Segment Information - (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022		Jun. 30, 2021
Summary of Segment Information
Total revenue	$ 851.7	$ 943.5	$ 1,681.5		$ 1,887.4
Operating income (loss) / Segment operating profit	91.5	(12.9)	174.9		(49.1)
Asset Impairment Charges	(5.4)	0.0	(60.6)		0.0
Restructuring and transformation expenses(4)	(78.3)	(17.1)	(78.3)		(23.1)
Other income (expense)	(41.7)	(53.9)	(90.6)		(95.9)
Income (loss) from continuing operations before taxes	(133.2)	(41.0)	(265.5)		(46.8)
Amortization of acquired intangible assets			(36.1)		(39.8)
Global Retail [Member]
Summary of Segment Information
Total revenue	255.8	305.0	517.5		609.4
Global Banking
Summary of Segment Information
Total revenue		638.5			1,278.0
Operating Segments [Member]
Summary of Segment Information
Operating income (loss) / Segment operating profit	(115.1)	(140.9)	(185.0)		(292.1)
Operating Segments [Member] | Global Retail [Member]
Summary of Segment Information
Total revenue	255.8	305.0	517.5		609.4
Operating income (loss) / Segment operating profit	(34.6)	(39.1)	(58.8)		(81.3)
Operating Segments [Member] | Global Banking
Summary of Segment Information
Total revenue	590.2	638.5	1,152.9		1,278.0
Operating income (loss) / Segment operating profit	(80.5)	(101.8)	(126.2)		(210.8)
Corporate and Reconciling Items [Member]
Summary of Segment Information
Reconciliation Of Operating Profit Loss From Segments To Consolidated, Amount	(206.6)	(128.0)	(359.9)		(243.0)
Segment Reconciling Items [Member]
Summary of Segment Information
Operating income (loss) / Segment operating profit	5.3	0.0	11.7		0.0
Asset Impairment Charges	5.4	0.0	(60.6)		0.0
Restructuring and transformation expenses(4)	(78.3)	(30.4)	(78.3)		(53.6)
Net non-routine expense(5)	(37.2)	0.1	(39.6)		0.4
Amortization of acquired intangible assets	17.6	(19.9)	(36.1)		(39.8)
Segment Reconciling Items [Member] | Inventory Valuation and Obsolescence
Summary of Segment Information
Net non-routine expense(5)	34.4
Corporate
Summary of Segment Information
Operating income (loss) / Segment operating profit	$ (62.8)	$ (77.8)	$ 133.6	[1]	$ 150.0	[1]

[1] Corporate charges not allocated to segments include headquarter-based costs associated primarily with human resources, finance, IT and legal that are not directly attributable to a particular segment and are separately assessed by the CODM for purposes of making decisions, assessing performance and allocating resources. (2)    Refer to Notes 20 and 21 for further information on the impairment charges taken in the first quarter of 2022. During the second quarter of 2022, and in connection with the organizational simplification, $5.4 of right-of-use assets and the related leasehold improvements and furniture and fixtures were impaired related to facilities identified for closure. (3)    The amortization of purchase accounting intangible assets is not included in the segment results used by the CODM to make decisions, allocate resources or assess performance. (4)    Refer to Note 8: Restructuring for further information. Consistent with the historical reportable segment structure, restructuring and transformation costs are not assigned to the segments, and are separately analyzed by the CODM. (5)    Net non-routine expense consists of items that the Company has determined are non-routine in nature and not allocated to the reportable operating segments as they are not included in the measure as used by the CODM to make decisions, allocate resources and assess performance. Net non-routine expense for the three and six months ended June 30, 2022 primarily consisted of inventory charges related to legacy product of $34.4 which management determined would no longer be sold as part of a product portfolio consolidation connected with the organizational simplification. Also included in net non-routine expense are charges related to the wind-down of our operations in Russia and Ukraine as discuss in Note 21 and charges related to mergers, acquisitions and divestitures. (6)    Held for sale non-core European retail business represents the revenue and operating profit of a business that has been classified as held for sale for all of the periods presented, but which was removed in 2022 from the retail segment's information used by the CODM to make decisions, assess performance and allocate resources, and now is individually analyzed. This change and timing thereof aligns with the build-out of a data center that makes the entity capable of operating autonomously and is consistent with material provided in connection with our refinancing effort which are exclusive of this entity. The presentation in the periods ended June 30, 2022 and 2021 is consistent with management reporting. Total revenue generated by this business was $5.7 and $11.1 in the three and six month periods ended June 30, 2022, compared to $5.2 and $13.5 for the three and six month periods ended June 30, 2021. Operating loss generated by this business was $5.3 and $11.7 in the three and six month periods ended June 30, 2022, compared to $3.7 and $7.5 for the three and six month periods ended June 30, 2021.