GOODWILL AND INTANGIBLE ASSETS - Schedule of Goodwill (Details) - USD ($) $ in Millions	5 Months Ended	7 Months Ended	12 Months Ended
	Dec. 31, 2023	Aug. 12, 2023	Dec. 31, 2022	Dec. 31, 2021
Goodwill [Line Items]
Goodwill		$ 621.0	$ 1,173.2	$ 1,214.5
Accumulated impairment reassignment			0.0
Accumulated impairment losses		0.0	(470.9)	(470.9)
Goodwill [Roll Forward]
Beginning balance	$ 621.0	702.3	743.6
Currency translation adjustment	(0.1)	12.0	(41.3)
Goodwill reassignment			0.0
Fresh Start adjustment goodwill		(564.2)
Fresh Start adjustment accumulated impairment losses		470.9
Divestitures	(4.2)
Ending balance	616.7	621.0	702.3
Eurasia Banking
Goodwill [Line Items]
Goodwill		0.0	0.0	561.4
Accumulated impairment reassignment			291.7
Accumulated impairment losses		0.0	0.0	(291.7)
Goodwill [Roll Forward]
Beginning balance	0.0	0.0	269.7
Currency translation adjustment	0.0	0.0	(6.3)
Goodwill reassignment			(555.1)
Fresh Start adjustment goodwill		0.0
Fresh Start adjustment accumulated impairment losses		0.0
Divestitures	0.0
Ending balance	0.0	0.0	0.0
Americas Banking
Goodwill [Line Items]
Goodwill		0.0	0.0	440.1
Accumulated impairment reassignment			122.0
Accumulated impairment losses		0.0	0.0	(122.0)
Goodwill [Roll Forward]
Beginning balance	0.0	0.0	318.1
Currency translation adjustment	0.0	0.0	(1.0)
Goodwill reassignment			(439.1)
Fresh Start adjustment goodwill		0.0
Fresh Start adjustment accumulated impairment losses		0.0
Divestitures	0.0
Ending balance	0.0	0.0	0.0
Banking
Goodwill [Line Items]
Goodwill		471.4	903.6	0.0
Accumulated impairment reassignment			(413.7)
Accumulated impairment losses		0.0	(413.7)	0.0
Goodwill [Roll Forward]
Beginning balance	471.4	489.9	0.0
Currency translation adjustment	0.0	8.5	(18.6)
Goodwill reassignment			922.2
Fresh Start adjustment goodwill		(440.7)
Fresh Start adjustment accumulated impairment losses		413.7
Divestitures	0.0
Ending balance	471.4	471.4	489.9
Retail
Goodwill [Line Items]
Goodwill		149.6	269.6	213.0
Accumulated impairment reassignment			0.0
Accumulated impairment losses		0.0	(57.2)	$ (57.2)
Goodwill [Roll Forward]
Beginning balance	149.6	212.4	155.8
Currency translation adjustment	(0.1)	3.5	(15.4)
Goodwill reassignment			72.0
Fresh Start adjustment goodwill		(123.5)
Fresh Start adjustment accumulated impairment losses		57.2
Divestitures	(4.2)
Ending balance	$ 145.3	$ 149.6	$ 212.4