Restructuring Costs - Reserve (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Restructuring Reserve [Roll Forward]
Beginning accrued restructuring balance 1/1/16		$ 24.5
Pre-tax restructuring costs		20.3	$ 35.0	$ 23.6
Utilization and foreign exchange		(23.9)
Ending accrued restructuring balance 12/31/2016	$ 24.5	20.9	24.5
2017 Restructuring Actions
Restructuring Reserve [Roll Forward]
Beginning accrued restructuring balance 1/1/16		0.0
Pre-tax restructuring costs		14.0
Utilization and foreign exchange		(8.6)
Ending accrued restructuring balance 12/31/2016	0.0	5.4	0.0
2016 Restructuring Actions
Restructuring Reserve [Roll Forward]
Beginning accrued restructuring balance 1/1/16		24.5
Pre-tax restructuring costs		6.3
Utilization and foreign exchange		(15.3)
Ending accrued restructuring balance 12/31/2016	24.5	15.5	24.5
Severance | 2017 Restructuring Actions
Restructuring Reserve [Roll Forward]
Beginning accrued restructuring balance 1/1/16		0.0
Pre-tax restructuring costs		7.4
Utilization and foreign exchange		(3.8)
Ending accrued restructuring balance 12/31/2016	0.0	3.6	0.0
Severance | 2016 Restructuring Actions
Restructuring Reserve [Roll Forward]
Beginning accrued restructuring balance 1/1/16		10.4
Pre-tax restructuring costs		(2.2)
Utilization and foreign exchange		(6.4)
Ending accrued restructuring balance 12/31/2016	10.4	1.8	10.4
Asset write-downs | 2017 Restructuring Actions
Restructuring Reserve [Roll Forward]
Beginning accrued restructuring balance 1/1/16		0.0
Pre-tax restructuring costs		0.5
Utilization and foreign exchange		(0.5)
Ending accrued restructuring balance 12/31/2016	0.0	0.0	0.0
Asset write-downs | 2016 Restructuring Actions
Restructuring Reserve [Roll Forward]
Beginning accrued restructuring balance 1/1/16		0.0
Pre-tax restructuring costs		0.0
Utilization and foreign exchange		0.0
Ending accrued restructuring balance 12/31/2016	0.0	0.0	0.0
Facility closure and other costs | 2017 Restructuring Actions
Restructuring Reserve [Roll Forward]
Beginning accrued restructuring balance 1/1/16		0.0
Pre-tax restructuring costs		6.1
Utilization and foreign exchange		(4.3)
Ending accrued restructuring balance 12/31/2016	0.0	1.8	0.0
Facility closure and other costs | 2016 Restructuring Actions
Restructuring Reserve [Roll Forward]
Beginning accrued restructuring balance 1/1/16		14.1
Pre-tax restructuring costs		8.5
Utilization and foreign exchange		(8.9)
Ending accrued restructuring balance 12/31/2016	14.1	$ 13.7	14.1
Withdrawal from Multiemployer Defined Benefit Plan
Restructuring Reserve [Roll Forward]
Pre-tax restructuring costs	12.5
Withdrawal from Multiemployer Defined Benefit Plan | 2016 Restructuring Actions
Restructuring Reserve [Roll Forward]
Pre-tax restructuring costs	$ 12.5		$ 12.5