Related Party Transactions - BSC and PHISCO Service Companies (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Exelon Business Services Co Affiliate
Related Party Transaction [Line Items]
Capitalized costs	$ 670	$ 707	$ 508
PHI Service Co Affiliate
Related Party Transaction [Line Items]
Capitalized costs	96	80	72
Commonwealth Edison Co | Exelon Business Services Co Affiliate
Related Party Transaction [Line Items]
Operating and maintenance from affiliates	353	316	304
Capitalized costs	307	311	207
PECO Energy Co | Exelon Business Services Co Affiliate
Related Party Transaction [Line Items]
Operating and maintenance from affiliates	213	197	169
Capitalized costs	120	115	81
Baltimore Gas and Electric Company | Exelon Business Services Co Affiliate
Related Party Transaction [Line Items]
Operating and maintenance from affiliates	221	204	189
Capitalized costs	90	122	92
Pepco Holdings LLC | Exelon Business Services Co Affiliate
Related Party Transaction [Line Items]
Operating and maintenance from affiliates	177	188	168
Capitalized costs	153	159	128
Pepco Holdings LLC | PHI Service Co Affiliate
Related Party Transaction [Line Items]
Operating and maintenance from affiliates	0	0	0
Capitalized costs	95	80	72
Potomac Electric Power Company | Exelon Business Services Co Affiliate
Related Party Transaction [Line Items]
Operating and maintenance from affiliates	114	110	96
Capitalized costs	59	60	50
Potomac Electric Power Company | PHI Service Co Affiliate
Related Party Transaction [Line Items]
Operating and maintenance from affiliates	122	112	114
Capitalized costs	39	33	31
Delmarva Power & Light Company | Exelon Business Services Co Affiliate
Related Party Transaction [Line Items]
Operating and maintenance from affiliates	73	71	61
Capitalized costs	43	45	43
Delmarva Power & Light Company | PHI Service Co Affiliate
Related Party Transaction [Line Items]
Operating and maintenance from affiliates	98	96	99
Capitalized costs	29	26	22
Atlantic City Electric Company | Exelon Business Services Co Affiliate
Related Party Transaction [Line Items]
Operating and maintenance from affiliates	59	57	53
Capitalized costs	47	54	33
Atlantic City Electric Company | PHI Service Co Affiliate
Related Party Transaction [Line Items]
Operating and maintenance from affiliates	92	84	86
Capitalized costs	$ 26	$ 21	$ 19