Consolidated Statements of Deficit - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	$ (1,378.6)	$ (1,452.4)	$ (663.9)
Consolidated net income (loss)	(36.7)	(103.2)	59.3
Stock-based compensation	8.8	12.1	13.5
Dividends declared to preferred holders			(4.0)
Preferred stock conversion			0.0
Sale of subsidiary			1.5
Common stock repurchases			(35.7)
Discount on debt issuance	33.6
Capped call on debt issuance	(27.3)
Expenses of convertible notes	(1.2)
Translation adjustments	(108.4)	(100.8)	(66.3)
Postretirement plans	(137.6)	265.7	(756.8)
Ending Balance	(1,647.4)	(1,378.6)	(1,452.4)
Total Unisys Corporation
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	(1,389.7)	(1,460.0)	(700.5)
Consolidated net income (loss)	(47.7)	(109.9)	46.7
Stock-based compensation	8.8	12.1	13.5
Dividends declared to preferred holders			(4.0)
Preferred stock conversion			0.0
Sale of subsidiary			0.0
Common stock repurchases			(35.7)
Discount on debt issuance	33.6
Capped call on debt issuance	(27.3)
Expenses of convertible notes	(1.2)
Translation adjustments	(93.3)	(96.0)	(61.0)
Postretirement plans	(114.2)	264.1	(719.0)
Ending Balance	(1,631.0)	(1,389.7)	(1,460.0)
Preferred Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	0.0	0.0	249.7
Preferred stock conversion			(249.7)
Ending Balance	0.0	0.0	0.0
Common Stock Par Value
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	0.5	0.5	0.4
Preferred stock conversion			0.1
Ending Balance	0.5	0.5	0.5
Accumulated Deficit
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	(1,845.7)	(1,735.8)	(1,782.5)
Consolidated net income (loss)	(47.7)	(109.9)	46.7
Ending Balance	(1,893.4)	(1,845.7)	(1,735.8)
Treasury Stock At Cost
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	(100.1)	(99.6)	(62.4)
Stock-based compensation	(0.4)	(0.5)	(1.5)
Common stock repurchases			(35.7)
Ending Balance	(100.5)	(100.1)	(99.6)
Paid-in Capital
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	4,500.9	4,488.3	4,227.7
Stock-based compensation	9.2	12.6	15.0
Dividends declared to preferred holders			(4.0)
Preferred stock conversion			249.6
Discount on debt issuance	33.6
Capped call on debt issuance	(27.3)
Expenses of convertible notes	(1.2)
Ending Balance	4,515.2	4,500.9	4,488.3
Accumulated Other Comprehensive Loss
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	(3,945.3)	(4,113.4)	(3,333.4)
Translation adjustments	(93.3)	(96.0)	(61.0)
Postretirement plans	(114.2)	264.1	(719.0)
Ending Balance	(4,152.8)	(3,945.3)	(4,113.4)
Noncontrolling Interests
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	11.1	7.6	36.6
Consolidated net income (loss)	11.0	6.7	12.6
Sale of subsidiary			1.5
Translation adjustments	(15.1)	(4.8)	(5.3)
Postretirement plans	(23.4)	1.6	(37.8)
Ending Balance	$ (16.4)	$ 11.1	$ 7.6