Basis of Presentation (Narrative) (Details)	3 Months Ended
	Mar. 31, 2018 USD ($) polymer_solution customer	Mar. 31, 2017 USD ($)	Dec. 31, 2017 USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Typical contract life (less than)	12 months
Number of polymer solutions (more than) | polymer_solution	35,000
Number of customers (over) | customer	10,000
Accounting Standards Update 2016-16
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of adoption			$ 17,000,000
Other Income | Accounting Standards Update 2017-07
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net periodic benefit gain	$ 1,400,000	$ 2,000,000
Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Accounting Standards Update 2014-09 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Retained earnings			$ 0