CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 953.0	$ 831.8
Marketable investments	79.6	122.0
Accounts receivable, net of allowance of none for 2016 and 2015	224.6	192.8
Inventories, net	92.4	81.3
Other current assets	36.4	47.4
Total current assets	1,386.0	1,275.3
Marketable investments	2.3	38.0
Goodwill and other intangibles, net	34.0	28.4
Property, plant and equipment, net	488.4	495.8
Deferred tax assets, net	188.8	192.7
Other assets	169.7	154.2
Total assets	2,269.2	2,184.4
Current liabilities:
Accounts payable and accrued expenses	119.0	103.4
Share tracking awards plan	134.7	274.5
Other current liabilities	60.9	62.8
Total current liabilities	314.6	440.7
Other liabilities	105.0	144.0
Total liabilities	419.6	584.7
Commitments and contingencies
Temporary equity	10.9	11.1
Stockholders' equity:
Common stock, par value $.01, 245,000,000 shares authorized, 69,294,345 and 68,987,919 shares issued, and 42,662,031 and 45,760,845 shares outstanding at September 30, 2016 and December 31, 2015, respectively	0.7	0.7
Additional paid-in capital	1,836.7	1,790.6
Accumulated other comprehensive loss	(16.8)	(20.4)
Treasury stock, 26,632,314 and 23,227,074 shares at September 30, 2016 and December 31, 2015, respectively	(2,305.1)	(1,902.1)
Retained earnings	2,323.2	1,719.8
Total stockholders' equity	1,838.7	1,588.6
Total liabilities and stockholders' equity	2,269.2	2,184.4
Preferred stock
Stockholders' equity:
Preferred stock, par value $.01, 10,000,000 shares authorized, no shares issued
Series A junior participating preferred stock
Stockholders' equity:
Preferred stock, par value $.01, 10,000,000 shares authorized, no shares issued