Segment information - Revenue And Operating Profits (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Segment Reporting Information [Line Items]
Revenues	$ 852.4	$ 849.5	$ 2,581.2	$ 2,443.8
Operating Profit	67.0	66.4	193.5	185.6
Foreign currency transaction gains (losses)			(5.9)	(9.1)
Reportable segments
Segment Reporting Information [Line Items]
Revenues	852.4	828.7	2,529.8	2,328.6
Operating Profit	110.7	97.9	310.9	251.3
Corporate expenses
Segment Reporting Information [Line Items]
General, administrative and other expenses	(20.6)	(22.4)	(72.6)	(59.9)
Foreign currency transaction gains (losses)	0.4	0.5	(1.8)	0.7
Reconciliation of segment policies to GAAP	4.8	0.4	6.5	(1.4)
Other items not allocated to segments
Segment Reporting Information [Line Items]
Acquisitions and dispositions, Revenues	0.0	0.0	0.0	0.0
Reorganization and Restructuring	(7.3)	(6.4)	(15.5)	(16.1)
Acquisitions and dispositions, Operating profit	(10.7)	(6.1)	(24.6)	(8.1)
Reporting compliance	(2.0)		(3.4)
Other items not allocated to segments \| Venezuela operations
Segment Reporting Information [Line Items]
Revenues	0.0	20.8	51.4	115.2
Operating Profit	0.0	2.5	2.3	19.1
Other items not allocated to segments \| Argentina
Segment Reporting Information [Line Items]
Argentina highly inflationary impact	(8.3)		(8.3)
North America \| Reportable segments
Segment Reporting Information [Line Items]
Revenues	383.4	316.5	1,027.5	932.1
Operating Profit	33.6	16.9	80.3	43.9
South America \| Reportable segments
Segment Reporting Information [Line Items]
Revenues	215.5	247.4	703.6	654.2
Operating Profit	46.3	47.7	148.0	123.3
Rest of World \| Reportable segments
Segment Reporting Information [Line Items]
Revenues	253.5	264.8	798.7	742.3
Operating Profit	$ 30.8	$ 33.3	$ 82.6	$ 84.1

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