Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2015

The following weighted average assumptions were used to calculate the fair values of stock option grants in each year:



	2015			2014		2013
Weighted average exercise price	$	118.02		$93.61		$65.78
Risk free interest rate	1.9		%	2.1	%	1.3	%
Expected life of option in years	6.5			6.5		6.5
Expected dividend yield	2.7		%	3.0	%	3.2	%
Expected volatility	29.2		%	30.1	%	29.9	%

A summary of stock options outstanding and exercisable and activity for the year ended December 31, 2015 is presented below:



	Number of Shares		Weighted Average Exercise Price		Weighted Average Remaining Contractual Life (in years)	Intrinsic Value (in millions)
Outstanding, January 1, 2015	4,442,362		$	54.01	6.8	$	273
Granted	589,350		$	118.02
Exercised	(1,257,508	)	$	42.16
Forfeited/Expired	(44,476	)	$	90.34
Outstanding, December 31, 2015	3,729,728		$	67.68	6.5	$	127
Vested or expected to vest, December 31, 2015	3,681,369		$	67.29	6.5	$	127
Exercisable, December 31, 2015	1,480,030		$	37.50	4.3	$	91

The following table presents stock option activity for the years ended December 31, 2015, 2014 and 2013:



($ in millions)	2015		2014		2013
Total intrinsic value of stock options exercised	$	92	$	92	$	110
Cash received from stock option exercises	53		57		68
Income tax benefit from the exercise of stock options	31		33		36
Total fair value of stock options vested	13		10		11

The following table summarizes RSU activity for the year ended December 31, 2015:



	Number of Shares		Weighted Average Fair Value		Intrinsic Value (in millions)
Outstanding, January 1, 2015	1,510,923		$	97.64	$	173
Granted	218,364		$	112.52
Additional shares vested	168,477		$	77.53
Released from restrictions	(744,954	)	$	42.84
Forfeited	(58,649	)	$	50.22
Outstanding, December 31, 2015	1,094,161		$	119.26	$	108
Vested or expected to vest, December 31, 2015	1,058,059		$	120.13	$	105