Supplemental Financial Information - Supplemental Cash Flow Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Depreciation, amortization and accretion
Depreciation	$ 2,690	$ 5,384	$ 4,364
Amortization of Regulatory Asset	718	594	588
Amortization of Intangible Assets	(182)	(83)	(98)
Amortization of Nuclear Fuel Lease	66	992	983
Accretion expense	44	514	500
Total depreciation, amortization and accretion	3,533	7,573	6,527
Cash paid (refunded) during the year:
Interest (net of amount capitalized)	1,434	1,505	1,521
Income taxes (net of refunds)	73	281	10
Other non-cash operating activities:
Pension and non-pension postretirement benefit costs	164	411	411
Provision for uncollectible accounts	173	160	150
Other decommissioning related-activity	36	(946)	(659)
Energy-related options	60	125	104
True-up Adjustments to Decoupling Mechanisms and Formula Rate	(161)	(171)	(6)
Restructuring Costs		(57)	105
Long-term incentive plan	42	137	56
Operating Leases, Income Statement, Depreciation Expense on Property Subject to or Held-for-lease	56	183	222
Public Utilities, Allowance for Funds Used During Construction, Capitalized Cost of Equity	(150)	(136)	(104)
Inventory Write-down			131
Asset impairments	48	552	591
Change in environmental liabilities			0
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract]
Cash and cash equivalents	407	672	432	$ 587
Restricted cash	566	321	349	358
Restricted cash included in other long-term assets	117	44	53	177
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Disposal Group, Including Discontinued Operations		582	332
Total cash, cash equivalents and restricted cash	1,090	1,619	1,166	1,122
Other Non-Cash [Member]
Other non-cash operating activities:
True-up Adjustments to Decoupling Mechanisms and Formula Rate	(168)	(171)	(6)
Return on borrowed funds
Other non-cash operating activities:
Public Utilities, Allowance for Funds Used During Construction, Capitalized Cost of Equity	(150)	(136)	(104)
Commonwealth Edison Co [Member]
Depreciation, amortization and accretion
Depreciation	1,031	970	922
Amortization of Regulatory Asset	292	235	211
Amortization of Nuclear Fuel Lease	0	0	0
Accretion expense	0	0	0
Total depreciation, amortization and accretion	1,323	1,205	1,133
Cash paid (refunded) during the year:
Interest (net of amount capitalized)	396	372	371
Income taxes (net of refunds)	23	(72)	(61)
Other non-cash operating activities:
Pension and non-pension postretirement benefit costs	60	129	114
Provision for uncollectible accounts	46	47	32
Other decommissioning related-activity	0	0	0
Energy-related options	0	0	0
True-up Adjustments to Decoupling Mechanisms and Formula Rate	(267)	(42)	47
Restructuring Costs		2	1
Long-term incentive plan	0	0	0
Operating Leases, Income Statement, Depreciation Expense on Property Subject to or Held-for-lease	2	1	2
Public Utilities, Allowance for Funds Used During Construction, Capitalized Cost of Equity	(35)	(34)	(29)
Inventory Write-down			2
Change in environmental liabilities			15
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract]
Cash and cash equivalents	67	131	83	90
Restricted cash	327	210	279	150
Restricted cash included in other long-term assets	117	43	43	163
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Disposal Group, Including Discontinued Operations		0	0
Total cash, cash equivalents and restricted cash	511	384	405	403
Commonwealth Edison Co [Member] | Other Non-Cash [Member]
Other non-cash operating activities:
True-up Adjustments to Decoupling Mechanisms and Formula Rate	(267)	(42)	47
Commonwealth Edison Co [Member] | Return on borrowed funds
Other non-cash operating activities:
Public Utilities, Allowance for Funds Used During Construction, Capitalized Cost of Equity	(35)	(34)	(29)
PECO Energy Co [Member]
Depreciation, amortization and accretion
Depreciation	359	336	319
Amortization of Regulatory Asset	14	12	28
Amortization of Nuclear Fuel Lease	0	0	0
Accretion expense	0	0	0
Total depreciation, amortization and accretion	373	348	347
Cash paid (refunded) during the year:
Interest (net of amount capitalized)	166	152	144
Income taxes (net of refunds)	31	(4)	(37)
Other non-cash operating activities:
Pension and non-pension postretirement benefit costs	(9)	8	5
Provision for uncollectible accounts	45	39	42
Other decommissioning related-activity	0	0	0
Energy-related options	0	0	0
True-up Adjustments to Decoupling Mechanisms and Formula Rate	(2)	(26)	(16)
Restructuring Costs		0	1
Long-term incentive plan	0	0	0
Operating Leases, Income Statement, Depreciation Expense on Property Subject to or Held-for-lease	0	0	1
Public Utilities, Allowance for Funds Used During Construction, Capitalized Cost of Equity	(31)	(26)	(17)
Inventory Write-down			1
Change in environmental liabilities			0
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract]
Cash and cash equivalents	59	36	19	21
Restricted cash	9	8	7	6
Restricted cash included in other long-term assets	0	0	0	0
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Disposal Group, Including Discontinued Operations		0	0
Total cash, cash equivalents and restricted cash	68	44	26	27
PECO Energy Co [Member] | Other Non-Cash [Member]
Other non-cash operating activities:
True-up Adjustments to Decoupling Mechanisms and Formula Rate	(2)	(26)	(16)
PECO Energy Co [Member] | Return on borrowed funds
Other non-cash operating activities:
Public Utilities, Allowance for Funds Used During Construction, Capitalized Cost of Equity	(31)	(26)	(17)
Baltimore Gas and Electric Company [Member]
Depreciation, amortization and accretion
Depreciation	476	439	397
Amortization of Regulatory Asset	154	152	153
Amortization of Nuclear Fuel Lease	0	0	0
Accretion expense	0	0	0
Total depreciation, amortization and accretion	630	591	550
Cash paid (refunded) during the year:
Interest (net of amount capitalized)	147	134	125
Income taxes (net of refunds)	16	(38)	(57)
Other non-cash operating activities:
Pension and non-pension postretirement benefit costs	44	61	62
Provision for uncollectible accounts	25	17	15
Other decommissioning related-activity	0	0	0
Energy-related options	0	0	0
True-up Adjustments to Decoupling Mechanisms and Formula Rate	47	(12)	(16)
Restructuring Costs		0	0
Long-term incentive plan	0	0	0
Operating Leases, Income Statement, Depreciation Expense on Property Subject to or Held-for-lease	14	29	31
Public Utilities, Allowance for Funds Used During Construction, Capitalized Cost of Equity	(21)	(27)	(22)
Inventory Write-down			0
Asset impairments	48	0	0
Change in environmental liabilities			0
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract]
Cash and cash equivalents	43	51	144	24
Restricted cash	24	4	1	1
Restricted cash included in other long-term assets	0	0	0	0
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Disposal Group, Including Discontinued Operations		0	0
Total cash, cash equivalents and restricted cash	67	55	145	25
Baltimore Gas and Electric Company [Member] | Other Non-Cash [Member]
Other non-cash operating activities:
True-up Adjustments to Decoupling Mechanisms and Formula Rate	47	(12)	(16)
Baltimore Gas and Electric Company [Member] | Return on borrowed funds
Other non-cash operating activities:
Public Utilities, Allowance for Funds Used During Construction, Capitalized Cost of Equity	(21)	(27)	(22)
Pepco Holdings LLC [Member]
Depreciation, amortization and accretion
Depreciation	680	627	586
Amortization of Regulatory Asset	258	194	196
Amortization of Intangible Assets	(190)	(92)	(115)
Amortization of Nuclear Fuel Lease	0	0	0
Accretion expense	0	0	0
Total depreciation, amortization and accretion	938	821	782
Cash paid (refunded) during the year:
Interest (net of amount capitalized)	274	255	257
Income taxes (net of refunds)	19	0	46
Other non-cash operating activities:
Pension and non-pension postretirement benefit costs	53	49	70
Provision for uncollectible accounts	58	24	43
Other decommissioning related-activity	0	0	0
Energy-related options	0	0	0
True-up Adjustments to Decoupling Mechanisms and Formula Rate	59	(91)	(21)
Restructuring Costs		1	0
Long-term incentive plan	0	0	0
Operating Leases, Income Statement, Depreciation Expense on Property Subject to or Held-for-lease	27	28	28
Public Utilities, Allowance for Funds Used During Construction, Capitalized Cost of Equity	(63)	(49)	(36)
Inventory Write-down			0
Change in environmental liabilities			13
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract]
Cash and cash equivalents	198	136	111	131
Restricted cash	175	77	39	36
Restricted cash included in other long-term assets	0	0	10	14
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Disposal Group, Including Discontinued Operations		0	0
Total cash, cash equivalents and restricted cash	373	213	160	181
Pepco Holdings LLC [Member] | Other Non-Cash [Member]
Other non-cash operating activities:
True-up Adjustments to Decoupling Mechanisms and Formula Rate	54	(91)	(21)
Pepco Holdings LLC [Member] | Return on borrowed funds
Other non-cash operating activities:
Public Utilities, Allowance for Funds Used During Construction, Capitalized Cost of Equity	(63)	(49)	(36)
Potomac Electric Power Company [Member]
Depreciation, amortization and accretion
Depreciation	288	274	257
Amortization of Regulatory Asset	129	129	120
Amortization of Nuclear Fuel Lease	0	0	0
Accretion expense	0	0	0
Total depreciation, amortization and accretion	417	403	377
Cash paid (refunded) during the year:
Interest (net of amount capitalized)	141	132	129
Income taxes (net of refunds)	28	12	40
Other non-cash operating activities:
Pension and non-pension postretirement benefit costs	9	6	15
Provision for uncollectible accounts	29	9	24
Other decommissioning related-activity	0	0	0
Energy-related options	0	0	0
True-up Adjustments to Decoupling Mechanisms and Formula Rate	31	(53)	(40)
Restructuring Costs		0	0
Long-term incentive plan	0	0	0
Operating Leases, Income Statement, Depreciation Expense on Property Subject to or Held-for-lease	7	6	7
Public Utilities, Allowance for Funds Used During Construction, Capitalized Cost of Equity	(48)	(40)	(28)
Inventory Write-down			0
Change in environmental liabilities			0
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract]
Cash and cash equivalents	45	34	30	30
Restricted cash	54	34	35	33
Restricted cash included in other long-term assets	0	0	0	0
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Disposal Group, Including Discontinued Operations		0	0
Total cash, cash equivalents and restricted cash	99	68	65	63
Potomac Electric Power Company [Member] | Other Non-Cash [Member]
Other non-cash operating activities:
True-up Adjustments to Decoupling Mechanisms and Formula Rate	31	(53)	(40)
Potomac Electric Power Company [Member] | Return on borrowed funds
Other non-cash operating activities:
Public Utilities, Allowance for Funds Used During Construction, Capitalized Cost of Equity	(48)	(40)	(28)
Delmarva Power & Light Company [Member]
Depreciation, amortization and accretion
Depreciation	191	169	155
Amortization of Regulatory Asset	41	41	36
Amortization of Nuclear Fuel Lease	0	0	0
Accretion expense	0	0	0
Total depreciation, amortization and accretion	232	210	191
Cash paid (refunded) during the year:
Interest (net of amount capitalized)	63	59	61
Income taxes (net of refunds)	(2)	(9)	12
Other non-cash operating activities:
Pension and non-pension postretirement benefit costs	3	2	7
Provision for uncollectible accounts	12	5	16
Other decommissioning related-activity	0	0	0
Energy-related options	0	0	0
True-up Adjustments to Decoupling Mechanisms and Formula Rate	9	(14)	7
Restructuring Costs		0	0
Long-term incentive plan	0	0	0
Operating Leases, Income Statement, Depreciation Expense on Property Subject to or Held-for-lease	8	8	8
Public Utilities, Allowance for Funds Used During Construction, Capitalized Cost of Equity	(7)	(6)	(4)
Inventory Write-down			0
Change in environmental liabilities			7
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract]
Cash and cash equivalents	31	28	15	13
Restricted cash	121	43	0	0
Restricted cash included in other long-term assets	0	0	0	0
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Disposal Group, Including Discontinued Operations		0	0
Total cash, cash equivalents and restricted cash	152	71	15	13
Delmarva Power & Light Company [Member] | Other Non-Cash [Member]
Other non-cash operating activities:
True-up Adjustments to Decoupling Mechanisms and Formula Rate	7	(14)	7
Delmarva Power & Light Company [Member] | Return on borrowed funds
Other non-cash operating activities:
Public Utilities, Allowance for Funds Used During Construction, Capitalized Cost of Equity	(7)	(6)	(4)
Atlantic City Electric Company [Member]
Depreciation, amortization and accretion
Depreciation	173	155	140
Amortization of Regulatory Asset	88	24	40
Amortization of Nuclear Fuel Lease	0	0	0
Accretion expense	0	0	0
Total depreciation, amortization and accretion	261	179	180
Cash paid (refunded) during the year:
Interest (net of amount capitalized)	60	56	57
Income taxes (net of refunds)	(6)	2	(3)
Other non-cash operating activities:
Pension and non-pension postretirement benefit costs	12	11	14
Provision for uncollectible accounts	16	10	2
Other decommissioning related-activity	0	0	0
Energy-related options	0	0	0
True-up Adjustments to Decoupling Mechanisms and Formula Rate	19	(24)	12
Restructuring Costs		0	0
Long-term incentive plan	0	0	0
Operating Leases, Income Statement, Depreciation Expense on Property Subject to or Held-for-lease	3	4	3
Public Utilities, Allowance for Funds Used During Construction, Capitalized Cost of Equity	(8)	(3)	(4)
Inventory Write-down			0
Change in environmental liabilities			6
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract]
Cash and cash equivalents	72	29	17	12
Restricted cash	0	0	3	2
Restricted cash included in other long-term assets	0	0	10	14
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Disposal Group, Including Discontinued Operations		0	0
Total cash, cash equivalents and restricted cash	72	29	30	$ 28
Atlantic City Electric Company [Member] | Other Non-Cash [Member]
Other non-cash operating activities:
True-up Adjustments to Decoupling Mechanisms and Formula Rate	16	(24)	12
Atlantic City Electric Company [Member] | Return on borrowed funds
Other non-cash operating activities:
Public Utilities, Allowance for Funds Used During Construction, Capitalized Cost of Equity	(8)	(3)	(4)
Other Intangible Assets [Member]
Depreciation, amortization and accretion
Amortization of Intangible Assets	12	58	62
Other Intangible Assets [Member] | Commonwealth Edison Co [Member]
Depreciation, amortization and accretion
Amortization of Intangible Assets	0	0	0
Other Intangible Assets [Member] | PECO Energy Co [Member]
Depreciation, amortization and accretion
Amortization of Intangible Assets	0	0	0
Other Intangible Assets [Member] | Baltimore Gas and Electric Company [Member]
Depreciation, amortization and accretion
Amortization of Intangible Assets	0	0	0
Other Intangible Assets [Member] | Pepco Holdings LLC [Member]
Depreciation, amortization and accretion
Amortization of Intangible Assets	0	0	0
Other Intangible Assets [Member] | Potomac Electric Power Company [Member]
Depreciation, amortization and accretion
Amortization of Intangible Assets	0	0	0
Other Intangible Assets [Member] | Delmarva Power & Light Company [Member]
Depreciation, amortization and accretion
Amortization of Intangible Assets	0	0	0
Other Intangible Assets [Member] | Atlantic City Electric Company [Member]
Depreciation, amortization and accretion
Amortization of Intangible Assets	0	0	0
Unamortized Energy Contracts [Member]
Depreciation, amortization and accretion
Amortization of Power Contracts Emission Credits	3	31	30
Unamortized Energy Contracts [Member] | Commonwealth Edison Co [Member]
Depreciation, amortization and accretion
Amortization of Power Contracts Emission Credits	0	0	0
Unamortized Energy Contracts [Member] | PECO Energy Co [Member]
Depreciation, amortization and accretion
Amortization of Power Contracts Emission Credits	0	0	0
Unamortized Energy Contracts [Member] | Baltimore Gas and Electric Company [Member]
Depreciation, amortization and accretion
Amortization of Power Contracts Emission Credits	0	0	0
Unamortized Energy Contracts [Member] | Pepco Holdings LLC [Member]
Depreciation, amortization and accretion
Amortization of Power Contracts Emission Credits	0	0	0
Unamortized Energy Contracts [Member] | Potomac Electric Power Company [Member]
Depreciation, amortization and accretion
Amortization of Power Contracts Emission Credits	0	0	0
Unamortized Energy Contracts [Member] | Delmarva Power & Light Company [Member]
Depreciation, amortization and accretion
Amortization of Power Contracts Emission Credits	0	0	0
Unamortized Energy Contracts [Member] | Atlantic City Electric Company [Member]
Depreciation, amortization and accretion
Amortization of Power Contracts Emission Credits	$ 0	$ 0	$ 0