Condensed Statements of Income (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Income Statement [Abstract]
Sales	$ 652.2	$ 508.7	$ 1,282.2	$ 1,015.9
Operating expenses:
Cost of goods sold	531.1	391.4	1,035.5	784.3
Selling and administration	48.7	45.1	97.8	88.8
Restructuring charges	0.2	1.8	2.5	3.7
Other operating income (expense)	1.5	(0.1)	1.7	0.4
Operating income	73.7	70.3	148.1	139.5
Earnings of non-consolidated affiliates	0.8	0.6	1.4	0.8
Interest expense	9.7	5.8	18.8	12.3
Interest income	0.1	0.3	0.2	0.5
Other expense	2.2	2.1	4.4	4.7
Income before taxes	62.7	63.3	126.5	123.8
Income tax provision	19.0	15.7	42.3	37.5
Net income	$ 43.7	$ 47.6	$ 84.2	$ 86.3
Net income per common share:
Basic	$ 0.54	$ 0.59	$ 1.05	$ 1.08
Diluted	$ 0.54	$ 0.59	$ 1.04	$ 1.07
Dividends per common share	$ 0.20	$ 0.20	$ 0.40	$ 0.40
Average common shares outstanding:
Basic	80.2	80.1	80.2	80.1
Diluted	81.2	80.7	81.2	80.8