Fair Value of Financial Assets and Liabilities - Fair Value of Financial Liabilities Recorded at Amortized Cost (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt (including amounts due within one year)	$ 41,085	$ 37,074
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)	34,259	32,229
Estimate of Fair Value Measurement [Member] | Related Party
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt to financing trusts	384	384
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)	31,584	29,902
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)	2,675	2,327
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	384	384
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)	11,484	10,518
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)	9,343	9,006
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	206	204
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)	9,343	9,006
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	206	204
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)	5,133	4,612
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)	4,110	3,914
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	179	180
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)	4,110	3,864
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	50
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	179	180
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)	4,601	4,207
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)	3,735	3,613
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)	3,735	3,613
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)	8,637	8,120
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)	7,027	6,784
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)	4,352	4,507
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)	2,675	2,277
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)	4,095	3,751
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)	3,602	3,434
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)	2,129	2,229
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)	1,473	1,205
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)	2,060	1,938
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)	1,669	1,622
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)	1,126	1,164
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)	543	458
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)	1,833	1,757
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)	1,552	1,523
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)	893	909
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)	$ 659	$ 614