Balance Sheet Details (Property And Equipment, Net Schedule) (Details) - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Property, Plant and Equipment [Line Items]
Depreciation expense	$ 120	$ 121	$ 120
Property and equipment, gross	1,391	1,359
Less accumulated depreciation	(942)	(911)
Property and equipment, net	449	448
Computer equipment and software
Property, Plant and Equipment [Line Items]
Property and equipment, gross	722	710
Buildings
Property, Plant and Equipment [Line Items]
Property and equipment, gross	340	343
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	161	139
Equipment, furniture and fixtures, and other
Property, Plant and Equipment [Line Items]
Property and equipment, gross	83	80
Land
Property, Plant and Equipment [Line Items]
Property and equipment, gross	65	66
Construction in progress
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 20	$ 21