Earnings Per Common Share (Detail) (USD $) In Millions, except Share data in Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Basic earnings per common share computation
Net income attributable to Unisys Corporation common stockholders	$ 44.0	$ 92.3	$ 129.4
Weighted average shares	49,280	43,899	43,864
Basic earnings per common share	$ 0.89us-gaap_EarningsPerShareBasic	$ 2.10us-gaap_EarningsPerShareBasic	$ 2.95us-gaap_EarningsPerShareBasic
Diluted earnings per common share computation
Net income attributable to Unisys Corporation common stockholders	44.0	92.3	129.4
Add preferred stock dividends	2.7	16.2	16.2
Net income attributable to Unisys Corporation for diluted earnings per share	$ 44.0	$ 92.3	$ 145.6
Weighted average shares	49,280	43,899	43,864
Plus incremental shares from assumed conversions
Employee stock plans	304	448	439
Preferred stock			6,913
Adjusted weighted average shares	49,584	44,347	51,216
Diluted earnings per common share	$ 0.89us-gaap_EarningsPerShareDiluted	$ 2.08us-gaap_EarningsPerShareDiluted	$ 2.84us-gaap_EarningsPerShareDiluted

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of convertible preferred stock using the if-converted method.

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Net income after adjustments for dividends on preferred stock (declared in the period) and/or cumulative preferred stock (accumulated for the period).

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