Commercial Commitments (Details) - USD ($) $ in Millions		Dec. 31, 2018	Dec. 31, 2017
Guarantor Obligations [Line Items]
Guarantor Obligations, Current Carrying Value		$ 0.9	$ 2.0
Total commercial commitments	[1]	11.5	22.7
Standby letters of credit [Member]
Guarantor Obligations [Line Items]
Total commercial commitments		$ 9.5	$ 17.8

[1] (1) The carrying value of liabilities on the balance sheet for commercial commitments was $0.9 million at December 31, 2018 and $2.0 million at December 31, 2017. The expirations of these commitments range from 2019 to 2023. We are not aware of any event that would require us to satisfy any of our commitments.