General and Summary of Significant Accounting Policies Post-retirement and Post-employment Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accounting Policies [Abstract]
Pension and Other Postretirement Benefits Cost (Reversal of Cost)	$ 2.0	$ 1.5	$ 1.3