Acquisitions - Allocation of Purchase Price (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Business Acquisition [Line Items]
Goodwill	$ 17,090	$ 16,134	$ 14,424
Virtustream
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets	20
Intangible assets	379
Deferred tax liabilities, net	(41)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Other	(9)
Total purchase price	$ 1,220
Finite-Lived Intangible Assets, Net [Abstract]
Weighted-average useful life	9 years
Business Acquisition, Goodwill, Expected Tax Deductible Amount	$ 873
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Noncurrent Assets	12
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets	1,298
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities	(28)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities	(78)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment	14
VMware | AirWatch
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets		61
Intangible assets		250
Other current liabilities, net of current assets		(72)
Total purchase price		1,092
Finite-Lived Intangible Assets, Net [Abstract]
Business Acquisition, Goodwill, Expected Tax Deductible Amount		868
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Noncurrent Assets		30
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets		1,209
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Deferred Revenue		(45)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities		(117)
Purchased technology | Virtustream
Business Acquisition [Line Items]
Intangible assets	$ 302
Finite-Lived Intangible Assets, Net [Abstract]
Weighted-average useful life	8 years 7 months
Purchased technology | VMware | AirWatch
Business Acquisition [Line Items]
Intangible assets		$ 118
Finite-Lived Intangible Assets, Net [Abstract]
Weighted-average useful life		6 years
Tradename and trademark | Virtustream
Business Acquisition [Line Items]
Intangible assets	$ 27
Finite-Lived Intangible Assets, Net [Abstract]
Weighted-average useful life	7 years 7 months
Tradename and trademark | VMware | AirWatch
Business Acquisition [Line Items]
Intangible assets		$ 40
Finite-Lived Intangible Assets, Net [Abstract]
Weighted-average useful life		8 years
Customer relationships and customer lists | Virtustream
Business Acquisition [Line Items]
Intangible assets	$ 50
Finite-Lived Intangible Assets, Net [Abstract]
Weighted-average useful life	12 years 3 months
Customer relationships and customer lists | VMware | AirWatch
Business Acquisition [Line Items]
Intangible assets		$ 78
Finite-Lived Intangible Assets, Net [Abstract]
Weighted-average useful life		8 years
Other | VMware | AirWatch
Business Acquisition [Line Items]
Intangible assets		$ 14
Finite-Lived Intangible Assets, Net [Abstract]
Weighted-average useful life		3 years