Consolidated Balance Sheets (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
CURRENT ASSETS
Cash and cash equivalents	$ 125	$ 25
Restricted cash equivalents	10	10
Accounts receivable, less allowance for uncollectible accounts	838	837
Inventories	153	155
Derivative assets		1
Prepayments of income taxes	50	59
Deferred income tax assets, net	36	28
Income taxes receivable	243	69
Prepaid expenses and other	66	76
Assets held for sale		1
Total Current Assets	1,521	1,261
INVESTMENTS AND OTHER ASSETS
Goodwill	1,407	1,407
Regulatory assets	2,566	2,614
Investment in finance leases held in trust	869	1,237
Income taxes receivable	51	217
Restricted cash equivalents	16	17
Assets and accrued interest related to uncertain tax positions	9	18
Derivative assets	8	8
Other	174	163
Total Investments and Other Assets	5,100	5,681
PROPERTY, PLANT AND EQUIPMENT
Property, plant and equipment	13,830	13,625
Accumulated depreciation	(4,796)	(4,779)
Net Property, Plant and Equipment	9,034	8,846
TOTAL ASSETS	15,655	15,788
CURRENT LIABILITIES
Short-term debt	1,041	965
Current portion of long-term debt and project funding	569	569
Accounts payable and accrued liabilities	486	574
Capital lease obligations due within one year	9	8
Taxes accrued	50	75
Interest accrued	84	47
Liabilities and accrued interest related to uncertain tax positions	379	9
Derivative liabilities	2	7
Other	256	273
Liabilities associated with assets held for sale	7	10
Total Current Liabilities	2,883	2,537
DEFERRED CREDITS
Regulatory liabilities	492	501
Deferred income taxes, net	2,685	3,176
Investment tax credits	20	20
Pension benefit obligation	388	449
Other postretirement benefit obligations	451	454
Liabilities and accrued interest related to uncertain tax positions	27	15
Derivative liabilities	11	11
Other	195	191
Liabilities associated with assets held for sale	1	2
Total Deferred Credits	4,270	4,819
LONG-TERM LIABILITIES
Long-term debt	3,898	3,648
Transition bonds issued by ACE Funding	246	256
Long-term project funding	11	12
Capital lease obligations	69	70
Total Long-Term Liabilities	4,224	3,986
COMMITMENTS AND CONTINGENCIES
EQUITY
Common stock	2	2
Premium on stock and other capital contributions	3,706	3,383
Accumulated other comprehensive loss	(42)	(48)
Retained earnings	612	1,109
Total Equity	4,278	4,446
TOTAL LIABILITIES AND EQUITY	15,655	15,788
Potomac Electric Power Co [Member]
CURRENT ASSETS
Cash and cash equivalents	97	9
Accounts receivable, less allowance for uncollectible accounts	321	318
Inventories	71	69
Prepayments of income taxes	9	9
Income taxes receivable	120	31
Prepaid expenses and other	23	25
Total Current Assets	641	461
INVESTMENTS AND OTHER ASSETS
Regulatory assets	493	487
Prepaid pension expense	349	353
Investment in trust	31	31
Income taxes receivable	18	102
Other	63	59
Total Investments and Other Assets	954	1,032
PROPERTY, PLANT AND EQUIPMENT
Property, plant and equipment	6,939	6,850
Accumulated depreciation	(2,704)	(2,705)
Net Property, Plant and Equipment	4,235	4,145
TOTAL ASSETS	5,830	5,638
CURRENT LIABILITIES
Short-term debt		231
Current portion of long-term debt and project funding	200	200
Accounts payable and accrued liabilities	175	214
Accounts payable due to associated companies	49	41
Capital lease obligations due within one year	9	8
Taxes accrued	22	58
Interest accrued	39	17
Liabilities and accrued interest related to uncertain tax positions	24
Other	110	106
Total Current Liabilities	628	875
DEFERRED CREDITS
Regulatory liabilities	145	141
Deferred income taxes, net	1,249	1,219
Investment tax credits	3	4
Other postretirement benefit obligations	66	66
Liabilities and accrued interest related to uncertain tax positions	10	53
Other	68	66
Total Deferred Credits	1,541	1,549
LONG-TERM LIABILITIES
Long-term debt	1,751	1,501
Capital lease obligations	69	70
Total Long-Term Liabilities	1,820	1,571
COMMITMENTS AND CONTINGENCIES
EQUITY
Common stock
Premium on stock and other capital contributions	930	755
Retained earnings	911	888
Total Equity	1,841	1,643
TOTAL LIABILITIES AND EQUITY	5,830	5,638
Delmarva Power & Light Co/De [Member]
CURRENT ASSETS
Cash and cash equivalents	10	6
Accounts receivable, less allowance for uncollectible accounts	216	201
Inventories	48	53
Prepayments of income taxes	10	10
Income taxes receivable	6	10
Assets and accrued interest related to uncertain tax positions	17
Prepaid expenses and other	19	20
Total Current Assets	326	300
INVESTMENTS AND OTHER ASSETS
Goodwill	8	8
Regulatory assets	276	288
Prepaid pension expense	239	232
Assets and accrued interest related to uncertain tax positions	3	20
Other	12	12
Total Investments and Other Assets	538	560
PROPERTY, PLANT AND EQUIPMENT
Property, plant and equipment	3,479	3,422
Accumulated depreciation	(1,002)	(1,000)
Net Property, Plant and Equipment	2,477	2,422
TOTAL ASSETS	3,341	3,282
CURRENT LIABILITIES
Short-term debt	175	137
Current portion of long-term debt and project funding	250	250
Accounts payable and accrued liabilities	100	125
Accounts payable due to associated companies	22	20
Taxes accrued	5	4
Interest accrued	15	6
Derivative liabilities		4
Other	61	61
Total Current Liabilities	628	607
DEFERRED CREDITS
Regulatory liabilities	258	258
Deferred income taxes, net	716	697
Investment tax credits	5	5
Other postretirement benefit obligations	22	22
Other	34	41
Total Deferred Credits	1,035	1,023
LONG-TERM LIABILITIES
Long-term debt	667	667
COMMITMENTS AND CONTINGENCIES
EQUITY
Common stock
Premium on stock and other capital contributions	407	407
Retained earnings	604	578
Total Equity	1,011	985
TOTAL LIABILITIES AND EQUITY	3,341	3,282
Atlantic City Electric Co [Member]
CURRENT ASSETS
Cash and cash equivalents	10	6
Restricted cash equivalents	10	10
Accounts receivable, less allowance for uncollectible accounts	191	192
Inventories	30	30
Prepayments of income taxes	27	27
Income taxes receivable	112	5
Assets and accrued interest related to uncertain tax positions	10
Prepaid expenses and other	9	11
Total Current Assets	399	281
INVESTMENTS AND OTHER ASSETS
Regulatory assets	670	694
Prepaid pension expense	115	88
Income taxes receivable	31	133
Restricted cash equivalents	16	17
Assets and accrued interest related to uncertain tax positions	6	12
Derivative assets	8	8
Other	11	12
Total Investments and Other Assets	857	964
PROPERTY, PLANT AND EQUIPMENT
Property, plant and equipment	2,820	2,771
Accumulated depreciation	(794)	(787)
Net Property, Plant and Equipment	2,026	1,984
TOTAL ASSETS	3,282	3,229
CURRENT LIABILITIES
Short-term debt	208	133
Current portion of long-term debt and project funding	108	108
Accounts payable and accrued liabilities	122	147
Accounts payable due to associated companies	17	14
Taxes accrued	20	10
Interest accrued	20	15
Other	44	47
Total Current Liabilities	539	474
DEFERRED CREDITS
Regulatory liabilities	89	102
Deferred income taxes, net	769	766
Investment tax credits	6	6
Other postretirement benefit obligations	34	34
Derivative liabilities	11	11
Other	17	18
Total Deferred Credits	926	937
LONG-TERM LIABILITIES
Long-term debt	760	760
Transition bonds issued by ACE Funding	246	256
Total Long-Term Liabilities	1,006	1,016
COMMITMENTS AND CONTINGENCIES
EQUITY
Common stock	26	26
Premium on stock and other capital contributions	576	576
Retained earnings	209	200
Total Equity	811	802
TOTAL LIABILITIES AND EQUITY	$ 3,282	$ 3,229