Fair Value of Financial Assets and Liabilities - Fair Value of Financial Liabilities Recorded at Amortized Cost (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt (including amounts due within one year)	$ 44,655	$ 41,095
Reported Value Measurement [Member] | Related Party
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt to financing trusts	390	390
Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt (including amounts due within one year)	41,579	37,246
Estimate of Fair Value Measurement [Member] | Related Party
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt to financing trusts	409	390
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt (including amounts due within one year)	0	0
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member] | Related Party
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt to financing trusts	0	0
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt (including amounts due within one year)	37,642	33,804
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member] | Related Party
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt to financing trusts	0	0
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt (including amounts due within one year)	3,937	3,442
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member] | Related Party
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt to financing trusts	409	390
Long-term debt to financing trusts	390	390
Related Party
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt to financing trusts	390	390
Commonwealth Edison Co | Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt (including amounts due within one year)	12,028	11,486
Commonwealth Edison Co | Reported Value Measurement [Member] | Related Party
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt to financing trusts	206	205
Commonwealth Edison Co | Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt (including amounts due within one year)	10,957	10,210
Commonwealth Edison Co | Estimate of Fair Value Measurement [Member] | Related Party
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt to financing trusts	215	208
Commonwealth Edison Co | Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt (including amounts due within one year)	0	0
Commonwealth Edison Co | Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member] | Related Party
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt to financing trusts	0	0
Commonwealth Edison Co | Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt (including amounts due within one year)	10,957	10,210
Commonwealth Edison Co | Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member] | Related Party
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt to financing trusts	0	0
Commonwealth Edison Co | Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt (including amounts due within one year)	0	0
Commonwealth Edison Co | Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member] | Related Party
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt to financing trusts	215	208
Commonwealth Edison Co | Related Party
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt to financing trusts	206	205
PECO Energy Co | Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt (including amounts due within one year)	5,703	5,134
PECO Energy Co | Reported Value Measurement [Member] | Related Party
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt to financing trusts	184	184
PECO Energy Co | Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt (including amounts due within one year)	5,156	4,562
PECO Energy Co | Estimate of Fair Value Measurement [Member] | Related Party
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt to financing trusts	194	182
PECO Energy Co | Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt (including amounts due within one year)	0	0
PECO Energy Co | Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member] | Related Party
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt to financing trusts	0	0
PECO Energy Co | Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt (including amounts due within one year)	5,156	4,562
PECO Energy Co | Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member] | Related Party
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt to financing trusts	0	0
PECO Energy Co | Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt (including amounts due within one year)	0	0
PECO Energy Co | Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member] | Related Party
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt to financing trusts	194	182
PECO Energy Co | Related Party
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt to financing trusts	184	184
Baltimore Gas and Electric Company | Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt (including amounts due within one year)	5,395	4,602
Baltimore Gas and Electric Company | Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt (including amounts due within one year)	5,021	4,145
Baltimore Gas and Electric Company | Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt (including amounts due within one year)	0	0
Baltimore Gas and Electric Company | Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt (including amounts due within one year)	5,021	4,145
Baltimore Gas and Electric Company | Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt (including amounts due within one year)	0	0
Pepco Holdings LLC | Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt (including amounts due within one year)	9,135	8,648
Pepco Holdings LLC | Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt (including amounts due within one year)	8,270	7,602
Pepco Holdings LLC | Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt (including amounts due within one year)	0	0
Pepco Holdings LLC | Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt (including amounts due within one year)	4,333	4,160
Pepco Holdings LLC | Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt (including amounts due within one year)	3,937	3,442
Potomac Electric Power Company | Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt (including amounts due within one year)	4,362	4,096
Potomac Electric Power Company | Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt (including amounts due within one year)	4,272	3,911
Potomac Electric Power Company | Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt (including amounts due within one year)	0	0
Potomac Electric Power Company | Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt (including amounts due within one year)	2,638	2,311
Potomac Electric Power Company | Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt (including amounts due within one year)	1,634	1,600
Delmarva Power and Light Company | Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt (including amounts due within one year)	2,221	2,080
Delmarva Power and Light Company | Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt (including amounts due within one year)	1,996	1,828
Delmarva Power and Light Company | Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt (including amounts due within one year)	0	0
Delmarva Power and Light Company | Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt (including amounts due within one year)	667	694
Delmarva Power and Light Company | Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt (including amounts due within one year)	1,329	1,134
Atlantic City Electric Company | Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt (including amounts due within one year)	1,935	1,833
Atlantic City Electric Company | Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt (including amounts due within one year)	1,783	1,647
Atlantic City Electric Company | Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt (including amounts due within one year)	0	0
Atlantic City Electric Company | Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt (including amounts due within one year)	809	939
Atlantic City Electric Company | Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt (including amounts due within one year)	$ 974	$ 708