Income Taxes - Unrecognized Tax Benefits (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Income Tax Contingency [Line Items]
Unrecognized tax benefits	$ 85	$ 94
Offsetting receivable	4,322	3,232
Constellation Energy Corp
Income Tax Contingency [Line Items]
Unrecognized tax benefits	31	31
Deferred Costs and Other Assets
Income Tax Contingency [Line Items]
Offsetting receivable	31	31
Pepco Holdings LLC
Income Tax Contingency [Line Items]
Unrecognized tax benefits	38	51
Atlantic City Electric Company
Income Tax Contingency [Line Items]
Unrecognized tax benefits	$ 1	$ 15