CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Cash flows from operating activities:
Net income	$ 603.4	$ 547.0
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	23.8	25.0
Share-based compensation (benefit) expense	(93.2)	162.9
Gain on sale of intangible asset		(350.0)
Other	2.5	5.9
Excess tax benefits from share-based compensation	(4.6)	(31.4)
Changes in operating assets and liabilities:
Accounts receivable	(31.7)	(17.4)
Inventories	(12.9)	(7.8)
Accounts payable and accrued expenses	13.9	25.8
Other assets and liabilities	(21.0)	(2.7)
Net cash provided by operating activities	480.2	357.3
Cash flows from investing activities:
Purchases of property, plant and equipment	(23.3)	(18.3)
Purchases of held-to-maturity investments	(0.8)	(62.8)
Maturities of held-to-maturity investments	78.8	232.4
Gain on sale of intangible asset		350.0
Purchase of investments under the cost method, net	(7.6)	(54.2)
Purchase of investments under the equity method	(2.1)
Intangible assets acquired	(5.2)
Net cash provided by investing activities	39.8	447.1
Cash flows from financing activities:
Principal payments of debt	(8.8)	(107.1)
Payments of debt issuance costs	(6.8)
Payments to repurchase common stock	(395.5)	(394.5)
Proceeds from the exercise of stock options	6.2	33.0
Issuance of stock under employee stock purchase plan	4.3	4.0
Excess tax benefits from share-based compensation	4.6	31.4
Net cash used in financing activities	(396.0)	(433.2)
Effect of exchange rate changes on cash and cash equivalents	(2.8)	(3.7)
Net increase in cash and cash equivalents	121.2	367.5
Cash and cash equivalents, beginning of period	831.8	397.7
Cash and cash equivalents, end of period	953.0	765.2
Supplemental schedule of cash flow information:
Cash paid for interest	0.1	1.0
Cash paid for income taxes	283.7	116.9
Non-cash investing and financing activities:
Non-cash additions to property, plant and equipment	3.2	2.4
Issuance of common stock upon conversion of convertible notes	$ 7.5	$ 270.6