Inventories (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Inventories [Line Items]
Inventories stated on the LIFO basis	$ 18.2	$ 21.9
Inventories stated value below replacement costs	16.4	15.9
PE Films [Member]
Inventories [Line Items]
Cost of goods sold stated at below current replacement costs	$ 0.3	$ 1.5