Acquisition (Components of Intangible Assets Recognized) (Details) - Blue Coat, Inc. $ in Millions	Aug. 01, 2016 USD ($)
Business Acquisition [Line Items]
Total identified finite-lived intangible assets	$ 1,589
In-process research and development	19
Intangible assets	1,608
Customer relationships
Business Acquisition [Line Items]
Total identified finite-lived intangible assets	$ 844
Weighted-Average Estimated Useful Life	7 years
Developed technology and patents
Business Acquisition [Line Items]
Total identified finite-lived intangible assets	$ 739
Weighted-Average Estimated Useful Life	4 years 3 months 18 days
Finite-lived trade names
Business Acquisition [Line Items]
Total identified finite-lived intangible assets	$ 4
Weighted-Average Estimated Useful Life	2 years
Product backlog
Business Acquisition [Line Items]
Total identified finite-lived intangible assets	$ 2
Weighted-Average Estimated Useful Life	4 months