Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Comprehensive Income [Abstract]
Consolidated net income (loss)	$ (13.3)	$ 78.9	$ (66.6)
Other comprehensive income
Foreign currency translation	24.4	(81.8)	117.8
Postretirement adjustments, net of tax of $(11.3) in 2019, $7.1 in 2018 and $18.3 in 2017	(38.9)	33.8	265.1
Total other comprehensive income (loss)	(14.5)	(48.0)	382.9
Comprehensive income (loss)	(27.8)	30.9	316.3
Comprehensive income (loss) attributable to noncontrolling interests	(6.8)	15.7	44.6
Comprehensive income (loss) attributable to Unisys Corporation	$ (21.0)	$ 15.2	$ 271.7