UNAUDITED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
OPERATING ACTIVITIES:
Net income	$ 1,514,721	$ 1,134,442
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	33,965	23,321
Amortization	46,889	24,192
Provision for uncollectible accounts, net	12,678	11,287
Deferred income taxes	11,450	16,446
Stock-based compensation expense and other stock-based payments	91,810	52,042
Amortization of debt issuance costs	4,352	3,790
Amortization of debt discount	41,225	28,831
Changes in assets and liabilities:
Accounts receivable	(283,961)	(232,660)
Prepaid expenses and other current assets	(8,514)	(97,057)
Accounts payable, accrued expenses and other current liabilities	280,945	318,054
Other	1,403	6,243
Net cash provided by operating activities	1,746,963	1,288,931
INVESTING ACTIVITIES:
Purchase of investments	(7,100,081)	(4,790,106)
Proceeds from sale of investments	5,341,488	3,069,242
Additions to property and equipment	(56,958)	(38,950)
Acquisitions and other equity investments, net of cash acquired	(331,557)	(13,871)
Proceeds from settlement of foreign currency contracts	3,266	78,828
Payments on foreign currency contracts	(56,045)	(2,222)
Change in restricted cash	(1,506)	(3,474)
Net cash used in investing activities	(2,201,393)	(1,700,553)
FINANCING ACTIVITIES:
Proceeds from the issuance of convertible debt	980,000	1,000,000
Payment of debt issuance costs	(910)	(20,916)
Payments related to conversion of senior notes	(8)	(1)
Repurchase of common stock	(883,008)	(255,397)
Payments to purchase subsidiary shares from noncontrolling interests	(192,530)	(61,079)
Payments of stock issuance costs	(1,191)	0
Proceeds from exercise of stock options	86,310	2,655
Excess tax benefit from stock-based compensation	13,318	12,911
Net cash provided by financing activities	1,981	678,173
Effect of exchange rate changes on cash and cash equivalents	12,194	(917)
Net (decrease) increase in cash and cash equivalents	(440,255)	265,634
Cash and cash equivalents, beginning of period	1,536,349	632,836
Cash and cash equivalents, end of period	1,096,094	898,470
SUPPLEMENTAL CASH FLOW INFORMATION:
Cash paid during the period for income taxes	265,303	205,256
Cash paid during the period for interest	18,614	13,463
Non-cash fair value increase for redeemable noncontrolling interests	42,522	59,255
Non-cash financing activity for acquisitions	$ 1,546,748	$ 0