Lessee - Supplemental Cash Flow Information Related to Leases (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Supplemental Cash Flow Information [Line Items]
Operating cash flows from operating leases	$ 66	$ 93	$ 67
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	46	1	(2)
Commonwealth Edison Co [Member]
Supplemental Cash Flow Information [Line Items]
Operating cash flows from operating leases	3	3	3
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	0	0	0
PECO Energy Co [Member]
Supplemental Cash Flow Information [Line Items]
Operating cash flows from operating leases	0	0	1
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	0	0	1
Baltimore Gas and Electric Company [Member]
Supplemental Cash Flow Information [Line Items]
Operating cash flows from operating leases	16	46	20
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	0	(1)	0
Pepco Holdings LLC [Member]
Supplemental Cash Flow Information [Line Items]
Operating cash flows from operating leases	37	39	39
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	2	1	(1)
Finance Lease, Principal Payments	13	10	6
Right-of-Use Asset Obtained in Exchange for Finance Lease Liability	14	32	29
Potomac Electric Power Company [Member]
Supplemental Cash Flow Information [Line Items]
Operating cash flows from operating leases	8	8	8
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	0	0	0
Finance Lease, Principal Payments	5	3	2
Right-of-Use Asset Obtained in Exchange for Finance Lease Liability	4	12	8
Delmarva Power & Light Company [Member]
Supplemental Cash Flow Information [Line Items]
Operating cash flows from operating leases	9	9	9
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	1	1	(1)
Finance Lease, Principal Payments	5	4	3
Right-of-Use Asset Obtained in Exchange for Finance Lease Liability	7	12	14
Atlantic City Electric Company [Member]
Supplemental Cash Flow Information [Line Items]
Operating cash flows from operating leases	4	4	4
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	1	0	0
Finance Lease, Principal Payments	3	3	1
Right-of-Use Asset Obtained in Exchange for Finance Lease Liability	$ 3	$ 8	$ 7