Supplemental Financial Information - Supplemental Cash Flow Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Depreciation, amortization and accretion
Depreciation	$ 2,778	$ 2,690	$ 5,384
Amortization of Regulatory Asset	720	718	594
Amortization of Intangible Assets	1	182	83
Amortization of Nuclear Fuel Lease		66	992
Accretion expense		44	514
Total depreciation, amortization and accretion	3,506	3,533	7,573
Cash paid (refunded) during the year:
Interest (net of amount capitalized)	1,616	1,434	1,505
Income taxes (net of refunds)	10	73	281
Other non-cash operating activities:
Pension and non-pension postretirement benefit costs	198	164	411
Provision for uncollectible accounts	125	173	160
Other decommissioning related-activity		36	(946)
Energy-related options		60	125
True-up Adjustments to Decoupling Mechanisms and Formula Rate	(696)	(161)	(171)
Restructuring Costs			(57)
Long-term incentive plan		42	137
Operating Leases, Income Statement, Depreciation Expense on Property Subject to or Held-for-lease	39	56	183
Change in environmental liabilities	37
Public Utilities, Allowance for Funds Used During Construction, Capitalized Cost of Equity	(151)	(150)	(136)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract]
Cash and cash equivalents	445	407	672	$ 432
Restricted cash	482	566	321	349
Restricted cash included in other long-term assets	174	117	44	53
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Disposal Group, Including Discontinued Operations			582	332
Total cash, cash equivalents and restricted cash	1,101	1,090	1,619	1,166
Other Non-Cash
Other non-cash operating activities:
True-up Adjustments to Decoupling Mechanisms and Formula Rate	(708)	(168)	(171)
Return on borrowed funds
Other non-cash operating activities:
Public Utilities, Allowance for Funds Used During Construction, Capitalized Cost of Equity	(151)	(150)	(136)
Commonwealth Edison Co
Depreciation, amortization and accretion
Depreciation	1,095	1,031	970
Amortization of Regulatory Asset	308	292	235
Amortization of Nuclear Fuel Lease		0	0
Accretion expense		0	0
Total depreciation, amortization and accretion	1,403	1,323	1,205
Cash paid (refunded) during the year:
Interest (net of amount capitalized)	441	396	372
Income taxes (net of refunds)	11	23	(72)
Other non-cash operating activities:
Pension and non-pension postretirement benefit costs	26	60	129
Provision for uncollectible accounts	4	46	47
Other decommissioning related-activity		0	0
Energy-related options		0	0
True-up Adjustments to Decoupling Mechanisms and Formula Rate	(556)	(267)	(42)
Restructuring Costs			2
Long-term incentive plan		0	0
Operating Leases, Income Statement, Depreciation Expense on Property Subject to or Held-for-lease	2	2	1
Change in environmental liabilities	0
Public Utilities, Allowance for Funds Used During Construction, Capitalized Cost of Equity	(33)	(35)	(34)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract]
Cash and cash equivalents	110	67	131	83
Restricted cash	402	327	210	279
Restricted cash included in other long-term assets	174	117	43	43
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Disposal Group, Including Discontinued Operations			0	0
Total cash, cash equivalents and restricted cash	686	511	384	405
Commonwealth Edison Co | Other Non-Cash
Other non-cash operating activities:
True-up Adjustments to Decoupling Mechanisms and Formula Rate	(556)	(267)	(42)
Commonwealth Edison Co | Return on borrowed funds
Other non-cash operating activities:
Public Utilities, Allowance for Funds Used During Construction, Capitalized Cost of Equity	(33)	(35)	(34)
PECO Energy Co
Depreciation, amortization and accretion
Depreciation	383	359	336
Amortization of Regulatory Asset	14	14	12
Amortization of Nuclear Fuel Lease		0	0
Accretion expense		0	0
Total depreciation, amortization and accretion	397	373	348
Cash paid (refunded) during the year:
Interest (net of amount capitalized)	200	166	152
Income taxes (net of refunds)	(24)	31	(4)
Other non-cash operating activities:
Pension and non-pension postretirement benefit costs	(14)	(9)	8
Provision for uncollectible accounts	45	45	39
Other decommissioning related-activity		0	0
Energy-related options		0	0
True-up Adjustments to Decoupling Mechanisms and Formula Rate	7	(2)	(26)
Restructuring Costs			0
Long-term incentive plan		0	0
Operating Leases, Income Statement, Depreciation Expense on Property Subject to or Held-for-lease	0	0	0
Change in environmental liabilities	0
Public Utilities, Allowance for Funds Used During Construction, Capitalized Cost of Equity	(31)	(31)	(26)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract]
Cash and cash equivalents	42	59	36	19
Restricted cash	9	9	8	7
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	51	68	44	26
PECO Energy Co | Other Non-Cash
Other non-cash operating activities:
True-up Adjustments to Decoupling Mechanisms and Formula Rate	7	(2)	(26)
PECO Energy Co | Return on borrowed funds
Other non-cash operating activities:
Public Utilities, Allowance for Funds Used During Construction, Capitalized Cost of Equity	(31)	(31)	(26)
Baltimore Gas and Electric Company
Depreciation, amortization and accretion
Depreciation	509	476	439
Amortization of Regulatory Asset	145	154	152
Amortization of Nuclear Fuel Lease		0	0
Accretion expense		0	0
Total depreciation, amortization and accretion	654	630	591
Cash paid (refunded) during the year:
Interest (net of amount capitalized)	171	147	134
Income taxes (net of refunds)	29	16	(38)
Other non-cash operating activities:
Pension and non-pension postretirement benefit costs	56	44	61
Provision for uncollectible accounts	16	25	17
Other decommissioning related-activity		0	0
Energy-related options		0	0
True-up Adjustments to Decoupling Mechanisms and Formula Rate	(84)	47	(12)
Restructuring Costs			0
Long-term incentive plan		0	0
Operating Leases, Income Statement, Depreciation Expense on Property Subject to or Held-for-lease	5	14	29
Change in environmental liabilities	0
Public Utilities, Allowance for Funds Used During Construction, Capitalized Cost of Equity	(16)	(21)	(27)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract]
Cash and cash equivalents	47	43	51	144
Restricted cash	1	24	4	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	48	67	55	145
Baltimore Gas and Electric Company | Other Non-Cash
Other non-cash operating activities:
True-up Adjustments to Decoupling Mechanisms and Formula Rate	(84)	47	(12)
Baltimore Gas and Electric Company | Return on borrowed funds
Other non-cash operating activities:
Public Utilities, Allowance for Funds Used During Construction, Capitalized Cost of Equity	(16)	(21)	(27)
Pepco Holdings LLC
Depreciation, amortization and accretion
Depreciation	737	680	627
Amortization of Regulatory Asset	253	258	194
Amortization of Intangible Assets	10	190	92
Amortization of Nuclear Fuel Lease		0	0
Accretion expense		0	0
Total depreciation, amortization and accretion	990	938	821
Cash paid (refunded) during the year:
Interest (net of amount capitalized)	301	274	255
Income taxes (net of refunds)	21	19	0
Other non-cash operating activities:
Pension and non-pension postretirement benefit costs	99	53	49
Provision for uncollectible accounts	60	58	24
Other decommissioning related-activity		0	0
Energy-related options		0	0
True-up Adjustments to Decoupling Mechanisms and Formula Rate	(64)	59	(91)
Restructuring Costs			1
Long-term incentive plan		0	0
Operating Leases, Income Statement, Depreciation Expense on Property Subject to or Held-for-lease	28	27	28
Change in environmental liabilities	37
Public Utilities, Allowance for Funds Used During Construction, Capitalized Cost of Equity	(71)	(63)	(49)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract]
Cash and cash equivalents	180	198	136	111
Restricted cash	24	175	77	39
Restricted cash included in other long-term assets	0	0	0	10
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Disposal Group, Including Discontinued Operations			0	0
Total cash, cash equivalents and restricted cash	204	373	213	160
Pepco Holdings LLC | Other Non-Cash
Other non-cash operating activities:
True-up Adjustments to Decoupling Mechanisms and Formula Rate	(77)	54	(91)
Pepco Holdings LLC | Return on borrowed funds
Other non-cash operating activities:
Public Utilities, Allowance for Funds Used During Construction, Capitalized Cost of Equity	(71)	(63)	(49)
Potomac Electric Power Company
Depreciation, amortization and accretion
Depreciation	311	288	274
Amortization of Regulatory Asset	130	129	129
Amortization of Nuclear Fuel Lease		0	0
Accretion expense		0	0
Total depreciation, amortization and accretion	441	417	403
Cash paid (refunded) during the year:
Interest (net of amount capitalized)	153	141	132
Income taxes (net of refunds)	6	28	12
Other non-cash operating activities:
Pension and non-pension postretirement benefit costs	34	9	6
Provision for uncollectible accounts	33	29	9
Other decommissioning related-activity		0	0
Energy-related options		0	0
True-up Adjustments to Decoupling Mechanisms and Formula Rate	(22)	31	(53)
Restructuring Costs			0
Long-term incentive plan		0	0
Operating Leases, Income Statement, Depreciation Expense on Property Subject to or Held-for-lease	6	7	6
Change in environmental liabilities	37
Public Utilities, Allowance for Funds Used During Construction, Capitalized Cost of Equity	(54)	(48)	(40)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract]
Cash and cash equivalents	48	45	34	30
Restricted cash	24	54	34	35
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	72	99	68	65
Potomac Electric Power Company | Other Non-Cash
Other non-cash operating activities:
True-up Adjustments to Decoupling Mechanisms and Formula Rate	(22)	31	(53)
Potomac Electric Power Company | Return on borrowed funds
Other non-cash operating activities:
Public Utilities, Allowance for Funds Used During Construction, Capitalized Cost of Equity	(54)	(48)	(40)
Delmarva Power & Light Company
Depreciation, amortization and accretion
Depreciation	208	191	169
Amortization of Regulatory Asset	36	41	41
Amortization of Nuclear Fuel Lease		0	0
Accretion expense		0	0
Total depreciation, amortization and accretion	244	232	210
Cash paid (refunded) during the year:
Interest (net of amount capitalized)	69	63	59
Income taxes (net of refunds)	6	(2)	(9)
Other non-cash operating activities:
Pension and non-pension postretirement benefit costs	18	3	2
Provision for uncollectible accounts	10	12	5
Other decommissioning related-activity		0	0
Energy-related options		0	0
True-up Adjustments to Decoupling Mechanisms and Formula Rate	(15)	9	(14)
Restructuring Costs			0
Long-term incentive plan		0	0
Operating Leases, Income Statement, Depreciation Expense on Property Subject to or Held-for-lease	8	8	8
Change in environmental liabilities	0
Public Utilities, Allowance for Funds Used During Construction, Capitalized Cost of Equity	(10)	(7)	(6)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract]
Cash and cash equivalents	16	31	28	15
Restricted cash	0	121	43	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	16	152	71	15
Delmarva Power & Light Company | Other Non-Cash
Other non-cash operating activities:
True-up Adjustments to Decoupling Mechanisms and Formula Rate	(21)	7	(14)
Delmarva Power & Light Company | Return on borrowed funds
Other non-cash operating activities:
Public Utilities, Allowance for Funds Used During Construction, Capitalized Cost of Equity	(10)	(7)	(6)
Atlantic City Electric Company
Depreciation, amortization and accretion
Depreciation	195	173	155
Amortization of Regulatory Asset	88	88	24
Amortization of Nuclear Fuel Lease		0	0
Accretion expense		0	0
Total depreciation, amortization and accretion	283	261	179
Cash paid (refunded) during the year:
Interest (net of amount capitalized)	68	60	56
Income taxes (net of refunds)	9	(6)	2
Other non-cash operating activities:
Pension and non-pension postretirement benefit costs	13	12	11
Provision for uncollectible accounts	17	16	10
Other decommissioning related-activity		0	0
Energy-related options		0	0
True-up Adjustments to Decoupling Mechanisms and Formula Rate	(27)	19	(24)
Restructuring Costs			0
Long-term incentive plan		0	0
Operating Leases, Income Statement, Depreciation Expense on Property Subject to or Held-for-lease	3	3	4
Change in environmental liabilities	0
Public Utilities, Allowance for Funds Used During Construction, Capitalized Cost of Equity	(7)	(8)	(3)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract]
Cash and cash equivalents	21	72	29	17
Restricted cash	0	0	0	3
Restricted cash included in other long-term assets	0	0	0	10
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Disposal Group, Including Discontinued Operations			0	0
Total cash, cash equivalents and restricted cash	21	72	29	$ 30
Atlantic City Electric Company | Other Non-Cash
Other non-cash operating activities:
True-up Adjustments to Decoupling Mechanisms and Formula Rate	(34)	16	(24)
Atlantic City Electric Company | Return on borrowed funds
Other non-cash operating activities:
Public Utilities, Allowance for Funds Used During Construction, Capitalized Cost of Equity	(7)	(8)	(3)
Other Intangible Assets
Depreciation, amortization and accretion
Amortization of Intangible Assets	8	12	58
Other Intangible Assets | Commonwealth Edison Co
Depreciation, amortization and accretion
Amortization of Intangible Assets	0	0	0
Other Intangible Assets | PECO Energy Co
Depreciation, amortization and accretion
Amortization of Intangible Assets	0	0	0
Other Intangible Assets | Baltimore Gas and Electric Company
Depreciation, amortization and accretion
Amortization of Intangible Assets	0	0	0
Other Intangible Assets | Pepco Holdings LLC
Depreciation, amortization and accretion
Amortization of Intangible Assets	0	0	0
Other Intangible Assets | Potomac Electric Power Company
Depreciation, amortization and accretion
Amortization of Intangible Assets	0	0	0
Other Intangible Assets | Delmarva Power & Light Company
Depreciation, amortization and accretion
Amortization of Intangible Assets	0	0	0
Other Intangible Assets | Atlantic City Electric Company
Depreciation, amortization and accretion
Amortization of Intangible Assets	$ 0	0	0
Unamortized Energy Contracts
Depreciation, amortization and accretion
Amortization of Power Contracts Emission Credits		3	31
Unamortized Energy Contracts | Commonwealth Edison Co
Depreciation, amortization and accretion
Amortization of Power Contracts Emission Credits		0	0
Unamortized Energy Contracts | PECO Energy Co
Depreciation, amortization and accretion
Amortization of Power Contracts Emission Credits		0	0
Unamortized Energy Contracts | Baltimore Gas and Electric Company
Depreciation, amortization and accretion
Amortization of Power Contracts Emission Credits		0	0
Unamortized Energy Contracts | Pepco Holdings LLC
Depreciation, amortization and accretion
Amortization of Power Contracts Emission Credits		0	0
Unamortized Energy Contracts | Potomac Electric Power Company
Depreciation, amortization and accretion
Amortization of Power Contracts Emission Credits		0	0
Unamortized Energy Contracts | Delmarva Power & Light Company
Depreciation, amortization and accretion
Amortization of Power Contracts Emission Credits		0	0
Unamortized Energy Contracts | Atlantic City Electric Company
Depreciation, amortization and accretion
Amortization of Power Contracts Emission Credits		$ 0	$ 0