Stock Option Activity (Detail) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
EMC Information Infrastructure
Number of Shares
Outstanding shares - beginning balance	172,416,000	234,918,000	250,119,000
Options granted relating to business acquisitions	141,000	12,595,000	24,089,000
Granted	1,665,000	3,286,000	14,243,000
Forfeited	(4,159,000)	(6,632,000)	(10,178,000)
Expired	(13,866,000)	(14,970,000)	(14,953,000)
Exercised	(44,659,000)	(56,781,000)	(28,402,000)
Outstanding shares - ending balance	111,538,000	172,416,000	234,918,000
Exercisable shares, at year end	78,845,000
Vested and expected to vest	109,546,000
Weighted Average Exercise Price (per share)
Outstanding - weighted average exercise price - beginning balance	$ 15.23	$ 18.31	$ 19.14
Options granted relating to business acquisitions	$ 3.24	$ 5.57	$ 5.68
Granted	$ 25.31	$ 20.07	$ 15.20
Forfeited	$ 13.00	$ 14.36	$ 14.64
Expired	$ 40.05	$ 70.59	$ 29.35
Exercised	$ 11.91	$ 11.63	$ 8.85
Outstanding - weighted average exercise price - ending balance	$ 13.69	$ 15.23	$ 18.31
Exercisable - weighted average exercise price, at year end	$ 13.33
Vested and expected to vest	$ 13.68
VMware Virtual Infrastructure Within EMC
Number of Shares
Outstanding shares - beginning balance	26,924,000	41,507,000	42,436,000
Granted	171,000	3,362,000	12,500,000
Forfeited	(1,011,000)	(2,220,000)	(3,736,000)
Expired	(112,000)	(151,000)	(177,000)
Exercised	(9,798,000)	(15,574,000)	(9,516,000)
Outstanding shares - ending balance	16,174,000	26,924,000	41,507,000
Exercisable shares, at year end	9,863,000
Vested and expected to vest	15,808,000
Weighted Average Exercise Price (per share)
Outstanding - weighted average exercise price - beginning balance	$ 33.54	$ 28.34	$ 26.54
Granted	$ 5.68	$ 57.60	$ 29.86
Forfeited	$ 40.98	$ 30.78	$ 28.11
Expired	$ 101.66	$ 83.86	$ 45.24
Exercised	$ 28.64	$ 24.79	$ 22.01
Outstanding - weighted average exercise price - ending balance	$ 35.27	$ 33.54	$ 28.34
Exercisable - weighted average exercise price, at year end	$ 32.75
Vested and expected to vest	$ 35.05