Acquisitions - Additional Information (Details) (USD $) Share data in Millions, except Per Share data, unless otherwise specified	12 Months Ended				12 Months Ended		12 Months Ended		3 Months Ended	12 Months Ended			0 Months Ended		12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Jun. 30, 2012	Dec. 31, 2012 2012 Acquisitions Entity	Jun. 30, 2012 XtremIO	Dec. 31, 2011 All 2011 Acquisitions Entity	Dec. 31, 2010 All 2010 Acquisitions	Dec. 31, 2010 Isilon	Dec. 31, 2010 2010 Acquisitions, excluding Isilon Entity	Dec. 31, 2012 EMC 2012 Acquisitions Entity	Dec. 31, 2012 VMware 2012 Acquisitions Entity	Aug. 24, 2012 VMware Nicira	Dec. 31, 2012 VMware Nicira	Dec. 31, 2011 VMware All 2011 Acquisitions Entity	Dec. 31, 2010 VMware 2010 Acquisitions, excluding Isilon Entity	Dec. 31, 2010 In-process research and development Isilon	Dec. 31, 2012 In-process research and development VMware Nicira
Business Acquisition [Line Items]
Business acquisition, aggregate consideration for businesses					$ 1,059,700,000		$ 539,800,000		$ 2,327,900,000	$ 895,500,000			$ 1,099,600,000
Cash consideration for acquisition of business, net of cash acquired					1,052,800,000		536,600,000		2,301,100,000	893,500,000			1,083,000,000
Business acquisition, fair value of stock options issued					6,900,000		3,200,000		26,800,000	1,900,000			16,600,000
Number of stock options issued in acquisition													1.1
Number of shares of stock issued in acquisition													0.6
Acquisition-date closing share price													$ 92.21
Stock options issued in acquisition, expected term													2 years 8 months 12 days
Stock options issued in acquisition, risk-free interest rate								0.70%					0.30%
Stock options issued in acquisition, annualized volatility								29.00%					35.70%
Stock options issued in acquisition, dividend yield													0.00%
Businesses acquired (in number of entities)					16		7			3	11	5			6	6
Business acquisition, adjustment to fair value of previously held interests, recognized in other income				(31,600,000)		31,600,000
Consideration of acquisitions allocated to goodwill	13,839,700,000	12,154,970,000	11,772,650,000		818,900,000		375,800,000	2,605,900,000	1,974,536,000	631,400,000				905,140,000
Consideration of acquisitions allocated to intangibles					311,400,000		157,100,000		469,400,000	249,139,000				334,600,000			43,900,000	48,500,000
Consideration of acquisitions allocated to net assets (liabilities)					(70,600,000)		(6,900,000)
Transaction costs for financial advisory, legal and accounting services	9,700,000	11,300,000	7,700,000						600,000
Consideration of acquisitions allocated to in-process research and development									$ 43,900,000