Consolidated Statements Of Cash Flows (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
OPERATING ACTIVITIES
Net income	$ 285	$ 257	$ 32
Loss from discontinued operations, net of income taxes	0	3	107
Adjustments to reconcile net income to net cash from operating activities:
Depreciation and amortization	454	426	393
Non-cash rents from cross-border energy lease investments	(50)	(55)	(55)
Gains on early terminations of finance leases held in trust	(39)	(39)
Non-cash charge to reduce equity value of PHI's cross-border energy lease investments		7	2
Effects of Pepco divestiture-related claims			11
Deferred income taxes	274	140	345
Net unrealized (gains) losses on derivatives	(24)	30	3
Investment tax credit amortization	(3)	(4)	(3)
Losses on treasury rate locks reclassified into income		1	18
Impairment losses	12
Other	(15)	(19)	(20)
Changes in:
Accounts receivable	59	135	(12)
Inventories	(24)	(6)	(2)
Prepaid expenses	(11)	(4)	7
Regulatory assets and liabilities, net	(174)	(148)	(154)
Accounts payable and accrued liabilities	(2)	(90)	73
Pension contributions	(200)	(110)	(100)
Pension benefit obligation, excluding contributions	65	53	68
Cash collateral related to derivative activities	88	9	13
Income tax-related prepayments, receivables and payables	(122)	11	(213)
Other assets and liabilities	16	43	49
Net Conectiv Energy assets held for sale		42	248
Net Cash From (Used By) Operating Activities	592	686	813
INVESTING ACTIVITIES
Investment in property, plant and equipment	(1,216)	(941)	(802)
Department of Energy capital reimbursement awards received	40	52	13
Proceeds from sale of Conectiv Energy wholesale power generation business			1,640
Proceeds from early terminations of finance leases held in trust	202	161
Changes in restricted cash equivalents	(1)	(10)	(2)
Net other investing activities	6	(9)	7
Investment in property, plant and equipment associated with Conectiv Energy assets held for sale			(138)
Net Cash (Used By) From Investing Activities	(969)	(747)	718
FINANCING ACTIVITIES
Dividends paid on common stock	(248)	(244)	(241)
Common stock issued for the Dividend Reinvestment Plan and employee-related compensation	51	47	47
Redemption of preferred stock		(6)
Issuances of long-term debt	450	235	383
Reacquisitions of long-term debt	(176)	(70)	(1,726)
(Repayments) issuances of short-term debt, net	233	198	4
Cost of issuances	(9)	(10)	(7)
Net other financing activities	(8)	(1)	(6)
Net financing activities associated with Conectiv Energy assets held for sale			(10)
Net Cash (Used By) From Financing Activities	293	149	(1,556)
Net (Decrease) Increase In Cash and Cash Equivalents	(84)	88	(25)
Cash and Cash Equivalents of Discontinued Operations			(1)
Cash and cash equivalents at beginning of year	109	21	46
CASH AND CASH EQUIVALENTS AT END OF YEAR	25	109	21
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION
Cash paid for interest, net	253	240	310
Cash paid (received) for income taxes		4	(13)
Non-cash activities:
Reclassification of property, plant and equipment to regulatory assets	88
Reclassification of asset removal costs regulatory liability to accumulated depreciation	61
Potomac Electric Power Co [Member]
OPERATING ACTIVITIES
Net income	126	99	108
Adjustments to reconcile net income to net cash from operating activities:
Depreciation and amortization	190	171	162
Effects of Pepco divestiture-related claims			11
Deferred income taxes	160	73	74
Investment tax credit amortization	(1)	(2)	(2)
Changes in:
Accounts receivable	22	33	(15)
Inventories	(19)	(6)	(1)
Prepaid expenses	6	1	3
Regulatory assets and liabilities, net	(110)	(43)	(34)
Accounts payable and accrued liabilities	(10)	(27)	15
Pension contributions	(85)	(40)	0
Pension benefit obligation, excluding contributions	21	24	22
Income tax-related prepayments, receivables and payables	(69)	73	6
Interest accrued		(1)	(1)
Other assets and liabilities	(8)	2	11
Net Cash From (Used By) Operating Activities	223	357	359
INVESTING ACTIVITIES
Investment in property, plant and equipment	(592)	(521)	(359)
Department of Energy capital reimbursement awards received	38	48	11
Changes in restricted cash equivalents			1
Net other investing activities	4	(7)	3
Net Cash (Used By) From Investing Activities	(550)	(480)	(344)
FINANCING ACTIVITIES
Dividends paid on common stock	(35)	(25)	(115)
Capital contribution from Parent	50
Issuances of long-term debt	200
Reacquisitions of long-term debt	(38)		(16)
(Repayments) issuances of short-term debt, net	157	74
Cost of issuances	(4)
Net other financing activities	(6)	(2)	(9)
Net Cash (Used By) From Financing Activities	324	47	(140)
Net (Decrease) Increase In Cash and Cash Equivalents	(3)	(76)	(125)
Cash and cash equivalents at beginning of year	12	88	213
CASH AND CASH EQUIVALENTS AT END OF YEAR	9	12	88
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION
Cash paid for interest, net	97	91	94
Cash paid (received) for income taxes	(40)	(108)	(20)
Non-cash activities:
Reclassification of property, plant and equipment to regulatory assets	50
Reclassification of asset removal costs regulatory liability to accumulated depreciation	19
Delmarva Power & Light Co/De [Member]
OPERATING ACTIVITIES
Net income	73	71	45
Adjustments to reconcile net income to net cash from operating activities:
Depreciation and amortization	102	89	83
Deferred income taxes	55	57	74
Investment tax credit amortization	(1)	(1)	(1)
Changes in:
Accounts receivable	(15)	26	(21)
Inventories	(9)	(3)	(1)
Regulatory assets and liabilities, net	(29)	(30)	(9)
Accounts payable and accrued liabilities	26	(23)	31
Pension contributions	(85)	(40)	0
Pension benefit obligation, excluding contributions	15	17	18
Income tax-related prepayments, receivables and payables	8	14	11
Other assets and liabilities	(9)	1	(4)
Net Cash From (Used By) Operating Activities	131	178	226
INVESTING ACTIVITIES
Investment in property, plant and equipment	(320)	(229)	(250)
Net other investing activities		(4)	2
Net Cash (Used By) From Investing Activities	(320)	(233)	(248)
FINANCING ACTIVITIES
Dividends paid on common stock		(60)	(23)
Capital contribution from Parent	60		11
Issuances of long-term debt	250	35	109
Reacquisitions of long-term debt	(97)	(35)	(31)
(Repayments) issuances of short-term debt, net	(15)	47
Cost of issuances	(3)
Net other financing activities	(5)	4	(1)
Net Cash (Used By) From Financing Activities	190	(9)	65
Net (Decrease) Increase In Cash and Cash Equivalents	1	(64)	43
Cash and cash equivalents at beginning of year	5	69	26
CASH AND CASH EQUIVALENTS AT END OF YEAR	6	5	69
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION
Cash paid for interest, net	44	43	40
Cash paid (received) for income taxes	(24)	(24)	(49)
Non-cash activities:
Reclassification of property, plant and equipment to regulatory assets	38
Reclassification of asset removal costs regulatory liability to accumulated depreciation	42
Atlantic City Electric Co [Member]
OPERATING ACTIVITIES
Net income	35	39	53
Adjustments to reconcile net income to net cash from operating activities:
Depreciation and amortization	124	134	112
Deferred income taxes	62	42	49
Investment tax credit amortization	(1)	(1)	(1)
Changes in:
Accounts receivable	(7)	26	(35)
Inventories	(5)	(8)	(2)
Regulatory assets and liabilities, net	(33)	(74)	(107)
Accounts payable and accrued liabilities	12	(18)	(24)
Pension contributions	(30)	(30)	0
Income tax-related prepayments, receivables and payables	(43)	45	(10)
Other assets and liabilities	19	16	24
Net Cash From (Used By) Operating Activities	133	171	59
INVESTING ACTIVITIES
Investment in property, plant and equipment	(256)	(138)	(156)
Department of Energy capital reimbursement awards received	2	4	2
Net other investing activities	(1)	(9)	(3)
Net Cash (Used By) From Investing Activities	(255)	(143)	(157)
FINANCING ACTIVITIES
Dividends paid on common stock	(35)		(35)
Capital contribution from Parent		60	43
Redemption of preferred stock		(6)
Issuances of long-term debt		200	23
Reacquisitions of long-term debt	(41)	(35)	(35)
(Repayments) issuances of short-term debt, net	110	(158)	98
Net other financing activities	3	(2)	1
Net Cash (Used By) From Financing Activities	37	59	95
Net (Decrease) Increase In Cash and Cash Equivalents	(85)	87	(3)
Cash and cash equivalents at beginning of year	91	4	7
CASH AND CASH EQUIVALENTS AT END OF YEAR	6	91	4
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION
Cash paid for interest, net	68	64	61
Cash paid (received) for income taxes	$ 1	$ (51)	$ 10