Fair Value of Financial Assets and Liabilities - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended		9 Months Ended				9 Months Ended				12 Months Ended
	Sep. 30, 2014	Jun. 30, 2014	Sep. 30, 2014 Security	Dec. 31, 2013	Sep. 30, 2014 Minimum	Sep. 30, 2014 Maximum	Sep. 30, 2014 Foreign debt securities	Dec. 31, 2013 Foreign debt securities	Sep. 30, 2014 Foreign Sovereign Debt Securities	Sep. 30, 2014 Auction rate securities	Dec. 31, 2013 Auction rate securities	Sep. 30, 2014 Variable Rate Demand Note	Dec. 31, 2012 LenovoEMC	Sep. 30, 2014 LenovoEMC
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available-for-sale Securities							$ 2,747	$ 2,155		$ 52	$ 60
Average credit rating							A+		AA+	AA
Percentage of securities									5.00%
Number of auction rate securities			1
Auction rate securities that have partial guarantees by the U.S. government, market value	7		7
Percentage of loans guaranteed	95.00%		95.00%
Investment holding period			5 years
Coupon rate used to estimate fair value of investments - Start Range					0.00%
Coupon rate used to estimate fair value of investments - End Range						3.00%
Discount rate used to estimate fair value of investments			1.00%										6.00%
The rate used for the discount margin to determine the estimated fair value of investment in auction rate securities	1.00%		1.00%	1.00%
Ownership percentage, joint venture														49.00%
Fair value input, discounted cash flow, term													3 years
Unrealized gain	76	88
Short-term investments	$ 2,092		$ 2,092	$ 2,773								$ 51