CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 1,005.9	$ 1,023.0
Marketable investments	109.3	27.8
Accounts receivable, no allowance for 2017 and 2016	273.9	214.5
Inventories, net	114.1	100.0
Other current assets	60.5	59.5
Total current assets	1,563.7	1,424.8
Marketable investments	216.2	2.3
Goodwill and other intangible assets, net	45.8	33.8
Property, plant and equipment, net	501.9	489.3
Deferred tax assets, net	178.0	178.3
Other non-current assets	185.9	197.1
Total assets	2,691.5	2,325.6
Current liabilities:
Accounts payable and accrued expenses	126.8	104.2
Line of credit	250.0
Share tracking awards plan	192.0	194.8
Other current liabilities	270.0	33.5
Total current liabilities	838.8	332.5
Non-current liabilities	57.4	130.9
Total liabilities	896.2	463.4
Commitments and contingencies
Temporary equity	19.2	10.9
Stockholders' equity:
Common stock, par value $.01, 245,000,000 shares authorized, 69,768,128 and 69,340,985 shares issued, and 43,436,076 and 42,965,856 shares outstanding at June 30, 2017 and December 31, 2016, respectively	0.7	0.7
Additional paid-in capital	1,785.5	1,813.5
Accumulated other comprehensive loss	(16.6)	(16.8)
Treasury stock, 26,332,052 and 26,375,129 shares at June 30, 2017 and December 31, 2016, respectively	(2,543.8)	(2,379.6)
Retained earnings	2,550.3	2,433.5
Total stockholders' equity	1,776.1	1,851.3
Total liabilities and stockholders' equity	2,691.5	2,325.6
Preferred stock
Stockholders' equity:
Preferred stock, par value $.01, no shares issued
Series A junior participating preferred stock
Stockholders' equity:
Preferred stock, par value $.01, no shares issued