Revenues (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
	Jun. 29, 2018	Jun. 30, 2017	Mar. 30, 2018
Disaggregation of Revenue [Line Items]
Revenues	$ 1,156	$ 1,175
Revenue recognized from beginning contract liabilities	848
Amortization expense from capitalized contract acquisition costs	23
Capitalized contract costs, impairment loss	0
Revenue, remaining performance obligation	2,800
Total Enterprise Security
Disaggregation of Revenue [Line Items]
Revenue, remaining performance obligation	1,747
Total Consumer Digital Safety
Disaggregation of Revenue [Line Items]
Revenue, remaining performance obligation	1,053
Transferred at Point in Time
Disaggregation of Revenue [Line Items]
Revenues	111
Transferred at Point in Time | Total Enterprise Security
Disaggregation of Revenue [Line Items]
Revenues	99
Transferred at Point in Time | Total Consumer Digital Safety
Disaggregation of Revenue [Line Items]
Revenues	12
Transferred over Time
Disaggregation of Revenue [Line Items]
Revenues	1,045
Transferred over Time | Total Enterprise Security
Disaggregation of Revenue [Line Items]
Revenues	457
Transferred over Time | Total Consumer Digital Safety
Disaggregation of Revenue [Line Items]
Revenues	588
Other Current Liabilities | Total Enterprise Security
Disaggregation of Revenue [Line Items]
Rebate Reserves	5
Other Current Liabilities | Total Consumer Digital Safety
Disaggregation of Revenue [Line Items]
Rebate Reserves	11
Accounts Receivable | Total Enterprise Security
Disaggregation of Revenue [Line Items]
Rebate Reserves			$ 6
Accounts Receivable | Total Consumer Digital Safety
Disaggregation of Revenue [Line Items]
Rebate Reserves			$ 21
Calculated under Revenue Guidance in Effect before Topic 606 | Transferred at Point in Time
Disaggregation of Revenue [Line Items]
Revenues	73
Calculated under Revenue Guidance in Effect before Topic 606 | Transferred at Point in Time | Total Enterprise Security
Disaggregation of Revenue [Line Items]
Revenues	61
Calculated under Revenue Guidance in Effect before Topic 606 | Transferred at Point in Time | Total Consumer Digital Safety
Disaggregation of Revenue [Line Items]
Revenues	12
Calculated under Revenue Guidance in Effect before Topic 606 | Transferred over Time
Disaggregation of Revenue [Line Items]
Revenues	1,078
Calculated under Revenue Guidance in Effect before Topic 606 | Transferred over Time | Total Enterprise Security
Disaggregation of Revenue [Line Items]
Revenues	490
Calculated under Revenue Guidance in Effect before Topic 606 | Transferred over Time | Total Consumer Digital Safety
Disaggregation of Revenue [Line Items]
Revenues	588
Accounting Standards Update 2014-09 | Difference between Revenue Guidance in Effect before and after Topic 606
Disaggregation of Revenue [Line Items]
Revenues	5
Accounting Standards Update 2014-09 | Difference between Revenue Guidance in Effect before and after Topic 606 | Transferred at Point in Time
Disaggregation of Revenue [Line Items]
Revenues	38
Accounting Standards Update 2014-09 | Difference between Revenue Guidance in Effect before and after Topic 606 | Transferred at Point in Time | Total Enterprise Security
Disaggregation of Revenue [Line Items]
Revenues	38
Accounting Standards Update 2014-09 | Difference between Revenue Guidance in Effect before and after Topic 606 | Transferred at Point in Time | Total Consumer Digital Safety
Disaggregation of Revenue [Line Items]
Revenues	0
Accounting Standards Update 2014-09 | Difference between Revenue Guidance in Effect before and after Topic 606 | Transferred over Time
Disaggregation of Revenue [Line Items]
Revenues	(33)
Accounting Standards Update 2014-09 | Difference between Revenue Guidance in Effect before and after Topic 606 | Transferred over Time | Total Enterprise Security
Disaggregation of Revenue [Line Items]
Revenues	(33)
Accounting Standards Update 2014-09 | Difference between Revenue Guidance in Effect before and after Topic 606 | Transferred over Time | Total Consumer Digital Safety
Disaggregation of Revenue [Line Items]
Revenues	$ 0