Related Party Transactions - Current Receivables From/Payables To Affiliates (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Related Party
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	$ 259	$ 251
Accounts payable	5	5
Commonwealth Edison Co | Affiliated Entity
Related Party Transaction [Line Items]
Accounts payable	72	72
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	72	72
Receivables from affiliates	3	3
PECO Energy Co | Affiliated Entity
Related Party Transaction [Line Items]
Accounts payable	41	39
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	0	1
PECO Energy Co | Atlantic City Electric Co Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	0	1
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	41	39
Receivables from affiliates	0	2
Baltimore Gas and Electric Company | Affiliated Entity
Related Party Transaction [Line Items]
Accounts payable	37	35
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	37	35
Receivables from affiliates	0	0
Pepco Holdings LLC | Affiliated Entity
Related Party Transaction [Line Items]
Accounts payable	17	15
Pepco Holdings LLC | Related Party
Related Party Transaction [Line Items]
Accounts payable	60	59
Receivables from affiliates	4	3
Potomac Electric Power Company | Affiliated Entity
Related Party Transaction [Line Items]
Accounts payable	37	32
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	1
Potomac Electric Power Company | Other Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	1	1
Potomac Electric Power Company | Related Party
Related Party Transaction [Line Items]
Accounts payable	37	32
Receivables from affiliates	1	2
Delmarva Power and Light Company | Affiliated Entity
Related Party Transaction [Line Items]
Accounts payable	25	25
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	1
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	25
Receivables from affiliates	0	1
Atlantic City Electric Company | Affiliated Entity
Related Party Transaction [Line Items]
Accounts payable	22	25
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	4	3
Atlantic City Electric Company | Related Party
Related Party Transaction [Line Items]
Accounts payable	22	25
Receivables from affiliates	4	3
Business Services Company | Commonwealth Edison Co Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	66	64
Business Services Company | PECO Energy Co Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	33	36
Business Services Company | Baltimore Gas And Electric Company Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	35	33
Business Services Company | Pepco Holdings LLC Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	6	5
Business Services Company | Potomac Electric Power Co Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	19	17
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	10	11
Business Services Company | Other Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	0	1
Business Services Company | Related Party
Related Party Transaction [Line Items]
Receivables from affiliates	182	179
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	17	14
PHI Service Company | Delmarva Power and Light Co Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	12	11
PHI Service Company | Atlantic City Electric Co Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	12	11
PHI Service Company | Other Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current		0
PHI Service Company | Related Party
Related Party Transaction [Line Items]
Receivables from affiliates	41	36
Other Legal Entities | Affiliated Entity
Related Party Transaction [Line Items]
Accounts payable	8	8
Other Legal Entities | Commonwealth Edison Co Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	6	8
Other Legal Entities | PECO Energy Co Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	8	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	2
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	1
Other Legal Entities | Atlantic City Electric Co Affiliate
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party, current	0	0
Other Legal Entities | Related Party
Related Party Transaction [Line Items]
Receivables from affiliates	$ 28	$ 25