Segment information - Revenue And Operating Profits (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Segment Reporting Information [Line Items]
Revenues	$ 776.1	$ 949.6
Operating profit	12.9	(73.7)
Largest 5 Markets [Member]
Segment Reporting Information [Line Items]
Revenues	487.6	535.6
Operating profit	28.1	23.6
Global Markets [Member]
Segment Reporting Information [Line Items]
Revenues	245.2	260.5
Operating profit	31.2	24.5
Payment Services [Member]
Segment Reporting Information [Line Items]
Revenues	22.8	22.2
Operating profit	0.5	0.8
Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues	755.6	818.3
Operating profit	59.8	48.9
Reconciling Items [Member] | General, administrative and other expenses [Member]
Segment Reporting Information [Line Items]
Operating profit	(17.6)	(29.6)
Reconciling Items [Member] | Foreign currency transaction losses [Member]
Segment Reporting Information [Line Items]
Operating profit	(4.8)	(0.7)
Reconciling Items [Member] | Reconciliation Of Segment Policies To GAAP [Member]
Segment Reporting Information [Line Items]
Operating profit	3.2	2.2
Reconciling Items [Member] | FX devaluation in Venezuela [Member]
Segment Reporting Information [Line Items]
Operating profit	(20.6)	(123.3)
Reconciling Items [Member] | Venezuela operations [Member]
Segment Reporting Information [Line Items]
Revenues	20.5	131.3
Operating profit	2.7	34.4
Reconciling Items [Member] | 2014 Reorganization and Restructuring [Member]
Segment Reporting Information [Line Items]
Operating profit	(1.5)	0
Reconciling Items [Member] | Mexican settlement losses [Member]
Segment Reporting Information [Line Items]
Operating profit	(1.3)	(0.8)
Reconciling Items [Member] | US retirement plans [Member]
Segment Reporting Information [Line Items]
Operating profit	(7.0)	(6.0)
Reconciling Items [Member] | Acquisition and Disposition [Member]
Segment Reporting Information [Line Items]
Operating profit	0	1.2
Latin America [Member]
Segment Reporting Information [Line Items]
Revenues	90.8	90.6
Operating profit	16.5	10.1
Europe, Middle East and Africa [Member]
Segment Reporting Information [Line Items]
Revenues	115.7	136.9
Operating profit	8.2	9.2
Asia Pacific [Member]
Segment Reporting Information [Line Items]
Revenues	38.7	33.0
Operating profit	6.5	5.2
US [Member]
Segment Reporting Information [Line Items]
Revenues	183.6	175.8
Operating profit	8.3	1.3
France [Member]
Segment Reporting Information [Line Items]
Revenues	105.7	128.8
Operating profit	4.1	6.6
Mexico [Member]
Segment Reporting Information [Line Items]
Revenues	85.7	100.2
Operating profit	7.9	3.7
Brazil [Member]
Segment Reporting Information [Line Items]
Revenues	73.8	86.4
Operating profit	6.1	9.7
Canada [Member]
Segment Reporting Information [Line Items]
Revenues	38.8	44.4
Operating profit	$ 1.7	$ 2.3