CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Statement of Comprehensive Income [Abstract]
Consolidated loss from continuing operations	$ (18.5)	$ (13.3)	$ (318.3)	$ (142.5)
Income from discontinued operations, net of tax	0.0	0.4	0.0	1,066.8
Total	(18.5)	(12.9)	(318.3)	924.3
Other comprehensive income (loss)
Foreign currency translation	(36.5)	40.1	(36.8)	(41.1)
Postretirement adjustments, net of tax of $7.4 and $45.2 in 2021 and $(7.8) and $6.4 in 2020	63.4	8.2	408.6	139.4
Total other comprehensive income	26.9	48.3	371.8	98.3
Comprehensive income	8.4	35.4	53.5	1,022.6
Less comprehensive (loss) income attributable to noncontrolling interests	(0.8)	2.0	(0.5)	0.5
Comprehensive income attributable to Unisys Corporation	$ 9.2	$ 33.4	$ 54.0	$ 1,022.1