Acquisitions (Integration Costs) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Oct. 02, 2015	Sep. 30, 2016	Oct. 02, 2015
Business Acquisition [Line Items]
Total acquisition and integration costs	$ 44	$ 0	$ 68	$ 0
Information Systems & Global Solutions Business of Lockheed Martin
Business Acquisition [Line Items]
Acquisition costs	27		40
Integration costs	17		28
Total acquisition and integration costs	$ 44		$ 68