Divestiture and Discontinued Operations (Narrative) (Details) - USD ($)				12 Months Ended
	Jan. 31, 2020	Nov. 04, 2019	Oct. 31, 2017	Apr. 03, 2020	Mar. 29, 2019	Mar. 30, 2018	Aug. 08, 2019
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Direct costs, net of income, from transition service agreement				$ 19,000,000	$ 0	$ 0
Gain on sale of divestiture				250,000,000	0	653,000,000
Income tax expense (benefit)				241,000,000	3,000,000	(720,000,000)
Equity investment received as consideration in divestitures				0	0	160,000,000
Income from discontinued operations				3,309,000,000	141,000,000	174,000,000
Discontinued Operations, Disposed of by Sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income before income taxes				4,000,000	234,000,000	214,000,000
Revenue from discontinued operations				1,368,000,000	2,288,000,000	2,329,000,000
Income from discontinued operations				3,309,000,000	141,000,000	174,000,000
Tax expense of discontinued operation				2,122,000,000	87,000,000	29,000,000
Enterprise Security | Discontinued Operations, Disposed of by Sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration from sale of businesses, including discontinued operations		$ 10,700,000,000					$ 10,700,000,000
Transition services agreement, term		6 months
Direct costs, net of income, from transition service agreement				19,000,000
Total net assets sold		$ 5,211,000,000
Cash proceeds		10,582,000,000
Foreign exchange impact		$ (7,000,000)
ID Analytics | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration from sale of businesses, including discontinued operations	$ 375,000,000
Gain on sale of divestiture	250,000,000
Total net assets sold	125,000,000
Goodwill and net intangible assets sold	114,000,000
Other assets sold, net of liabilities	11,000,000
Income tax expense (benefit)	$ 86,000,000
WSS and PKI Solutions | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration from sale of businesses, including discontinued operations			$ 1,100,000,000
Gain on sale of divestiture			653,000,000
Total net assets sold			450,000,000
Goodwill and net intangible assets sold			670,000,000
Income tax expense (benefit)			123,000,000
Cash proceeds			951,000,000
Equity investment received as consideration in divestitures			160,000,000
Foreign exchange impact			(8,000,000)
Transaction costs			8,000,000
Gain on sale of short-term investment			$ 7,000,000
Income before income taxes						66,000,000
Veritas | Discontinued Operations, Disposed of by Sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenue from discontinued operations					13,000,000	54,000,000
Income from discontinued operations				$ 0	$ 15,000,000	$ 11,000,000
DigiCert
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Ownership percentage			28.00%