CONDENSED CONSOLIDATED STATEMENTS OF INCOME (unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Statement [Abstract]
Net sales	$ 410.3	$ 464.5	$ 1,312.5	$ 1,275.7
Cost of sales	291.2	309.5	846.8	882.3
Gross margin	119.1	155.0	465.7	393.4
Selling, general and administrative expense	57.3	51.3	173.7	147.6
Other operating income (expense):
Currency transactions, net	(0.6)	(4.3)	4.2	(8.0)
Other operating expense, net	(3.1)	(3.3)	(10.7)	(11.0)
Income from operations	58.1	96.1	285.5	226.8
Other income (expense):
Interest and dividend income	1.5	0.4	3.7	0.7
Marketable equity securities	(4.3)		(6.7)
Other components of net periodic pension and OPEB cost	(3.7)	(4.5)	(11.3)	(12.8)
Loss on prepayment of debt, net		(7.1)		(7.1)
Interest expense	(4.9)	(5.0)	(14.7)	(14.5)
Income before income taxes	46.7	79.9	256.5	193.1
Income tax expense (benefit)	14.1	6.1	75.5	(114.0)
Net income	$ 32.6	$ 73.8	$ 181.0	$ 307.1
Net income per basic and diluted share	$ 0.28	$ 0.64	$ 1.56	$ 2.65
Cash dividends per share	$ 0.17	$ 0.15	$ 0.51	$ 0.45
Weighted average shares used in the calculation of net income per share	115.9	115.9	115.9	115.9