Computation of Loss Per Common Share Attributable to Unisys Corporation (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Basic Loss Per Common Share
Net loss attributable to Unisys Corporation	$ (39.9)	$ (43.2)
Weighted average shares	50,004	49,821
Total	$ (0.80)	$ (0.87)
Diluted Loss Per Share
Net loss attributable to Unisys Corporation	$ (39.9)	$ (43.2)
Weighted average shares	50,004	49,821
Total	$ (0.80)	$ (0.87)