Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Statement of Comprehensive Income [Abstract]
Consolidated net loss from continuing operations	$ (157.5)	$ (52.7)
Income from discontinued operations, net of tax	0.0	1,068.5
Total	(157.5)	1,015.8
Other comprehensive income
Foreign currency translation	(17.1)	(87.6)
Postretirement adjustments, net of tax of $3.1 in 2021 and $13.9 in 2020	202.2	91.2
Total other comprehensive income	185.1	3.6
Comprehensive income	27.6	1,019.4
Less comprehensive income (loss) attributable to noncontrolling interests	1.1	(1.8)
Comprehensive income attributable to Unisys Corporation	$ 26.5	$ 1,021.2