Derivative Financial Instruments - Narrative (Details) MWh in Millions, $ in Millions	1 Months Ended	3 Months Ended	9 Months Ended
	Jun. 30, 2012 MWh	Sep. 30, 2023 USD ($)	Sep. 30, 2023 USD ($)	Jan. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Derivative [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax		$ (596)	$ (596)		$ (638)
Corporate, Non-Segment | Notes Payable to Banks
Derivative [Line Items]
Debt instrument, face amount		$ 2,500	2,500
Commonwealth Edison Co
Derivative [Line Items]
Long-term Purchase Commitment, Minimum Energy Volume Required | MWh	1.3
PECO Energy Co
Derivative [Line Items]
Estimated Percent of Gas Purchases Being Hedged		10.00%
Incremental Collateral For Loss Of Investment Grade Credit Rating		$ 20	20
Baltimore Gas and Electric Company
Derivative [Line Items]
Incremental Collateral For Loss Of Investment Grade Credit Rating		$ 30	30
Baltimore Gas and Electric Company | Maximum [Member]
Derivative [Line Items]
Estimated Percent of Gas Purchases Being Hedged		20.00%
Baltimore Gas and Electric Company | Minimum [Member]
Derivative [Line Items]
Estimated Percent of Gas Purchases Being Hedged		10.00%
Delmarva Power and Light Company
Derivative [Line Items]
Estimated Percent of Gas Purchases Being Hedged		50.00%
Incremental Collateral For Loss Of Investment Grade Credit Rating		$ 9	9
InterestRateSwapNotional5YR | Cash Flow Hedging
Derivative [Line Items]
Derivative, Notional Amount		390	390	$ 115	635
InterestRateSwapNotional10YR | Cash Flow Hedging
Derivative [Line Items]
Derivative, Notional Amount		390	390	115	635
Interest Rate Swap [Member] | Cash Flow Hedging
Derivative [Line Items]
Derivative, Notional Amount		780	780	230	1,270
Derivative, Cash Received on Hedge		10
Derivative, Gain (Loss) on Derivative, Net		22	31
InterestRateSwapNotionalTerminated | Cash Flow Hedging
Derivative [Line Items]
Derivative, Notional Amount				1,500
Accumulated Other Comprehensive Income (Loss), Net of Tax				$ 7
Interest Rate Cap | Not Designated as Hedging Instrument, Economic Hedge [Member]
Derivative [Line Items]
Derivative, Notional Amount		$ 1,000	$ 1,000		1,850
InterestRateCap18month | Not Designated as Hedging Instrument, Economic Hedge [Member]
Derivative [Line Items]
Derivative, Notional Amount					1,000
InterestRateCapNotional6month | Not Designated as Hedging Instrument, Economic Hedge [Member]
Derivative [Line Items]
Derivative, Notional Amount					$ 850