Other Expense Restructuring and Related Charges (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2018
Restructuring Cost and Reserve [Line Items]
Payments to acquire property, plant, and equipment			$ 48.2	$ 67.0
Severance charges	$ 1.3	$ 0.0	3.3	0.0
Other charges	0.6	0.0	1.8	0.0
Restructuring and related charges	2.2		5.5
Restructuring Reserve [Roll Forward]
Charges	2.2	$ 0.0	5.5	$ 0.0
Asset-related charges [Member]
Restructuring Reserve [Roll Forward]
Cash payments			0.0
Other charges [Member]
Restructuring Reserve [Roll Forward]
Cash payments			0.0
2018 Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Severance charges	1.3		3.3
Asset impairment charges, patent and equipment	0.3		0.4
Other charges	0.6		1.8
Restructuring and related charges	2.2		5.5
Restructuring Reserve [Roll Forward]
Balance, December 31, 2017			0.0		$ 0.0
Charges			5.5
Cash payments			(0.1)
Non-cash asset-write-downs			(2.2)
Balance, June 30, 2018	3.2		3.2
2018 Restructuring Plan [Member] | Severance and benefits [Member]
Restructuring Reserve [Roll Forward]
Balance, December 31, 2017			0.0		0.0
Charges			3.3
Cash payments			(0.1)
Non-cash asset-write-downs			0.0
Balance, June 30, 2018	3.2		3.2
2018 Restructuring Plan [Member] | Asset-related charges [Member]
Restructuring Reserve [Roll Forward]
Balance, December 31, 2017			0.0		0.0
Charges			0.4
Non-cash asset-write-downs			(0.4)
Balance, June 30, 2018	0.0		0.0
2018 Restructuring Plan [Member] | Other charges [Member]
Restructuring Reserve [Roll Forward]
Balance, December 31, 2017			0.0		0.0
Charges			1.8
Non-cash asset-write-downs			(1.8)
Balance, June 30, 2018	0.0		0.0
2018 Restructuring Plan [Member] | Minimum [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost					8.0
Payments to acquire property, plant, and equipment					9.0
Effect on future earnings					17.0
2018 Restructuring Plan [Member] | Maximum [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost					13.0
Payments to acquire property, plant, and equipment					14.0
Effect on future earnings					$ 22.0
2016 Restructuring Plan [Member]
Restructuring Reserve [Roll Forward]
Balance, June 30, 2018	$ 1.0		$ 1.0