FAIR VALUE MEASUREMENTS (Details) - Recurring Basis [Member] - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
ASSETS:
Total assets at fair value	$ 11,205,077	$ 9,640,707
Foreign Currency Contracts [Member]
ASSETS:
Total assets at fair value	782	363
LIABILITIES:
Total liabilities at fair value	351	644
Money market funds | Cash Equivalents [Member]
ASSETS:
Total assets at fair value	1,344,815	99,117
U.S. government securities | Cash Equivalents [Member]
ASSETS:
Total assets at fair value	222,264	90,441
U.S. government securities | Short-term Investments [Member]
ASSETS:
Total assets at fair value	427,535	456,494
U.S. government securities | Long-term Investments [Member]
ASSETS:
Total assets at fair value	547,230	578,450
Commercial paper | Cash Equivalents [Member]
ASSETS:
Total assets at fair value	5,560	335,663
Commercial paper | Short-term Investments [Member]
ASSETS:
Total assets at fair value	8,007	11,688
Foreign government securities | Cash Equivalents [Member]
ASSETS:
Total assets at fair value		10,659
Foreign government securities | Short-term Investments [Member]
ASSETS:
Total assets at fair value	287,112	395,797
Foreign government securities | Long-term Investments [Member]
ASSETS:
Total assets at fair value	646,437	719,631
Corporate debt securities | Cash Equivalents [Member]
ASSETS:
Total assets at fair value		1,855
Corporate debt securities | Short-term Investments [Member]
ASSETS:
Total assets at fair value	951,211	305,260
Corporate debt securities | Long-term Investments [Member]
ASSETS:
Total assets at fair value	4,583,347	4,276,614
U.S. government agency securities | Short-term Investments [Member]
ASSETS:
Total assets at fair value	3,377	2,007
U.S. government agency securities | Long-term Investments [Member]
ASSETS:
Total assets at fair value	1,000
U.S. municipal securities | Long-term Investments [Member]
ASSETS:
Total assets at fair value	1,074	1,083
Level 1 [Member]
ASSETS:
Total assets at fair value	2,213,666	1,076,152
Level 1 [Member] | Foreign Currency Contracts [Member]
ASSETS:
Total assets at fair value	0	0
LIABILITIES:
Total liabilities at fair value	0	0
Level 1 [Member] | Money market funds | Cash Equivalents [Member]
ASSETS:
Total assets at fair value	1,344,815	99,117
Level 1 [Member] | U.S. government securities | Cash Equivalents [Member]
ASSETS:
Total assets at fair value	0	0
Level 1 [Member] | U.S. government securities | Short-term Investments [Member]
ASSETS:
Total assets at fair value	0	0
Level 1 [Member] | U.S. government securities | Long-term Investments [Member]
ASSETS:
Total assets at fair value	0	0
Level 1 [Member] | Commercial paper | Cash Equivalents [Member]
ASSETS:
Total assets at fair value	0	0
Level 1 [Member] | Commercial paper | Short-term Investments [Member]
ASSETS:
Total assets at fair value	0	0
Level 1 [Member] | Foreign government securities | Cash Equivalents [Member]
ASSETS:
Total assets at fair value		0
Level 1 [Member] | Foreign government securities | Short-term Investments [Member]
ASSETS:
Total assets at fair value	0	0
Level 1 [Member] | Foreign government securities | Long-term Investments [Member]
ASSETS:
Total assets at fair value	0	0
Level 1 [Member] | Corporate debt securities | Cash Equivalents [Member]
ASSETS:
Total assets at fair value		0
Level 1 [Member] | Corporate debt securities | Short-term Investments [Member]
ASSETS:
Total assets at fair value	0	0
Level 1 [Member] | Corporate debt securities | Long-term Investments [Member]
ASSETS:
Total assets at fair value	0	0
Level 1 [Member] | U.S. government agency securities | Short-term Investments [Member]
ASSETS:
Total assets at fair value	0	0
Level 1 [Member] | U.S. government agency securities | Long-term Investments [Member]
ASSETS:
Total assets at fair value	0
Level 1 [Member] | U.S. municipal securities | Long-term Investments [Member]
ASSETS:
Total assets at fair value	0	0
Level 2 [Member]
ASSETS:
Total assets at fair value	8,991,411	8,564,555
Level 2 [Member] | Foreign Currency Contracts [Member]
ASSETS:
Total assets at fair value	782	363
LIABILITIES:
Total liabilities at fair value	351	644
Level 2 [Member] | Money market funds | Cash Equivalents [Member]
ASSETS:
Total assets at fair value	0	0
Level 2 [Member] | U.S. government securities | Cash Equivalents [Member]
ASSETS:
Total assets at fair value	222,264	90,441
Level 2 [Member] | U.S. government securities | Short-term Investments [Member]
ASSETS:
Total assets at fair value	427,535	456,494
Level 2 [Member] | U.S. government securities | Long-term Investments [Member]
ASSETS:
Total assets at fair value	547,230	578,450
Level 2 [Member] | Commercial paper | Cash Equivalents [Member]
ASSETS:
Total assets at fair value	5,560	335,663
Level 2 [Member] | Commercial paper | Short-term Investments [Member]
ASSETS:
Total assets at fair value	8,007	11,688
Level 2 [Member] | Foreign government securities | Cash Equivalents [Member]
ASSETS:
Total assets at fair value		10,659
Level 2 [Member] | Foreign government securities | Short-term Investments [Member]
ASSETS:
Total assets at fair value	287,112	395,797
Level 2 [Member] | Foreign government securities | Long-term Investments [Member]
ASSETS:
Total assets at fair value	646,437	719,631
Level 2 [Member] | Corporate debt securities | Cash Equivalents [Member]
ASSETS:
Total assets at fair value		1,855
Level 2 [Member] | Corporate debt securities | Short-term Investments [Member]
ASSETS:
Total assets at fair value	951,211	305,260
Level 2 [Member] | Corporate debt securities | Long-term Investments [Member]
ASSETS:
Total assets at fair value	4,583,347	4,276,614
Level 2 [Member] | U.S. government agency securities | Short-term Investments [Member]
ASSETS:
Total assets at fair value	3,377	2,007
Level 2 [Member] | U.S. government agency securities | Long-term Investments [Member]
ASSETS:
Total assets at fair value	1,000
Level 2 [Member] | U.S. municipal securities | Long-term Investments [Member]
ASSETS:
Total assets at fair value	1,074	1,083
Ctrip.com International, Ltd. [Member] | Ctrip convertible debt securities | Long-term Investments [Member]
ASSETS:
Total assets at fair value	1,306,475	1,378,550
Ctrip.com International, Ltd. [Member] | Ctrip equity securities | Long-term Investments [Member]
ASSETS:
Total assets at fair value	868,851	977,035
Ctrip.com International, Ltd. [Member] | Level 1 [Member] | Ctrip convertible debt securities | Long-term Investments [Member]
ASSETS:
Total assets at fair value	0	0
Ctrip.com International, Ltd. [Member] | Level 1 [Member] | Ctrip equity securities | Long-term Investments [Member]
ASSETS:
Total assets at fair value	868,851	977,035
Ctrip.com International, Ltd. [Member] | Level 2 [Member] | Ctrip convertible debt securities | Long-term Investments [Member]
ASSETS:
Total assets at fair value	1,306,475	1,378,550
Ctrip.com International, Ltd. [Member] | Level 2 [Member] | Ctrip equity securities | Long-term Investments [Member]
ASSETS:
Total assets at fair value	$ 0	$ 0