Debt and Credit Agreements - Narrative (Details) - USD ($) $ in Millions				12 Months Ended
	May 09, 2023	Oct. 04, 2022	Feb. 01, 2022	Dec. 31, 2023	Dec. 31, 2022	Mar. 24, 2023	Mar. 14, 2023	Jan. 13, 2023	Mar. 23, 2017
Debt Instrument [Line Items]
Long-term debt, current maturities				$ (1,403)	$ (1,802)
Revolving Credit Facility
Debt Instrument [Line Items]
Credit facility, amount outstanding during period				$ 0
Exelon Generation Co L L C
Debt Instrument [Line Items]
Proceeds from sale and collection of notes receivable					258
Prime Rate | Maximum
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate				0.275%
Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate | Maximum
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate				1.275%
Corporate, Non-Segment
Debt Instrument [Line Items]
Long-term debt, current maturities				$ (500)	(850)
Corporate, Non-Segment | Revolving Credit Facility
Debt Instrument [Line Items]
Credit facility, term			5 years
Corporate, Non-Segment | Prime Rate
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate				0.275%
Corporate, Non-Segment | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate				1.275%
Corporate, Non-Segment | ShortTermDebt03232017
Debt Instrument [Line Items]
Short-term loans									$ 500
Corporate, Non-Segment | ShortTermDebt03232017 | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate				0.90%
Corporate, Non-Segment | ShortTermDebt03142023
Debt Instrument [Line Items]
Short-term loans							$ 300
Corporate, Non-Segment | ShortTermDebt03242023
Debt Instrument [Line Items]
Short-term loans						$ 200
Commonwealth Edison Co
Debt Instrument [Line Items]
Credit facility, term			5 years
Long-term debt, current maturities				$ (250)	0
Commonwealth Edison Co | Revolving Credit Facility
Debt Instrument [Line Items]
Credit facility, amount outstanding during period				$ 0
Commonwealth Edison Co | Prime Rate
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate				0.00%
Commonwealth Edison Co | Prime Rate | Maximum | External Credit Rating, Non Investment Grade
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate				0.65%
Commonwealth Edison Co | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate				1.00%
Commonwealth Edison Co | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate | Maximum | External Credit Rating, Non Investment Grade
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate				1.65%
Commonwealth Edison Co | ShortTermDebtSOFRplus075Oct2023
Debt Instrument [Line Items]
Short-term loans		$ 150
Commonwealth Edison Co | ShortTermDebtSOFRplus075Oct2023 | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate		0.75%
Commonwealth Edison Co | FMB490Feb2033 | First Mortgage
Debt Instrument [Line Items]
Debt instrument, face amount								$ 400
Commonwealth Edison Co | FMB530Feb2053 | First Mortgage
Debt Instrument [Line Items]
Debt instrument, face amount								$ 575
Commonwealth Edison Co | ShortTermDebtSOFRplus100May72024
Debt Instrument [Line Items]
Short-term loans	$ 400
Commonwealth Edison Co | ShortTermDebtSOFRplus100May72024 | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	1.00%
PECO Energy Co
Debt Instrument [Line Items]
Credit facility, term			5 years
Long-term debt, current maturities				$ 0	(50)
PECO Energy Co | Revolving Credit Facility
Debt Instrument [Line Items]
Credit facility, amount outstanding during period				$ 0
PECO Energy Co | Prime Rate
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate				0.00%
PECO Energy Co | Prime Rate | Maximum | External Credit Rating, Non Investment Grade
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate				0.65%
PECO Energy Co | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate				0.90%
PECO Energy Co | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate | Maximum | External Credit Rating, Non Investment Grade
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate				1.65%
Baltimore Gas and Electric Company
Debt Instrument [Line Items]
Credit facility, term			5 years
Long-term debt, current maturities				$ 0	(300)
Baltimore Gas and Electric Company | Revolving Credit Facility
Debt Instrument [Line Items]
Credit facility, amount outstanding during period				$ 0
Baltimore Gas and Electric Company | Prime Rate
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate				0.00%
Baltimore Gas and Electric Company | Prime Rate | Maximum | External Credit Rating, Non Investment Grade
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate				0.65%
Baltimore Gas and Electric Company | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate				0.90%
Baltimore Gas and Electric Company | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate | Maximum | External Credit Rating, Non Investment Grade
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate				1.65%
Potomac Electric Power Company
Debt Instrument [Line Items]
Credit facility, term			5 years
Potomac Electric Power Company | Revolving Credit Facility
Debt Instrument [Line Items]
Credit facility, amount outstanding during period				$ 0
Potomac Electric Power Company | Prime Rate
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate				0.075%
Potomac Electric Power Company | Prime Rate | Maximum | External Credit Rating, Non Investment Grade
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate				0.65%
Potomac Electric Power Company | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate				1.075%
Potomac Electric Power Company | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate | Maximum | External Credit Rating, Non Investment Grade
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate				1.65%
Delmarva Power & Light Company
Debt Instrument [Line Items]
Credit facility, term			5 years
Long-term debt, current maturities				$ (79)	$ (79)
Delmarva Power & Light Company | Revolving Credit Facility
Debt Instrument [Line Items]
Credit facility, amount outstanding during period				$ 0
Delmarva Power & Light Company | Prime Rate
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate				0.00%
Delmarva Power & Light Company | Prime Rate | Maximum | External Credit Rating, Non Investment Grade
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate				0.65%
Delmarva Power & Light Company | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate				1.00%
Delmarva Power & Light Company | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate | Maximum | External Credit Rating, Non Investment Grade
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate				1.65%
Atlantic City Electric Company
Debt Instrument [Line Items]
Credit facility, term			5 years
Atlantic City Electric Company | Revolving Credit Facility
Debt Instrument [Line Items]
Credit facility, amount outstanding during period				$ 0
Atlantic City Electric Company | Prime Rate
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate				0.00%
Atlantic City Electric Company | Prime Rate | Maximum | External Credit Rating, Non Investment Grade
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate				0.65%
Atlantic City Electric Company | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate				1.00%
Atlantic City Electric Company | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate | Maximum | External Credit Rating, Non Investment Grade
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate				1.65%