Balance Sheet Details (Property And Equipment, Net Schedule) (Details) - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Property, Plant and Equipment [Line Items]
Depreciation expense	$ 138	$ 120	$ 121
Property and equipment, gross	1,521	1,391
Less accumulated depreciation	(1,030)	(942)
Property and equipment, net	491	449
Computer equipment and software
Property, Plant and Equipment [Line Items]
Property and equipment, gross	808	722
Buildings
Property, Plant and Equipment [Line Items]
Property and equipment, gross	370	340
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	172	161
Equipment, furniture and fixtures, and other
Property, Plant and Equipment [Line Items]
Property and equipment, gross	93	83
Land
Property, Plant and Equipment [Line Items]
Property and equipment, gross	66	65
Construction in progress
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 12	$ 20