Commitments and Contingencies - Schedule of Commercial Commitments (Details) $ in Millions	Sep. 30, 2023 USD ($)
Other Commitments [Line Items]
Other Commitment	$ 634
Other Commitment, to be Paid, Remainder of Fiscal Year	94
Other Commitment, to be Paid, Year One	137
Other Commitment, to be Paid, Year Two	6
Other Commitment, to be Paid, Year Three	5
Other Commitment, to be Paid, Year Four	4
Other Commitment, to be Paid, Year Five and Beyond	388
Guarantor Obligations, Maximum Exposure, Undiscounted	66
Letters of Credit
Other Commitments [Line Items]
Other Commitment	20
Other Commitment, to be Paid, Remainder of Fiscal Year	9
Other Commitment, to be Paid, Year One	11
Other Commitment, to be Paid, Year Two	0
Other Commitment, to be Paid, Year Three	0
Other Commitment, to be Paid, Year Four	0
Other Commitment, to be Paid, Year Five and Beyond	0
Surety Bonds
Other Commitments [Line Items]
Other Commitment	207
Other Commitment, to be Paid, Remainder of Fiscal Year	85
Other Commitment, to be Paid, Year One	122
Other Commitment, to be Paid, Year Two	0
Other Commitment, to be Paid, Year Three	0
Other Commitment, to be Paid, Year Four	0
Other Commitment, to be Paid, Year Five and Beyond	0
Financing trust guarantees
Other Commitments [Line Items]
Other Commitment	378
Other Commitment, to be Paid, Remainder of Fiscal Year	0
Other Commitment, to be Paid, Year One	0
Other Commitment, to be Paid, Year Two	0
Other Commitment, to be Paid, Year Three	0
Other Commitment, to be Paid, Year Four	0
Other Commitment, to be Paid, Year Five and Beyond	378
Guaranteed lease residual values
Other Commitments [Line Items]
Other Commitment	29
Other Commitment, to be Paid, Remainder of Fiscal Year	0
Other Commitment, to be Paid, Year One	4
Other Commitment, to be Paid, Year Two	6
Other Commitment, to be Paid, Year Three	5
Other Commitment, to be Paid, Year Four	4
Other Commitment, to be Paid, Year Five and Beyond	10
Commonwealth Edison Co
Other Commitments [Line Items]
Other Commitment	258
Other Commitment, to be Paid, Remainder of Fiscal Year	11
Other Commitment, to be Paid, Year One	47
Other Commitment, to be Paid, Year Two	0
Other Commitment, to be Paid, Year Three	0
Other Commitment, to be Paid, Year Four	0
Other Commitment, to be Paid, Year Five and Beyond	200
Commonwealth Edison Co | Letters of Credit
Other Commitments [Line Items]
Other Commitment	12
Other Commitment, to be Paid, Remainder of Fiscal Year	6
Other Commitment, to be Paid, Year One	6
Other Commitment, to be Paid, Year Two	0
Other Commitment, to be Paid, Year Three	0
Other Commitment, to be Paid, Year Four	0
Other Commitment, to be Paid, Year Five and Beyond	0
Commonwealth Edison Co | Surety Bonds
Other Commitments [Line Items]
Other Commitment	46
Other Commitment, to be Paid, Remainder of Fiscal Year	5
Other Commitment, to be Paid, Year One	41
Other Commitment, to be Paid, Year Two	0
Other Commitment, to be Paid, Year Three	0
Other Commitment, to be Paid, Year Four	0
Other Commitment, to be Paid, Year Five and Beyond	0
Commonwealth Edison Co | Financing trust guarantees
Other Commitments [Line Items]
Other Commitment	200
Other Commitment, to be Paid, Remainder of Fiscal Year	0
Other Commitment, to be Paid, Year One	0
Other Commitment, to be Paid, Year Two	0
Other Commitment, to be Paid, Year Three	0
Other Commitment, to be Paid, Year Four	0
Other Commitment, to be Paid, Year Five and Beyond	200
PECO Energy Co
Other Commitments [Line Items]
Other Commitment	181
Other Commitment, to be Paid, Remainder of Fiscal Year	0
Other Commitment, to be Paid, Year One	3
Other Commitment, to be Paid, Year Two	0
Other Commitment, to be Paid, Year Three	0
Other Commitment, to be Paid, Year Four	0
Other Commitment, to be Paid, Year Five and Beyond	178
PECO Energy Co | Surety Bonds
Other Commitments [Line Items]
Other Commitment	2
Other Commitment, to be Paid, Remainder of Fiscal Year	0
Other Commitment, to be Paid, Year One	2
Other Commitment, to be Paid, Year Two	0
Other Commitment, to be Paid, Year Three	0
Other Commitment, to be Paid, Year Four	0
Other Commitment, to be Paid, Year Five and Beyond	0
PECO Energy Co | Financing trust guarantees
Other Commitments [Line Items]
Other Commitment	178
Other Commitment, to be Paid, Remainder of Fiscal Year	0
Other Commitment, to be Paid, Year One	0
Other Commitment, to be Paid, Year Two	0
Other Commitment, to be Paid, Year Three	0
Other Commitment, to be Paid, Year Four	0
Other Commitment, to be Paid, Year Five and Beyond	178
PECO Energy Co | Standby Letters of Credit
Other Commitments [Line Items]
Other Commitment	1
Other Commitment, to be Paid, Remainder of Fiscal Year	0
Other Commitment, to be Paid, Year One	1
Other Commitment, to be Paid, Year Two	0
Other Commitment, to be Paid, Year Three	0
Other Commitment, to be Paid, Year Four	0
Other Commitment, to be Paid, after Year Five	0
Baltimore Gas and Electric Company
Other Commitments [Line Items]
Other Commitment	7
Other Commitment, to be Paid, Remainder of Fiscal Year	3
Other Commitment, to be Paid, Year One	4
Other Commitment, to be Paid, Year Two	0
Other Commitment, to be Paid, Year Three	0
Other Commitment, to be Paid, Year Four	0
Other Commitment, to be Paid, Year Five and Beyond	0
Baltimore Gas and Electric Company | Letters of Credit
Other Commitments [Line Items]
Other Commitment	4
Other Commitment, to be Paid, Remainder of Fiscal Year	2
Other Commitment, to be Paid, Year One	2
Other Commitment, to be Paid, Year Two	0
Other Commitment, to be Paid, Year Three	0
Other Commitment, to be Paid, Year Four	0
Other Commitment, to be Paid, Year Five and Beyond	0
Baltimore Gas and Electric Company | Surety Bonds
Other Commitments [Line Items]
Other Commitment	3
Other Commitment, to be Paid, Remainder of Fiscal Year	1
Other Commitment, to be Paid, Year One	2
Other Commitment, to be Paid, Year Two	0
Other Commitment, to be Paid, Year Three	0
Other Commitment, to be Paid, Year Four	0
Other Commitment, to be Paid, Year Five and Beyond	0
Pepco Holdings LLC
Other Commitments [Line Items]
Other Commitment	126
Other Commitment, to be Paid, Remainder of Fiscal Year	75
Other Commitment, to be Paid, Year One	26
Other Commitment, to be Paid, Year Two	6
Other Commitment, to be Paid, Year Three	5
Other Commitment, to be Paid, Year Four	4
Other Commitment, to be Paid, Year Five and Beyond	10
Guarantor Obligations, Maximum Exposure, Undiscounted	66
Pepco Holdings LLC | Surety Bonds
Other Commitments [Line Items]
Other Commitment	97
Other Commitment, to be Paid, Remainder of Fiscal Year	75
Other Commitment, to be Paid, Year One	22
Other Commitment, to be Paid, Year Two	0
Other Commitment, to be Paid, Year Three	0
Other Commitment, to be Paid, Year Four	0
Other Commitment, to be Paid, Year Five and Beyond	0
Pepco Holdings LLC | Guaranteed lease residual values
Other Commitments [Line Items]
Other Commitment	29
Other Commitment, to be Paid, Remainder of Fiscal Year	0
Other Commitment, to be Paid, Year One	4
Other Commitment, to be Paid, Year Two	6
Other Commitment, to be Paid, Year Three	5
Other Commitment, to be Paid, Year Four	4
Other Commitment, to be Paid, Year Five and Beyond	10
Potomac Electric Power Company
Other Commitments [Line Items]
Other Commitment	95
Other Commitment, to be Paid, Remainder of Fiscal Year	71
Other Commitment, to be Paid, Year One	15
Other Commitment, to be Paid, Year Two	3
Other Commitment, to be Paid, Year Three	2
Other Commitment, to be Paid, Year Four	1
Other Commitment, to be Paid, Year Five and Beyond	3
Guarantor Obligations, Maximum Exposure, Undiscounted	22
Potomac Electric Power Company | Surety Bonds
Other Commitments [Line Items]
Other Commitment	85
Other Commitment, to be Paid, Remainder of Fiscal Year	71
Other Commitment, to be Paid, Year One	14
Other Commitment, to be Paid, Year Two	0
Other Commitment, to be Paid, Year Three	0
Other Commitment, to be Paid, Year Four	0
Other Commitment, to be Paid, Year Five and Beyond	0
Potomac Electric Power Company | Guaranteed lease residual values
Other Commitments [Line Items]
Other Commitment	10
Other Commitment, to be Paid, Remainder of Fiscal Year	0
Other Commitment, to be Paid, Year One	1
Other Commitment, to be Paid, Year Two	3
Other Commitment, to be Paid, Year Three	2
Other Commitment, to be Paid, Year Four	1
Other Commitment, to be Paid, Year Five and Beyond	3
Delmarva Power and Light Company
Other Commitments [Line Items]
Other Commitment	19
Other Commitment, to be Paid, Remainder of Fiscal Year	2
Other Commitment, to be Paid, Year One	7
Other Commitment, to be Paid, Year Two	2
Other Commitment, to be Paid, Year Three	2
Other Commitment, to be Paid, Year Four	2
Other Commitment, to be Paid, Year Five and Beyond	4
Guarantor Obligations, Maximum Exposure, Undiscounted	26
Delmarva Power and Light Company | Surety Bonds
Other Commitments [Line Items]
Other Commitment	7
Other Commitment, to be Paid, Remainder of Fiscal Year	2
Other Commitment, to be Paid, Year One	5
Other Commitment, to be Paid, Year Two	0
Other Commitment, to be Paid, Year Three	0
Other Commitment, to be Paid, Year Four	0
Other Commitment, to be Paid, Year Five and Beyond	0
Delmarva Power and Light Company | Guaranteed lease residual values
Other Commitments [Line Items]
Other Commitment	12
Other Commitment, to be Paid, Remainder of Fiscal Year	0
Other Commitment, to be Paid, Year One	2
Other Commitment, to be Paid, Year Two	2
Other Commitment, to be Paid, Year Three	2
Other Commitment, to be Paid, Year Four	2
Other Commitment, to be Paid, Year Five and Beyond	4
Atlantic City Electric Company
Other Commitments [Line Items]
Other Commitment	12
Other Commitment, to be Paid, Remainder of Fiscal Year	2
Other Commitment, to be Paid, Year One	4
Other Commitment, to be Paid, Year Two	1
Other Commitment, to be Paid, Year Three	1
Other Commitment, to be Paid, Year Four	1
Other Commitment, to be Paid, Year Five and Beyond	3
Guarantor Obligations, Maximum Exposure, Undiscounted	18
Atlantic City Electric Company | Surety Bonds
Other Commitments [Line Items]
Other Commitment	5
Other Commitment, to be Paid, Remainder of Fiscal Year	2
Other Commitment, to be Paid, Year One	3
Other Commitment, to be Paid, Year Two	0
Other Commitment, to be Paid, Year Three	0
Other Commitment, to be Paid, Year Four	0
Other Commitment, to be Paid, Year Five and Beyond	0
Atlantic City Electric Company | Guaranteed lease residual values
Other Commitments [Line Items]
Other Commitment	7
Other Commitment, to be Paid, Remainder of Fiscal Year	0
Other Commitment, to be Paid, Year One	1
Other Commitment, to be Paid, Year Two	1
Other Commitment, to be Paid, Year Three	1
Other Commitment, to be Paid, Year Four	1
Other Commitment, to be Paid, Year Five and Beyond	$ 3
Minimum [Member] | Guaranteed lease residual values
Other Commitments [Line Items]
Lessor, Operating Lease, Term of Contract	1 year
Maximum [Member] | Guaranteed lease residual values
Other Commitments [Line Items]
Lessor, Operating Lease, Term of Contract	9 years