Stock-Based Compensation

6 Months Ended

Jun. 30, 2021

Share-based Payment Arrangement [Abstract]

The Company recorded stock-based compensation expense of $10 million and $4 million ($7 million and $2 million, net of tax) during the three months ended June 30, 2021 and 2020, respectively, and $14 million and $2 million ($10 million and $1 million, net of tax) during the six months ended June 30, 2021 and 2020, respectively.

In June 2020, the Company granted market-based restricted stock units (“RSUs”) that vest based on absolute stock price attainment. The grant date fair value of this award is estimated using a Monte Carlo simulation model.

The weighted average assumptions used in the model are as follows:


Expected volatility of stock price						91%
Risk-free interest rate						0.18%
Valuation period						3 years
Dividend yield						—%

The activity related to RSUs consisted of (in thousands of shares):


			Number of Shares	Weighted Average Grant Date Fair Value		Weighted Average Remaining Contractual Term (years)	Aggregate Intrinsic Value (in millions)
Time-based RSUs
	Outstanding at January 1, 2021		1,070	$	27.47
		Granted (a)	240	63.12
		Vested (b)	(459)	28.78
		Forfeited	(35)	32.97
	Outstanding and expected to vest at June 30, 2021 (c)		816	$	36.98	1.2	$	64
Performance-based and market-based RSUs
	Outstanding at January 1, 2021		988	$	32.41
		Granted (a)	236	62.27
		Vested (b)	—	—
		Forfeited	(316)	46.59
	Outstanding at June 30, 2021		908	$	35.23	1.8	$	71
	Outstanding and expected to vest at June 30, 2021 (c)		563	$	40.63	1.8	$	44

(a)Reflects the maximum number of stock units assuming achievement of all performance-, market- and time-vesting criteria and does not include those for non-employee directors. The weighted-average fair value of time-based RSUs and performance-based and market-based RSUs granted during the six months ended June 30, 2020 was $21.67 and $21.06, respectively.

(b)The total fair value of RSUs vested during June 30, 2021 and 2020 was $13 million and $18 million, respectively.

(c)Aggregate unrecognized compensation expense related to time-based RSUs and performance-based and market-based RSUs amounted to $40 million and will be recognized over a weighted average vesting period of 1.4 years.