Balance Sheet Details (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Mar. 31, 2015	[1]
Balance Sheet Related Disclosures [Abstract]
Depreciation expense	$ 30	$ 33	$ 60	$ 64
Deferred Revenue, Current	$ 1,113		$ 1,113		$ 1,283

[1] Derived from audited Consolidated Financial Statements.