Basis of Presentation Merger (Details) - USD ($) $ / shares in Units, $ in Billions	Oct. 12, 2015	Sep. 30, 2015	Dec. 31, 2014
Business Acquisition [Line Items]
Common stock, par value (in usd per share)		$ 0.01	$ 0.01
VMware
Business Acquisition [Line Items]
Noncontrolling Interest, Ownership Percentage by Parent		81.00%
Subsequent Event | Denali
Business Acquisition [Line Items]
Resulting Percent of VMware which represents Merger consideration	53.00%
Economic interest of VMware Parent will retain	28.00%
Percent of EMC's interest in VMware which represents Merger consideration	65.00%
Business Acquisition, Share Price	$ 24.05
Common stock, par value (in usd per share)	$ 0.01
Investment Owned, Balance, Shares	222,966,450
Tracker Stock Fractional Share	0.111
Termination Fee Paid by EMC to Denali	$ 2.5
Termination Fee Paid by EMC to Denali if before December 12, 2015	2.0
Termination Fee Paid by Denali to EMC	4.0
Alternative Termination Fee Paid by Denali to EMC	$ 6.0