Balance Sheet Details (Property And Equipment, Net Schedule) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Mar. 31, 2020
Property and Equipment, Net [Line Items]
Property and equipment, gross	$ 1,516		$ 1,516		$ 1,391
Less: accumulated depreciation	(1,049)		(1,049)		(942)
Property and equipment, net	467		467		449	[1]
Depreciation expense	37	$ 29	100	$ 89
Computer, equipment and software
Property and Equipment, Net [Line Items]
Property and equipment, gross	827		827		722
Buildings
Property and Equipment, Net [Line Items]
Property and equipment, gross	357		357		340
Leasehold improvements
Property and Equipment, Net [Line Items]
Property and equipment, gross	172		172		161
Equipment, furniture and fixtures, and other
Property and Equipment, Net [Line Items]
Property and equipment, gross	89		89		83
Land
Property and Equipment, Net [Line Items]
Property and equipment, gross	66		66		65
Construction in progress
Property and Equipment, Net [Line Items]
Property and equipment, gross	$ 5		$ 5		$ 20

[1] Derived from audited Consolidated Financial Statements.