Business Combinations, Intangibles and Goodwill - Goodwill (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended	12 Months Ended
	Sep. 30, 2012	Dec. 31, 2011
Goodwill [Roll Forward]
Balance, beginning of the year	$ 12,154,970	$ 11,772,650
Goodwill resulting from acquisitions	1,583,711	375,840
Tax deduction from exercise of stock options	(6)	(1,020)
Finalization of purchase price allocations	(10,419)	7,500
Balance, end of the period	13,728,256	12,154,970
Information Storage
Goodwill [Roll Forward]
Balance, beginning of the year	7,033,965	7,029,341
Goodwill resulting from acquisitions	427,553	0
Tax deduction from exercise of stock options	(6)	(73)
Finalization of purchase price allocations	(659)	4,697
Balance, end of the period	7,460,853	7,033,965
Information Intelligence Group
Goodwill [Roll Forward]
Balance, beginning of the year	1,469,216	1,467,903
Goodwill resulting from acquisitions	14,493	0
Tax deduction from exercise of stock options		(852)
Finalization of purchase price allocations	0	2,165
Balance, end of the period	1,483,709	1,469,216
RSA Information Security
Goodwill [Roll Forward]
Balance, beginning of the year	1,849,116	1,663,213
Goodwill resulting from acquisitions	3,751	187,445
Tax deduction from exercise of stock options		(95)
Finalization of purchase price allocations	(6,099)	(1,447)
Balance, end of the period	1,846,768	1,849,116
VMware Virtual Infrastructure Within EMC
Goodwill [Roll Forward]
Balance, beginning of the year	1,802,673	1,612,193
Goodwill resulting from acquisitions	1,137,914	188,395
Tax deduction from exercise of stock options		0
Finalization of purchase price allocations	(3,661)	2,085
Balance, end of the period	$ 2,936,926	$ 1,802,673