Related Party Transactions - Current Receivables From/Payables To Affiliates (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Related Party
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	$ 234	$ 255
Accounts payable	5	5
Commonwealth Edison Co | Affiliated Entity
Related Party Transaction [Line Items]
Accounts payable	62	74
Commonwealth Edison Co | PECO Energy Co Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	0	0
Commonwealth Edison Co | Baltimore Gas And Electric Company Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	0	0
Commonwealth Edison Co | Pepco Holdings LLC Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	0	0
Commonwealth Edison Co | Potomac Electric Power Co Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	0	0
Commonwealth Edison Co | Delmarva Power and Light Co Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	0	0
Commonwealth Edison Co | Atlantic City Electric Co Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	0	0
Commonwealth Edison Co | Other Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	3	3
Commonwealth Edison Co | Related Party
Related Party Transaction [Line Items]
Accounts payable	62	74
Receivables from affiliates	3	3
PECO Energy Co | Affiliated Entity
Related Party Transaction [Line Items]
Accounts payable	37	42
PECO Energy Co | Commonwealth Edison Co Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	0	0
PECO Energy Co | Baltimore Gas And Electric Company Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	0	0
PECO Energy Co | Pepco Holdings LLC Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	0	0
PECO Energy Co | Potomac Electric Power Co Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	0	0
PECO Energy Co | Delmarva Power and Light Co Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	1	2
PECO Energy Co | Atlantic City Electric Co Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	0	2
PECO Energy Co | Other Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	0	0
PECO Energy Co | Related Party
Related Party Transaction [Line Items]
Accounts payable	37	42
Receivables from affiliates	1	4
Baltimore Gas and Electric Company | Affiliated Entity
Related Party Transaction [Line Items]
Accounts payable	33	39
Baltimore Gas and Electric Company | Commonwealth Edison Co Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	0	0
Baltimore Gas and Electric Company | PECO Energy Co Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	0	0
Baltimore Gas and Electric Company | Pepco Holdings LLC Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	0	0
Baltimore Gas and Electric Company | Potomac Electric Power Co Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	0	0
Baltimore Gas and Electric Company | Delmarva Power and Light Co Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	0	0
Baltimore Gas and Electric Company | Atlantic City Electric Co Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	0	0
Baltimore Gas and Electric Company | Other Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	0	0
Baltimore Gas and Electric Company | Related Party
Related Party Transaction [Line Items]
Accounts payable	33	39
Receivables from affiliates	0	0
Pepco Holdings LLC | Affiliated Entity
Related Party Transaction [Line Items]
Accounts payable	17	14
Pepco Holdings LLC | Related Party
Related Party Transaction [Line Items]
Accounts payable	59	66
Receivables from affiliates	3	2
Potomac Electric Power Company | Affiliated Entity
Related Party Transaction [Line Items]
Accounts payable	32	34
Potomac Electric Power Company | Commonwealth Edison Co Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	0	0
Potomac Electric Power Company | PECO Energy Co Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	0	0
Potomac Electric Power Company | Baltimore Gas And Electric Company Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	0	0
Potomac Electric Power Company | Pepco Holdings LLC Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	0	0
Potomac Electric Power Company | Delmarva Power and Light Co Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	0	0
Potomac Electric Power Company | Atlantic City Electric Co Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	0	0
Potomac Electric Power Company | Other Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	0	0
Potomac Electric Power Company | Related Party
Related Party Transaction [Line Items]
Accounts payable	32	34
Receivables from affiliates	0	0
Delmarva Power and Light Company | Affiliated Entity
Related Party Transaction [Line Items]
Accounts payable	25	22
Delmarva Power and Light Company | Commonwealth Edison Co Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	0	0
Delmarva Power and Light Company | PECO Energy Co Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	0	0
Delmarva Power and Light Company | Baltimore Gas And Electric Company Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	0	0
Delmarva Power and Light Company | Pepco Holdings LLC Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	0	0
Delmarva Power and Light Company | Potomac Electric Power Co Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	0	0
Delmarva Power and Light Company | Atlantic City Electric Co Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	0	0
Delmarva Power and Light Company | Other Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	0	0
Delmarva Power and Light Company | Related Party
Related Party Transaction [Line Items]
Accounts payable	25	22
Receivables from affiliates	0	0
Atlantic City Electric Company | Affiliated Entity
Related Party Transaction [Line Items]
Accounts payable	22	26
Atlantic City Electric Company | Commonwealth Edison Co Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	0	0
Atlantic City Electric Company | PECO Energy Co Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	0	0
Atlantic City Electric Company | Baltimore Gas And Electric Company Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	0	0
Atlantic City Electric Company | Pepco Holdings LLC Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	0	0
Atlantic City Electric Company | Potomac Electric Power Co Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	0	0
Atlantic City Electric Company | Delmarva Power and Light Co Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	0	0
Atlantic City Electric Company | Other Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	3	1
Atlantic City Electric Company | Related Party
Related Party Transaction [Line Items]
Accounts payable	22	26
Receivables from affiliates	3	1
Business Services Company | Commonwealth Edison Co Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	57	66
Business Services Company | PECO Energy Co Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	31	39
Business Services Company | Baltimore Gas And Electric Company Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	31	38
Business Services Company | Pepco Holdings LLC Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	6	4
Business Services Company | Potomac Electric Power Co Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	16	20
Business Services Company | Delmarva Power and Light Co Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	13	12
Business Services Company | Atlantic City Electric Co Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	11	14
Business Services Company | Other Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	(1)	0
Business Services Company | Related Party
Related Party Transaction [Line Items]
Receivables from affiliates	164	193
PHI Service Company | Commonwealth Edison Co Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	0	0
PHI Service Company | PECO Energy Co Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	0	0
PHI Service Company | Baltimore Gas And Electric Company Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	0	0
PHI Service Company | Pepco Holdings LLC Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	0	0
PHI Service Company | Potomac Electric Power Co Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	15	13
PHI Service Company | Delmarva Power and Light Co Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	11	8
PHI Service Company | Atlantic City Electric Co Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	10	9
PHI Service Company | Other Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	1	0
PHI Service Company | Related Party
Related Party Transaction [Line Items]
Receivables from affiliates	37	30
Other Legal Entities | Affiliated Entity
Related Party Transaction [Line Items]
Accounts payable	6	4
Other Legal Entities | Commonwealth Edison Co Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	5	8
Other Legal Entities | PECO Energy Co Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	6	3
Other Legal Entities | Baltimore Gas And Electric Company Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	2	1
Other Legal Entities | Pepco Holdings LLC Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	11	10
Other Legal Entities | Potomac Electric Power Co Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	1	1
Other Legal Entities | Delmarva Power and Light Co Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	0	0
Other Legal Entities | Atlantic City Electric Co Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	1	1
Other Legal Entities | Related Party
Related Party Transaction [Line Items]
Receivables from affiliates	$ 26	$ 24