Segment information (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Segment Revenue and Operating Profit [Line Items]
Revenues	$ 901.5	$ 969.9	$ 1,893.1	$ 1,920.4
Operating profit	10.7	32.8	(61.8)	50.1
Capital expenditures			56.9	78.2
Depreciation and amortization			86.2	84.3
Total assets	2,400.0		2,400.0		2,498.0
Unconsolidated Equity Affiliates held by International Segment [Abstract]
Carrying value of investments at year end	62.7		62.7		125.3
Latin America [Member]
Segment Revenue and Operating Profit [Line Items]
Revenues	336.5	413.6	774.9	826.5
Operating profit	(1.5)	24.4	(76.3)	47.8
Europe, Middle East and Africa [Member]
Segment Revenue and Operating Profit [Line Items]
Revenues	302.9	293.4	600.9	571.2
Operating profit	17.3	18.7	32.1	27.3
North America [Member]
Segment Revenue and Operating Profit [Line Items]
Revenues	225.7	226.3	445.8	449.5
Operating profit	5.7	6.3	6.8	4.3
Asia Pacific [Member]
Segment Revenue and Operating Profit [Line Items]
Revenues	36.4	36.6	71.5	73.2
Operating profit	4.6	5.0	9.0	9.3
Segment operating profit [Member]
Segment Revenue and Operating Profit [Line Items]
Operating profit	26.1	54.4	(28.4)	88.7
Non Segment [Member]
Segment Revenue and Operating Profit [Line Items]
Operating profit	$ (15.4)	$ (21.6)	$ (33.4)	$ (38.6)