Income Taxes - Reconciliation to Effective Tax Rate (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
	Jan. 01, 2023	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
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		9.00%	7.10%	9.50%	3.80%
Plant basis differences		(5.30%)	(4.70%)	(4.20%)	(4.00%)
Excess deferred tax amortization		(11.60%)	(15.50%)	(11.30%)	(13.50%)
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		(0.60%)	(0.60%)	0.30%	(0.60%)
Other		(0.40%)	(0.10%)	2.80%	(1.10%)
Effective income tax rate		12.00%	7.10%	18.00%	5.50%
Increase (Decrease) in Income Taxes	$ 200
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount				$ 67
Income Tax Credits and Adjustments				15
Total transaction costs relating to the Separation				19
Effective Income Tax Rate Reconciliation, Other Adjustments, Amount				40
PENNSYLVANIA
Increase (decrease) due to:
Increase (Decrease) in Income Taxes				38
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
Income Tax Credits and Adjustments				17
Current State and Local Tax Expense (Benefit)				43
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		8.00%	8.00%	7.90%	7.60%
Plant basis differences		(0.40%)	(0.80%)	(0.50%)	(0.70%)
Excess deferred tax amortization		(5.60%)	(7.60%)	(5.70%)	(7.20%)
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%)	(0.50%)	(0.30%)	(0.50%)
Other		(0.10%)	0.30%	0.00%	(1.30%)
Effective income tax rate		22.40%	20.30%	22.30%	18.80%
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		20.70%	(4.10%)	6.60%	(2.60%)
Plant basis differences		(14.20%)	(16.20%)	(12.20%)	(12.60%)
Excess deferred tax amortization		(3.20%)	(3.40%)	(3.20%)	(3.30%)
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		0.00%	0.00%	0.00%	0.00%
Other		0.30%	(0.10%)	0.20%	(0.20%)
Effective income tax rate		24.60%	(2.80%)	12.40%	2.30%
PECO Energy Co [Member] | PENNSYLVANIA
Increase (decrease) due to:
Increase (Decrease) in Income Taxes				$ 38
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%	(13.00%)	2.80%	(10.80%)
Plant basis differences		(2.60%)	(1.40%)	(1.10%)	(1.50%)
Excess deferred tax amortization		(47.30%)	(17.30%)	(20.70%)	(16.00%)
Amortization of investment tax credit, including deferred taxes on basis difference		(0.20%)	(0.10%)	(0.10%)	(0.10%)
Effective Income Tax Rate Reconciliation, Tax Credit, Other, Percent		(1.90%)	(0.90%)	(0.70%)	(0.90%)
Other		(2.70%)	(0.80%)	(0.10%)	(0.70%)
Effective income tax rate		(26.90%)	(12.50%)	1.10%	(9.00%)
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		1.40%	5.00%	2.00%	4.60%
Plant basis differences		(1.70%)	(1.30%)	(1.70%)	(1.30%)
Excess deferred tax amortization		(19.30%)	(24.90%)	(18.80%)	(22.80%)
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		(0.90%)	(0.50%)	(0.70%)	(0.50%)
Other		0.30%	0.00%	0.20%	(0.30%)
Effective income tax rate		0.70%	(0.80%)	1.90%	0.60%
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		(2.70%)	3.40%	(3.20%)	2.50%
Plant basis differences		(2.30%)	(2.00%)	(2.40%)	(1.90%)
Excess deferred tax amortization		(14.60%)	(17.60%)	(15.40%)	(17.40%)
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		(0.80%)	(0.50%)	(0.60%)	(0.50%)
Other		0.10%	0.10%	(0.20%)	(0.40%)
Effective income tax rate		0.70%	4.40%	(0.80%)	3.30%
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		6.50%	6.40%	6.50%	6.50%
Plant basis differences		(0.80%)	(0.60%)	(0.70%)	(0.70%)
Excess deferred tax amortization		(21.70%)	(19.90%)	(20.40%)	(19.70%)
Amortization of investment tax credit, including deferred taxes on basis difference		(0.20%)	(0.20%)	(0.20%)	(0.20%)
Effective Income Tax Rate Reconciliation, Tax Credit, Other, Percent		(1.30%)	(0.40%)	(0.70%)	(0.40%)
Other		0.20%	(0.60%)	0.30%	(0.20%)
Effective income tax rate		3.70%	5.70%	5.80%	6.30%
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		7.00%	7.00%	6.90%	7.30%
Plant basis differences		(1.00%)	(0.60%)	(1.10%)	(0.60%)
Excess deferred tax amortization		(25.50%)	(41.40%)	(24.70%)	(36.30%)
Amortization of investment tax credit, including deferred taxes on basis difference		(0.20%)	(0.20%)	(0.20%)	(0.20%)
Effective Income Tax Rate Reconciliation, Tax Credit, Other, Percent		(0.70%)	(0.50%)	(0.60%)	(0.50%)
Other		0.50%	0.80%	0.20%	0.00%
Effective income tax rate		1.10%	(13.90%)	1.50%	(9.30%)