Defined Benefit Pension Plans Schedule of Significant Actuarial Weighted Average Assumptions Used in Determining the Benefit Obligation and Net Periodic Benefit Cost (Details)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan [Abstract]
Discount rate	2.21%	2.18%	2.59%
Expected annual rate of compensation increase	3.64%	3.65%	3.60%
Discount rate	2.18%	2.59%	2.36%
Expected rate of return on plan assets	5.58%	5.29%	5.45%
Expected annual rate of compensation increase	3.65%	3.60%	3.37%