Condensed Consolidated Statements of Cash Flows (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Operating activities:
Net income	$ 148.3	$ 348.0
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	24.8	21.3
Amortization of intangible assets	9.4	11.3
Loss on investment, accretion of discounts and amortization of premiums on investments, net	18.3	20.2
Deferred income taxes	(47.0)	(15.7)
Income tax benefits from employee stock plans	0.9	25.8
Excess tax benefit from share-based compensation	(6.1)	(26.5)
Share-based compensation expense	82.7	76.9
Changes in operating assets and liabilities, net of effects of acquisitions:
Accounts receivable	30.3	11.7
Inventories	(38.9)	(53.2)
Prepaids and other assets	(19.8)	16.1
Accounts payable	14.1	9.7
Accrued compensation and employee benefits	1.2	(34.0)
Other liabilities	102.1	35.5
Net cash provided by operating activities	320.3	447.1
Investing activities:
Purchase of investments	(614.6)	(947.6)
Proceeds from sales of investments	608.0	257.2
Proceeds from maturities of investments	422.7	441.1
Purchase of property, plant and equipment, and intellectual property	(26.6)	(41.7)
Acquisition of businesses, net of cash	81.2	0
Net cash provided by (used in) investing activities	308.3	(291.0)
Financing activities:
Proceeds from issuance of common stock	90.5	112.1
Excess tax benefit from share-based compensation	6.1	26.5
Repurchase and retirement of common stock	(1,000.0)	(415.4)
Net cash used in financing activities	(903.4)	(276.8)
Effect of exchange rate changes on cash and cash equivalents	0.3	(0.3)
Net decrease in cash and cash equivalents	(274.5)	(121.0)
Cash and cash equivalents, beginning of period	782.1	553.7
Cash and cash equivalents, end of period	507.6	432.7
Supplemental non-cash investing activities:
Demonstration equipment transfers from inventories to property, plant and equipment	$ 16.1	$ 5.4