Environmental Commitments and Contingencies Summary of Environmental Liabilities (Tables)

3 Months Ended

Mar. 31, 2020

Environmental Commitments and Contingencies [Abstract]

Environmental Remedies [Table Text Block]

MGP Site (Jurisdiction)	Status	Estimated Cost to Clean up (Expect to Recover through Rates with Customers)
West Palm Beach (Florida)	Remedial actions approved by the Florida Department of Environmental Protection have been implemented on the east parcel of the site. We expect to implement similar remedial actions on the site's west parcel in 2020.	Between $4.5 million to $15.4 million, including costs associated with the relocation of FPU’s operations at this site, and any potential costs associated with future redevelopment of the properties.
Sanford (Florida)	In March 2018, the United States Environmental Protection Agency ("EPA") approved a "site-wide ready for anticipated use" status, which is the final step before delisting a site. Construction has been completed and restrictive covenants are in place to ensure protection of human health. The only remaining activity is long-term groundwater monitoring.	FPU's remaining remediation expenses, including attorneys' fees and costs, are anticipated to be immaterial.
Winter Haven (Florida)	Remediation is ongoing.	Not expected to exceed $0.4 million.
Seaford (Delaware)	Conducted investigations of on-site and off-site impacts in the vicinity of the site, from 2014 through 2018, and submitted the findings to Delaware Department of Natural Resources and Environmental Control ("DNREC") in a March 2019 report. An interim action involving air-sparging/vapor extraction is being implemented, in accordance with the DNREC-approved Work Plan.	Between $0.2 million and $0.5 million.