CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 1,122.6	$ 1,023.0
Marketable Investments	33.7	27.8
Accounts receivable, no allowance for 2017 and 2016	188.0	214.5
Inventories, net	106.9	100.0
Other current assets	52.9	59.5
Total current assets	1,504.1	1,424.8
Marketable Investments	144.5	2.3
Goodwill and other intangible assets, net	33.6	33.8
Property, plant and equipment, net	493.5	489.3
Deferred tax assets, net	181.5	178.3
Other non-current assets	204.1	197.1
Total assets	2,561.3	2,325.6
Current liabilities:
Accounts payable and accrued expenses	105.6	104.2
Share tracking awards plan	218.1	194.8
Other current liabilities	104.0	33.5
Total current liabilities	427.7	332.5
Other non-current liabilities	57.4	130.9
Total liabilities	485.1	463.4
Commitments and contingencies
Temporary equity	10.9	10.9
Stockholders' equity:
Common stock, par value $.01, 245,000,000 shares authorized, 69,695,007 and 69,340,985 shares issued, and 45,052,579 and 42,965,856 shares outstanding at March 31, 2017 and December 31, 2016, respectively	0.7	0.7
Additional paid-in capital	1,801.4	1,813.5
Accumulated other comprehensive loss	(16.7)	(16.8)
Treasury stock, 24,642,428 and 26,375,129 shares at March 31, 2017 and December 31, 2016, respectively	(2,326.4)	(2,379.6)
Retained earnings	2,606.3	2,433.5
Total stockholders' equity	2,065.3	1,851.3
Total liabilities and stockholders' equity	2,561.3	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