Commitments and Contingencies Environmental (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Accrual for Environmental Loss Contingencies	$ 2.1	$ 3.0
Number of years expected for future environmental remediation expenditures duration	10 years
Accrual for Environmental Loss Contingencies, Significant Assumptions	We accrue for certain environmental remediation-related activities for which commitments or remediation plans have been developed and for which costs can be reasonably estimated. These estimates are determined based upon currently available facts and circumstances regarding each facility. Actual costs incurred may vary from these estimates due to the inherent uncertainties involved. Future expenditures relating to these environmental remediation efforts are expected to be made over the next 10 years as ongoing costs of remediation programs.