STOCK-BASED COMPENSATION

Our 2014 Long Term Stock Incentive Plan provides for the issuance of stock-based incentives in various forms to our employees and non-employee Directors. At June 30, 2018, outstanding stock-based incentives were in the form of long-term stock awards, stock options, restricted stock units, phantom stock awards and stock appreciation rights.

Pre-tax compensation expense for these stock-based incentives was as follows, in millions:



	Three Months Ended June 30,					Six Months Ended June 30,
	2018			2017		2018			2017
Long-term stock awards	$	7		$	7	$	12		$	13
Stock options	1			1		2			2
Restricted stock units	1			1		2			1
Phantom stock awards and stock appreciation rights	(1		)	3		(1		)	5
Total	$	8		$	12	$	15		$	21

Long-Term Stock Awards. Long-term stock awards are granted to our key employees and non-employee Directors and do not cause net share dilution inasmuch as we continue the practice of repurchasing and retiring an equal number of shares in the open market. We granted 629,970 shares of long-term stock awards in the six-month period ended June 30, 2018.

J. STOCK-BASED COMPENSATION (Continued)

Our long-term stock award activity was as follows, shares in millions:



	Six Months Ended June 30,
	2018		2017
Unvested stock award shares at January 1	3		4
Weighted average grant date fair value	$	24	$	20

Stock award shares granted	1		1
Weighted average grant date fair value	$	42	$	34

Stock award shares vested	1		2
Weighted average grant date fair value	$	21	$	18

Stock award shares forfeited	—		—
Weighted average grant date fair value	$	30	$	24

Unvested stock award shares at June 30	3		3
Weighted average grant date fair value	$	30	$	24

There was $56 million of total unrecognized compensation expense related to unvested stock awards at both June 30, 2018 and 2017; such awards had a weighted average remaining vesting period of three years at both June 30, 2018 and 2017.

The total market value (at the vesting date) of stock award shares which vested during the six-month periods ended June 30, 2018 and 2017 was $54 million and $41 million, respectively.

Stock Options. Stock options are granted to certain key employees. The exercise price equals the market price of our common stock at the grant date. These options generally become exercisable (vest ratably) over five years beginning on the first anniversary from the date of grant and expire no later than 10 years after the grant date.

J. STOCK-BASED COMPENSATION (Continued)

We granted 385,220 shares of stock options in the six-month period ended June 30, 2018 with a grant date weighted-average exercise price of approximately $42 per share. In the six-month period ended June 30, 2018, 68,927 shares of stock options were forfeited (including options that expired unexercised).

Our stock option activity was as follows, shares in millions:



		Six Months Ended June 30,
		2018		2017
Option shares outstanding, January 1		5		7
Weighted average exercise price	$	16	$	15

Option shares granted		—		—
Weighted average exercise price	$	42	$	34

Option shares exercised		1		1
Aggregate intrinsic value on date of exercise (A)	$	36 million	$	33 million
Weighted average exercise price	$	12	$	15

Option shares forfeited		—		—
Weighted average exercise price	$	31	$	—

Option shares outstanding, June 30		4		6
Weighted average exercise price	$	19	$	16
Weighted average remaining option term (in years)		5		4

Option shares vested and expected to vest, June 30		4		6
Weighted average exercise price	$	19	$	16
Aggregate intrinsic value (A)	$	82 million	$	130 million
Weighted average remaining option term (in years)		5		4

Option shares exercisable (vested), June 30		3		4
Weighted average exercise price	$	15	$	13
Aggregate intrinsic value (A)	$	74 million	$	113 million
Weighted average remaining option term (in years)		4		3


(A)	Aggregate intrinsic value is calculated using our stock price at each respective date, less the exercise price (grant date price), multiplied by the number of shares.

At June 30, 2018 and 2017, there was $10 million and $9 million, respectively, of unrecognized compensation expense (using the Black-Scholes option pricing model at the grant date) related to unvested stock options; such options had a weighted average remaining vesting period of three years at both June 30, 2018 and 2017.

J. STOCK-BASED COMPENSATION (Concluded)

The weighted average grant date fair value of option shares granted and the assumptions used to estimate those values using a Black-Scholes option pricing model were as follows:



	Six Months Ended June 30,
	2018			2017
Weighted average grant date fair value	$	12.52		$	9.68
Risk-free interest rate	2.71		%	2.16		%
Dividend yield	1.00		%	1.19		%
Volatility factor	29.00		%	30.00		%
Expected option life	6 years			6 years

Restricted Stock Units. Under the Long Term Incentive Program, we granted restricted stock units to certain senior executives. These restricted stock units vest and share awards are issued at no cost to the employees, subject to our achievement of specified return on invested capital performance goals over a three-year period that have been established by our Organization and Compensation Committee for the performance period and the recipient's continued employment through the share award date. We granted 113,260 restricted stock units in the six-month period ended June 30, 2018, with a grant date fair value of approximately $42 per share, and 124,780 restricted stock units in the six-month period ended June 30, 2017, with a grant date fair value of approximately $34 per share. During the six-month period ended June 30, 2018, 11,600 restricted stock units were forfeited.