Business Combinations - Additional Information (Detail) - USD ($) $ in Millions	Sep. 17, 2018	Aug. 04, 2017	Jun. 15, 2017	Mar. 24, 2017
Privately Held Software
Business Acquisition [Line Items]
Business acquisition cash paid	$ 3
Plexistor Limited
Business Acquisition [Line Items]
Business acquisition cash paid			$ 24
Plexistor Limited | Developed Technology
Business Acquisition [Line Items]
Business acquisition cash paid			6
Plexistor Limited | Goodwill
Business Acquisition [Line Items]
Business acquisition cash paid			$ 17
Greenqloud ehf
Business Acquisition [Line Items]
Business acquisition cash paid		$ 51
Greenqloud ehf | Developed Technology
Business Acquisition [Line Items]
Business acquisition cash paid		10
Greenqloud ehf | Goodwill
Business Acquisition [Line Items]
Business acquisition cash paid		$ 38
Privately Held Consulting and Software Development
Business Acquisition [Line Items]
Business acquisition cash paid				$ 8