Present and Prospective Accounting Pronouncements Effect of change related to ASU 2014-09 (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Jun. 30, 2018	Sep. 30, 2018	Sep. 30, 2017	Jan. 01, 2018	Dec. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net sales	$ 736.8	$ 718.3		$ 2,238.9	$ 2,023.3
Cost of sales	524.0	507.7		1,588.7	1,502.3
Selling, general and administrative expense	(51.2)	(49.3)		(151.9)	(145.3)
Provision for income taxes	41.8	46.4		122.7	97.9
Net income	124.0	$ 109.8	$ 377.6	377.6	$ 259.2
Receivables, net of allowance of doubtful accounts	(143.5)			(143.5)			$ (142.5)
Inventories	284.4			284.4			259.1
Income taxes payable	11.6			11.6			4.5
Retained earnings	(1,613.9)			(1,613.9)			$ (1,280.1)
Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net sales	11.7			7.0
Cost of sales	6.4			3.9
Selling, general and administrative expense	(1.2)			(3.1)
Provision for income taxes	1.6			0.0
Net income	4.9			0.0
Receivables, net of allowance of doubtful accounts	(25.6)			(25.6)
Inventories	19.7			19.7
Income taxes payable	1.5			1.5
Retained earnings	4.4			4.4
Calculated under Revenue Guidance in Effect before Topic 606 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net sales	725.1			2,245.9
Cost of sales	517.6			1,592.6
Selling, general and administrative expense	(52.4)			(155.0)
Provision for income taxes	40.2			122.7
Net income	119.1			377.6
Receivables, net of allowance of doubtful accounts	(169.1)			(169.1)
Inventories	264.7			264.7
Income taxes payable	10.1			10.1
Retained earnings	$ (1,618.3)			$ (1,618.3)
Accounting Standards Update 2014-09 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Receivables, net of allowance of doubtful accounts						$ 21.7
Inventories						15.8
Retained earnings						$ 4.4