Income Taxes - Summary of Interest and Penalties Receivable (Payable) (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Income Taxes [Line Items]
Net interest receivable payable related to uncertain tax positions	$ 62	$ 45
Other Accounts Receivable
Income Taxes [Line Items]
Interest Receivable, Current	21
Interest Receivable, Noncurrent	41
Other Assets
Income Taxes [Line Items]
Other	$ 5
Exelon Generation Co L L C
Income Taxes [Line Items]
Other		$ 1