Defined Benefit Pension Plans and Other Post-Employment Benefit Plans - Net Period Benefit Costs Charged to Discontinued Operations (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Defined Benefit Plan Disclosure [Line Items]
Total income included in discontinued operations	$ (0.6)	$ 0.2	$ (4.9)	$ (0.4)
Discontinued Operations
Defined Benefit Plan Disclosure [Line Items]
Total income included in discontinued operations		0.0		(0.4)
Defined benefit pension plans | Discontinued Operations
Defined Benefit Plan Disclosure [Line Items]
Total income included in discontinued operations		(0.1)		(0.5)
Other employee benefit plans
Defined Benefit Plan Disclosure [Line Items]
Total income included in discontinued operations	$ 0.4	(13.4)	$ 0.8	(13.3)
Other employee benefit plans | Discontinued Operations
Defined Benefit Plan Disclosure [Line Items]
Total income included in discontinued operations		$ 0.1		$ 0.1