Common Stock (Tables)

12 Months Ended

Dec. 31, 2014

The following summarizes options activity:


	Years Ended December 31,
	2014					2013					2012
	Number of Shares			Average Exercise Price		Number of Shares			Average Exercise Price		Number of Shares			Average Exercise Price
Shares under option at beginning of year		11,535,566		$	58.36		10,274,477		$	54.11		11,367,995		$	43.52
Granted		3,389,547			69.00		3,072,086			63.96		2,428,406			77.99
Spin-off		(1,567,348	)				—			—		—			—
Cancelled		(498,967	)		70.32		(329,002	)		66.78		(247,426	)		55.58
Exercised		(1,977,665	)		53.56		(1,481,995	)		38.75		(3,274,498	)		34.59

Shares under option at end of year		10,881,133		$	61.22		11,535,566		$	58.36		10,274,477		$	54.11

Exercisable at end of year		5,903,712		$	55.06		6,324,117		$	49.29		5,231,150		$	40.56

Summary of Stock Option Outstanding Information

The following summarizes information about stock options outstanding at December 31, 2014:


	Weighted-Avg		Options Outstanding				Options Exercisable
Range of Exercise Price	Remaining Contractual		Shares		Weighted- Exercise		Shares		Weighted- Exercise
$8.43 - $45.00		3.49		2,428,973	$	32.39		2,428,973	$	32.39
$45.01 - $70.00		8.19		5,458,369		65.94		1,102,784		61.06
$70.01 - $77.99		6.68		2,993,791		75.99		2,371,955		75.49

Total		6.72		10,881,133	$	61.22		5,903,712	$	55.06

Assumption Used in Determination of Fair Value of Share Based Payment Awards

The use of the Black Scholes model requires the use of extensive actual employee exercise activity data and the use of a number of complex assumptions including expected volatility, risk-free interest rate, expected dividends and expected term.


	Years Ended December 31,
	2014			2013			2012
Valuation Assumptions:
Expected volatility		49.4	%		50.1	%		51.7	%
Risk-free interest rate		1.5	%		0.9	%		0.9	%
Expected dividends	$	1.39		$	0.75		$	0.57
Expected term (in years)		3.7			3.4			3.2

Summary of Information and Changes in Stock Options with Regard to Stock Option Plans

The following summary presents information regarding outstanding options at December 31, 2014 and changes during 2014 with regard to options under all stock option plans:


	Shares			Weighted- Average Exercise Price		Weighted Remaining Contractual Term (years)		Aggregate Intrinsic Value
Outstanding at December 31, 2013		11,535,566		$	58.36		5.37	$	155,892,094
Granted		3,389,547		$	69.00
Spin-off		(1,567,348	)	$	—
Cancelled		(498,967	)	$	70.32
Exercised		(1,977,665	)	$	53.56

Outstanding at December 31, 2014		10,881,133		$	61.22		6.72	$	87,998,114

Vested or expected to vest		10,739,679		$	61.22		6.72	$	86,854,138

Exercisable at December 31, 2014		5,903,712		$	55.06		5.15	$	85,503,217

Summary of Information Regarding Outstanding Restricted Shares

The following summary presents information regarding outstanding restricted shares:


	Years Ended December 31,
	2014					2013					2012
	Number of Units			Weighted- Average Grant Date Fair Value		Number of Units			Weighted- Average Grant Date Fair Value		Number of Units			Weighted- Average Grant Date Fair Value
Nonvested at beginning of year		1,643,193		$	67.98		1,449,683		$	62.29		1,741,840		$	40.76
Granted		708,821			70.14		822,281			63.69		523,218			77.26
Spin-off		(319,949	)		70.56		—			—		—			—
Vested		(348,981	)		74.97		(368,984	)		63.89		(441,243	)		76.85
Cancelled		(113,943	)		70.32		(259,787	)		37.78		(374,132	)		28.02

Nonvested at end of year		1,569,141		$	73.73		1,643,193		$	67.98		1,449,683		$	62.29