Balance Sheet Details (Property And Equipment, Net Schedule) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Mar. 31, 2021
Property and Equipment, Net [Line Items]
Property and equipment, gross	$ 1,581		$ 1,581		$ 1,521
Less: accumulated depreciation	(1,065)		(1,065)		(1,030)
Property and equipment, net	516		516		491	[1]
Depreciation expense	39	$ 32	79	$ 63
Computer, equipment and software
Property and Equipment, Net [Line Items]
Property and equipment, gross	821		821		808
Buildings
Property and Equipment, Net [Line Items]
Property and equipment, gross	369		369		370
Leasehold improvements
Property and Equipment, Net [Line Items]
Property and equipment, gross	186		186		172
Equipment, furniture and fixtures, and other
Property and Equipment, Net [Line Items]
Property and equipment, gross	93		93		93
Land
Property and Equipment, Net [Line Items]
Property and equipment, gross	66		66		66
Construction in progress
Property and Equipment, Net [Line Items]
Property and equipment, gross	$ 46		$ 46		$ 12

[1] Derived from audited Consolidated Financial Statements.