Consolidated Balance Sheets (Unaudited) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012
Current assets
CashAndCashEquivalentsNonvariableInterestEntity	$ 1,547		$ 1,411
Cash and cash equivalents	1,609		1,486
Cash and cash equivalents of variable interest entities	62		75
Restricted cash and investments	87		86
Restricted cash and investments of variable interest entity	80		47
Accounts receivable, net
Customer	2,721		2,795
Other	1,175		1,141
Accounts receivable of variable interest entities	260		292
Mark-to-market derivative assets	727		938
Unamortized energy contracts assets	374		886
Inventories, net
Fossil fuel	276		246
Materials and supplies	829		768
Deferred income taxes	573		131
Regulatory assets	760		764
Other	666		560
Total current assets	10,137		10,140
Property, plant and equipment, net	47,330		45,186
Deferred debits and other assets
Regulatory assets	5,910		6,497
Nuclear decommissioning trust funds	8,071		7,248
Investments	1,165		1,184
Investments in affiliates	22		22
Investment in CENG	1,925		1,849
Goodwill	2,625		2,625
Receivable from affiliate			2,039
Mark-to-market derivative assets	607		937
Pledged assets for Zion Station decommissioning	458		614
Unamortized energy contracts assets	710		1,073
Other	964		1,128
Deferred income taxes	0		58
Total deferred debits and other assets	22,457		23,235
Total assets	79,924		78,561
Current liabilities
Short-term borrowings	341
Short-term notes payable - accounts receivable agreement			210
Long-term debt due within one year	1,424		975
Long-term debt of variable interest entities due within one year	85		72
Accounts payable	2,314		2,378
Accounts payable of variable interest entities	170		202
Accrued expenses	1,633		1,796
Payables to affiliates			112
Deferred income taxes	40		58
Regulatory liabilities	327		368
Mark-to-market derivative liabilities	159		352
Unamortized energy contract liabilities	261		455
Other	858		813
Total current liabilities	7,728		7,791
Long-term debt	17,325		17,190
Long-term debt of variable financing trusts	298		648
Long-term debt of variable interest entity	648		508
Deferred credits and other liabilities
Deferred income taxes and unamortized investment tax credits	12,905		11,551
Asset retirement obligations	5,194		5,074
Pension obligations	1,876		3,428
Non-pension postretirement benefit obligations	2,190		2,662
Spent nuclear fuel obligation	1,021		1,020
Regulatory liabilities	4,388		3,981
Mark-to-market derivative liabilities	300		281
Unamortized energy contract liabilities	266		528
Payable for Zion Station decommissioning	305		432
Other	2,540		1,650
Total deferred credits and other liabilities	30,985		30,607
Total liabilities	56,984		56,744
Commitments and contingencies	0		0
Preferred securities			87
Shareholders' equity
Common stock	16,741		16,632
Treasury stock, at cost (35 and 35 shares held at December 31, 2010 and December 31, 2009, respectively)	(2,327)		(2,327)
Retained earnings	10,358		9,893
Accumulated other comprehensive income (loss), net	(2,040)		(2,767)
Total shareholders' equity	22,732		21,431
BGE preference stock not subject to mandatory redemption	193		193
Noncontrolling interest	15		106
Total equity	22,940		21,730
Total liabilities and shareholders' equity	79,924		78,561
Member's equity
Accumulated other comprehensive income (loss), net	(2,040)		(2,767)
Removal Costs [Member]
Current liabilities
Regulatory liabilities	99		97
Deferred credits and other liabilities
Regulatory liabilities	1,423		1,406
Exelon Generation Co L L C [Member]
Current assets
CashAndCashEquivalentsNonvariableInterestEntity	1,196		596
Cash and cash equivalents	1,258		671
Cash and cash equivalents of variable interest entities	62		75
Restricted cash and cash equivalents	19		0
Restricted cash and investments of variable interest entity	52		16
Accounts receivable, net
Customer	1,429		1,482
Other	353		472
Accounts receivable of variable interest entities	260		292
Mark-to-market derivative assets	727		938
Mark-to-market derivative assets with affiliates			226
Receivables from affiliates	108		141
Unamortized energy contracts assets	374		886
Inventories, net
Fossil fuel	164		130
Materials and supplies	671		626
Deferred income taxes	475
Receivable from Exelon intercompany money pool	44
Other	505		331
Total current assets	6,439		6,211
Property, plant and equipment, net	20,111		19,531
Deferred debits and other assets
Nuclear decommissioning trust funds	8,071		7,248
Investments	400		420
Investment in CENG	1,925		1,849
Receivable from affiliate	22		22
Mark-to-market derivative assets	600		924
Prepaid pension asset	1,873		1,975
Pledged assets for Zion Station decommissioning	458		614
Unamortized energy contracts assets	710		1,073
Other	645		836
Total deferred debits and other assets	14,682		14,939
Total assets	41,232		40,681
Current liabilities
Short-term borrowings	22		0
Long-term debt due within one year	556		24
Long-term debt of variable interest entities due within one year	5		4
Accounts payable	1,152		1,326
Accounts payable of variable interest entities	170		202
Accrued expenses	976		1,116
Payables to affiliates	181		213
Deferred income taxes	25		128
Mark-to-market derivative liabilities	142		334
Unamortized energy contract liabilities	249		378
Other	389		372
Total current liabilities	3,867		4,097
Long-term debt	5,559		5,245
Long-term debt to affiliate			2,007
Long-term debt of variable financing trusts	1,523
Long-term debt of variable interest entity	86		203
Deferred credits and other liabilities
Deferred income taxes and unamortized investment tax credits	6,295		5,398
Asset retirement obligations	5,047		4,938
Non-pension postretirement benefit obligations	850		755
Spent nuclear fuel obligation	1,021		1,020
Payables to affiliates	2,740		2,397
Mark-to-market derivative liabilities	120		232
Unamortized energy contract liabilities	266		516
Payable for Zion Station decommissioning	305		432
Other	811		776
Total deferred credits and other liabilities	17,455		16,464
Total liabilities	28,490		28,016
Commitments and contingencies	0		0
Shareholders' equity
Accumulated other comprehensive income (loss), net	214		513
Noncontrolling interest	17		108
Member's equity
Membership interest	8,898		8,876
Undistributed earnings	3,613		3,168
Accumulated other comprehensive income (loss), net	214		513
Total member's equity	12,725		12,557
Total equity	12,742		12,665
Total liabilities and equity	41,232		40,681
Commonwealth Edison Co [Member]
Current assets
Cash and cash equivalents	36		144
Restricted cash and cash equivalents	2		0
Accounts receivable, net
Customer	451		539
Other	584		452
Receivables from affiliates	3		3
Inventories, net
Inventories, net	109		91
Deferred income taxes	0		83
Counterparty collateral deposited	0		53
Regulatory assets	329		388
Other	29		25
Total current assets	1,540		1,775
Property, plant and equipment, net	14,666		13,826
Deferred debits and other assets
Regulatory assets	933		666
Investments	5		8
Investments in affiliates	6		6
Goodwill	2,625		2,625
Receivable from affiliate	2,469		2,039
Mark-to-market derivative assets	0		0
Prepaid pension asset	1,583		1,661
Other	291		299
Total deferred debits and other assets	7,912		7,304
Total assets	24,118		22,905
Current liabilities
Short-term borrowings	184		0
Long-term debt due within one year	617		252
Accounts payable	449		379
Accrued expenses	307		295
Payables to affiliates	83		97
Customer deposits	133		136
Regulatory liabilities	170		170
Mark-to-market derivative liabilities	17		18
Mark-to-market derivative liabilities with affiliate	0		226
Other	72		82
Total current liabilities	2,048		1,655
Long-term debt	5,058		5,315
Long-term debt of variable financing trusts	206		206
Deferred credits and other liabilities
Deferred income taxes and unamortized investment tax credits	4,116		4,272
Asset retirement obligations	99		99
Non-pension postretirement benefit obligations	381		273
Regulatory liabilities	3,512		3,229
Mark-to-market derivative liabilities	176		49
Mark-to-market derivative liabilities with affiliate	0		0
Deferred income taxes	16
Other	994		484
Total deferred credits and other liabilities	9,278		8,406
Total liabilities	16,590		15,582
Commitments and contingencies	0		0
Shareholders' equity
Common stock	1,588		1,588
Other paid-in capital	5,190		5,014
Retained earnings	750		721
Total shareholders' equity	7,528		7,323
Total liabilities and shareholders' equity	24,118		22,905
Commonwealth Edison Co [Member] | Removal Costs [Member]
Current liabilities
Regulatory liabilities	78		75
Deferred credits and other liabilities
Regulatory liabilities	1,219		1,192
PECO Energy Co [Member]
Current assets
Cash and cash equivalents	217		362
Restricted cash and cash equivalents	2		0
Accounts receivable, net
Customer	360		364
Other	107		161
Inventories, net
Fossil fuel	60		65
Materials and supplies	21		19
Deferred income taxes	83		40
Receivable from Exelon intercompany money pool	0		0
Prepaid utility taxes	3		21
Regulatory assets	17		32
Other	36		30
Total current assets	906		1,094
Property, plant and equipment, net	6,384		6,078
Deferred debits and other assets
Regulatory assets	1,448		1,378
Investments	23		22
Investments in affiliates	8		8
Receivable from affiliate	447		360
Prepaid pension asset	363		373
Other	38		40
Total deferred debits and other assets	2,327		2,181
Total assets	9,617		9,353
Current liabilities
Short-term notes payable - accounts receivable agreement	0		210
Long-term debt due within one year	250		300
Long-term debt to PECO Energy Transition Trust due within one year	0		0
Accounts payable	285		244
Accrued expenses	106		82
Payables to affiliates	58		76
Deferred income taxes	0		0
Customer deposits	49		51
Regulatory liabilities	106		169
Mark-to-market derivative liabilities	0		0
Mark-to-market derivative liabilities with affiliate	0		0
Other	37		26
Total current liabilities	891		1,158
Long-term debt	1,947		1,647
Long-term debt of variable financing trusts	184	[1]	184	[1]
Deferred credits and other liabilities
Deferred income taxes and unamortized investment tax credits	2,487		2,331
Asset retirement obligations	29		29
Non-pension postretirement benefit obligations	286		284
Regulatory liabilities	629		538
Mark-to-market derivative liabilities	0		0
Mark-to-market derivative liabilities with affiliate	0		0
Other	99		113
Total deferred credits and other liabilities	3,530		3,295
Total liabilities	6,552		6,284
Preferred securities	0		87
Shareholders' equity
Common stock	2,415		2,388
Receivable from parent	0		0
Retained earnings	649		593
Accumulated other comprehensive income (loss), net	1		1
Total shareholders' equity	3,065		2,982
Total liabilities and shareholders' equity	9,617		9,353
Member's equity
Accumulated other comprehensive income (loss), net	1		1
PECO Energy Co [Member] | Removal Costs [Member]
Current liabilities
Regulatory liabilities	0		0
Deferred credits and other liabilities
Regulatory liabilities	0		0
Baltimore Gas and Electric Company [Member]
Current assets
Cash and cash equivalents	31		89
Restricted cash and investments of variable interest entity	28		30
Accounts receivable, net
Customer	480		409
Other	114		111
Income taxes receivable	30		3
Inventories, net
Fossil fuel	53		51
Materials and supplies	28		31
Deferred income taxes	2		1
Prepaid utility taxes	57		57
Regulatory assets	181		190
Other	7		8
Total current assets	1,011		980
Property, plant and equipment, net	5,864		5,498
Deferred debits and other assets
Regulatory assets	524		522
Investments	5		5
Investments in affiliates	8		8
Prepaid pension asset	423		467
Other	26		26
Deferred income taxes	0
Total deferred debits and other assets	986		1,028
Total assets	7,861		7,506
Current liabilities
Short-term borrowings	135
Long-term debt due within one year	0		400
Long-term debt of variable interest entities due within one year	70		67
Accounts payable	270		235
Accrued expenses	111		102
Payables to affiliates	55		69
Deferred income taxes	27		0
Customer deposits	76		71
Regulatory liabilities	48		29
Other	35		7
Total current liabilities	827		980
Long-term debt	1,746		1,446
Long-term debt of variable financing trusts	258		258
Long-term debt of variable interest entity	195		265
Deferred credits and other liabilities
Deferred income taxes and unamortized investment tax credits	1,773		1,658
Asset retirement obligations	19		8
Non-pension postretirement benefit obligations	217		229
Regulatory liabilities	204		214
Other	67		90
Total deferred credits and other liabilities	2,280		2,199
Total liabilities	5,306		5,148
Shareholders' equity
Common stock	1,360		1,360
Retained earnings	1,005		808
Total shareholders' equity	2,365		2,168
BGE preference stock not subject to mandatory redemption	190		190
Total equity	2,555		2,358
Total liabilities and shareholders' equity	7,861		7,506
Baltimore Gas and Electric Company [Member] | Removal Costs [Member]
Current liabilities
Regulatory liabilities	21		22
Deferred credits and other liabilities
Regulatory liabilities	$ 204		$ 214

[1] Amounts owed to this financing trust are recorded as debt to financing trusts within PECO's Consolidated Balance Sheets.