Segment information - Revenue And Operating Profits (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Segment Reporting Information [Line Items]
Revenues	$ 849.5	$ 755.8	$ 2,443.8	$ 2,217.1
Operating Profit	66.4	59.7	185.6	115.4
Reportable segments
Segment Reporting Information [Line Items]
Revenues	828.7	734.9	2,328.6	2,140.3
Operating Profit	97.9	76.9	251.3	177.1
Corporate expenses
Segment Reporting Information [Line Items]
General, administrative and other expenses	(22.4)	(12.9)	(59.9)	(46.6)
Foreign currency transaction gains	0.5	(0.2)	0.7	2.5
Reconciliation of segment policies to GAAP	0.4	(0.8)	(1.4)	3.7
Other items not allocated to segments
Segment Reporting Information [Line Items]
Acquisitions and dispositions, Revenues	0.0	0.5	0.0	2.8
Reorganization and Restructuring	(6.4)	(2.3)	(16.1)	(10.4)
Acquisitions and dispositions, Operating profit	(6.1)	(3.2)	(8.1)	(17.4)
Other items not allocated to segments | Venezuela operations
Segment Reporting Information [Line Items]
Revenues	20.8	20.4	115.2	74.0
Operating Profit	2.5	2.2	19.1	6.5
North America | Reportable segments
Segment Reporting Information [Line Items]
Revenues	316.5	297.0	932.1	890.5
Operating Profit	16.9	8.9	43.9	16.4
South America | Reportable segments
Segment Reporting Information [Line Items]
Revenues	247.4	186.7	654.2	513.8
Operating Profit	47.7	35.0	123.3	81.1
Rest of World | Reportable segments
Segment Reporting Information [Line Items]
Revenues	264.8	251.2	742.3	736.0
Operating Profit	$ 33.3	$ 33.0	$ 84.1	$ 79.6