Share Plans - Schedule of Share-based Compensation Expense (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation associated with discontinued operations				$ 3.4
Total share-based compensation expense	$ 4.6	$ 5.1	$ 15.3	16.4
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	2.5	2.4	8.2	6.7
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	0.9	1.3	3.4	3.5
Performance share units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	$ 1.2	$ 1.4	$ 3.7	$ 6.2