Income Taxes - Reconciliation to Effective Tax Rate (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Effective Income Tax Rate Reconciliation, Percent [Abstract]
U.S. Federal statutory rate	21.00%	21.00%	21.00%	21.00%
Increase (decrease) due to:
State income taxes, net of Federal income tax benefit	6.50%	(5.40%)	6.20%	9.90%
Plant basis differences	(4.80%)	(3.30%)	(4.30%)	(3.50%)
Excess deferred tax amortization	(7.40%)	(10.50%)	(6.70%)	(11.00%)
Amortization of investment tax credit, including deferred taxes on basis difference	(0.10%)	(0.10%)	(0.10%)	(0.10%)
Effective Income Tax Rate Reconciliation, Tax Credit, Other, Percent	(0.50%)	(0.40%)	(0.50%)	0.80%
Other	2.80%	7.70%	1.30%	4.70%
Effective income tax rate	17.50%	9.00%	16.90%	21.80%
Income Tax Credits and Adjustments			$ 15
Total transaction costs relating to the Separation			19
Current State and Local Tax Expense (Benefit)			43
Effective Income Tax Rate Reconciliation, Other Adjustments, Amount			48
Federal and State
Increase (decrease) due to:
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount			67
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount			40
UNITED STATES
Increase (decrease) due to:
Effective Income Tax Rate Reconciliation, Other Adjustments, Amount	$ 5
Indemnification Agreement
Increase (decrease) due to:
Effective Income Tax Rate Reconciliation, Other Adjustments, Amount			$ 4
Commonwealth Edison Co [Member]
Effective Income Tax Rate Reconciliation, Percent [Abstract]
U.S. Federal statutory rate	21.00%	21.00%	21.00%	21.00%
Increase (decrease) due to:
State income taxes, net of Federal income tax benefit	7.80%	7.90%	7.80%	7.90%
Plant basis differences	(0.60%)	(0.50%)	(0.40%)	(0.50%)
Excess deferred tax amortization	(5.60%)	(5.50%)	(5.60%)	(5.80%)
Amortization of investment tax credit, including deferred taxes on basis difference	(0.10%)	(0.10%)	(0.10%)	(0.10%)
Effective Income Tax Rate Reconciliation, Tax Credit, Other, Percent	(0.30%)	(0.30%)	(0.30%)	(0.30%)
Other	0.00%	0.00%	0.10%	0.10%
Effective income tax rate	22.20%	22.50%	22.50%	22.30%
PECO Energy Co [Member]
Effective Income Tax Rate Reconciliation, Percent [Abstract]
U.S. Federal statutory rate	21.00%	21.00%	21.00%	21.00%
Increase (decrease) due to:
State income taxes, net of Federal income tax benefit	(1.20%)	(0.60%)	(1.30%)	(0.30%)
Plant basis differences	(15.80%)	(11.00%)	(15.40%)	(11.20%)
Excess deferred tax amortization	(2.40%)	(3.10%)	(2.40%)	(3.20%)
Amortization of investment tax credit, including deferred taxes on basis difference	0.00%	0.00%	0.00%	0.00%
Effective Income Tax Rate Reconciliation, Tax Credit, Other, Percent	0.00%	0.00%	0.00%	0.00%
Other	0.40%	0.00%	0.00%	0.30%
Effective income tax rate	2.00%	6.30%	1.90%	6.60%
Baltimore Gas and Electric Company [Member]
Effective Income Tax Rate Reconciliation, Percent [Abstract]
U.S. Federal statutory rate	21.00%	21.00%	21.00%	21.00%
Increase (decrease) due to:
State income taxes, net of Federal income tax benefit	6.80%	2.10%	6.40%	2.30%
Plant basis differences	0.10%	(1.30%)	(0.60%)	(1.00%)
Excess deferred tax amortization	(5.30%)	(19.00%)	(5.40%)	(17.80%)
Amortization of investment tax credit, including deferred taxes on basis difference	(0.10%)	(0.10%)	(0.10%)	(0.10%)
Effective Income Tax Rate Reconciliation, Tax Credit, Other, Percent	(0.40%)	(1.50%)	(0.40%)	(0.60%)
Other	0.10%	1.40%	0.30%	0.30%
Effective income tax rate	22.20%	2.60%	21.20%	4.10%
Pepco Holdings LLC [Member]
Effective Income Tax Rate Reconciliation, Percent [Abstract]
U.S. Federal statutory rate	21.00%	21.00%	21.00%	21.00%
Increase (decrease) due to:
State income taxes, net of Federal income tax benefit	6.20%	1.50%	6.10%	2.80%
Plant basis differences	(1.60%)	(1.70%)	(1.70%)	(1.70%)
Excess deferred tax amortization	(8.00%)	(19.20%)	(7.40%)	(18.30%)
Amortization of investment tax credit, including deferred taxes on basis difference	(0.10%)	(0.10%)	(0.10%)	(0.10%)
Effective Income Tax Rate Reconciliation, Tax Credit, Other, Percent	(0.90%)	(0.40%)	(0.60%)	(0.40%)
Other	(0.30%)	(0.10%)	0.00%	0.10%
Effective income tax rate	16.30%	1.00%	17.30%	3.40%
Potomac Electric Power Company [Member]
Effective Income Tax Rate Reconciliation, Percent [Abstract]
U.S. Federal statutory rate	21.00%	21.00%	21.00%	21.00%
Increase (decrease) due to:
State income taxes, net of Federal income tax benefit	5.60%	(3.40%)	5.50%	(3.80%)
Plant basis differences	(2.60%)	(2.40%)	(2.60%)	(2.50%)
Excess deferred tax amortization	(9.90%)	(15.70%)	(9.10%)	(16.30%)
Amortization of investment tax credit, including deferred taxes on basis difference	0.00%	0.00%	0.00%	0.00%
Effective Income Tax Rate Reconciliation, Tax Credit, Other, Percent	(1.10%)	(0.40%)	(0.80%)	(0.40%)
Other	0.50%	(0.50%)	0.50%	(0.70%)
Effective income tax rate	13.50%	(1.40%)	14.50%	(2.70%)
Delmarva Power and Light Company [Member]
Effective Income Tax Rate Reconciliation, Percent [Abstract]
U.S. Federal statutory rate	21.00%	21.00%	21.00%	21.00%
Increase (decrease) due to:
State income taxes, net of Federal income tax benefit	6.30%	7.20%	6.30%	6.50%
Plant basis differences	(1.10%)	(0.70%)	(1.00%)	(0.70%)
Excess deferred tax amortization	(9.90%)	(20.00%)	(9.20%)	(19.50%)
Amortization of investment tax credit, including deferred taxes on basis difference	(0.10%)	(0.20%)	(0.10%)	(0.20%)
Effective Income Tax Rate Reconciliation, Tax Credit, Other, Percent	(0.40%)	(0.40%)	(0.40%)	(0.30%)
Other	0.90%	1.80%	0.10%	0.40%
Effective income tax rate	16.70%	8.70%	16.70%	7.20%
Atlantic City Electric Company [Member]
Effective Income Tax Rate Reconciliation, Percent [Abstract]
U.S. Federal statutory rate	21.00%	21.00%	21.00%	21.00%
Increase (decrease) due to:
State income taxes, net of Federal income tax benefit	7.10%	6.70%	6.90%	6.70%
Plant basis differences	0.00%	(1.00%)	(0.60%)	(1.20%)
Excess deferred tax amortization	(2.00%)	(24.50%)	(2.00%)	(22.90%)
Amortization of investment tax credit, including deferred taxes on basis difference	(0.10%)	(0.20%)	(0.10%)	(0.20%)
Effective Income Tax Rate Reconciliation, Tax Credit, Other, Percent	(0.30%)	(0.40%)	(0.30%)	(0.30%)
Other	(0.70%)	(1.60%)	0.10%	(0.50%)
Effective income tax rate	25.00%	0.00%	25.00%	2.60%