Segment Information - Additional Information (Detail) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2015 USD ($) Country	Sep. 30, 2014 Country	Sep. 30, 2015 USD ($) Country segment	Sep. 30, 2014 Country	Dec. 31, 2014 USD ($) Country
United States
Segment Reporting Information [Line Items]
Long-lived assets, excluding financial instruments, deferred tax assets, goodwill and intangible assets | $	$ 4,496		$ 4,496		$ 4,355
International
Segment Reporting Information [Line Items]
Long-lived assets, excluding financial instruments, deferred tax assets, goodwill and intangible assets | $	$ 985		$ 985		$ 1,021
Geographic Concentration | Sales Revenue, Segment
Segment Reporting Information [Line Items]
Number of countries other than the US that accounted for 10% or more	0	0	0	0
Geographic Concentration | Long-lived Assets, Total
Segment Reporting Information [Line Items]
Number of countries other than the US that accounted for 10% or more			0		0
EMC Information Infrastructure
Segment Reporting Information [Line Items]
Number of operating segments | segment			3