Balance Sheet Details (Property And Equipment, Net Schedule) (Details) - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Property, Plant and Equipment [Line Items]
Depreciation expense	$ 121	$ 120	$ 115
Property and equipment, gross	1,359	1,376
Less accumulated depreciation	(911)	(923)
Property and equipment, net	448	453
Computer equipment and software
Property, Plant and Equipment [Line Items]
Property and equipment, gross	710	744
Buildings
Property, Plant and Equipment [Line Items]
Property and equipment, gross	343	336
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	139	139
Equipment, furniture and fixtures, and other
Property, Plant and Equipment [Line Items]
Property and equipment, gross	80	84
Land
Property, Plant and Equipment [Line Items]
Property and equipment, gross	66	66
Construction in progress
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 21	$ 7