Shareholders' Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended		3 Months Ended	9 Months Ended		31 Months Ended
	Mar. 17, 2014	Nov. 30, 2006	Sep. 30, 2015	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Jan. 27, 2015	Dec. 01, 2014	Feb. 28, 2013
Sold warrants to acquire shares of our common stock, exercise price per share		$ 19.55
Common stock excluded from calculation of diluted earnings per share			19,000,000	7,000,000	3,000,000
Repurchases of Common Stock, shares authorized to repurchase			500,000,000	500,000,000		500,000,000		250,000,000	250,000,000
Total Repurchases of Common Stock, cost				$ 2,000		$ 7,400
Total Repurchases of Common Stock, shares				76,000,000		277,000,000
Shares authorized for future repurchases			223,000,000	223,000,000		223,000,000
Payments for Repurchase of Common Stock				$ 2,063	$ 1,374
Sold Warrants
Sold warrants to acquire shares of our common stock		215,000,000
Warrant
Warrants exercised	$ 109
Exercised Warrants
Conversion of Stock, Shares Issued	29,000,000
VMware
Total Repurchases of Common Stock, shares				13,000,000
Payments for Repurchase of Common Stock				$ 1,050	$ 450
Stock Repurchase Program, Authorized Amount							$ 1,000
Stock Repurchase Program, Remaining Authorized Repurchase Amount			$ 910	$ 910		$ 910