Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2015

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Summary of stock based compensation expense

The following table summarizes the Company’s stock-based compensation expense:

In millions	2015			2014			2013
Pre-tax compensation expense	$	35		$	34		$	30
Tax benefit	(12		)	(12		)	(10		)
Total stock-based compensation expense, net of tax	$	23		$	22		$	20

Summary of activity related to non-vested equity awards

The following table summarizes activity related to non-vested RSUs during 2015:

Shares in millions	Number of Shares		Weighted-Average Grant-Date Fair Value
Unvested, January 1, 2015	1.0		$60.68
Granted	0.3		92.44
Vested	(0.4	)	52.11
Canceled	(0.1	)	70.96
Unvested, December 31, 2015	0.8		73.58

Summary of stock option activity

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

In millions except exercise price and contractual terms	Number of Shares		Weighted-Average Exercise Price	Weighted-Average Remaining Contractual Term	Aggregate Intrinsic Value
Under option, January 1, 2015	7.1		$56.25
Granted	0.6		98.26
Exercised	(1.2	)	49.41
Canceled or expired	(0.1	)	71.41
Under option, December 31, 2015	6.4		61.44	5.7	$201
Exercisable, December 31, 2015	4.5		54.19	4.7	$175

Summary of assumptions used in option models

The Company uses a binomial option pricing model to estimate the fair value of the stock options granted. The following summarizes the assumptions used in the models:

	2015	2014	2013
Risk-free interest rate	0.23-2.25%	0.16-2.83%	0.2-2.9%
Weighted-average volatility	23.0%	22.9%	21.1%
Dividend yield	2.11%	2.46%	2.72%
Expected years until exercise	6.9-8.0	6.7-7.9	6.6-7.6