Stock Option Plans (Tables)

12 Months Ended

Dec. 31, 2013

Black-Scholes Option Pricing Model with Weighted Average

For purposes of expense recognition in 2013, 2012 and 2011, the estimated fair values of the stock option grants are amortized to expense over the options’ vesting period. We estimated the fair value of stock options at the date of grant using the Black-Scholes option pricing model with the following weighted average assumptions:


	Year Ended December 31,
	2013			2012			2011
Expected dividend yield		3.5	%		4.0	%		4.5	%
Expected risk-free interest rate		1.2	%		1.2	%		2.7	%
Volatility		29.6	%		26.9	%		26.8	%
Expected life (in years)		6.0			5.0			6.0

Stock Option Activity and Related Information

The following is a summary of our stock option activity and related information for 2013, 2012 and 2011 (in millions, except exercise price and year data):


	Shares Under Option			Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value
Year Ended December 31, 2013
Beginning balance		9.0		$	28.80
Granted		1.7			39.17
Exercised		(2.3	)		27.11
Forfeited or canceled		(0.1	)		26.01

Ending balance		8.3		$	31.35		3.62	$	129.4

Exercisable at end of year		3.8		$	27.64		2.15	$	72.5

Ending vested and expected to vest		8.2		$	31.28		3.59	$	128.3


	Shares Under			Weighted Average Exercise		Weighted Average Remaining Contractual Term		Aggregate Intrinsic
Year Ended December 31, 2012
Beginning balance		10.6		$	27.20
Granted		1.4			35.71
Exercised		(2.8	)		26.14
Forfeited or canceled		(0.2	)		29.46

Ending balance		9.0		$	28.80		3.41	$	53.9

Exercisable at end of year		5.1		$	27.50		2.52	$	36.3

Ending vested and expected to vest		8.9		$	28.76		3.39	$	53.8

Year Ended December 31, 2011
Beginning balance		12.5		$	26.71
Granted		0.9			30.95
Exercised		(2.6	)		25.87
Forfeited or canceled		(0.2	)		29.03

Ending balance		10.6		$	27.20		3.42	$	66.3

Exercisable at end of year		6.8		$	27.10		2.83	$	43.2

Ending vested and expected to vest		10.5		$	27.20		3.41	$	66.1

Other Information Regarding Stock Options Outstanding and Exercisable

Other information regarding stock options outstanding and exercisable at December 31, 2013 is summarized as follows (in millions, except exercise price and year data):


		Options Outstanding						Options Exercisable
Range of Exercise Prices		Number Outstanding		Weighted Average Remaining Contractual Term (in years)		Weighted Average Exercise Price		Number Exercisable		Weighted Average Exercise Price
$	10.58 - $ 27.25		2.8		2.53	$	25.86		2.0	$	25.86
	27.35 - 30.95		2.3		2.34		29.74		1.6		29.43
	31.24 - 35.71		1.5		4.71		35.43		0.2		32.97
	35.95 - 35.95		—		5.58		35.95		—		—
	39.17 - 39.17		1.7		6.20		39.17		—		—

$	10.58 - $ 39.17		8.3		3.62	$	31.35		3.8	$	27.64