Balance Sheet Details (Property And Equipment, Net Schedule) (Details) - USD ($) $ in Millions	Sep. 30, 2017	Mar. 31, 2017
Property and Equipment, Net [Line Items]
Property and equipment, gross	$ 1,336	$ 1,315
Less: accumulated depreciation	(892)	(881)
Property and equipment, net	444	434	[1]
Computer, equipment and software
Property and Equipment, Net [Line Items]
Property and equipment, gross	726	723
Buildings
Property and Equipment, Net [Line Items]
Property and equipment, gross	327	316
Leasehold improvements
Property and Equipment, Net [Line Items]
Property and equipment, gross	136	126
Equipment, furniture and fixtures, and other
Property and Equipment, Net [Line Items]
Property and equipment, gross	80	82
Land
Property and Equipment, Net [Line Items]
Property and equipment, gross	61	61
Construction in progress
Property and Equipment, Net [Line Items]
Property and equipment, gross	$ 6	$ 7

[1] Derived from audited Consolidated Financial Statements.