Stock Compensation Plans (Tables)

3 Months Ended

Mar. 31, 2019

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

Schedule of Stock-based Compensation Expense

Stock-based compensation expense for the following periods were:

In millions	Three months ended March 31
	2019			2018
Restricted stock units	$	20		$	13
Stock options	2			—
Employee stock purchase plan	1			1
Stock-based compensation expense	23			14
Tax benefit	(3		)	(3)
Total stock-based compensation expense (net of tax)	$	20		$	11

Schedule of Valuation Assumptions Used To Estimate Fair Value of Stock Options

he Company granted stock options and the weighted average fair value of option grants was estimated based on the below weighted average assumptions, which was $8.07 and $9.80 for the three months ended March 31, 2019 and 2018, respectively. The stock options that were granted for the three months ended March 31, 2019 and 2018 had a seven year contractual term and will vest over four years.

	Three months ended March 31
	2019			2018
Dividend yield	$	—		$	—
Risk-free interest rate	2.50		%	2.47		%
Expected volatility	34.79		%	34.81		%
Expected holding period (years)	3.9			3.8

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