Restructuring Reserves (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended		6 Months Ended		12 Months Ended
	Jan. 31, 2018	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2016	Dec. 31, 2017
Restructuring Cost and Reserve [Line Items]
Assets held-for-sale, not part of disposal group, current	$ 8.0			$ 8.5	$ 3.5
Minimum [Member] | Other expense, net [Member]
Restructuring Cost and Reserve [Line Items]
Severance expense						$ 28.0
Maximum [Member] | Other expense, net [Member]
Restructuring Cost and Reserve [Line Items]
Severance expense						$ 29.0
2017 Restructuring Actions [Member] | Other current liabilities [Member]
Restructuring Cost and Reserve [Line Items]
Liability, severance-related actions		$ 0.3		0.3			$ 1.2
2017 Restructuring Actions [Member] | Other expense, net [Member]
Restructuring Cost and Reserve [Line Items]
Severance expense			$ 2.7		2.7
2016 Restructuring Actions [Member] | Other current liabilities [Member]
Restructuring Cost and Reserve [Line Items]
Liability, severance-related actions		14.1		14.1			$ 11.1
2016 Restructuring Actions [Member] | Other expense, net [Member]
Restructuring Cost and Reserve [Line Items]
Severance expense		$ 3.2	$ 2.7	$ 9.6	$ 5.3