Income Taxes - Reconciliation to Effective Tax Rate (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Effective Income Tax Rate Reconciliation, Percent [Abstract]
U.S. Federal statutory rate	21.00%	21.00%
Increase (decrease) due to:
State income taxes, net of Federal income tax benefit	6.00%	21.10%
Plant basis differences	(4.00%)	(3.60%)
Excess deferred tax amortization	(6.30%)	(11.50%)
Amortization of investment tax credit, including deferred taxes on basis difference	(0.10%)	(0.10%)
Effective Income Tax Rate Reconciliation, Tax Credit, Other, Percent	(0.50%)	1.70%
Other	0.60%	2.60%
Effective income tax rate	16.70%	31.20%
Income Tax Credits and Adjustments	$ 15
Total transaction costs relating to the Separation	19
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
Commonwealth Edison Co [Member]
Effective Income Tax Rate Reconciliation, Percent [Abstract]
U.S. Federal statutory rate	21.00%	21.00%
Increase (decrease) due to:
State income taxes, net of Federal income tax benefit	7.90%	8.00%
Plant basis differences	(0.30%)	(0.60%)
Excess deferred tax amortization	(5.70%)	(6.30%)
Amortization of investment tax credit, including deferred taxes on basis difference	(0.10%)	(0.10%)
Effective Income Tax Rate Reconciliation, Tax Credit, Other, Percent	(0.30%)	(0.30%)
Other	0.30%	0.00%
Effective income tax rate	22.80%	21.70%
PECO Energy Co [Member]
Effective Income Tax Rate Reconciliation, Percent [Abstract]
U.S. Federal statutory rate	21.00%	21.00%
Increase (decrease) due to:
State income taxes, net of Federal income tax benefit	(1.40%)	(0.10%)
Plant basis differences	(15.20%)	(11.30%)
Excess deferred tax amortization	(2.40%)	(3.20%)
Amortization of investment tax credit, including deferred taxes on basis difference	0.00%	0.00%
Effective Income Tax Rate Reconciliation, Tax Credit, Other, Percent	0.00%	0.00%
Other	0.40%	0.00%
Effective income tax rate	2.40%	6.40%
Baltimore Gas and Electric Company [Member]
Effective Income Tax Rate Reconciliation, Percent [Abstract]
U.S. Federal statutory rate	21.00%	21.00%
Increase (decrease) due to:
State income taxes, net of Federal income tax benefit	6.40%	2.40%
Plant basis differences	(0.70%)	(0.90%)
Excess deferred tax amortization	(5.40%)	(17.60%)
Amortization of investment tax credit, including deferred taxes on basis difference	(0.10%)	(0.10%)
Effective Income Tax Rate Reconciliation, Tax Credit, Other, Percent	(0.50%)	(0.40%)
Other	(0.10%)	(0.10%)
Effective income tax rate	20.60%	4.30%
Pepco Holdings LLC [Member]
Effective Income Tax Rate Reconciliation, Percent [Abstract]
U.S. Federal statutory rate	21.00%	21.00%
Increase (decrease) due to:
State income taxes, net of Federal income tax benefit	6.00%	3.70%
Plant basis differences	(1.80%)	(1.60%)
Excess deferred tax amortization	(7.00%)	(17.70%)
Amortization of investment tax credit, including deferred taxes on basis difference	(0.10%)	(0.10%)
Effective Income Tax Rate Reconciliation, Tax Credit, Other, Percent	(0.40%)	(0.40%)
Other	0.30%	0.20%
Effective income tax rate	18.00%	5.10%
Potomac Electric Power Company [Member]
Effective Income Tax Rate Reconciliation, Percent [Abstract]
U.S. Federal statutory rate	21.00%	21.00%
Increase (decrease) due to:
State income taxes, net of Federal income tax benefit	5.40%	(4.50%)
Plant basis differences	(2.50%)	(2.60%)
Excess deferred tax amortization	(8.40%)	(17.40%)
Amortization of investment tax credit, including deferred taxes on basis difference	0.00%	0.00%
Effective Income Tax Rate Reconciliation, Tax Credit, Other, Percent	(0.40%)	(0.40%)
Other	0.50%	(0.60%)
Effective income tax rate	15.60%	(4.50%)
Delmarva Power and Light Company [Member]
Effective Income Tax Rate Reconciliation, Percent [Abstract]
U.S. Federal statutory rate	21.00%	21.00%
Increase (decrease) due to:
State income taxes, net of Federal income tax benefit	6.30%	6.20%
Plant basis differences	(1.00%)	(0.70%)
Excess deferred tax amortization	(8.80%)	(19.40%)
Amortization of investment tax credit, including deferred taxes on basis difference	(0.10%)	(0.20%)
Effective Income Tax Rate Reconciliation, Tax Credit, Other, Percent	(0.40%)	(0.30%)
Other	(0.30%)	0.10%
Effective income tax rate	16.70%	6.70%
Atlantic City Electric Company [Member]
Effective Income Tax Rate Reconciliation, Percent [Abstract]
U.S. Federal statutory rate	21.00%	21.00%
Increase (decrease) due to:
State income taxes, net of Federal income tax benefit	6.90%	6.80%
Plant basis differences	(0.90%)	(1.30%)
Excess deferred tax amortization	(2.00%)	(22.20%)
Amortization of investment tax credit, including deferred taxes on basis difference	(0.10%)	(0.20%)
Effective Income Tax Rate Reconciliation, Tax Credit, Other, Percent	(0.30%)	(0.30%)
Other	0.40%	(0.10%)
Effective income tax rate	25.00%	3.70%