Environmental Commitments and Contingencies Summary of Environmental Liabilities (Tables)

6 Months Ended

Jun. 30, 2019

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 other remaining portions, including the anticipated demolition of buildings on the site's west parcel in 2019.	Between $4.5 million to $15.4 million, including costs associated with the relocation of FPU’s operations at this site, which is necessary to implement the remedial plan, 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, which includes costs of implementing institutional controls at the site.
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 to mitigate on-site impact will be implemented, after the Work Plan submitted in June 2019 is approved by DNREC.	Between $0.2 million and $0.5 million.
Cambridge (Maryland)	Currently in discussions with the MDE.	Unable to estimate.