Segment information - Assets, Long Lived Assets, Revnues, Net Assets by Geographic Area (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting Information [Line Items]
Revenues by Geographic Area(a)	$ 765.8	$ 759.2	$ 760.3	$ 776.1	$ 881.2	$ 872.5	$ 859.0	$ 949.6	$ 3,061.4	$ 3,562.3	$ 3,778.6
Total assets	1,946.7				2,192.0				1,946.7	2,192.0	2,497.4
Long-Lived Assets by Geographic Area(a)	549.0				669.5				549.0	669.5	758.7
Net assets outside the U.S.	647.8				746.9				647.8	746.9	912.8
Business segments
Segment Reporting Information [Line Items]
Revenues by Geographic Area(a)									2,976.9	3,350.5	3,331.5
Total assets	1,567.4				1,759.0				1,567.4	1,759.0	1,934.5
Corporate items
Segment Reporting Information [Line Items]
Total assets	332.4				326.8				332.4	326.8	282.4
U.S. | Business segments
Segment Reporting Information [Line Items]
Revenues by Geographic Area(a)									730.4	727.8	707.5
Total assets	325.0				327.4				325.0	327.4	330.0
France | Business segments
Segment Reporting Information [Line Items]
Revenues by Geographic Area(a)									431.5	517.4	517.6
Total assets	239.6				244.7				239.6	244.7	246.6
Mexico | Business segments
Segment Reporting Information [Line Items]
Revenues by Geographic Area(a)									333.0	388.2	423.9
Total assets	229.0				258.9				229.0	258.9	285.1
Brazil | Business segments
Segment Reporting Information [Line Items]
Revenues by Geographic Area(a)									270.4	364.1	354.4
Total assets	109.7				165.0				109.7	165.0	165.8
Canada | Business segments
Segment Reporting Information [Line Items]
Revenues by Geographic Area(a)									153.7	179.7	191.4
Total assets	81.3				92.3				81.3	92.3	96.5
Latin America | Business segments
Segment Reporting Information [Line Items]
Revenues by Geographic Area(a)									369.9	380.6	407.1
Total assets	155.3				189.8				155.3	189.8	240.6
EMEA | Business segments
Segment Reporting Information [Line Items]
Revenues by Geographic Area(a)									444.7	556.3	540.6
Total assets	274.6				308.0				274.6	308.0	382.8
Asia | Business segments
Segment Reporting Information [Line Items]
Revenues by Geographic Area(a)									157.4	139.8	134.2
Total assets	99.8				109.2				99.8	109.2	115.1
Payment Services | Business segments
Segment Reporting Information [Line Items]
Revenues by Geographic Area(a)									85.9	96.6	54.8
Total assets	53.1				63.7				53.1	63.7	72.0
Largest 5 Markets | Business segments
Segment Reporting Information [Line Items]
Revenues by Geographic Area(a)									1,919.0	2,177.2	2,194.8
Total assets	984.6				1,088.3				984.6	1,088.3	1,124.0
France
Segment Reporting Information [Line Items]
Revenues by Geographic Area(a)									431.5	517.4	542.5
Long-Lived Assets by Geographic Area(a)	68.1				75.7				68.1	75.7	88.5
Net assets outside the U.S.	87.1				96.3				87.1	96.3	110.8
Mexico
Segment Reporting Information [Line Items]
Revenues by Geographic Area(a)									333.7	388.5	424.1
Long-Lived Assets by Geographic Area(a)	93.2				114.4				93.2	114.4	136.8
Net assets outside the U.S.	86.1				88.4				86.1	88.4	101.2
Brazil
Segment Reporting Information [Line Items]
Revenues by Geographic Area(a)									336.4	442.3	392.0
Long-Lived Assets by Geographic Area(a)	34.0				47.9				34.0	47.9	47.6
Net assets outside the U.S.	87.9				111.1				87.9	111.1	105.2
Canada
Segment Reporting Information [Line Items]
Revenues by Geographic Area(a)									153.7	179.7	191.4
Long-Lived Assets by Geographic Area(a)	38.9				47.9				38.9	47.9	50.7
Net assets outside the U.S.	50.3				53.4				50.3	53.4	69.3
Other
Segment Reporting Information [Line Items]
Revenues by Geographic Area(a)									1,069.6	1,305.8	1,521.1
Long-Lived Assets by Geographic Area(a)	122.7				175.5				122.7	175.5	216.3
Global Markets | Business segments
Segment Reporting Information [Line Items]
Revenues by Geographic Area(a)									972.0	1,076.7	1,081.9
Total assets	529.7				607.0				529.7	607.0	738.5
Venezuela
Segment Reporting Information [Line Items]
Long-Lived Assets by Geographic Area(a)	6.4								6.4
Venezuela | Reconciling items
Segment Reporting Information [Line Items]
Revenues by Geographic Area(a)									84.5	211.8	447.1
Total assets	46.9				106.2				46.9	106.2	280.5
Subtotal
Segment Reporting Information [Line Items]
Revenues by Geographic Area(a)									2,324.9	2,833.7	3,071.1
Long-Lived Assets by Geographic Area(a)	356.9				461.4				356.9	461.4	539.9
U.S.
Segment Reporting Information [Line Items]
Revenues by Geographic Area(a)									736.5	728.6	707.5
Long-Lived Assets by Geographic Area(a)	192.1				208.1				192.1	208.1	218.8
Other EMEA countries
Segment Reporting Information [Line Items]
Net assets outside the U.S.	147.5				146.1				147.5	146.1	180.6
Other Latin American countries
Segment Reporting Information [Line Items]
Net assets outside the U.S.	115.2				182.4				115.2	182.4	273.0
Asian countries
Segment Reporting Information [Line Items]
Net assets outside the U.S.	$ 73.7				$ 69.2				$ 73.7	$ 69.2	$ 72.7