Commitments and Contingencies - Narrative (Details) $ in Millions		12 Months Ended
	Mar. 23, 2016 MW	Dec. 31, 2022 USD ($) MGPSite MW	Dec. 31, 2018 MW	Dec. 31, 2017 MW	Dec. 31, 2021 USD ($)
Commitments and Contingencies [Line Items]
Other Commitment		$ 631
Accrual for Environmental Loss Contingencies, Gross		409			$ 352
Deferred Prosecution Payment		200
Commonwealth Edison Co [Member]
Commitments and Contingencies [Line Items]
Other Commitment		$ 258
Sites under study/remediation | MGPSite		20
Accrual for Environmental Loss Contingencies, Gross		$ 325			279
Deferred Prosecution Payment		200
Customer Refund Liability, Current		38
Customer Refund Liability, Current		38
Commonwealth Edison Co [Member] | Illinois Chamber of Commerce
Commitments and Contingencies [Line Items]
Customer Refund Liability, Current		31
Customer Refund Liability, Current		31
Commonwealth Edison Co [Member] | Accrual For MGP Investigation And Remediation [Member]
Commitments and Contingencies [Line Items]
Accrual for Environmental Loss Contingencies, Period Increase (Decrease)		60
Accrual for Environmental Loss Contingencies, Period Increase (Decrease)		60
PECO Energy Co [Member]
Commitments and Contingencies [Line Items]
Other Commitment		$ 181
Sites under study/remediation | MGPSite		6
Accrual for Environmental Loss Contingencies, Gross		$ 25			22
Baltimore Gas and Electric Company [Member]
Commitments and Contingencies [Line Items]
Other Commitment		$ 4
Sites under study/remediation | MGPSite		4
Accrual for Environmental Loss Contingencies, Gross		$ 9			6
Banking Regulation, Common Equity Tier One Risk-Based Capital Ratio, Actual		0.48
Pepco Holdings LLC [Member]
Commitments and Contingencies [Line Items]
Other Commitment		$ 125
Accrual for Environmental Loss Contingencies, Gross		46			42
Potomac Electric Power Company [Member]
Commitments and Contingencies [Line Items]
Other Commitment		94
Accrual for Environmental Loss Contingencies, Gross		$ 44			40
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		$ 19
Sites under study/remediation | MGPSite		1
Accrual for Environmental Loss Contingencies, Gross		$ 1			1
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
Accrual for Environmental Loss Contingencies, Gross		$ 1			$ 1
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
PEPCO Holdings Inc [Member] | Pepco Holdings LLC [Member]
Commitments and Contingencies [Line Items]
Other Commitment		320
PEPCO Holdings Inc [Member] | Potomac Electric Power Company [Member]
Commitments and Contingencies [Line Items]
Other Commitment		120
PEPCO Holdings Inc [Member] | Delmarva Power & Light Company [Member]
Commitments and Contingencies [Line Items]
Other Commitment		89
PEPCO Holdings Inc [Member] | Atlantic City Electric Company [Member]
Commitments and Contingencies [Line Items]
Other Commitment		$ 111
PEPCO Holdings Inc [Member] | Wind Assets [Member] | Delmarva Power & Light Company [Member]
Commitments and Contingencies [Line Items]
Purchase Commitment | MW	120	40	40	40