Changes in Carrying Amount of Goodwill (Detail) (USD $)	9 Months Ended	12 Months Ended
	Sep. 30, 2011	Dec. 31, 2010
Goodwill [Line Items]
Balance, beginning of the year	$ 11,772,650,000	$ 9,210,376,000
Goodwill resulting from acquisitions	375,840,000	2,605,926,000
Tax deduction from exercise of stock options	(168,000)	(4,075,000)
Other adjustments		0
Finalization of purchase price allocations	5,329,000	(39,577,000)
Balance, end of the period	12,153,651,000	11,772,650,000
Information Storage
Goodwill [Line Items]
Balance, beginning of the year	7,029,341,000	5,045,086,000
Goodwill resulting from acquisitions		2,287,712,000
Tax deduction from exercise of stock options	(73,000)	(548,000)
Other adjustments		(275,405,000)
Finalization of purchase price allocations	4,038,000	(27,504,000)
Balance, end of the period	7,033,306,000	7,029,341,000
Information Intelligence Group
Goodwill [Line Items]
Balance, beginning of the year		1,476,520,000
Tax deduction from exercise of stock options		(2,424,000)
Finalization of purchase price allocations		(6,193,000)
Balance, end of the period	1,467,903,000	1,467,903,000
RSA Information Security
Goodwill [Line Items]
Balance, beginning of the year	1,663,213,000	1,529,408,000
Goodwill resulting from acquisitions	187,445,000	140,013,000
Tax deduction from exercise of stock options	(95,000)	(1,103,000)
Finalization of purchase price allocations		(5,105,000)
Balance, end of the period	1,848,581,000	1,663,213,000
VMware Virtual Infrastructure Within EMC
Goodwill [Line Items]
Balance, beginning of the year	1,612,193,000	1,159,362,000
Goodwill resulting from acquisitions	188,395,000	178,201,000
Other adjustments		275,405,000
Finalization of purchase price allocations	3,273,000	(775,000)
Balance, end of the period	$ 1,803,861,000	$ 1,612,193,000