Balance Sheet Details (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Mar. 31, 2021	[1]
Remaining Performance Obligations
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	12 months		12 months
Depreciation expense	$ 39	$ 32	$ 79	$ 63
Deferred Revenue, Current	1,322		1,322		$ 1,527
Deferred Revenue, Revenue Recognized			1,504	$ 985
Unsatisfied Performance Obligations [Member]
Remaining Performance Obligations
Revenue, Remaining Performance Obligation, Amount	$ 89		$ 89

[1] Derived from audited Consolidated Financial Statements.