Acquisitions and Divestitures, Goodwill and Intangible Assets - Consideration and Fair Value of Net Assets Acquired (Details) - CSRA $ / shares in Units, shares in Millions, $ in Millions	Apr. 03, 2018 USD ($) $ / shares shares
Business Acquisition [Line Items]
Cash consideration per CSRA share (in dollars per share) | $ / shares	$ 41.25
Cash paid to purchase outstanding CSRA shares	$ 6,825
Cash paid to extinguish CSRA debt	2,846
Cash settlement of outstanding CSRA stock options and restricted stock units	78
Total purchase price	$ 9,749
CSRA
Business Acquisition [Line Items]
CSRA shares outstanding (in millions) (shares) | shares	165.4