Income Taxes - Unrecognized Tax Benefits (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Income Tax Contingency [Line Items]
Unrecognized tax benefits	$ 95	$ 94
Offsetting receivable	3,382	3,232
Constellation Energy Corp
Income Tax Contingency [Line Items]
Income taxes receivable, noncurrent	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	51	51
Atlantic City Electric Company
Income Tax Contingency [Line Items]
Unrecognized tax benefits	$ 15	$ 15