Intangibles and Goodwill - Changes in Carrying Amount of Goodwill (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Goodwill [Roll Forward]
Balance, beginning of the year	$ 12,154,970	$ 11,772,650
Goodwill resulting from acquisitions	1,724,027	375,840
Tax deduction from exercise of stock options	(100)	(1,020)
Finalization of purchase price allocations	(10,003)	7,500
Balance, end of the year	13,839,700	12,154,970
Information Storage
Goodwill [Roll Forward]
Balance, beginning of the year	7,033,965	7,029,341
Goodwill resulting from acquisitions	437,868	0
Tax deduction from exercise of stock options	(7)	(73)
Finalization of purchase price allocations	(1,281)	4,697
Balance, end of the year	7,441,351	7,033,965
Information Intelligence Group
Goodwill [Roll Forward]
Balance, beginning of the year	1,469,216	1,467,903
Goodwill resulting from acquisitions	15,097	0
Tax deduction from exercise of stock options	(93)	(852)
Finalization of purchase price allocations	0	2,165
Balance, end of the year	1,484,220	1,469,216
RSA Information Security
Goodwill [Roll Forward]
Balance, beginning of the year	1,849,116	1,663,213
Goodwill resulting from acquisitions	179,389	187,445
Tax deduction from exercise of stock options	0	(95)
Finalization of purchase price allocations	(6,099)	(1,447)
Balance, end of the year	2,022,406	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	1,091,673	188,395
Tax deduction from exercise of stock options	0	0
Finalization of purchase price allocations	(2,623)	2,085
Balance, end of the year	2,891,723	1,802,673
Iomega [Member]
Goodwill [Roll Forward]
Goodwill derecognized in divestiture of business	(29,194)
Iomega [Member] | Information Storage
Goodwill [Roll Forward]
Goodwill derecognized in divestiture of business	(29,194)
Iomega [Member] | Information Intelligence Group
Goodwill [Roll Forward]
Goodwill derecognized in divestiture of business	0
Iomega [Member] | RSA Information Security
Goodwill [Roll Forward]
Goodwill derecognized in divestiture of business	0
Iomega [Member] | VMware Virtual Infrastructure within EMC
Goodwill [Roll Forward]
Goodwill derecognized in divestiture of business	$ 0