Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2018

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	2018			2017			2016
Pre-tax compensation expense	$	40		$	36		$	39
Tax benefit	(5		)	(9		)	(13		)
Total stock-based compensation expense, net of tax	$	35		$	27		$	26

Summary of Activity Related to Non-vested RSUs

The following table summarizes activity related to non-vested RSUs during 2018:

Shares in millions	Number of Shares		Weighted-Average Grant-Date Fair Value
Unvested, January 1, 2018	0.6		$99.87
Granted	0.2		162.49
Vested	(0.3	)	92.71
Unvested, December 31, 2018	0.5		121.24

Summary of Stock Option Activity

The following table summarizes stock option activity for the year ended December 31, 2018:

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, 2018	4.5		$80.88
Granted	0.5		163.36
Exercised	(0.4	)	61.22
Under option, December 31, 2018	4.6		90.56	5.6	$165
Exercisable, December 31, 2018	3.2		74.08	4.6	$168

Summary of Assumptions Used in Options Pricing Model

The following summarizes the assumptions used in the models:

	2018	2017	2016
Risk-free interest rate	2.07-3.06%	0.91-2.61%	0.56-1.86%
Weighted-average volatility	22.0%	22.0%	24.0%
Dividend yield	2.10%	2.22%	2.12%
Expected years until exercise	7.5-8.4	7.2-7.9	6.9-7.7