CONSOLIDATED STATEMENTS OF DEFICIT (Unaudited) - USD ($) $ in Millions	3 Months Ended						9 Months Ended
	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2022	Sep. 30, 2021
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	$ (98.5)	$ (79.6)	$ (64.4)	$ (263.8)	$ (285.8)	$ (312.1)	$ (64.4)	$ (312.1)
Consolidated net (loss) income	(39.9)	(16.8)	(57.0)	(18.5)	(142.3)	(157.5)	(113.7)	(318.3)
Stock-based activity	4.9	5.1	2.2	5.3	4.5	(1.3)
Translation adjustments	(90.9)	(95.6)	(17.7)	(36.5)	16.8	(17.1)	(204.2)	(36.8)
Postretirement plans	89.1	88.4	57.3	63.4	143.0	202.2	234.8	408.6
Ending balance	(135.3)	(98.5)	(79.6)	(250.1)	(263.8)	(285.8)	(135.3)	(250.1)
Total Unisys Corporation
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(147.2)	(128.0)	(113.7)	(308.8)	(331.6)	(356.8)	(113.7)	(356.8)
Consolidated net (loss) income	(40.1)	(17.1)	(57.3)	(18.7)	(140.8)	(157.8)
Stock-based activity	4.9	5.1	2.2	5.3	4.5	(1.3)
Translation adjustments	(87.4)	(92.3)	(14.9)	(33.9)	16.4	(17.9)
Postretirement plans	85.7	85.1	55.7	61.8	142.7	202.2
Ending balance	(184.1)	(147.2)	(128.0)	(294.3)	(308.8)	(331.6)	(184.1)	(294.3)
Common Stock Par Value
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	0.7	0.7	0.7	0.7	0.7	0.7	0.7	0.7
Ending balance	0.7	0.7	0.7	0.7	0.7	0.7	0.7	0.7
Accumu-lated Deficit
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(1,483.4)	(1,466.3)	(1,409.0)	(1,259.1)	(1,118.3)	(960.5)	(1,409.0)	(960.5)
Consolidated net (loss) income	(40.1)	(17.1)	(57.3)	(18.7)	(140.8)	(157.8)
Ending balance	(1,523.5)	(1,483.4)	(1,466.3)	(1,277.8)	(1,259.1)	(1,118.3)	(1,523.5)	(1,277.8)
Treasury Stock At Cost
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(155.9)	(155.7)	(152.2)	(152.1)	(151.9)	(114.4)	(152.2)	(114.4)
Capped call on conversion of notes						(30.8)
Stock-based activity		(0.2)	(3.5)		(0.2)	(6.7)
Ending balance	(155.9)	(155.9)	(155.7)	(152.1)	(152.1)	(151.9)	(155.9)	(152.1)
Paid-in Capital
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	4,721.9	4,716.6	4,710.9	4,697.8	4,693.1	4,656.9	4,710.9	4,656.9
Capped call on conversion of notes						30.8
Stock-based activity	4.9	5.3	5.7	5.3	4.7	5.4
Ending balance	4,726.8	4,721.9	4,716.6	4,703.1	4,697.8	4,693.1	4,726.8	4,703.1
Accumu-lated Other Compre-hensive Loss
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(3,230.5)	(3,223.3)	(3,264.1)	(3,596.1)	(3,755.2)	(3,939.5)	(3,264.1)	(3,939.5)
Translation adjustments	(87.4)	(92.3)	(14.9)	(33.9)	16.4	(17.9)
Postretirement plans	85.7	85.1	55.7	61.8	142.7	202.2
Ending balance	(3,232.2)	(3,230.5)	(3,223.3)	(3,568.2)	(3,596.1)	(3,755.2)	(3,232.2)	(3,568.2)
Non-controlling Interests
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	48.7	48.4	49.3	45.0	45.8	44.7	49.3	44.7
Consolidated net (loss) income	0.2	0.3	0.3	0.2	(1.5)	0.3
Translation adjustments	(3.5)	(3.3)	(2.8)	(2.6)	0.4	0.8
Postretirement plans	3.4	3.3	1.6	1.6	0.3
Ending balance	$ 48.8	$ 48.7	$ 48.4	$ 44.2	$ 45.0	$ 45.8	$ 48.8	$ 44.2