Leases - Supplemental Balance Sheet Information (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Supplemental Balance Sheet Information [Line Items]
Other deferred debits and other assets	Other	Other
Other current liabilities	$ 968	$ 1,155
Other deferred credits and other liabilities	$ 2,088	$ 1,967
Total operating lease liabilities	Other current liabilities, Other deferred credits and other liabilities	Other current liabilities, Other deferred credits and other liabilities
Other Current Liabilities
Supplemental Balance Sheet Information [Line Items]
Other current liabilities	$ 38	$ 40
Other Noncurrent Liabilities
Supplemental Balance Sheet Information [Line Items]
Other deferred credits and other liabilities	$ 248	$ 266
Commonwealth Edison Co
Supplemental Balance Sheet Information [Line Items]
Other deferred debits and other assets	Other	Other
Other current liabilities	$ 219	$ 191
Other deferred credits and other liabilities	$ 865	$ 642
Total operating lease liabilities	Other current liabilities, Other deferred credits and other liabilities	Other current liabilities, Other deferred credits and other liabilities
Commonwealth Edison Co | Other Current Liabilities
Supplemental Balance Sheet Information [Line Items]
Other current liabilities	$ 0	$ 2
Commonwealth Edison Co | Other Noncurrent Liabilities
Supplemental Balance Sheet Information [Line Items]
Other deferred credits and other liabilities	$ 0	$ 0
PECO Energy Co
Supplemental Balance Sheet Information [Line Items]
Other deferred debits and other assets	Other	Other
Other current liabilities	$ 59	$ 32
Other deferred credits and other liabilities	$ 79	$ 85
Total operating lease liabilities	Other current liabilities, Other deferred credits and other liabilities	Other current liabilities, Other deferred credits and other liabilities
PECO Energy Co | Other Current Liabilities
Supplemental Balance Sheet Information [Line Items]
Other current liabilities	$ 0	$ 0
PECO Energy Co | Other Noncurrent Liabilities
Supplemental Balance Sheet Information [Line Items]
Other deferred credits and other liabilities	$ 0	$ 1
Baltimore Gas and Electric Company
Supplemental Balance Sheet Information [Line Items]
Other deferred debits and other assets	Other	Other
Other current liabilities	$ 34	$ 55
Other deferred credits and other liabilities	$ 91	$ 88
Total operating lease liabilities	Other current liabilities, Other deferred credits and other liabilities	Other current liabilities, Other deferred credits and other liabilities
Baltimore Gas and Electric Company | Other Current Liabilities
Supplemental Balance Sheet Information [Line Items]
Other current liabilities	$ 4	$ 0
Baltimore Gas and Electric Company | Other Noncurrent Liabilities
Supplemental Balance Sheet Information [Line Items]
Other deferred credits and other liabilities	$ 17	$ 4
Pepco Holdings LLC
Supplemental Balance Sheet Information [Line Items]
Other deferred debits and other assets	Other	Other
Other deferred credits and other liabilities	$ 511	$ 536
Total operating lease liabilities	Other current liabilities, Other deferred credits and other liabilities	Other current liabilities, Other deferred credits and other liabilities
Plant, property and equipment, net	Property, plant and equipment, net	Property, plant and equipment, net
Long-term debt due within one year	$ 15	$ 12
Long-term debt	59	64
Total finance lease liabilities	74	76
Pepco Holdings LLC | Other Current Liabilities
Supplemental Balance Sheet Information [Line Items]
Other current liabilities	30	31
Pepco Holdings LLC | Other Noncurrent Liabilities
Supplemental Balance Sheet Information [Line Items]
Other deferred credits and other liabilities	$ 141	$ 167
Potomac Electric Power Company
Supplemental Balance Sheet Information [Line Items]
Other deferred debits and other assets	Other	Other
Other current liabilities	$ 61	$ 93
Other deferred credits and other liabilities	$ 280	$ 244
Total operating lease liabilities	Other current liabilities, Other deferred credits and other liabilities	Other current liabilities, Other deferred credits and other liabilities
Plant, property and equipment, net	Property, plant and equipment, net	Property, plant and equipment, net
Long-term debt due within one year	$ 5	$ 4
Long-term debt	21	21
Total finance lease liabilities	26	25
Potomac Electric Power Company | Other Current Liabilities
Supplemental Balance Sheet Information [Line Items]
Other current liabilities	5	6
Potomac Electric Power Company | Other Noncurrent Liabilities
Supplemental Balance Sheet Information [Line Items]
Other deferred credits and other liabilities	$ 30	$ 34
Delmarva Power & Light Company
Supplemental Balance Sheet Information [Line Items]
Other deferred debits and other assets	Other	Other
Other current liabilities	$ 21	$ 136
Other deferred credits and other liabilities	$ 93	$ 84
Total operating lease liabilities	Other current liabilities, Other deferred credits and other liabilities	Other current liabilities, Other deferred credits and other liabilities
Plant, property and equipment, net	Property, plant and equipment, net	Property, plant and equipment, net
Long-term debt due within one year	$ 6	$ 5
Long-term debt	23	27
Total finance lease liabilities	29	32
Delmarva Power & Light Company | Other Current Liabilities
Supplemental Balance Sheet Information [Line Items]
Other current liabilities	7	8
Delmarva Power & Light Company | Other Noncurrent Liabilities
Supplemental Balance Sheet Information [Line Items]
Other deferred credits and other liabilities	$ 36	$ 42
Atlantic City Electric Company
Supplemental Balance Sheet Information [Line Items]
Other deferred debits and other assets	Other	Other
Other current liabilities	$ 12	$ 58
Other deferred credits and other liabilities	$ 49	$ 100
Total operating lease liabilities	Other current liabilities, Other deferred credits and other liabilities	Other current liabilities, Other deferred credits and other liabilities
Plant, property and equipment, net	Property, plant and equipment, net	Property, plant and equipment, net
Long-term debt due within one year	$ 4	$ 3
Long-term debt	15	16
Total finance lease liabilities	19	19
Atlantic City Electric Company | Other Current Liabilities
Supplemental Balance Sheet Information [Line Items]
Other current liabilities	3	3
Atlantic City Electric Company | Other Noncurrent Liabilities
Supplemental Balance Sheet Information [Line Items]
Other deferred credits and other liabilities	$ 6	$ 7