Balance Sheet Details (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Mar. 31, 2020	[1]
Remaining Performance Obligations
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	12 months		12 months
Depreciation expense	$ 32	$ 30	$ 63	$ 60
Deferred Revenue, Current	$ 639		639		$ 945
Deferred Revenue, Revenue Recognized			$ 985	$ 1,131

[1] Derived from audited Consolidated Financial Statements.