FAIR VALUE MEASUREMENTS (Details Tables) (Recurring Basis [Member], USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
ASSETS:
Total assets at fair value	$ 7,196,711	$ 6,003,064
Money Market Funds [Member] | Cash Equivalents [Member]
ASSETS:
Total assets at fair value	69,430	273,850
Foreign government securities [Member] | Short-term Investments [Member]
ASSETS:
Total assets at fair value	189,515	4,019,407
Foreign government securities [Member] | Cash Equivalents [Member]
ASSETS:
Total assets at fair value	838,090	238,202
U.S. government securities [Member] | Short-term Investments [Member]
ASSETS:
Total assets at fair value	650,513	1,443,313
U.S. government securities [Member] | Long-term Investments [Member]
ASSETS:
Total assets at fair value	231,991
U.S. government securities [Member] | Cash Equivalents [Member]
ASSETS:
Total assets at fair value	2,135,978	28,000
U.S. commercial paper [Member] | Short-term Investments [Member]
ASSETS:
Total assets at fair value	182,630
U.S. commercial paper [Member] | Cash Equivalents [Member]
ASSETS:
Total assets at fair value	731,788
U.S. corporate debt securities [Member] | Long-term Investments [Member]
ASSETS:
Total assets at fair value	1,043,777
U.S. government agency securities [Member] | Short-term Investments [Member]
ASSETS:
Total assets at fair value	170,695
U.S. government agency securities [Member] | Long-term Investments [Member]
ASSETS:
Total assets at fair value	70,246
U.S. government agency securities [Member] | Cash Equivalents [Member]
ASSETS:
Total assets at fair value	262,467
Ctrip corporate debt securities [Member] | Long-term Investments [Member]
ASSETS:
Total assets at fair value	479,500
Ctrip equity securities [Member] | Long-term Investments [Member]
ASSETS:
Total assets at fair value	139,668
Level 1 [Member]
ASSETS:
Total assets at fair value	209,098	273,850
Level 1 [Member] | Money Market Funds [Member] | Cash Equivalents [Member]
ASSETS:
Total assets at fair value	69,430	273,850
Level 1 [Member] | Foreign government securities [Member] | Short-term Investments [Member]
ASSETS:
Total assets at fair value	0	0
Level 1 [Member] | Foreign government securities [Member] | Cash Equivalents [Member]
ASSETS:
Total assets at fair value	0	0
Level 1 [Member] | U.S. government securities [Member] | Short-term Investments [Member]
ASSETS:
Total assets at fair value	0	0
Level 1 [Member] | U.S. government securities [Member] | Long-term Investments [Member]
ASSETS:
Total assets at fair value	0
Level 1 [Member] | U.S. government securities [Member] | Cash Equivalents [Member]
ASSETS:
Total assets at fair value	0	0
Level 1 [Member] | U.S. commercial paper [Member] | Short-term Investments [Member]
ASSETS:
Total assets at fair value	0
Level 1 [Member] | U.S. commercial paper [Member] | Cash Equivalents [Member]
ASSETS:
Total assets at fair value	0
Level 1 [Member] | U.S. corporate debt securities [Member] | Long-term Investments [Member]
ASSETS:
Total assets at fair value	0
Level 1 [Member] | U.S. government agency securities [Member] | Short-term Investments [Member]
ASSETS:
Total assets at fair value	0
Level 1 [Member] | U.S. government agency securities [Member] | Long-term Investments [Member]
ASSETS:
Total assets at fair value	0
Level 1 [Member] | U.S. government agency securities [Member] | Cash Equivalents [Member]
ASSETS:
Total assets at fair value	0
Level 1 [Member] | Ctrip corporate debt securities [Member] | Long-term Investments [Member]
ASSETS:
Total assets at fair value	0
Level 1 [Member] | Ctrip equity securities [Member] | Long-term Investments [Member]
ASSETS:
Total assets at fair value	139,668
Level 2 [Member]
ASSETS:
Total assets at fair value	6,987,613	5,729,214
Level 2 [Member] | Money Market Funds [Member] | Cash Equivalents [Member]
ASSETS:
Total assets at fair value	0	0
Level 2 [Member] | Foreign government securities [Member] | Short-term Investments [Member]
ASSETS:
Total assets at fair value	189,515	4,019,407
Level 2 [Member] | Foreign government securities [Member] | Cash Equivalents [Member]
ASSETS:
Total assets at fair value	838,090	238,202
Level 2 [Member] | U.S. government securities [Member] | Short-term Investments [Member]
ASSETS:
Total assets at fair value	650,513	1,443,313
Level 2 [Member] | U.S. government securities [Member] | Long-term Investments [Member]
ASSETS:
Total assets at fair value	231,991
Level 2 [Member] | U.S. government securities [Member] | Cash Equivalents [Member]
ASSETS:
Total assets at fair value	2,135,978	28,000
Level 2 [Member] | U.S. commercial paper [Member] | Short-term Investments [Member]
ASSETS:
Total assets at fair value	182,630
Level 2 [Member] | U.S. commercial paper [Member] | Cash Equivalents [Member]
ASSETS:
Total assets at fair value	731,788
Level 2 [Member] | U.S. corporate debt securities [Member] | Long-term Investments [Member]
ASSETS:
Total assets at fair value	1,043,777
Level 2 [Member] | U.S. government agency securities [Member] | Short-term Investments [Member]
ASSETS:
Total assets at fair value	170,695
Level 2 [Member] | U.S. government agency securities [Member] | Long-term Investments [Member]
ASSETS:
Total assets at fair value	70,246
Level 2 [Member] | U.S. government agency securities [Member] | Cash Equivalents [Member]
ASSETS:
Total assets at fair value	262,467
Level 2 [Member] | Ctrip corporate debt securities [Member] | Long-term Investments [Member]
ASSETS:
Total assets at fair value	479,500
Level 2 [Member] | Ctrip equity securities [Member] | Long-term Investments [Member]
ASSETS:
Total assets at fair value	0
Foreign Currency Contracts [Member]
LIABILITIES:
Total liabilities at fair value	1,044	122,091
Foreign Currency Contracts [Member] | Short-term Investments [Member]
ASSETS:
Total assets at fair value	423	292
Foreign Currency Contracts [Member] | Level 1 [Member]
LIABILITIES:
Total liabilities at fair value	0	0
Foreign Currency Contracts [Member] | Level 1 [Member] | Short-term Investments [Member]
ASSETS:
Total assets at fair value	0	0
Foreign Currency Contracts [Member] | Level 2 [Member]
LIABILITIES:
Total liabilities at fair value	1,044	122,091
Foreign Currency Contracts [Member] | Level 2 [Member] | Short-term Investments [Member]
ASSETS:
Total assets at fair value	$ 423	$ 292