Summary of Significant Accounting Policies - Summary of Property, Plant and Equipment by Classification (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2021 USD ($) mi	Dec. 31, 2020 USD ($) mi	Dec. 31, 2019 USD ($)
Property, Plant and Equipment [Line Items]
Contributions in Aid of Construction	$ 6,300	$ 3,700
Public Utilities, Allowance for Funds Used During Construction, Description	$ 400	700	$ 700
Number of Months to Establish ROU Asset and Liability	12 months
Property, plant and equipment
Total property, plant and equipment	$ 2,112,964	1,908,992
Less: Accumulated depreciation and amortization	(417,479)	(368,743)
Net property, plant and equipment	1,744,878	1,601,178
Construction Work in Progress	49,393	60,929
Jointly Owned Pipeline [Member]
Property, plant and equipment
Accumulated Depreciation, Depletion and Amortization, Sale or Disposal of Property, Plant and Equipment	900
Natural Gas
Property, plant and equipment
Accumulated Depreciation, Depletion and Amortization, Sale or Disposal of Property, Plant and Equipment	1,800	1,700
Natural Gas Distribution [Member] | Delmarva and Florida [Member]
Property, plant and equipment
Total property, plant and equipment	859,627	782,329
Natural Gas Transmission [Member] | Delmarva Peninsula, Pennsylvania and Florida [Member]
Property, plant and equipment
Total property, plant and equipment	727,277	667,538
Natural Gas Transmission [Member] | OHIO
Property, plant and equipment
Total property, plant and equipment	112,050	87,962
Electric distribution | Florida
Property, plant and equipment
Total property, plant and equipment	133,383	127,710
Propane Operations [Member] | Mid-Atlantic and Florida [Member]
Property, plant and equipment
Total property, plant and equipment	176,095	151,258
Electricity and Steam Generation [Member] | Florida
Property, plant and equipment
Total property, plant and equipment	36,740	36,521
Mobile CNG Utility and Pipeline Solutions [Member] | Florida
Property, plant and equipment
Total property, plant and equipment	32,374	24,905
Other
Property, plant and equipment
Total property, plant and equipment	$ 35,418	$ 30,769
Natural Gas Operations
Property, plant and equipment
Miles Of Natural Gas Pipeline | mi	26	16
Jointly Owned Pipeline [Member]
Property, plant and equipment
Net property, plant and equipment	$ 27,600
Natural gas distribution operations [Member]
Property, plant and equipment
Net property, plant and equipment	$ 6,700