Income Taxes - Components of Income Tax Expense (Benefit) from Continuing Operations (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Income Taxes [Line Items]
Income taxes	$ 349	$ 38	$ (7)
Commonwealth Edison Co [Member]
Income Taxes [Line Items]
Income taxes	264	172	177
PECO Energy Co [Member]
Income Taxes [Line Items]
Income taxes	79	12	(30)
Baltimore Gas and Electric Company [Member]
Income Taxes [Line Items]
Income taxes	8	(35)	41
Pepco Holdings LLC [Member]
Income Taxes [Line Items]
Income taxes	9	42	(77)
Potomac Electric Power Company [Member]
Income Taxes [Line Items]
Income taxes	(9)	15	(7)
Delmarva Power & Light Company [Member]
Income Taxes [Line Items]
Income taxes	14	42	(25)
Atlantic City Electric Company [Member]
Income Taxes [Line Items]
Income taxes	3	(13)	(41)
Internal Revenue Service (IRS) [Member]
Income Taxes [Line Items]
Current	(24)	(152)	(180)
Deferred	106	89	10
Investment Tax Credit	(3)	(2)	(3)
Internal Revenue Service (IRS) [Member] | Commonwealth Edison Co [Member]
Income Taxes [Line Items]
Current	29	(30)	(24)
Deferred	117	113	112
Investment Tax Credit	(1)	(1)	(2)
Internal Revenue Service (IRS) [Member] | PECO Energy Co [Member]
Income Taxes [Line Items]
Current	13	1	(7)
Deferred	18	20	1
Investment Tax Credit	0	0	0
Internal Revenue Service (IRS) [Member] | Baltimore Gas and Electric Company [Member]
Income Taxes [Line Items]
Current	(1)	(18)	4
Deferred	(3)	34	10
Investment Tax Credit	0	0	0
Internal Revenue Service (IRS) [Member] | Pepco Holdings LLC [Member]
Income Taxes [Line Items]
Current	16	18	25
Deferred	(23)	(52)	(129)
Investment Tax Credit	(1)	(1)	(1)
Internal Revenue Service (IRS) [Member] | Potomac Electric Power Company [Member]
Income Taxes [Line Items]
Current	9	22	40
Deferred	(2)	(17)	(62)
Investment Tax Credit	0	0	0
Internal Revenue Service (IRS) [Member] | Delmarva Power & Light Company [Member]
Income Taxes [Line Items]
Current	(2)	2	(13)
Deferred	2	(14)	(20)
Investment Tax Credit	0	0	0
Internal Revenue Service (IRS) [Member] | Atlantic City Electric Company [Member]
Income Taxes [Line Items]
Current	6	1	(4)
Deferred	(15)	(26)	(43)
Investment Tax Credit	0	0	0
State and Local Jurisdiction [Member]
Income Taxes [Line Items]
Current	(13)	(46)	(37)
Deferred	283	149	203
State and Local Jurisdiction [Member] | Commonwealth Edison Co [Member]
Income Taxes [Line Items]
Current	(6)	(41)	(27)
Deferred	125	131	118
State and Local Jurisdiction [Member] | PECO Energy Co [Member]
Income Taxes [Line Items]
Current	(4)	0	0
Deferred	52	(9)	(24)
State and Local Jurisdiction [Member] | Baltimore Gas and Electric Company [Member]
Income Taxes [Line Items]
Current	0	0	0
Deferred	12	(51)	27
State and Local Jurisdiction [Member] | Pepco Holdings LLC [Member]
Income Taxes [Line Items]
Current	2	0	(5)
Deferred	15	77	33
State and Local Jurisdiction [Member] | Potomac Electric Power Company [Member]
Income Taxes [Line Items]
Current	0	1	0
Deferred	(16)	9	15
State and Local Jurisdiction [Member] | Delmarva Power & Light Company [Member]
Income Taxes [Line Items]
Current	0	1	0
Deferred	14	53	8
State and Local Jurisdiction [Member] | Atlantic City Electric Company [Member]
Income Taxes [Line Items]
Current	0	0	0
Deferred	$ 12	$ 12	$ 6