Regulatory Matters - Regulatory Assets and Liabilities (Details) $ in Millions	9 Months Ended
Sep. 30, 2026 USD ($)
Commonwealth Edison Co
Regulatory Matters Assets and Liabilities [Line Items]
Increase (Decrease) in Regulatory Assets	$ 290
Increase (Decrease) in Regulatory Liabilities	(86)
Commonwealth Edison Co \| Carbon Mitigation Credit rider
Regulatory Matters Assets and Liabilities [Line Items]
Increase (Decrease) in Regulatory Liabilities	(670)
Commonwealth Edison Co \| Nuclear Decommissioning [Member]
Regulatory Matters Assets and Liabilities [Line Items]
Increase (Decrease) in Regulatory Liabilities	285
Commonwealth Edison Co \| Renewable portfolio standards costs
Regulatory Matters Assets and Liabilities [Line Items]
Increase (Decrease) in Regulatory Liabilities	159
Commonwealth Edison Co \| Carbon Mitigation Credit rider
Regulatory Matters Assets and Liabilities [Line Items]
Increase (Decrease) in Regulatory Assets	137
PECO Energy Co
Regulatory Matters Assets and Liabilities [Line Items]
Increase (Decrease) in Regulatory Assets	194
Increase (Decrease) in Regulatory Liabilities	144
PECO Energy Co \| Nuclear Decommissioning [Member]
Regulatory Matters Assets and Liabilities [Line Items]
Increase (Decrease) in Regulatory Liabilities	156
PECO Energy Co \| Deferred Income Tax Charge
Regulatory Matters Assets and Liabilities [Line Items]
Increase (Decrease) in Regulatory Assets	148
Baltimore Gas and Electric Company
Regulatory Matters Assets and Liabilities [Line Items]
Increase (Decrease) in Regulatory Assets	(99)
Increase (Decrease) in Regulatory Liabilities	(25)
Baltimore Gas and Electric Company \| Deferred Income Tax Charge
Regulatory Matters Assets and Liabilities [Line Items]
Increase (Decrease) in Regulatory Liabilities	(47)
Baltimore Gas and Electric Company \| Electric energy and natural gas costs
Regulatory Matters Assets and Liabilities [Line Items]
Increase (Decrease) in Regulatory Assets	(47)
Baltimore Gas and Electric Company \| Energy efficiency and demand response programs
Regulatory Matters Assets and Liabilities [Line Items]
Increase (Decrease) in Regulatory Assets	(62)
Potomac Electric Power Company
Regulatory Matters Assets and Liabilities [Line Items]
Increase (Decrease) in Regulatory Assets	(40)
Increase (Decrease) in Regulatory Liabilities	(1)
Potomac Electric Power Company \| Removal Costs
Regulatory Matters Assets and Liabilities [Line Items]
Increase (Decrease) in Regulatory Liabilities	22
Potomac Electric Power Company \| Deferred Income Tax Charge
Regulatory Matters Assets and Liabilities [Line Items]
Increase (Decrease) in Regulatory Liabilities	(36)
Potomac Electric Power Company \| Energy efficiency and demand response programs
Regulatory Matters Assets and Liabilities [Line Items]
Increase (Decrease) in Regulatory Assets	(47)
Delmarva Power and Light Company
Regulatory Matters Assets and Liabilities [Line Items]
Increase (Decrease) in Regulatory Assets	8
Delmarva Power and Light Company \| Electric energy and natural gas costs
Regulatory Matters Assets and Liabilities [Line Items]
Increase (Decrease) in Regulatory Assets	8
Delmarva Power and Light Company \| Energy efficiency and demand response programs
Regulatory Matters Assets and Liabilities [Line Items]
Increase (Decrease) in Regulatory Assets	(21)
Delmarva Power and Light Company \| Removal Costs
Regulatory Matters Assets and Liabilities [Line Items]
Increase (Decrease) in Regulatory Assets	13
Atlantic City Electric Company
Regulatory Matters Assets and Liabilities [Line Items]
Increase (Decrease) in Regulatory Assets	26
Increase (Decrease) in Regulatory Liabilities	48
Atlantic City Electric Company \| Electric energy and natural gas costs
Regulatory Matters Assets and Liabilities [Line Items]
Increase (Decrease) in Regulatory Liabilities	30
Atlantic City Electric Company \| Zero Emission Credit
Regulatory Matters Assets and Liabilities [Line Items]
Increase (Decrease) in Regulatory Liabilities	24
Atlantic City Electric Company \| Under/Over Recovered Transmission Costs
Regulatory Matters Assets and Liabilities [Line Items]
Increase (Decrease) in Regulatory Liabilities	(11)
Atlantic City Electric Company \| Energy efficiency and demand response programs
Regulatory Matters Assets and Liabilities [Line Items]
Increase (Decrease) in Regulatory Assets	$ 58