Retirement Benefits - Allocated Portion of Pension and Postretirement Benefit Plan Costs (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Defined Benefit Plan Disclosure [Line Items]
Pension and Other Postretirement Benefits Costs			$ 136	$ 120
Pension and other post retirement benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension and Other Postretirement Benefits Costs	$ 68	$ 59	136	120
Commonwealth Edison Co
Defined Benefit Plan Disclosure [Line Items]
Pension and Other Postretirement Benefits Costs			42	36
Commonwealth Edison Co \| Pension and other post retirement benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension and Other Postretirement Benefits Costs	21	19	42	36
PECO Energy Co
Defined Benefit Plan Disclosure [Line Items]
Pension and Other Postretirement Benefits Costs			3	0
PECO Energy Co \| Pension and other post retirement benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension and Other Postretirement Benefits Costs	1	0	3	0
Baltimore Gas and Electric Company
Defined Benefit Plan Disclosure [Line Items]
Pension and Other Postretirement Benefits Costs			30	31
Baltimore Gas and Electric Company \| Pension and other post retirement benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension and Other Postretirement Benefits Costs	14	16	30	31
Pepco Holdings LLC
Defined Benefit Plan Disclosure [Line Items]
Pension and Other Postretirement Benefits Costs			49	46
Pepco Holdings LLC \| Pension and other post retirement benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension and Other Postretirement Benefits Costs	24	23	49	46
Potomac Electric Power Company
Defined Benefit Plan Disclosure [Line Items]
Pension and Other Postretirement Benefits Costs			18	16
Potomac Electric Power Company \| Pension and other post retirement benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension and Other Postretirement Benefits Costs	10	7	18	16
Delmarva Power and Light Company
Defined Benefit Plan Disclosure [Line Items]
Pension and Other Postretirement Benefits Costs			8	7
Delmarva Power and Light Company \| Pension and other post retirement benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension and Other Postretirement Benefits Costs	4	3	8	7
Atlantic City Electric Company
Defined Benefit Plan Disclosure [Line Items]
Pension and Other Postretirement Benefits Costs			6	7
Atlantic City Electric Company \| Pension and other post retirement benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension and Other Postretirement Benefits Costs	$ 3	$ 4	$ 6	$ 7