Retirement Benefits - Allocated Portion of Pension and Postretirement Benefit Plan Costs (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Defined Benefit Plan Disclosure [Line Items]
Pension and Other Postretirement Benefits Costs			$ 129	$ 136
Pension and other post retirement benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension and Other Postretirement Benefits Costs	$ 64	$ 68	129	136
Commonwealth Edison Co
Defined Benefit Plan Disclosure [Line Items]
Pension and Other Postretirement Benefits Costs			54	42
Commonwealth Edison Co \| Pension and other post retirement benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension and Other Postretirement Benefits Costs	27	21	54	42
PECO Energy Co
Defined Benefit Plan Disclosure [Line Items]
Pension and Other Postretirement Benefits Costs			8	3
PECO Energy Co \| Pension and other post retirement benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension and Other Postretirement Benefits Costs	4	1	8	3
Baltimore Gas and Electric Company
Defined Benefit Plan Disclosure [Line Items]
Pension and Other Postretirement Benefits Costs			14	30
Baltimore Gas and Electric Company \| Pension and other post retirement benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension and Other Postretirement Benefits Costs	7	14	14	30
Pepco Holdings LLC
Defined Benefit Plan Disclosure [Line Items]
Pension and Other Postretirement Benefits Costs			41	49
Pepco Holdings LLC \| Pension and other post retirement benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension and Other Postretirement Benefits Costs	21	24	41	49
Potomac Electric Power Company
Defined Benefit Plan Disclosure [Line Items]
Pension and Other Postretirement Benefits Costs			14	18
Potomac Electric Power Company \| Pension and other post retirement benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension and Other Postretirement Benefits Costs	7	10	14	18
Delmarva Power and Light Company
Defined Benefit Plan Disclosure [Line Items]
Pension and Other Postretirement Benefits Costs			7	8
Delmarva Power and Light Company \| Pension and other post retirement benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension and Other Postretirement Benefits Costs	3	4	7	8
Atlantic City Electric Company
Defined Benefit Plan Disclosure [Line Items]
Pension and Other Postretirement Benefits Costs			5	6
Atlantic City Electric Company \| Pension and other post retirement benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension and Other Postretirement Benefits Costs	$ 3	$ 3	$ 5	$ 6