Goodwill and Intangible Assets (Schedule of Intangible Assets, Net) (Details) - USD ($) $ in Millions	Sep. 30, 2016	Aug. 01, 2016	Apr. 01, 2016
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 2,170		$ 573
Accumulated Amortization	(509)		(424)
Net Carrying Amount	1,661		149
Indefinite-lived Intangible Assets [Line Items]
Gross Carrying Amount	2,470		867
Net Carrying Amount	1,961		443	[1]
Blue Coat, Inc.
Business Acquisition [Line Items]
Intangible assets recorded as part of acquisition		$ 1,608
Trade Names
Indefinite-lived Intangible Assets [Line Items]
Indefinite-lived intangible assets	281		294
In-process research and development
Indefinite-lived Intangible Assets [Line Items]
Indefinite-lived intangible assets	19		0
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	1,247		406
Accumulated Amortization	(361)		(320)
Net Carrying Amount	886		86
Developed technology
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	883		144
Accumulated Amortization	(125)		(84)
Net Carrying Amount	758		60
Trade Names
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	19		2
Accumulated Amortization	(4)		(2)
Net Carrying Amount	15		0
Patents
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	21		21
Accumulated Amortization	(19)		(18)
Net Carrying Amount	$ 2		$ 3

[1] Derived from audited financial statements.