Acquisitions (Pro Forma Information) (Details) - Information Systems & Global Solutions Business of Lockheed Martin $ / shares in Units, $ in Millions	3 Months Ended
Apr. 01, 2016 USD ($) $ / shares
Business Acquisition [Line Items]
Revenues	$ 2,637
Income from continuing operations	$ 52
Earnings per share:
Basic (usd per share) \| $ / shares	$ 0.34
Diluted (usd per share) \| $ / shares	$ 0.33
Leidos Holdings, Inc.
Business Acquisition [Line Items]
Income from continuing operations	$ 50

Business Acquisition, Pro Forma Earning Per Share [Abstract]

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

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The pro forma basic net income per share for a period as if the business combination or combinations had been completed at the beginning of a period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(2)-(3)
-URI http://asc.fasb.org/extlink&oid=65885119&loc=d3e1392-128463

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The pro forma diluted net income per share for a period as if the business combination or combinations had been completed at the beginning of a period.

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Amount after tax of pro forma income from continuing operations as if the business combination had been completed at the beginning of a period.

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The pro forma revenue for a period as if the business combination or combinations had been completed at the beginning of the period.

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