Basis of Presentation Basis of Presentation - Schedule of New Accounting Pronouncements and Changes (Details) - USD ($) $ in Millions	3 Months Ended					12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2017	Dec. 31, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Selling & administrative expenses	$ 183.3				$ 154.8
Operating Income	99.6				107.8
Net income	58.3				62.8
Net sales	991.2				852.3
Cost of goods sold	708.3				589.7
Accounts receivable, net	704.0	$ 540.3				$ 540.3
Inventories, net	714.3	634.7				634.7
Other current assets	70.7	39.6				39.6
Total Assets	4,975.4	3,720.6				3,720.6
Other accrued liabilities	210.9	174.9				174.9
Total Liabilities	3,296.9	2,072.7				2,072.7
Retained Earnings	1,908.9	1,892.4				1,892.4
Total Equity	1,678.5	1,647.9			1,588.8	1,647.9	$ 1,603.2
Accounting Standards Update 2017-07
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cost of goods sold		(0.9)	$ (0.8)	$ (0.8)	(0.8)	(3.3)
Selling & administrative expenses		(2.9)	(3.0)	(3.0)	(2.9)	(11.8)
Total operating expenses		(3.8)	(3.8)	(3.8)	(3.7)	(15.1)
Operating Income		3.8	3.8	3.8	3.7	15.1
Total other expense		(3.8)	(3.8)	(3.8)	(3.7)	(15.1)
Net income		$ 0.0	$ 0.0	$ 0.0	$ 0.0	$ 0.0
Balances Without Adoption of ASC 606 | Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net sales	990.4
Cost of goods sold	707.5
Accounts receivable, net	685.5
Inventories, net	725.8
Other current assets	59.9
Total Assets	4,957.6
Other accrued liabilities	193.7
Total Liabilities	3,279.7
Retained Earnings	1,908.3
Total Equity	1,677.9
Effect of Adoption Higher/(Lower) | Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net sales	0.8
Cost of goods sold	0.8
Accounts receivable, net	(18.5)
Inventories, net	11.5
Other current assets	(10.8)
Total Assets	(17.8)
Other accrued liabilities	(17.2)
Total Liabilities	(17.2)
Retained Earnings	(0.6)
Total Equity	$ (0.6)