Stockholders' Equity (Tables)

3 Months Ended

Mar. 31, 2016

Stockholders' Equity Note [Abstract]

Authorized, Issued, and Outstanding Shares

Our authorized, issued, and outstanding shares (stated in whole numbers) consist of the following:

	Par Value		March 31, 2016	December 31, 2015	March 31, 2015
Preferred stock	$.01	/share
Shares authorized			5,000,000	5,000,000	5,000,000
Shares issued and outstanding			—	—	—
Common stock	$.01	/share
Shares authorized			400,000,000	400,000,000	400,000,000
Shares issued and outstanding			288,872,549	289,581,682	293,955,044

Schedule of Dividends Paid Previously or Declared

The following table presents the dividends either paid previously or declared by our board of directors for future payment on a per share basis:

	2016		2015
First quarter	$	0.30	0.28
Second quarter	0.30		0.28
Third quarter			0.28
Fourth quarter			0.28
Total	$	0.60	1.12

Stock Options Granted

The following tables summarize the details of grants made under our stock option plan that are still outstanding, and the assumptions used to value these grants. All options granted were effective at the close of business on the date of grant.

	Options Granted	Option Exercise (Strike) Price		Closing Stock Price on Date of Grant		March 31, 2016
Date of Grant						Options Outstanding	Options Exercisable
April 21, 2015	893,220	$	42.00	$	41.26	806,206	—
April 22, 2014	955,000	$	56.00	$	50.53	690,000	5,000
April 16, 2013	205,000	$	54.00	$	49.25	125,000	2,500
April 17, 2012	1,235,000	$	54.00	$	49.01	1,033,250	341,250
April 19, 2011	410,000	$	35.00	$	31.78	245,300	145,300
April 20, 2010	530,000	$	30.00	$	27.13	186,700	96,700
April 21, 2009	790,000	$	27.00	$	17.61	269,100	179,100
April 15, 2008	550,000	$	27.00	$	24.35	118,250	93,250
April 17, 2007	4,380,000	$	22.50	$	20.15	38,275	38,275
Total	9,948,220					3,512,081	901,375

Fair Value Assumptions for Options Granted

Date of Grant	Risk-free Interest Rate		Expected Life of Option in Years	Expected Dividend Yield		Expected Stock Volatility		Estimated Fair Value of Stock Option
April 21, 2015	1.3	%	5.00	2.7	%	26.84	%	$	7.35
April 22, 2014	1.8	%	5.00	2.0	%	28.55	%	$	9.57
April 16, 2013	0.7	%	5.00	1.6	%	37.42	%	$	12.66
April 17, 2012	0.9	%	5.00	1.4	%	39.25	%	$	13.69
April 19, 2011	2.1	%	5.00	1.6	%	39.33	%	$	11.20
April 20, 2010	2.6	%	5.00	1.5	%	39.10	%	$	8.14
April 21, 2009	1.9	%	5.00	1.0	%	38.80	%	$	3.64
April 15, 2008	2.7	%	5.00	1.0	%	30.93	%	$	7.75
April 17, 2007	4.6	%	4.85	1.0	%	31.59	%	$	5.63

Reconciliation of Denominators used in Computation of Basic and Diluted Earnings Per Share

The following tables present a reconciliation of the denominators used in the computation of basic and diluted earnings per share and a summary of the options to purchase shares of common stock which were excluded from the diluted earnings calculation because they were anti-dilutive:

	Three-month Period
Reconciliation	2016	2015
Basic weighted average shares outstanding	288,808,019	295,237,625
Weighted shares assumed upon exercise of stock options	315,584	699,093
Diluted weighted average shares outstanding	289,123,603	295,936,718

Anti-Dilutive Options Excluded

	Three-month Period
Summary of Anti-dilutive Options Excluded	2016		2015
Options to purchase shares of common stock	2,661,571		2,066,000
Weighted average exercise price of options	$	50.89	$	54.82