CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
OPERATING ACTIVITIES:
Net income	$ 2,134,987	$ 2,551,360	$ 2,421,753
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	140,059	101,517	78,241
Amortization	169,076	170,977	129,579
Provision for uncollectible accounts, net	46,241	24,324	22,990
Deferred income tax expense (benefit)	(111,905)	(61,335)	31,707
Stock-based compensation expense and other stock-based payments	249,726	249,133	189,292
Amortization of debt issuance costs	7,758	7,578	5,229
Amortization of debt discount	68,974	66,687	54,731
Loss on early extinguishment of debt	0	3	6,270
Impairment of goodwill	940,700	0	0
Impairment of cost-method investments	63,208	0	0
Changes in assets and liabilities:
Accounts receivable	(284,221)	(68,694)	(182,209)
Prepaid expenses and other current assets	5,495	(81,611)	(48,932)
Accounts payable, accrued expenses and other current liabilities	516,356	166,201	203,870
Other	(21,757)	(23,909)	1,876
Net cash provided by operating activities	3,924,697	3,102,231	2,914,397
INVESTING ACTIVITIES:
Purchase of investments	(6,741,202)	(8,669,690)	(10,552,214)
Proceeds from sale of investments	3,684,103	5,084,238	10,902,500
Additions to property and equipment	(219,889)	(173,915)	(131,504)
Acquisitions and other investments, net of cash acquired	(7,813)	(140,338)	(2,496,366)
Acquisition of land use rights	(48,494)	0	0
Proceeds from foreign currency contracts	0	453,818	14,354
Payments on foreign currency contracts	0	(448,640)	(94,661)
Net cash used in investing activities	(3,333,295)	(3,894,527)	(2,357,891)
FINANCING ACTIVITIES:
Proceeds from revolving credit facility	0	225,000	995,000
Payments related to revolving credit facility	0	(225,000)	(995,000)
Proceeds from the issuance of long-term debt	994,705	2,399,034	2,264,753
Payment of debt issuance costs - revolving credit facility	0	(4,005)	0
Payments related to conversion of senior notes	0	(147,629)	(125,136)
Repurchase of common stock	(1,013,526)	(3,089,055)	(750,378)
Payments of contingent consideration	0	(10,700)	0
Proceeds from exercise of stock options	15,572	20,851	16,389
Excess tax benefits on stock-based awards and other equity deductions	60,986	101,508	23,366
Net cash provided by (used in) financing activities	57,737	(729,996)	1,428,994
Effect of exchange rate changes on cash, cash equivalents and restricted cash	(45,203)	(149,131)	(136,476)
Net increase (decrease) in cash, cash equivalents and restricted cash	603,936	(1,671,423)	1,849,024
Cash, cash equivalents and restricted cash, beginning of period	1,478,071	3,149,494	1,300,470
Cash, cash equivalents and restricted cash, end of period	2,082,007	1,478,071	3,149,494
SUPPLEMENTAL CASH FLOW INFORMATION:
Cash paid during the period for income taxes	636,550	534,105	491,530
Cash paid during the period for interest	125,912	54,299	16,950
Non-cash investing activity for contingent consideration	0	9,170	10,700
Non-cash financing activity for acquisitions	$ 0	$ 0	$ 13,751