Earnings Per Share - Computation of Loss Per Common Share Attributable to Unisys Corporation (Detail) - USD ($) $ / shares in Units, shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Basic Earnings (Loss) Per Share
Net income (loss) attributable to Unisys Corporation	$ (28,200,000)	$ (9,600,000)	$ (46,500,000)	$ (111,000,000)
Weighted average shares (in shares)	50,082	49,934	50,052	49,894
Total (in dollars per share)	$ (0.56)	$ (0.19)	$ (0.93)	$ (2.22)
Diluted Earnings (Loss) Per Share
Net income (loss) attributable to Unisys Corporation	$ (28,200,000)	$ (9,600,000)	$ (46,500,000)	$ (111,000,000)
Add interest expense on convertible notes, net of tax of zero	0	0	0	0
Interest expense on convertible notes, tax	0	0	0	0
Net income (loss) attributable to Unisys Corporation for diluted earnings per share	$ (28,200,000)	$ (9,600,000)	$ (46,500,000)	$ (111,000,000)
Weighted average shares (in shares)	50,082	49,934	50,052	49,894
Plus incremental shares from assumed conversions:
Employee stock plans (in shares)	0	0	0	0
Convertible notes (in shares)	0	0	0	0
Adjusted weighted average shares (in shares)	50,082	49,934	50,052	49,894
Total (in dollars per share)	$ (0.56)	$ (0.19)	$ (0.93)	$ (2.22)