FAIR VALUE MEASUREMENTS (Investments) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
LIABILITIES:
Cost Method Investments	$ 7,600	$ 62,300
Recurring Basis
ASSETS:
Total assets at fair value	13,055,008	9,640,707
Recurring Basis | Level 1
ASSETS:
Total assets at fair value	1,891,930	1,076,152
Recurring Basis | Level 2
ASSETS:
Total assets at fair value	11,163,078	8,564,555
Currency exchange derivatives | Recurring Basis
ASSETS:
Total assets at fair value	756	363
LIABILITIES:
Total liabilities at fair value	1,015	644
Currency exchange derivatives | Recurring Basis | Level 1
ASSETS:
Total assets at fair value	0	0
LIABILITIES:
Total liabilities at fair value	0	0
Currency exchange derivatives | Recurring Basis | Level 2
ASSETS:
Total assets at fair value	756	363
LIABILITIES:
Total liabilities at fair value	1,015	644
Short-term investments: | Recurring Basis | International government securities
ASSETS:
Total assets at fair value	249,684	395,797
Short-term investments: | Recurring Basis | U.S. government securities
ASSETS:
Total assets at fair value	456,888	456,494
Short-term investments: | Recurring Basis | Corporate debt securities
ASSETS:
Total assets at fair value	1,510,310	305,260
Short-term investments: | Recurring Basis | Commercial paper
ASSETS:
Total assets at fair value	1,998	11,688
Short-term investments: | Recurring Basis | U.S. government agency securities
ASSETS:
Total assets at fair value		2,007
Short-term investments: | Recurring Basis | Level 1 | International government securities
ASSETS:
Total assets at fair value	0	0
Short-term investments: | Recurring Basis | Level 1 | U.S. government securities
ASSETS:
Total assets at fair value	0	0
Short-term investments: | Recurring Basis | Level 1 | Corporate debt securities
ASSETS:
Total assets at fair value	0	0
Short-term investments: | Recurring Basis | Level 1 | Commercial paper
ASSETS:
Total assets at fair value	0	0
Short-term investments: | Recurring Basis | Level 1 | U.S. government agency securities
ASSETS:
Total assets at fair value		0
Short-term investments: | Recurring Basis | Level 2 | International government securities
ASSETS:
Total assets at fair value	249,684	395,797
Short-term investments: | Recurring Basis | Level 2 | U.S. government securities
ASSETS:
Total assets at fair value	456,888	456,494
Short-term investments: | Recurring Basis | Level 2 | Corporate debt securities
ASSETS:
Total assets at fair value	1,510,310	305,260
Short-term investments: | Recurring Basis | Level 2 | Commercial paper
ASSETS:
Total assets at fair value	1,998	11,688
Short-term investments: | Recurring Basis | Level 2 | U.S. government agency securities
ASSETS:
Total assets at fair value		2,007
Long-term investments: | Recurring Basis | International government securities
ASSETS:
Total assets at fair value	659,344	719,631
Long-term investments: | Recurring Basis | U.S. government securities
ASSETS:
Total assets at fair value	766,592	578,450
Long-term investments: | Recurring Basis | Corporate debt securities
ASSETS:
Total assets at fair value	6,001,789	4,276,614
Long-term investments: | Recurring Basis | U.S. municipal securities
ASSETS:
Total assets at fair value		1,083
Long-term investments: | Recurring Basis | U.S. government agency securities
ASSETS:
Total assets at fair value	4,952
Long-term investments: | Recurring Basis | Ctrip convertible debt securities
ASSETS:
Total assets at fair value	1,293,088	1,378,550
Long-term investments: | Recurring Basis | Ctrip equity securities
ASSETS:
Total assets at fair value	865,302	977,035
Long-term investments: | Recurring Basis | Level 1 | International government securities
ASSETS:
Total assets at fair value	0	0
Long-term investments: | Recurring Basis | Level 1 | U.S. government securities
ASSETS:
Total assets at fair value	0	0
Long-term investments: | Recurring Basis | Level 1 | Corporate debt securities
ASSETS:
Total assets at fair value	0	0
Long-term investments: | Recurring Basis | Level 1 | U.S. municipal securities
ASSETS:
Total assets at fair value		0
Long-term investments: | Recurring Basis | Level 1 | U.S. government agency securities
ASSETS:
Total assets at fair value	0
Long-term investments: | Recurring Basis | Level 1 | Ctrip convertible debt securities
ASSETS:
Total assets at fair value	0	0
Long-term investments: | Recurring Basis | Level 1 | Ctrip equity securities
ASSETS:
Total assets at fair value	865,302	977,035
Long-term investments: | Recurring Basis | Level 2 | International government securities
ASSETS:
Total assets at fair value	659,344	719,631
Long-term investments: | Recurring Basis | Level 2 | U.S. government securities
ASSETS:
Total assets at fair value	766,592	578,450
Long-term investments: | Recurring Basis | Level 2 | Corporate debt securities
ASSETS:
Total assets at fair value	6,001,789	4,276,614
Long-term investments: | Recurring Basis | Level 2 | U.S. municipal securities
ASSETS:
Total assets at fair value		1,083
Long-term investments: | Recurring Basis | Level 2 | U.S. government agency securities
ASSETS:
Total assets at fair value	4,952
Long-term investments: | Recurring Basis | Level 2 | Ctrip convertible debt securities
ASSETS:
Total assets at fair value	1,293,088	1,378,550
Long-term investments: | Recurring Basis | Level 2 | Ctrip equity securities
ASSETS:
Total assets at fair value	0	0
Cash equivalents: | Recurring Basis | Money market funds
ASSETS:
Total assets at fair value	977,468	99,117
Cash equivalents: | Recurring Basis | International government securities
ASSETS:
Total assets at fair value	30,266	10,659
Cash equivalents: | Recurring Basis | U.S. government securities
ASSETS:
Total assets at fair value	176,140	90,441
Cash equivalents: | Recurring Basis | Corporate debt securities
ASSETS:
Total assets at fair value	9,273	1,855
Cash equivalents: | Recurring Basis | Commercial paper
ASSETS:
Total assets at fair value	1,998	335,663
Cash equivalents: | Recurring Basis | Time deposits
ASSETS:
Total assets at fair value	49,160
Cash equivalents: | Recurring Basis | Level 1 | Money market funds
ASSETS:
Total assets at fair value	977,468	99,117
Cash equivalents: | Recurring Basis | Level 1 | International government securities
ASSETS:
Total assets at fair value	0	0
Cash equivalents: | Recurring Basis | Level 1 | U.S. government securities
ASSETS:
Total assets at fair value	0	0
Cash equivalents: | Recurring Basis | Level 1 | Corporate debt securities
ASSETS:
Total assets at fair value	0	0
Cash equivalents: | Recurring Basis | Level 1 | Commercial paper
ASSETS:
Total assets at fair value	0	0
Cash equivalents: | Recurring Basis | Level 1 | Time deposits
ASSETS:
Total assets at fair value	49,160
Cash equivalents: | Recurring Basis | Level 2 | Money market funds
ASSETS:
Total assets at fair value	0	0
Cash equivalents: | Recurring Basis | Level 2 | International government securities
ASSETS:
Total assets at fair value	30,266	10,659
Cash equivalents: | Recurring Basis | Level 2 | U.S. government securities
ASSETS:
Total assets at fair value	176,140	90,441
Cash equivalents: | Recurring Basis | Level 2 | Corporate debt securities
ASSETS:
Total assets at fair value	9,273	1,855
Cash equivalents: | Recurring Basis | Level 2 | Commercial paper
ASSETS:
Total assets at fair value	1,998	$ 335,663
Cash equivalents: | Recurring Basis | Level 2 | Time deposits
ASSETS:
Total assets at fair value	$ 0