UNAUDITED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $)	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
OPERATING ACTIVITIES:
Net income	$ 534,470,000	$ 360,291,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	15,150,000	9,225,000
Amortization	16,355,000	16,905,000
Provision for uncollectible accounts, net	6,843,000	4,852,000
Deferred income taxes	13,665,000	19,870,000
Stock-based compensation expense and other stock-based payments	34,370,000	27,341,000
Amortization of debt issuance costs	2,337,000	1,113,000
Amortization of debt discount	17,972,000	10,553,000
Loss on early extinguishment of debt	0	32,000
Changes in assets and liabilities:
Accounts receivable	(176,721,000)	(154,216,000)
Prepaid expenses and other current assets	(95,392,000)	9,089,000
Accounts payable, accrued expenses and other current liabilities	244,684,000	204,307,000
Other	253,000	(9,860,000)
Net cash provided by operating activities	613,986,000	499,502,000
INVESTING ACTIVITIES:
Purchase of investments	(2,989,951,000)	(1,006,694,000)
Proceeds from sale of investments	1,870,770,000	1,025,514,000
Additions to property and equipment	(28,423,000)	(18,077,000)
Acquisitions and other equity investments, net of cash acquired	(13,429,000)	(67,074,000)
Proceeds from settlement of foreign currency contracts	61,746,000	0
Payments on foreign currency contracts	0	(33,764,000)
Change in restricted cash	(2,987,000)	(35,000)
Net cash used in investing activities	(1,102,274,000)	(100,130,000)
FINANCING ACTIVITIES:
Proceeds from the issuance of convertible debt	1,000,000,000	0
Payment of debt issuance costs	(20,421,000)	0
Payments related to the conversion of convertible debt	0	(213,000)
Repurchase of common stock	(255,168,000)	(158,691,000)
Payments to purchase subsidiary shares from noncontrolling interests	(61,079,000)	(12,986,000)
Proceeds from exercise of stock options	1,693,000	3,870,000
Excess tax benefit from stock-based compensation	12,513,000	12,173,000
Net cash provided by (used in) financing activities	677,538,000	(155,847,000)
Effect of exchange rate changes on cash and cash equivalents	(9,300,000)	8,757,000
Net increase in cash and cash equivalents	179,950,000	252,282,000
Cash and cash equivalents, beginning of period	632,836,000	358,967,000
Cash and cash equivalents, end of period	812,786,000	611,249,000
SUPPLEMENTAL CASH FLOW INFORMATION:
Cash paid during the period for income taxes	189,061,000	55,461,000
Cash paid during the period for interest	4,349,000	3,717,000
Non-cash fair value increase for redeemable noncontrolling interests	$ 43,440,000	$ 33,740,000