Divestitures and Assets and Liabilities Held For Sale (Balance Sheet And Income Statement Disclosures) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Sep. 29, 2017	Sep. 30, 2016	Sep. 29, 2017	Sep. 30, 2016	Mar. 31, 2017	[1]
Assets:
Total assets held for sale	$ 746		$ 746		$ 0
Liabilities:
Total liabilities held for sale	303		303		$ 0
Income from Discontinued Operations
Income (loss) from discontinued operations, net of income taxes	4	$ (75)	(19)	$ (6)
Web Security and PKI Solutions | Discontinued Operations, Held-for-sale
Assets:
Accounts receivable, net	37		37
Goodwill and intangible assets, net	670		670
Other assets	39		39
Total assets held for sale	746		746
Liabilities:
Deferred revenue	291		291
Other liabilities	12		12
Total liabilities held for sale	303		303
Income from Discontinued Operations
Income (loss) from discontinued operations, net of income taxes	$ 23	$ 56	$ 58	$ 107

[1] Derived from audited financial statements.