287
Regulatory liabilities		517			527
Other		85			90
Total deferred credits and other liabilities		3,925			3,723
Total liabilities		7,416			7,131
Shareholders’ equity
Common stock		2,473			2,455
Accumulated other comprehensive loss, net		1			1
Total shareholders’ equity		3,415			3,236
Member’s equity
Retained earnings		941			780
Accumulated other comprehensive loss, net		1			1
Liabilities and Equity		10,831			10,367
Baltimore Gas and Electric Company [Member]
Current assets
Cash and cash equivalents		23			9
Restricted cash and cash equivalents		24			24
Accounts receivable, net
Customer		395			300
Other		102			112
Inventories, net
Fossil fuel		30			36
Materials and supplies		38			33
Prepaid utility taxes		15			61
Regulatory assets		208			267
Other		7			3
Total current assets		842			845
Property, plant and equipment, net		7,040			6,597
Deferred debits and other assets
Regulatory assets		504			514
Investments		12			12
Prepaid pension asset		297			319
Other		9			8
Deferred Costs and Other Assets		822			853
Total assets (a)	[3]	8,704			8,295
Current liabilities
Short-term borrowings		45			210
Long-term debt due within one year		41			378
Accounts payable		205			209
Accrued expenses		175			110
Accounts Payable, Related Parties, Current		55			52
Customer deposits		110			102
Regulatory liabilities		50			38
Other		26			35
Total current liabilities		707			1,134
Long-term debt		2,281			1,480
Long-term debt to financing trusts		252			252
Deferred credits and other liabilities
Deferred Income Taxes and Other Tax Liabilities, Noncurrent		2,219			2,081
Asset retirement obligations		21			17
Non-pension postretirement benefit obligations		205			209
Regulatory liabilities		110			184
Other		61			61
Total deferred credits and other liabilities		2,616			2,552
Preferred Stock, Value, Outstanding		0			190
Total liabilities	[3]	$ 5,856			$ 5,418
Preferred Stock, Shares Outstanding		0.00			1,900,000.00
Preferred stock(b)		$ 0			$ 190
Shareholders’ equity
Common stock		1,421			1,367
Total shareholders’ equity		2,848			2,687
BGE preference stock not subject to mandatory redemption		0			190
Total equity		2,848			2,877
Member’s equity
Retained earnings		1,427			1,320
Liabilities and Equity		8,704			8,295
Baltimore Gas and Electric Company [Member] | Variable Interest Entity, Primary Beneficiary, Aggregated Disclosure [Member]
Deferred debits and other assets
Total assets (a)		26			26
Deferred credits and other liabilities
Total liabilities		42			122
Pepco Holdings LLC [Member] | Predecessor [Member]
Current assets
Cash and cash equivalents					26
Restricted cash and cash equivalents					14
Accounts receivable, net
Customer					581
Other					319
Mark-to-market derivative assets					18
Inventories, net
Fossil fuel					9
Materials and supplies					122
Regulatory assets					305
Other					80
Total current assets					1,474
Property, plant and equipment, net					10,864
Deferred debits and other assets
Regulatory assets					2,277
Investments					80
Goodwill					1,406
Mark-to-market derivative assets					0
Prepaid pension asset					0
Deferred income taxes					14
Notes, Loans and Financing Receivable, Gross, Noncurrent					4
Other					69
Deferred Costs and Other Assets					3,850
Total assets (a)	[4]				16,188
Current liabilities
Short-term borrowings					958
Long-term debt due within one year					456
Accounts payable					404
Accrued expenses					266
Accounts Payable, Related Parties, Current					0
Mark-to-market derivative liabilities					0
Unamortized energy contract liabilities					0
Customer deposits					107
Payables to Customers					0
Regulatory liabilities					66
Other					70
Total current liabilities					2,327
Long-term debt					4,823
Deferred credits and other liabilities
Deferred Income Taxes and Other Tax Liabilities, Noncurrent					3,406
Asset retirement obligations					8
Pension obligations					466
Non-pension postretirement benefit obligations					215
Regulatory liabilities					147
Mark-to-market derivative liabilities					0
Unamortized energy contract liabilities					0
Other					200
Total deferred credits and other liabilities					4,442
Total liabilities	[4]				$ 11,592
Preferred Stock, Shares Outstanding					18,000
Preferred stock(b)	[5]				$ 183
Shareholders’ equity
Common stock					15
Accumulated other comprehensive loss, net					(36)
Total shareholders’ equity					4,413
BGE preference stock not subject to mandatory redemption	[5]				183
Member’s equity
Membership interest/Common stock(c)	[6]				3,832
Retained earnings					617
Accumulated other comprehensive loss, net					(36)
Total member’s equity					4,413
Liabilities and Equity					16,188
Pepco Holdings LLC [Member] | Predecessor [Member] | Additional Paid-in Capital [Member]
Shareholders’ equity
Common stock					3
Other paid-in capital					3,829
Pepco Holdings LLC [Member] | Successor [Member]
Current assets
Cash and cash equivalents		170
Restricted cash and cash equivalents		43
Accounts receivable, net
Customer		496
Other		283
Mark-to-market derivative assets		0
Inventories, net
Fossil fuel		6
Materials and supplies		116
Regulatory assets		653
Other		71
Total current assets		1,838
Property, plant and equipment, net		11,598
Deferred debits and other assets
Regulatory assets		2,851
Investments		133
Goodwill		4,005
Prepaid pension asset		509
Deferred income taxes		6
Notes, Loans and Financing Receivable, Gross, Noncurrent		4
Other		81
Deferred Costs and Other Assets		7,589
Total assets (a)	[4]	21,025
Current liabilities
Short-term borrowings		522
Long-term debt due within one year		253
Accounts payable		458
Accrued expenses		272
Accounts Payable, Related Parties, Current		94
Unamortized energy contract liabilities		335
Customer deposits		123
Payables to Customers		101
Regulatory liabilities		79
Other		47
Total current liabilities		2,284
Long-term debt		5,645
Deferred credits and other liabilities
Deferred Income Taxes and Other Tax Liabilities, Noncurrent		3,775
Asset retirement obligations		14
Pension obligations		0
Non-pension postretirement benefit obligations		134
Regulatory liabilities		158
Unamortized energy contract liabilities		750
Other		249
Total deferred credits and other liabilities		5,080
Total liabilities	[4]	13,009
Preferred stock(b)		0
Shareholders’ equity
Common stock			$ 165
Accumulated other comprehensive loss, net		0
BGE preference stock not subject to mandatory redemption		0
Member’s equity
Membership interest/Common stock(c)		8,077	7,200
Retained earnings		(61)
Accumulated other comprehensive loss, net		0
Total member’s equity		8,016	$ 7,200	[7]
Liabilities and Equity		21,025
Potomac Electric Power Company [Member]
Current assets
Cash and cash equivalents		9			5
Restricted cash and cash equivalents		33			2
Accounts receivable, net
Customer		235			230
Other		150			261
Inventories, net
Inventories, net		63			67
Regulatory assets		162			140
Other		32			21
Total current assets		684			726
Property, plant and equipment, net		5,571			5,162
Deferred debits and other assets
Regulatory assets		690			661
Investments		102			68
Prepaid pension asset		282			287
Other		6			4
Deferred Costs and Other Assets		1,080			1,020
Total assets (a)		7,335			6,908
Current liabilities
Short-term borrowings		23			64
Long-term debt due within one year		16			11
Accounts payable		209			145
Accrued expenses		113			119
Accounts Payable, Related Parties, Current		74			30
Customer deposits		53			46
Payables to Customers		68			0
Regulatory liabilities		11			15
Other		29			25
Total current liabilities		596			455
Long-term debt		2,333			2,340
Deferred credits and other liabilities
Deferred Income Taxes and Other Tax Liabilities, Noncurrent		1,910			1,723
Non-pension postretirement benefit obligations		43			49
Regulatory liabilities		20			29
Other		133			72
Total deferred credits and other liabilities		2,106			1,873
Total liabilities		5,035			4,668
Shareholders’ equity
Common stock		1,309			1,122
Total shareholders’ equity		2,300			2,240
Liabilities And Stockholders Equity Including Portion Attributable To Noncontrolling Interest		7,335			6,908
Member’s equity
Retained earnings		991			1,118
Atlantic City Electric Company [Member]
Current assets
Cash and cash equivalents		101			3
Restricted cash and cash equivalents		9			12
Accounts receivable, net
Customer		125			156
Other		44			242
Inventories, net
Inventories, net		22			23
Regulatory assets		96			98
Other		2			12
Total current assets		399			546
Property, plant and equipment, net		2,521			2,322
Deferred debits and other assets
Regulatory assets		405			414
Investments		0			0
Prepaid pension asset		84			82
Notes, Loans and Financing Receivable, Gross, Noncurrent		4			4
Other		44			19
Deferred Costs and Other Assets		537			519
Total assets (a)	[8]	3,457			3,387
Current liabilities
Short-term borrowings		0			5
Long-term debt due within one year		35			48
Accounts payable		132			96
Accrued expenses		38			70
Accounts Payable, Related Parties, Current		29			16
Customer deposits		33			30
Payables to Customers		20			0
Regulatory liabilities		25			18
Other		8			14
Total current liabilities		320			297
Long-term debt		1,120			1,153
Deferred credits and other liabilities
Deferred Income Taxes and Other Tax Liabilities, Noncurrent		917			885
Non-pension postretirement benefit obligations		34			33
Regulatory liabilities		0			7
Other		32			12
Total deferred credits and other liabilities		983			937
Total liabilities	[8]	2,423			2,387
Shareholders’ equity
Common stock		912			773
Total shareholders’ equity		1,034			1,000
Liabilities And Stockholders Equity Including Portion Attributable To Noncontrolling Interest		3,457			3,387
Member’s equity
Retained earnings		$ 122			$ 227

[1] Exelon’s consolidated assets include $8,893 million and $8,268 million at December 31, 2016 and December 31, 2015, respectively, of certain VIEs that can only be used to settle the liabilities of the VIE. Exelon’s consolidated liabilities include $3,356 million and $3,264 million at December 31, 2016 and December 31, 2015, respectively, of certain VIEs for which the VIE creditors do not have recourse to Exelon. See Note 2–Variable Interest Entities.

[2] Generation’s consolidated assets include $8,817 million and $8,235 million at December 31, 2016 and 2015, respectively, of certain VIEs that can only be used to settle the liabilities of the VIE. Generation’s consolidated liabilities include $3,170 million and $3,135 million at December 31, 2016 and 2015, respectively, of certain VIEs for which the VIE creditors do not have recourse to Generation. See Note 2–Variable Interest Entities.

[3] BGE’s consolidated assets include $26 million and $26 million at December 31, 2016 and December 31, 2015, respectively, of BGE’s consolidated VIE that can only be used to settle the liabilities of the VIE. BGE’s consolidated liabilities include $42 million and $122 million at December 31, 2016 and December 31, 2015, respectively, of BGE’s consolidated VIE for which the VIE creditors do not have recourse to BGE. See Note 2 - Variable Interest Entities.

[4] PHI’s consolidated total assets include $49 million and $30 million at December 31, 2016 and 2015, respectively, of PHI's consolidated VIE that can only be used to settle the liabilities of the VIE. PHI’s consolidated total liabilities include $143 million and $172 million at December 31, 2016 and 2015, respectively, of PHI's consolidated VIE for which the VIE creditors do not have recourse to PHI. See Note 2 - Variable Interest Entities.

[5] At December 31, 2015, PHI had 18,000 shares of Series A preferred stock authorized and outstanding, par value $0.01 per share.

[6] At December 31, 2015, PHI's (predecessor) shareholders' equity included $3,829 million of other paid-in capital and $3 million of common stock. At December 31, 2015, PHI had 400,000,000 shares of common stock authorized and 254,289,261 shares of common stock outstanding, par value $0.01 per share.

[7] The March 24, 2016, beginning balance differs from the PHI Merger total purchase price by $59 million related to an acquisition accounting adjustment recorded at Exelon Corporate to reflect unitary state income tax consequences of the merger.

[8] ACE’s consolidated assets include $32 million and $30 million at December 31, 2016 and 2015, respectively, of ACE’s consolidated VIE that can only be used to settle the liabilities of the VIE. ACE’s consolidated liabilities include $126 million and $172 million at December 31, 2016 and 2015, respectively, of ACE’s consolidated VIE for which the VIE creditors do not have recourse to ACE. See Note 2 - Variable Interest Entities.