Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2023

Share-Based Payment Arrangement [Abstract]

Schedule of Weighted Average Assumptions Used

During the years ended December 31, 2023 and 2022, we did not issue any stock unit awards containing a market condition.

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

Schedule of Stock Based Compensation Activity

Annual activity related to stock units 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, 2023		451	$	92.06
		Granted (a)	98	204.17
		Vested (b)	(252)	53.44
		Forfeited	(7)	165.67
	Outstanding and expected to vest at December 31, 2023 (c)		290	$	161.87	1.2	$	51
Performance-based and market-based RSUs
	Outstanding at January 1, 2023		691	$	57.56
		Granted (a)	111	204.13
		Vested (b)	(381)	21.05
		Forfeited	(10)	148.96
	Outstanding at December 31, 2023		411	$	128.77	0.9	$	73
	Outstanding and expected to vest at December 31, 2023 (c)		333	$	112.18	0.9	$	59

__________

(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, which are discussed separately below. The weighted-average fair value of time-based RSUs, and performance-based and market-based RSUs granted in 2022 was $172.34 and $193.48, respectively, and the weighted-average fair value of time-based RSUs and performance-based RSUs granted in 2021 was $65.23 and $62.27, respectively.

(b)The total fair value of RSUs vested during 2023, 2022 and 2021 was $21 million, $22 million and $17 million, respectively.

(c)Aggregate unrecognized compensation expense related to time-based RSUs and performance-based and market-based RSUs amounted to $45 million and will be recognized over a weighted average vesting period of 1.0 year.