Acquisitions (Details) (USD $) In Millions, unless otherwise specified	10 Months Ended
	Mar. 31, 2014		Mar. 31, 2015	Mar. 31, 2013	Jun. 30, 2013
Business Combinations [Abstract]
Accrued acquisition-related costs related to purchase price amounts withheld to support indemnification obligations	$ 30		$ 27
Purchase price allocation and estimated useful lives
Goodwill	5,922		5,806	5,864
Layer 7
Business Acquisition
Percentage of voting equity interest acquired					100.00%
Cash acquired from acquisition	9
Purchase price allocation and estimated useful lives
Finite-lived intangible assets	26	[1]
Goodwill	55
Deferred tax liabilities	(13)
Other assets net of other liabilities assumed	0	[2]
Purchase price	155				155
Estimated useful life
Finite-lived intangible assets, Estimated useful life (in years)	3 years	[1]
Goodwill, Estimated useful life	Indefinite
Layer 7 | Purchased Software
Purchase price allocation and estimated useful lives
Finite-lived intangible assets	$ 87
Estimated useful life
Finite-lived intangible assets, Estimated useful life (in years)	5 years

[1] Includes customer relationships and trade names.

[2] Includes approximately $9 million of cash acquired.