Lessor - Narrative (Details)	12 Months Ended
	Dec. 31, 2020
Minimum [Member]
Lessor, Lease, Description [Line Items]
Remaining lease terms, Lessor, Operating Lease	1 year
Options to extend the term, Lessor, Operating Lease	1 years
Maximum [Member]
Lessor, Lease, Description [Line Items]
Remaining lease terms, Lessor, Operating Lease	82 years
Options to extend the term, Lessor, Operating Lease	79 years
Long-term Contract for Purchase of Electric Power [Member]
Lessor, Lease, Description [Line Items]
Lessor, Operating Lease, Description	●
Real Estate [Member]
Lessor, Lease, Description [Line Items]
Lessor, Operating Lease, Description	●
Exelon Generation Co L L C [Member] | Minimum [Member]
Lessor, Lease, Description [Line Items]
Remaining lease terms, Lessor, Operating Lease	1 year
Options to extend the term, Lessor, Operating Lease	1 years
Exelon Generation Co L L C [Member] | Maximum [Member]
Lessor, Lease, Description [Line Items]
Remaining lease terms, Lessor, Operating Lease	31 years
Options to extend the term, Lessor, Operating Lease	5 years
Exelon Generation Co L L C [Member] | Long-term Contract for Purchase of Electric Power [Member]
Lessor, Lease, Description [Line Items]
Lessor, Operating Lease, Description	●
Exelon Generation Co L L C [Member] | Real Estate [Member]
Lessor, Lease, Description [Line Items]
Lessor, Operating Lease, Description	●
Commonwealth Edison Co [Member] | Minimum [Member]
Lessor, Lease, Description [Line Items]
Remaining lease terms, Lessor, Operating Lease	1 year
Options to extend the term, Lessor, Operating Lease	5 years
Commonwealth Edison Co [Member] | Maximum [Member]
Lessor, Lease, Description [Line Items]
Remaining lease terms, Lessor, Operating Lease	16 years
Options to extend the term, Lessor, Operating Lease	79 years
Commonwealth Edison Co [Member] | Real Estate [Member]
Lessor, Lease, Description [Line Items]
Lessor, Operating Lease, Description	●
PECO Energy Co [Member] | Minimum [Member]
Lessor, Lease, Description [Line Items]
Remaining lease terms, Lessor, Operating Lease	1 year
Options to extend the term, Lessor, Operating Lease	5 years
PECO Energy Co [Member] | Maximum [Member]
Lessor, Lease, Description [Line Items]
Remaining lease terms, Lessor, Operating Lease	82 years
Options to extend the term, Lessor, Operating Lease	50 years
PECO Energy Co [Member] | Real Estate [Member]
Lessor, Lease, Description [Line Items]
Lessor, Operating Lease, Description	●
Baltimore Gas and Electric Company [Member] | Minimum [Member]
Lessor, Lease, Description [Line Items]
Remaining lease terms, Lessor, Operating Lease	22 years
Baltimore Gas and Electric Company [Member] | Maximum [Member]
Lessor, Lease, Description [Line Items]
Remaining lease terms, Lessor, Operating Lease	22 years
Baltimore Gas and Electric Company [Member] | Real Estate [Member]
Lessor, Lease, Description [Line Items]
Lessor, Operating Lease, Description	●
Pepco Holdings LLC [Member] | Minimum [Member]
Lessor, Lease, Description [Line Items]
Remaining lease terms, Lessor, Operating Lease	1 year
Options to extend the term, Lessor, Operating Lease	5 years
Pepco Holdings LLC [Member] | Maximum [Member]
Lessor, Lease, Description [Line Items]
Remaining lease terms, Lessor, Operating Lease	12 years
Options to extend the term, Lessor, Operating Lease	5 years
Pepco Holdings LLC [Member] | Real Estate [Member]
Lessor, Lease, Description [Line Items]
Lessor, Operating Lease, Description	●
Potomac Electric Power Company [Member] | Minimum [Member]
Lessor, Lease, Description [Line Items]
Remaining lease terms, Lessor, Operating Lease	1 year
Potomac Electric Power Company [Member] | Maximum [Member]
Lessor, Lease, Description [Line Items]
Remaining lease terms, Lessor, Operating Lease	5 years
Potomac Electric Power Company [Member] | Real Estate [Member]
Lessor, Lease, Description [Line Items]
Lessor, Operating Lease, Description	●
Delmarva Power & Light Company [Member] | Minimum [Member]
Lessor, Lease, Description [Line Items]
Remaining lease terms, Lessor, Operating Lease	11 years
Delmarva Power & Light Company [Member] | Maximum [Member]
Lessor, Lease, Description [Line Items]
Remaining lease terms, Lessor, Operating Lease	12 years
Delmarva Power & Light Company [Member] | Real Estate [Member]
Lessor, Lease, Description [Line Items]
Lessor, Operating Lease, Description	●
Atlantic City Electric Company [Member] | Minimum [Member]
Lessor, Lease, Description [Line Items]
Remaining lease terms, Lessor, Operating Lease	1 year
Atlantic City Electric Company [Member] | Maximum [Member]
Lessor, Lease, Description [Line Items]
Remaining lease terms, Lessor, Operating Lease	1 year
Atlantic City Electric Company [Member] | Real Estate [Member]
Lessor, Lease, Description [Line Items]
Lessor, Operating Lease, Description	●