Commitments and Contingencies - Schedule of Accruals for Environmental Matters (Details) - USD ($) $ in Millions	Jun. 30, 2026	Dec. 31, 2025
Site Contingency [Line Items]
Total environmental investigation and remediation reserve	$ 362	$ 386
Commonwealth Edison Co
Site Contingency [Line Items]
Total environmental investigation and remediation reserve	285	289
PECO Energy Co
Site Contingency [Line Items]
Total environmental investigation and remediation reserve	19	23
Baltimore Gas and Electric Company
Site Contingency [Line Items]
Total environmental investigation and remediation reserve	13	13
Pepco Holdings LLC
Site Contingency [Line Items]
Total environmental investigation and remediation reserve	44	57
Potomac Electric Power Company
Site Contingency [Line Items]
Total environmental investigation and remediation reserve	43	55
Delmarva Power and Light Company
Site Contingency [Line Items]
Total environmental investigation and remediation reserve	1	1
Atlantic City Electric Company
Site Contingency [Line Items]
Total environmental investigation and remediation reserve	0	1
Environmental Remediation
Site Contingency [Line Items]
Total environmental investigation and remediation reserve	311	321
Environmental Remediation \| Commonwealth Edison Co
Site Contingency [Line Items]
Total environmental investigation and remediation reserve	285	289
Environmental Remediation \| PECO Energy Co
Site Contingency [Line Items]
Total environmental investigation and remediation reserve	16	22
Environmental Remediation \| Baltimore Gas and Electric Company
Site Contingency [Line Items]
Total environmental investigation and remediation reserve	10	10
Environmental Remediation \| Pepco Holdings LLC
Site Contingency [Line Items]
Total environmental investigation and remediation reserve	0	0
Environmental Remediation \| Potomac Electric Power Company
Site Contingency [Line Items]
Total environmental investigation and remediation reserve	0	0
Environmental Remediation \| Delmarva Power and Light Company
Site Contingency [Line Items]
Total environmental investigation and remediation reserve	0	0
Environmental Remediation \| Atlantic City Electric Company
Site Contingency [Line Items]
Total environmental investigation and remediation reserve	$ 0	$ 0