Condensed Consolidated Statements of Cash Flows (USD $) In Millions	6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010
Operating Activities:
Net income	$ 221.5	$ 174.0
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	13.8	11.4
Amortization of intangible assets	8.7	7.9
Deferred income taxes	0.8	0.4
Income tax benefits from employee stock option plans	21.1	40.7
Excess tax benefit from stock-based compensation	(24.4)	(46.9)
Share-based compensation expense	66.9	57.1
Changes in operating assets and liabilities:
Accounts receivable	(3.5)	10.7
Inventory	(13.3)	(16.4)
Prepaids and other assets	(3.1)	0.8
Accounts payable	1.8	14.3
Accrued compensation and employee benefits	(9.0)	(7.5)
Deferred revenue	8.5	8.3
Accrued liabilities	6.5	36.3
Net cash provided by operating activities	296.3	291.1
Investing Activities:
Purchase of investments	(725.9)	(604.3)
Proceeds from sales and maturities of investments	619.3	386.6
Purchase of property and equipment and acquisition of intellectual property	(53.2)	(36.5)
Net cash used in investing activities	(159.8)	(254.2)
Financing Activities:
Proceeds from issuance of common stock, net	91.2	115.9
Excess tax benefit from stock-based compensation	24.4	46.9
Repurchase and retirement of common stock	(150.7)	0
Net cash provided by (used in) financing activities	(35.1)	162.8
Effect of exchange rate changes on cash and cash equivalents	0.8	(1.1)
Net increase in cash and cash equivalents	102.2	198.6
Cash and cash equivalents, beginning of period	279.8	221.4
Cash and cash equivalents, end of period	$ 382.0	$ 420.0