Business Combinations, Intangibles and Goodwill - Additional Information (Details) $ in Millions	6 Months Ended
	Jun. 30, 2015 USD ($) acquisition	Jun. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)
Business Acquisition [Line Items]
Cash paid	$ 61	$ 1,694
Number of Businesses Acquired | acquisition	4
Aggregate allocation to goodwill	$ 16,185		$ 16,134
All 2015 Acquisitions
Business Acquisition [Line Items]
Aggregate consideration	65
Cash paid	64
Aggregate allocation to goodwill	49
Aggregate allocation to intangibles	24
Aggregate allocation to net liabilities	$ 8
Weighted average amortization period of intangible assets acquired	3 years 7 months
EMC Information Infrastructure Plus Pivotal
Business Acquisition [Line Items]
Number of Businesses Acquired | acquisition	3