Segment Information - (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2022	Jun. 30, 2022	Sep. 30, 2021	Sep. 30, 2022		Sep. 30, 2021
Summary of Segment Information
Total revenue	$ 810.4		$ 958.2	$ 2,491.9		$ 2,845.6
Operating income (loss) / Segment operating profit	(5.5)		(38.7)	169.4		(87.8)
Asset Impairment Charges		$ (4.1)	(0.3)	(64.7)		(0.3)
Restructuring and transformation expenses(4)	(20.7)		0.0	(98.9)		(23.1)
Other income (expense)	(51.5)		(41.3)	(142.1)		(137.2)
Income (loss) from continuing operations before taxes	(46.0)		(2.6)	(311.5)		(49.4)
Amortization of acquired intangible assets				(52.8)		(59.3)
Global Retail [Member]
Summary of Segment Information
Total revenue	225.0		288.1	742.4		897.5
Global Banking
Summary of Segment Information
Total revenue	580.3		670.1	1,733.3		1,948.1
Other Segments
Summary of Segment Information
Total revenue	5.1		0.0	16.2		0.0
Operating Segments [Member]
Summary of Segment Information
Operating income (loss) / Segment operating profit	(114.2)		(153.2)	(299.4)		(445.2)
Operating Segments [Member] | Global Retail [Member]
Summary of Segment Information
Total revenue	225.0		288.1	742.4		897.5
Operating income (loss) / Segment operating profit	(31.1)		(43.6)	(90.0)		(124.9)
Operating Segments [Member] | Global Banking
Summary of Segment Information
Total revenue	580.3		670.1	1,733.3		1,948.1
Operating income (loss) / Segment operating profit	(83.1)		(109.6)	(209.4)		(320.3)
Corporate and Reconciling Items [Member]
Summary of Segment Information
Reconciliation Of Operating Profit Loss From Segments To Consolidated, Amount	(108.7)		(114.5)	(468.8)		(357.4)
Segment Reconciling Items [Member]
Summary of Segment Information
Operating income (loss) / Segment operating profit	5.0		0.0	16.7		0.0
Asset Impairment Charges	4.1	$ (5.4)	(0.3)	(64.7)		(0.3)
Restructuring and transformation expenses(4)	(20.7)		(20.9)	(98.9)		(74.4)
Net non-routine expense(6)	5.3		(1.9)	(34.3)		(1.5)
Amortization of acquired intangible assets	16.6		(19.5)	(52.8)		(59.3)
Segment Reconciling Items [Member] | Inventory Valuation and Obsolescence
Summary of Segment Information
Net non-routine expense(6)				34.4
Corporate
Summary of Segment Information
Operating income (loss) / Segment operating profit	$ (54.2)		$ (71.9)	$ 188.0	[1]	$ 221.9	[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 and second quarters of 2022. During the third quarter of 2022, and in connection with the organizational simplification, $4.1 of German capitalized software was identified as impaired. (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)    Refinancing related costs are fees earned by our advisors and the advisors of our potential lenders. As these costs were incurred prior to September 30, 2022, at which point an agreement with respect to a debt refinancing remained under negotiation and subject to material changes, these costs are not considered directly attributable to the Transaction Support Agreement and thus are accounted for as period expense. (6)    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 used by the CODM to make decisions, allocate resources and assess performance. Net non-routine expense for the three months ended September 30, 2022 related primarily to gains made on divestitures of certain assets. Net non-routine expense for the nine months ended September 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. (7)    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 September 30, 2022 and 2021 is consistent with management reporting. Total revenue generated by this business was $5.1 and $16.2 in the three and nine month periods ended September 30, 2022, compared to $4.6 and $18.1 for the three and nine month periods ended September 30, 2021. Operating loss generated by this business was $5.0 and $16.7 in the three and nine month periods ended September 30, 2022, compared to $2.8 and $10.3 for the three and nine month periods ended September 30, 2021.