Consolidated Statements Of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating activities:
Net income	$ 735.9	$ 588.8	$ 418.8
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and loss on disposal of property, plant, and equipment, net	73.9	65.1	52.0
Amortization of intangible assets	18.2	24.4	22.4
Loss (gain) on investment, accretion of discounts, and amortization of premiums on investments, net	35.9	26.4	33.9
Deferred income taxes	18.7	4.6	(35.0)
Income tax benefits from employee stock plans	29.8	21.5	13.9
Excess tax benefit from employee stock plans	(44.1)	(34.3)	(24.0)
Share-based compensation expense	177.6	167.9	168.9
Changes in operating assets and liabilities, net of effects of acquisition:
Accounts receivable	(35.9)	(79.2)	(13.7)
Inventory	(46.7)	(10.7)	(26.8)
Prepaids and other assets	(28.7)	(10.5)	(67.6)
Accounts payable	15.9	(11.3)	17.7
Accrued compensation and employee benefits	18.7	21.5	21.4
Deferred revenue	19.9	8.2	19.8
Other liabilities	53.8	(10.5)	63.4
Net cash provided by operating activities	1,042.9	771.9	665.1
Investing activities:
Purchase of investments	(2,585.5)	(1,827.4)	(1,344.6)
Proceeds from sales of investments	389.9	233.1	665.9
Proceeds from maturities of investments	970.1	825.8	714.7
Purchase of property, plant and equipment, intellectual property	(53.9)	(81.0)	(105.6)
Acquisition of business, net of cash acquired	0.0	0.0	(84.3)
Net cash used in investing activities	(1,279.4)	(849.5)	(153.9)
Financing activities:
Proceeds from issuance of common stock relating to employee stock plans	580.9	361.1	283.6
Excess tax benefit from employee stock plans	44.1	34.3	24.0
Taxes paid related to net share settlement of equity awards	(24.0)	(11.0)	0.0
Repurchase and retirement of common stock	(42.5)	(183.7)	(1,000.0)
Other financing activities	0.0	(7.3)	0.0
Net cash provided by (used in) financing activities	558.5	193.4	(692.4)
Effect of exchange rate changes on cash and cash equivalents	0.0	(1.5)	(0.6)
Net increase (decrease) in cash and cash equivalents	322.0	114.3	(181.8)
Cash and cash equivalents, beginning of year	714.6	600.3	782.1
Cash and cash equivalents, end of year	$ 1,036.6	$ 714.6	$ 600.3