Income Taxes - Reconciliation to Effective Tax Rate (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate [Line Items]
U.S. Federal statutory rate	21.00%	21.00%	21.00%
State income taxes, net of Federal income tax benefit	8.80%	5.00%	11.90%
Plant basis differences	(4.10%)	(5.40%)	(8.60%)
Excess deferred tax amortization	(11.80%)	(17.20%)	(29.10%)
Amortization of investment tax credit, including deferred taxes on basis difference	(0.10%)	(0.10%)	(0.30%)
Production tax credits and other credits	0.10%	(0.70%)	(0.50%)
Effective Income Tax Rate Reconciliation, Deferred Prosecution Agreement payments			3.80%
Other	0.60%	(0.30%)	1.20%
Effective income tax rate	14.50%	2.30%	(0.60%)
Effective Income Tax Rate Reconciliation, Other Adjustments, Amount	$ 9
Income Tax Credits and Adjustments	15
Federal and State
Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate [Line Items]
Effective Income Tax Rate Reconciliation, Other Adjustments, Amount	11
Current State and Local Tax Expense (Benefit)	43
Income Tax Credits and Adjustments	$ 17
Commonwealth Edison Co [Member]
Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate [Line Items]
U.S. Federal statutory rate	21.00%	21.00%	21.00%
State income taxes, net of Federal income tax benefit	8.00%	7.80%	11.60%
Plant basis differences	(0.60%)	(0.80%)	(0.60%)
Excess deferred tax amortization	(5.60%)	(7.60%)	(11.20%)
Amortization of investment tax credit, including deferred taxes on basis difference	(0.10%)	(0.10%)	(0.30%)
Production tax credits and other credits	(0.30%)	(0.50%)	(0.30%)
Effective Income Tax Rate Reconciliation, Deferred Prosecution Agreement payments			6.80%
Other	0.00%	(1.00%)	1.80%
Effective income tax rate	22.40%	18.80%	28.80%
PECO Energy Co [Member]
Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate [Line Items]
U.S. Federal statutory rate	21.00%	21.00%	21.00%
State income taxes, net of Federal income tax benefit	5.80%	(1.40%)	(4.50%)
Plant basis differences	(11.90%)	(13.60%)	(18.70%)
Excess deferred tax amortization	(3.00%)	(3.80%)	(4.60%)
Amortization of investment tax credit, including deferred taxes on basis difference	0.00%	0.00%	0.00%
Production tax credits and other credits	0.00%	0.00%	0.00%
Effective Income Tax Rate Reconciliation, Deferred Prosecution Agreement payments			0.00%
Other	0.20%	0.10%	(0.40%)
Effective income tax rate	12.10%	2.30%	(7.20%)
Baltimore Gas and Electric Company [Member]
Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate [Line Items]
U.S. Federal statutory rate	21.00%	21.00%	21.00%
State income taxes, net of Federal income tax benefit	2.60%	(10.80%)	5.50%
Plant basis differences	(1.00%)	(1.70%)	(1.50%)
Excess deferred tax amortization	(19.80%)	(16.30%)	(13.90%)
Amortization of investment tax credit, including deferred taxes on basis difference	(0.10%)	(0.10%)	(0.10%)
Production tax credits and other credits	(0.70%)	(0.90%)	(0.40%)
Effective Income Tax Rate Reconciliation, Deferred Prosecution Agreement payments			0.00%
Other	0.10%	(0.60%)	(0.10%)
Effective income tax rate	2.10%	(9.40%)	10.50%
Pepco Holdings LLC [Member]
Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate [Line Items]
U.S. Federal statutory rate	21.00%	21.00%	21.00%
State income taxes, net of Federal income tax benefit	2.10%	10.10%	5.10%
Plant basis differences	(1.70%)	(1.10%)	(1.60%)
Excess deferred tax amortization	(19.50%)	(22.40%)	(42.00%)
Amortization of investment tax credit, including deferred taxes on basis difference	(0.10%)	(0.10%)	(0.20%)
Production tax credits and other credits	(0.70%)	(0.50%)	(0.30%)
Effective Income Tax Rate Reconciliation, Deferred Prosecution Agreement payments			0.00%
Other	0.40%	0.00%	(0.40%)
Effective income tax rate	1.50%	7.00%	(18.40%)
Potomac Electric Power Company [Member]
Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate [Line Items]
U.S. Federal statutory rate	21.00%	21.00%	21.00%
State income taxes, net of Federal income tax benefit	(4.10%)	2.70%	4.50%
Plant basis differences	(2.70%)	(1.60%)	(1.70%)
Excess deferred tax amortization	(16.80%)	(16.40%)	(25.40%)
Amortization of investment tax credit, including deferred taxes on basis difference	0.00%	0.00%	(0.10%)
Production tax credits and other credits	(0.70%)	(0.50%)	(0.30%)
Effective Income Tax Rate Reconciliation, Deferred Prosecution Agreement payments			0.00%
Other	0.30%	(0.40%)	(0.70%)
Effective income tax rate	(3.00%)	4.80%	(2.70%)
Delmarva Power & Light Company [Member]
Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate [Line Items]
U.S. Federal statutory rate	21.00%	21.00%	21.00%
State income taxes, net of Federal income tax benefit	6.50%	25.00%	6.60%
Plant basis differences	(0.70%)	(0.80%)	(0.40%)
Excess deferred tax amortization	(18.40%)	(20.00%)	(51.70%)
Amortization of investment tax credit, including deferred taxes on basis difference	(0.20%)	(0.20%)	(0.30%)
Production tax credits and other credits	(0.60%)	(0.40%)	(0.30%)
Effective Income Tax Rate Reconciliation, Deferred Prosecution Agreement payments			0.00%
Other	0.10%	0.10%	0.10%
Effective income tax rate	7.70%	24.70%	(25.00%)
Atlantic City Electric Company [Member]
Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate [Line Items]
U.S. Federal statutory rate	21.00%	21.00%	21.00%
State income taxes, net of Federal income tax benefit	6.90%	7.40%	7.00%
Plant basis differences	(0.70%)	(0.20%)	(3.00%)
Excess deferred tax amortization	(24.50%)	(37.10%)	(82.10%)
Amortization of investment tax credit, including deferred taxes on basis difference	(0.20%)	(0.20%)	(0.50%)
Production tax credits and other credits	(0.50%)	(0.50%)	(0.50%)
Effective Income Tax Rate Reconciliation, Deferred Prosecution Agreement payments			0.00%
Other	0.00%	(0.20%)	0.40%
Effective income tax rate	2.00%	(9.80%)	(57.70%)
Delmarva Power & Light Co
Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate [Line Items]
Operating Loss Carryforwards, Valuation Allowance	$ 31