Fair Value of Financial Assets and Liabilities - Changes In Fair Value of Level 3 Financial Assets (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Other-than-temporary impairment loss			$ (33)	$ 0
LenovoEMC
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of the period	36	34	35	33
Realized gain included in other expense, net	0	0	1	1
Balance, end of the period	36	34	36	34
Auction rate securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of the period	59	68	60	70
Calls at par value	(7)	0	(7)	(1)
Other-than-temporary impairment loss	0	0	0	(1)
(Increase) decrease in previously recognized unrealized losses included in other comprehensive income	0	(1)	(1)	(1)
Balance, end of the period	$ 52	$ 67	$ 52	$ 67