Commitments and Contingencies (Details) $ / shares in Units, $ in Millions				3 Months Ended			9 Months Ended		69 Months Ended
	Nov. 20, 2016 USD ($) $ / shares	Aug. 04, 2015 USD ($) patent	Aug. 28, 2013 patent	Mar. 31, 2017 USD ($)	Dec. 30, 2016 USD ($)	Jan. 01, 2016 USD ($)	Dec. 30, 2016 USD ($)	Jan. 01, 2016 USD ($)	Sep. 30, 2012 USD ($)	Aug. 31, 2015 USD ($)	Jan. 31, 2014 USD ($)
Loss Contingencies [Line Items]
Net revenues					$ 1,041	$ 909	$ 2,904	$ 2,727
GSA Schedule Contract
Loss Contingencies [Line Items]
Net revenues									$ 222
GSA initial analysis of damage exposure											$ 145
GSA Schedule Contract | Minimum
Loss Contingencies [Line Items]
Estimated loss					25		25
Class Action Lawsuit vs. Symantec, Extended Download Services and Norton Download Insurance
Loss Contingencies [Line Items]
Accrual for settlement										$ 30
Finjan, Inc vs. Blue Coat Systems, Inc. | Pending Litigation
Loss Contingencies [Line Items]
Number of patents allegedly infringed | patent			6
Finjan, Inc vs. Blue Coat Systems, Inc. | Judicial Ruling
Loss Contingencies [Line Items]
Estimated loss					$ 40		$ 40
Number of patents found infringed | patent		5
Damages awarded		$ 40
LifeLock
Business Acquisition [Line Items]
Share price (in usd per share) | $ / shares	$ 24
Enterprise value	$ 2,300
LifeLock | Line of Credit | Senior Bridge Loan Facility | Forecast
Business Acquisition [Line Items]
Aggregate borrowings				$ 1,000