Segment information (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Segment Revenue and Operating Profit [Line Items]
Revenues	$ 913.1	$ 982.4	$ 2,806.2	$ 2,902.8
Operating profit	47.5	59.2	(14.3)	109.3
Latin America [Member]
Segment Revenue and Operating Profit [Line Items]
Revenues	343.2	423.8	1,118.1	1,250.3
Operating profit	(5.1)	42.8	(81.4)	90.6
Europe, Middle East and Africa [Member]
Segment Revenue and Operating Profit [Line Items]
Revenues	303.5	301.2	904.4	872.4
Operating profit	15.6	32.1	47.7	59.4
North America [Member]
Segment Revenue and Operating Profit [Line Items]
Revenues	227.9	222.5	673.7	672.0
Operating profit	1.5	0.2	8.3	4.5
Asia Pacific [Member]
Segment Revenue and Operating Profit [Line Items]
Revenues	38.5	34.9	110.0	108.1
Operating profit	5.0	4.8	14.0	14.1
Segment operating profit [Member]
Segment Revenue and Operating Profit [Line Items]
Operating profit	17.0	79.9	(11.4)	168.6
Non Segment [Member]
Segment Revenue and Operating Profit [Line Items]
Operating profit	$ 30.5	$ (20.7)	$ (2.9)	$ (59.3)