Fair Value of Financial Assets and Liabilities - Fair Value of Financial Liabilities Recorded at Amortized Cost (Details) - USD ($) $ in Millions	Mar. 31, 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)	$ 42,774	$ 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)	38,039	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	392	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)	34,426	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)	3,613	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	392	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)	11,487	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	205	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)	9,910	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	209	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)	9,910	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	209	208
Commonwealth Edison Co | Related Party
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt to financing trusts	205	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)	5,134	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)	4,391	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	183	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)	4,391	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	183	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)	4,602	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)	4,015	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)	4,015	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)	9,153	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)	7,969	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)	4,356	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)	3,613	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)	4,359	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)	4,119	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)	2,549	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)	1,570	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)	2,254	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)	1,942	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)	668	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)	1,274	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)	1,909	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)	1,697	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)	929	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)	$ 768	$ 708