CONSOLIDATED STATEMENTS OF DEFICIT (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	$ (64.4)	$ (312.1)
Consolidated net (loss) income	(57.0)	(157.5)
Capped call on conversion of notes		0.0
Stock-based activity	2.2	(1.3)
Translation adjustments	(17.7)	(17.1)
Postretirement plans	57.3	202.2
Ending balance	(79.6)	(285.8)
Total Unisys Corporation
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(113.7)	(356.8)
Consolidated net (loss) income	(57.3)	(157.8)
Capped call on conversion of notes		0.0
Stock-based activity	2.2	(1.3)
Translation adjustments	(14.9)	(17.9)
Postretirement plans	55.7	202.2
Ending balance	(128.0)	(331.6)
Common Stock Par Value
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	0.7	0.7
Ending balance	0.7	0.7
Accumu-lated Deficit
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(1,409.0)	(960.5)
Consolidated net (loss) income	(57.3)	(157.8)
Ending balance	(1,466.3)	(1,118.3)
Treasury Stock At Cost
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(152.2)	(114.4)
Capped call on conversion of notes		(30.8)
Stock-based activity	(3.5)	(6.7)
Ending balance	(155.7)	(151.9)
Paid-in Capital
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	4,710.9	4,656.9
Capped call on conversion of notes		30.8
Stock-based activity	5.7	5.4
Ending balance	4,716.6	4,693.1
Accumu-lated Other Compre-hensive Loss
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(3,264.1)	(3,939.5)
Translation adjustments	(14.9)	(17.9)
Postretirement plans	55.7	202.2
Ending balance	(3,223.3)	(3,755.2)
Non-controlling Interests
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	49.3	44.7
Consolidated net (loss) income	0.3	0.3
Translation adjustments	(2.8)	0.8
Postretirement plans	1.6
Ending balance	$ 48.4	$ 45.8