Income Taxes - Reconciliation to Effective Tax Rate (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Income Tax Expense (Benefit), Effective Income Tax Rate Reconciliation, Amount [Abstract]
Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount	$ 104	$ 96	$ 339	$ 323
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount	31	28	95	85
Effective Income Tax Rate Reconciliation, Tax Credit, Amount	(2)	(2)	(5)	(7)
Unrecognized Tax Benefits, Period Increase (Decrease)	0		(17)
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Amount	5	1	16	5
Effective Income Tax Rate Reconciliation, Plant Flow Through	(22)	(24)	(75)	(66)
Effective Income Tax Rate Reconciliation, Amortization Of Excess Deferred Taxes, Amount	(17)	(29)	(52)	(99)
Effective Income Tax Rate Reconciliation, Tax Credit, Investment, Amount	0	0	(1)	(1)
Income taxes	$ 99	$ 70	$ 300	$ 240
Effective Income Tax Rate Reconciliation, Percent [Abstract]
U.S. Federal statutory rate	21.00%	21.00%	21.00%	21.00%
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent	6.30%	6.10%	5.90%	5.50%
Effective Income Tax Rate Reconciliation, Tax Credit, Percent	(0.40%)	(0.40%)	(0.30%)	(0.50%)
Change in Unrecognized Tax Benefits, Percent	0.00%		(1.10%)
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Percent	0.90%	0.20%	1.00%	0.40%
Effective Income Tax Rate Reconciliation, Plant Flow Through, Percent	(4.40%)	(5.20%)	(4.60%)	(4.30%)
Effective Income Tax Rate Reconciliation, Amortization Of Excess Deferred Taxes, Percent	(3.40%)	(6.40%)	(3.20%)	(6.40%)
Effective Income Tax Rate Reconciliation, Tax Credit, Investment, Percent	0.00%	(0.10%)	(0.10%)	(0.10%)
Effective Income Tax Rate Reconciliation, Percent	20.00%	15.20%	18.60%	15.60%
Commonwealth Edison Co
Income Tax Expense (Benefit), Effective Income Tax Rate Reconciliation, Amount [Abstract]
Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount	$ 70	$ 59	$ 156	$ 136
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount	25	21	55	49
Effective Income Tax Rate Reconciliation, Tax Credit, Amount	(2)	(2)	(3)	(4)
Unrecognized Tax Benefits, Period Increase (Decrease)	0		(2)
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Amount	0	(1)	1	0
Effective Income Tax Rate Reconciliation, Plant Flow Through	(4)	(2)	(9)	(6)
Effective Income Tax Rate Reconciliation, Amortization Of Excess Deferred Taxes, Amount	(6)	(23)	(14)	(58)
Effective Income Tax Rate Reconciliation, Tax Credit, Investment, Amount	0	0	0	0
Income taxes	$ 83	$ 52	$ 184	$ 117
Effective Income Tax Rate Reconciliation, Percent [Abstract]
U.S. Federal statutory rate	21.00%	21.00%	21.00%	21.00%
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent	7.50%	7.60%	7.40%	7.60%
Effective Income Tax Rate Reconciliation, Tax Credit, Percent	(0.60%)	(0.70%)	(0.40%)	(0.60%)
Change in Unrecognized Tax Benefits, Percent	0.00%		(0.30%)
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Percent	0.00%	(0.40%)	0.20%	0.00%
Effective Income Tax Rate Reconciliation, Plant Flow Through, Percent	(1.20%)	(0.70%)	(1.20%)	(0.90%)
Effective Income Tax Rate Reconciliation, Amortization Of Excess Deferred Taxes, Percent	(1.70%)	(8.20%)	(1.90%)	(9.00%)
Effective Income Tax Rate Reconciliation, Tax Credit, Investment, Percent	0.00%	0.00%	0.00%	0.00%
Effective Income Tax Rate Reconciliation, Percent	25.00%	18.60%	24.80%	18.10%
PECO Energy Co
Income Tax Expense (Benefit), Effective Income Tax Rate Reconciliation, Amount [Abstract]
Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount	$ 26	$ 29	$ 88	$ 88
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount	(1)	(2)	(4)	(12)
Effective Income Tax Rate Reconciliation, Tax Credit, Amount	0	0	0	0
Unrecognized Tax Benefits, Period Increase (Decrease)	0		0
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Amount	1	1	1	1
Effective Income Tax Rate Reconciliation, Plant Flow Through	(16)	(22)	(55)	(54)
Effective Income Tax Rate Reconciliation, Amortization Of Excess Deferred Taxes, Amount	(2)	(2)	(7)	(6)
Effective Income Tax Rate Reconciliation, Tax Credit, Investment, Amount	0	0	0	0
Income taxes	$ 8	$ 4	$ 23	$ 17
Effective Income Tax Rate Reconciliation, Percent [Abstract]
U.S. Federal statutory rate	21.00%	21.00%	21.00%	21.00%
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent	(0.80%)	(1.40%)	(1.00%)	(2.90%)
Effective Income Tax Rate Reconciliation, Tax Credit, Percent	0.00%	0.00%	0.00%	0.00%
Change in Unrecognized Tax Benefits, Percent	0.00%		0.00%
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Percent	0.30%	0.70%	0.30%	0.30%
Effective Income Tax Rate Reconciliation, Plant Flow Through, Percent	(12.60%)	(16.00%)	(13.10%)	(12.90%)
Effective Income Tax Rate Reconciliation, Amortization Of Excess Deferred Taxes, Percent	(1.60%)	(1.40%)	(1.70%)	(1.40%)
Effective Income Tax Rate Reconciliation, Tax Credit, Investment, Percent	0.00%	0.00%	0.00%	0.00%
Effective Income Tax Rate Reconciliation, Percent	6.30%	2.90%	5.50%	4.10%
Baltimore Gas and Electric Company
Income Tax Expense (Benefit), Effective Income Tax Rate Reconciliation, Amount [Abstract]
Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount	$ 15	$ 15	$ 94	$ 84
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount	4	4	27	25
Effective Income Tax Rate Reconciliation, Tax Credit, Amount	0	(1)	(1)	(2)
Unrecognized Tax Benefits, Period Increase (Decrease)	0		(1)
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Amount	1	0	1	0
Effective Income Tax Rate Reconciliation, Plant Flow Through	0	(1)	(8)	(6)
Effective Income Tax Rate Reconciliation, Amortization Of Excess Deferred Taxes, Amount	(3)	(2)	(16)	(16)
Effective Income Tax Rate Reconciliation, Tax Credit, Investment, Amount	0	0	0	0
Income taxes	$ 17	$ 15	$ 96	$ 85
Effective Income Tax Rate Reconciliation, Percent [Abstract]
U.S. Federal statutory rate	21.00%	21.00%	21.00%	21.00%
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent	5.60%	5.90%	6.00%	6.30%
Effective Income Tax Rate Reconciliation, Tax Credit, Percent	0.00%	(1.40%)	(0.20%)	(0.50%)
Change in Unrecognized Tax Benefits, Percent	0.00%		(0.20%)
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Percent	1.20%	0.00%	0.20%	0.00%
Effective Income Tax Rate Reconciliation, Plant Flow Through, Percent	0.00%	(1.40%)	(1.80%)	(1.50%)
Effective Income Tax Rate Reconciliation, Amortization Of Excess Deferred Taxes, Percent	(4.20%)	(2.70%)	(3.60%)	(4.00%)
Effective Income Tax Rate Reconciliation, Tax Credit, Investment, Percent	0.00%	0.00%	0.00%	0.00%
Effective Income Tax Rate Reconciliation, Percent	23.60%	21.40%	21.40%	21.30%
Pepco Holdings LLC
Income Tax Expense (Benefit), Effective Income Tax Rate Reconciliation, Amount [Abstract]
Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount	$ 30	$ 39	$ 75	$ 92
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount	9	13	23	29
Effective Income Tax Rate Reconciliation, Tax Credit, Amount	0	(1)	(1)	(2)
Unrecognized Tax Benefits, Period Increase (Decrease)	0		0
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Amount	1	0	1	1
Effective Income Tax Rate Reconciliation, Plant Flow Through	(1)	(1)	(3)	(3)
Effective Income Tax Rate Reconciliation, Amortization Of Excess Deferred Taxes, Amount	(7)	(8)	(16)	(18)
Effective Income Tax Rate Reconciliation, Tax Credit, Investment, Amount	0	0	0	0
Income taxes	$ 32	$ 42	$ 79	$ 99
Effective Income Tax Rate Reconciliation, Percent [Abstract]
U.S. Federal statutory rate	21.00%	21.00%	21.00%	21.00%
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent	6.40%	7.00%	6.40%	6.70%
Effective Income Tax Rate Reconciliation, Tax Credit, Percent	0.00%	(0.50%)	(0.30%)	(0.50%)
Change in Unrecognized Tax Benefits, Percent	0.00%		0.00%
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Percent	1.00%	0.00%	0.30%	0.30%
Effective Income Tax Rate Reconciliation, Plant Flow Through, Percent	(0.70%)	(0.50%)	(0.80%)	(0.70%)
Effective Income Tax Rate Reconciliation, Amortization Of Excess Deferred Taxes, Percent	(5.00%)	(4.30%)	(4.50%)	(4.10%)
Effective Income Tax Rate Reconciliation, Tax Credit, Investment, Percent	0.00%	0.00%	0.00%	0.00%
Effective Income Tax Rate Reconciliation, Percent	22.70%	22.70%	22.10%	22.70%
Potomac Electric Power Company
Income Tax Expense (Benefit), Effective Income Tax Rate Reconciliation, Amount [Abstract]
Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount	$ 17	$ 22	$ 35	$ 48
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount	5	6	10	14
Effective Income Tax Rate Reconciliation, Tax Credit, Amount	0	0	0	(1)
Unrecognized Tax Benefits, Period Increase (Decrease)	0		0
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Amount	0	0	0	1
Effective Income Tax Rate Reconciliation, Plant Flow Through	(1)	(1)	(2)	(2)
Effective Income Tax Rate Reconciliation, Amortization Of Excess Deferred Taxes, Amount	(4)	(5)	(10)	(12)
Effective Income Tax Rate Reconciliation, Tax Credit, Investment, Amount	0	0	0	0
Income taxes	$ 17	$ 22	$ 33	$ 48
Effective Income Tax Rate Reconciliation, Percent [Abstract]
U.S. Federal statutory rate	21.00%	21.00%	21.00%	21.00%
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent	6.10%	5.70%	6.00%	6.10%
Effective Income Tax Rate Reconciliation, Tax Credit, Percent	0.00%	0.00%	0.00%	(0.40%)
Change in Unrecognized Tax Benefits, Percent	0.00%		0.00%
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Percent	0.00%	0.00%	0.00%	0.40%
Effective Income Tax Rate Reconciliation, Plant Flow Through, Percent	(1.20%)	(0.90%)	(1.20%)	(0.90%)
Effective Income Tax Rate Reconciliation, Amortization Of Excess Deferred Taxes, Percent	(5.20%)	(5.00%)	(5.90%)	(5.20%)
Effective Income Tax Rate Reconciliation, Tax Credit, Investment, Percent	0.00%	0.00%	0.00%	0.00%
Effective Income Tax Rate Reconciliation, Percent	20.70%	20.80%	19.90%	21.00%
Delmarva Power and Light Company
Income Tax Expense (Benefit), Effective Income Tax Rate Reconciliation, Amount [Abstract]
Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount	$ 7	$ 10	$ 28	$ 29
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount	3	3	9	9
Effective Income Tax Rate Reconciliation, Tax Credit, Amount	0	0	0	0
Unrecognized Tax Benefits, Period Increase (Decrease)	0		0
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Amount	0	0	0	0
Effective Income Tax Rate Reconciliation, Plant Flow Through	0	0	(1)	(1)
Effective Income Tax Rate Reconciliation, Amortization Of Excess Deferred Taxes, Amount	(2)	(2)	(5)	(5)
Effective Income Tax Rate Reconciliation, Tax Credit, Investment, Amount	0	0	0	0
Income taxes	$ 8	$ 11	$ 31	$ 32
Effective Income Tax Rate Reconciliation, Percent [Abstract]
U.S. Federal statutory rate	21.00%	21.00%	21.00%	21.00%
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent	8.80%	5.00%	6.70%	6.30%
Effective Income Tax Rate Reconciliation, Tax Credit, Percent	0.00%	0.00%	0.00%	0.00%
Change in Unrecognized Tax Benefits, Percent	0.00%		0.00%
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Percent	0.00%	0.00%	0.00%	0.00%
Effective Income Tax Rate Reconciliation, Plant Flow Through, Percent	0.00%	0.00%	(0.80%)	(0.70%)
Effective Income Tax Rate Reconciliation, Amortization Of Excess Deferred Taxes, Percent	(6.30%)	(4.00%)	(3.80%)	(3.70%)
Effective Income Tax Rate Reconciliation, Tax Credit, Investment, Percent	0.00%	0.00%	0.00%	0.00%
Effective Income Tax Rate Reconciliation, Percent	23.50%	22.00%	23.10%	22.90%
Atlantic City Electric Company
Income Tax Expense (Benefit), Effective Income Tax Rate Reconciliation, Amount [Abstract]
Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount	$ 6	$ 7	$ 14	$ 16
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount	2	2	5	5
Effective Income Tax Rate Reconciliation, Tax Credit, Amount	0	0	0	0
Unrecognized Tax Benefits, Period Increase (Decrease)	0		0
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Amount	0	0	0	0
Effective Income Tax Rate Reconciliation, Plant Flow Through	0	0	0	0
Effective Income Tax Rate Reconciliation, Amortization Of Excess Deferred Taxes, Amount	0	0	(2)	(1)
Effective Income Tax Rate Reconciliation, Tax Credit, Investment, Amount	0	0	0	0
Income taxes	$ 8	$ 9	$ 17	$ 20
Effective Income Tax Rate Reconciliation, Percent [Abstract]
U.S. Federal statutory rate	21.00%	21.00%	21.00%	21.00%
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent	5.70%	6.30%	7.60%	6.60%
Effective Income Tax Rate Reconciliation, Tax Credit, Percent	0.00%	0.00%	0.00%	0.00%
Change in Unrecognized Tax Benefits, Percent	0.00%		0.00%
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Percent	0.00%	0.00%	0.00%	0.00%
Effective Income Tax Rate Reconciliation, Plant Flow Through, Percent	0.00%	0.00%	0.00%	0.00%
Effective Income Tax Rate Reconciliation, Amortization Of Excess Deferred Taxes, Percent	0.00%	0.00%	(2.80%)	(1.30%)
Effective Income Tax Rate Reconciliation, Tax Credit, Investment, Percent	0.00%	0.00%	0.00%	0.00%
Effective Income Tax Rate Reconciliation, Percent	26.70%	27.30%	25.80%	26.30%

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Effective Income Tax Rate Reconciliation, Plant Flow Through, Amount

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Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to nondeductible expenses.

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