Stock-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2019

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

Schedule of pre-tax compensation expense and the related income tax benefit for these stock-based incentives

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

	Three Months Ended March 31,
	2019		2018
Long-term stock awards	$	5	$	5
Stock options	1		1
Restricted stock units	1		1
Phantom stock awards and stock appreciation rights	1		—
Total	$	8	$	7

Schedule of the Company's long-term stock award activity

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

	Three Months Ended March 31,
	2019		2018
Unvested stock award shares at January 1	2		3
Weighted average grant date fair value	$	30	$	24
Stock award shares granted	1		1
Weighted average grant date fair value	$	36	$	42
Stock award shares vested	1		1
Weighted average grant date fair value	$	24	$	21
Stock award shares forfeited	—		—
Weighted average grant date fair value	$	29	$	30
Unvested stock award shares at March 31	2		3
Weighted average grant date fair value	$	34	$	30

Schedule of the Company's stock option activity

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

		Three Months Ended March 31,
		2019		2018
Option shares outstanding, January 1		4		5
Weighted average exercise price	$	21	$	16
Option shares granted		1		—
Weighted average exercise price	$	36	$	42
Option shares exercised		1		—
Aggregate intrinsic value on date of exercise (A)	$	13 million	$	33 million
Weighted average exercise price	$	11	$	11
Option shares forfeited		—		—
Weighted average exercise price	$	—	$	—
Option shares outstanding, March 31		4		5
Weighted average exercise price	$	25	$	19
Weighted average remaining option term (in years)		6		5
Option shares vested and expected to vest, March 31		4		5
Weighted average exercise price	$	25	$	19
Aggregate intrinsic value (A)	$	57 million	$	98 million
Weighted average remaining option term (in years)		6		5
Option shares exercisable (vested), March 31		2		3
Weighted average exercise price	$	19	$	15
Aggregate intrinsic value (A)	$	50 million	$	88 million
Weighted average remaining option term (in years)		4		4

(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.

Schedule of 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

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: 

	Three Months Ended March 31,
	2019			2018
Weighted average grant date fair value	$	8.81		$	12.52
Risk-free interest rate	2.57		%	2.71		%
Dividend yield	1.35		%	1.00		%
Volatility factor	25.00		%	29.00		%
Expected option life	6 years			6 years