Commitments and Contingencies - Narrative (Details)		12 Months Ended
	Mar. 23, 2016 USD ($) MW	Dec. 31, 2022 MW	Dec. 31, 2021 USD ($) MGPSite Open_claim MW	Dec. 31, 2018 MW	Dec. 31, 2017 MW	Mar. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Commitments and Contingencies [Line Items]
Other Commitment			$ 3,814,000,000
Accrual for Environmental Loss Contingencies, Gross			469,000,000				$ 483,000,000
Deferred Prosecution Payment			200,000,000
Exelon Generation Co L L C [Member]
Commitments and Contingencies [Line Items]
Nuclear financial protection pool value			450,000,000
Maximum recovery limit from a nuclear industry mutual insurance company in the event of multiple losses			13,100,000,000
Maximum annual assessment payment mandated by Price-Anderson Act for a nuclear incident			2,800,000,000
Cost of spent nuclear fuel disposal per kWh of net nuclear generation			0.001
Spent Nuclear Fuel Storage Reimbursement Net Co Owners			1,294,000,000
Spent Nuclear Fuel Storage Reimbursement			$ 1,492,000,000
Spent Nuclear Fuel Treasury Interest Rate			0.051%
Spent Nuclear Fuel Treasury Interest Rate - FitzPatrick			0.041%
Asbestos Liability Reserve			$ 81,000,000				89,000,000
LDC Damages | Exelon Generation Co L L C [Member]
Commitments and Contingencies [Line Items]
Estimated Litigation Liability, Current						$ 40,000,000
LDC Damages - Accrued Liability | Exelon Generation Co L L C [Member]
Commitments and Contingencies [Line Items]
Estimated Litigation Liability, Current			40,000,000
West Lake [Member]
Commitments and Contingencies [Line Items]
Accrual for Environmental Loss Contingencies, Gross			290,000,000
West Lake [Member] | Exelon Generation Co L L C [Member]
Commitments and Contingencies [Line Items]
Accrual for Environmental Loss Contingencies, Gross			40,000,000
Environmental loss contingencies			90,000,000
Nuclear Insurance Premiums [Member] | Exelon Generation Co L L C [Member]
Commitments and Contingencies [Line Items]
Nuclear insurance liability limit per incident			13,500,000,000
Nuclear Insurance Premiums [Member] | Maximum [Member] | Exelon Generation Co L L C [Member]
Commitments and Contingencies [Line Items]
Nuclear financial protection pool value			413,000,000
Guarantees Other Than Letters Of Credit and Nuclear Insurance Premiums [Member] | Exelon Generation Co L L C [Member]
Commitments and Contingencies [Line Items]
Mutual Property Insurance Distribution To Members			113,000,000				75,000,000	$ 136,000,000
Commonwealth Edison Co [Member]
Commitments and Contingencies [Line Items]
Other Commitment			$ 224,000,000
Sites under study/remediation | MGPSite			21
Accrual for Environmental Loss Contingencies, Gross			$ 279,000,000				293,000,000
Deferred Prosecution Payment			200,000,000
PECO Energy Co [Member]
Commitments and Contingencies [Line Items]
Other Commitment			$ 181,000,000
Sites under study/remediation | MGPSite			6
Accrual for Environmental Loss Contingencies, Gross			$ 22,000,000				23,000,000
Baltimore Gas and Electric Company [Member]
Commitments and Contingencies [Line Items]
Other Commitment			$ 5,000,000
Sites under study/remediation | MGPSite			4
Accrual for Environmental Loss Contingencies, Gross			$ 6,000,000				2,000,000
Banking Regulation, Common Equity Tier One Risk-Based Capital Ratio, Actual			0.48
Pepco Holdings LLC [Member]
Commitments and Contingencies [Line Items]
Other Commitment			$ 54,000,000
Accrual for Environmental Loss Contingencies, Gross			42,000,000				44,000,000
Potomac Electric Power Company [Member]
Commitments and Contingencies [Line Items]
Other Commitment			24,000,000
Accrual for Environmental Loss Contingencies, Gross			$ 40,000,000				42,000,000
Banking Regulation, Common Equity Tier One Risk-Based Capital Ratio, Actual			0.48
Delmarva Power & Light Company [Member]
Commitments and Contingencies [Line Items]
Other Commitment			$ 18,000,000
Sites under study/remediation | MGPSite			1
Accrual for Environmental Loss Contingencies, Gross			$ 1,000,000				1,000,000
Banking Regulation, Common Equity Tier One Risk-Based Capital Ratio, Actual			0.48
Atlantic City Electric Company [Member]
Commitments and Contingencies [Line Items]
Other Commitment			$ 12,000,000
Accrual for Environmental Loss Contingencies, Gross			$ 1,000,000				$ 1,000,000
Banking Regulation, Common Equity Tier One Risk-Based Capital Ratio, Actual			0.48
Atlantic City Electric Company [Member] | Minimum [Member]
Commitments and Contingencies [Line Items]
Banking Regulation, Common Equity Tier One Risk-Based Capital Ratio, Actual			0.30
PEPCO Holdings Inc [Member]
Commitments and Contingencies [Line Items]
Other Commitment			$ 513,000,000
PEPCO Holdings Inc [Member] | Pepco Holdings LLC [Member]
Commitments and Contingencies [Line Items]
Other Commitment			320,000,000
PEPCO Holdings Inc [Member] | Potomac Electric Power Company [Member]
Commitments and Contingencies [Line Items]
Other Commitment			120,000,000
PEPCO Holdings Inc [Member] | Delmarva Power & Light Company [Member]
Commitments and Contingencies [Line Items]
Other Commitment			89,000,000
PEPCO Holdings Inc [Member] | Atlantic City Electric Company [Member]
Commitments and Contingencies [Line Items]
Other Commitment			$ 111,000,000
PEPCO Holdings Inc [Member] | Other Solar Projects [Member]
Commitments and Contingencies [Line Items]
Business Acquisition, Expected New Generation Mwh | MW	37		33
Other Commitment	$ 135,000,000		$ 121,000,000
PEPCO Holdings Inc [Member] | Other Solar Projects [Member] | Exelon Generation Co L L C [Member] | Subsequent Event [Member]
Commitments and Contingencies [Line Items]
Business Acquisition, Expected New Generation Mwh | MW		4
PEPCO Holdings Inc [Member] | Other Solar Projects [Member] | Generation Solar Business
Commitments and Contingencies [Line Items]
OtherNonFinancialCommitment1 | MW			30
PEPCO Holdings Inc [Member] | Wind Assets [Member]
Commitments and Contingencies [Line Items]
OtherNonFinancialCommitment1 | MW	100
PEPCO Holdings Inc [Member] | Wind Assets [Member] | Delmarva Power & Light Company [Member]
Commitments and Contingencies [Line Items]
Purchase Commitment | MW	120			40	40
PEPCO Holdings Inc [Member] | Wind Assets [Member] | Delmarva Power & Light Company [Member] | Subsequent Event [Member]
Commitments and Contingencies [Line Items]
Purchase Commitment | MW		40
Open Claims [Member] | Exelon Generation Co L L C [Member]
Commitments and Contingencies [Line Items]
Asbestos Liability Reserve			$ 17,000,000
Open Asbestos Liability Claims | Open_claim			211
Estimated Future Claims [Member] | Exelon Generation Co L L C [Member]
Commitments and Contingencies [Line Items]
Asbestos Liability Reserve			$ 64,000,000