Organization and Operations - EEGH (Details) - Eastern Energy Gas Holdings, LLC [Member]	12 Months Ended
	Dec. 31, 2020 mi
Iroquois Gas Transmission System L.P. [Member]
Variable Interest Entity [Line Items]
Variable interest entity, ownership percentage	50.00%
Variable Interest Entity, Primary Beneficiary [Member] | Limited Partner [Member] | Cove Point LNG, LP [Member]
Variable Interest Entity [Line Items]
Variable interest entity, ownership percentage	25.00%
Variable Interest Entity, Primary Beneficiary [Member] | General Partner [Member] | Cove Point LNG, LP [Member]
Variable Interest Entity [Line Items]
Variable interest entity, ownership percentage	100.00%
Variable Interest Entity, Primary Beneficiary [Member] | Federal Energy Regulatory Commission [Member] | Iroquois Gas Transmission System L.P. [Member]
Variable Interest Entity [Line Items]
Miles of interstate natural gas transportation pipeline	416