Investments in Equity Interests - Additional Information (Detail) (USD $) Share data in Millions, except Per Share data, unless otherwise specified	1 Months Ended	3 Months Ended		12 Months Ended		0 Months Ended			1 Months Ended	3 Months Ended	12 Months Ended				12 Months Ended					3 Months Ended		12 Months Ended
	Sep. 30, 2012	Dec. 31, 2013	Sep. 30, 2012	Dec. 31, 2013	Dec. 31, 2012	Sep. 18, 2012 Alibaba Group	Jul. 29, 2011 Alibaba Group	Oct. 23, 2005 Alibaba Group	May 16, 2013 Alibaba Group	Dec. 31, 2013 Alibaba Group	Dec. 31, 2013 Alibaba Group	Dec. 31, 2012 Alibaba Group	Dec. 31, 2011 Alibaba Group	Oct. 14, 2013 Alibaba Group	Dec. 31, 2013 Alibaba Group Before Amendment	Dec. 31, 2012 Alibaba Group Before Amendment	Dec. 31, 2011 Alibaba Group Before Amendment	Dec. 31, 2013 Alibaba Group Maximum	Dec. 31, 2013 Alibaba Group Minimum	Jun. 30, 2011 Yahoo Japan	Mar. 31, 2011 Yahoo Japan	Dec. 31, 2013 Yahoo Japan	Dec. 31, 2012 Yahoo Japan	Dec. 31, 2011 Yahoo Japan
Schedule of Equity Method Investments [Line Items]
Percent ownership of common stock as of balance sheet date								46.00%		24.00%	24.00%	24.00%										35.00%	35.00%	35.00%
Equity investment common stock diluted								40.00%
Cash paid								$ 1,000,000,000
Direct transaction costs								8,000,000
Aggregate consideration on patents sold		70,000,000		79,950,000						70,000,000
IPCo promissory note							500,000,000
Promissory note maturity period, years							7 years
Sale of investments in equity interests, shares						523						523
Shares of Alibaba Group owned by Yahoo						1,047
Sale of investments in equity interests, price per share						$ 13.54
Sale of investments in equity interests, total consideration received						7,100,000,000
Sale of investments in equity interests, cash received					6,247,728,000	6,300,000,000
Sale of investments in equity interests, value of preference shares						800,000,000
Gain related to sale of Alibaba shares	4,603,322,000		4,603,322,000		4,603,322,000							4,603,322,000
Expected rate of annual dividend on the issuance of preference shares by Alibaba Group																		10.00%
Expected rate of annual dividend payable in cash of preference shares by Alibaba Group																			3.00%
Proceeds related to the redemption of Alibaba Group Preference Shares and dividends									846,000,000
Proceeds related to the redemption of Alibaba Group Preference Shares				800,000,000					800,000,000
Cash dividend received related to Preference Shares									46,000,000
Maximum number of shares required to sell in connection with Qualified IPO						261.5								208.0
Future Royalty Payment received										550,000,000	550,000,000
Technology and Intellectual Property License Agreement, remaining term											4 years
Royalty received											137,000,000	39,000,000			122,000,000	86,000,000	44,000,000
Cumulative earnings recorded in retained earnings										1,078,000,000	1,078,000,000	661,000,000										2,800,000,000	2,300,000,000
Impairment charge, net of tax																				7,000,000	26,000,000			33,000,000
Fair value of the company's ownership interest in the common stock of Yahoo Japan																						11,000,000,000
Cash dividends received																						77,000,000	84,000,000	75,000,000
Revenue received through commercial arrangements with Yahoo Japan																						266,000,000	281,000,000	287,000,000
Net receivables balance from Yahoo Japan																						$ 42,000,000	$ 43,000,000