STOCK-BASED COMPENSATION

3 Months Ended

Mar. 31, 2022

Share-based Payment Arrangement, Noncash Expense [Abstract]

Presented below is a summary of the stock-based compensation cost and associated tax benefit included in the accompanying consolidated statements of operations:


	Three Months Ended March 31,
		2022		2021
Stock-based compensation cost		$	46	$	45
Tax benefit		$	11	$	11

During the first three months of 2022, the Company granted 0.1 million employee stock options, which had a weighted average grant date fair value of $84.15 per share. The Company also granted 0.5 million shares of restricted stock in the first three months of 2022, which had a weighted average grant date fair value of $325.99 per share. Both the employee stock options and restricted stock generally vest ratably over four years. Additionally, the Company granted 0.1 million shares of performance-based awards whereby the number of shares that ultimately vest are based on the achievement of certain non-market-based performance metrics of the Company over three years. The weighted average grant date fair value of these awards was $317.21 per share.

The following weighted average assumptions were used in determining the fair value using the Black-Scholes option-pricing model for options granted in 2022:


Expected dividend yield	0.86	%
Expected stock volatility	27	%
Risk-free interest rate	1.88	%
Expected holding period	5.6 years

Unrecognized stock-based compensation expense at March 31, 2022 was $27 million and $332 million for stock options and unvested restricted stock, respectively, which is expected to be recognized over a weighted average period of 2.3 years and 2.8 years, respectively. Additionally, there was $68 million of unrecognized stock-based compensation expense relating to the aforementioned non-market-based performance-based awards, which is expected to be recognized over a weighted average period of 2.1 years.

The following table summarizes information relating to stock option exercises and restricted stock vesting:


	Three Months Ended March 31,
	2022		2021
Exercise of stock options:
Proceeds from stock option exercises	$	3	$	6
Aggregate intrinsic value	$	4	$	9
Tax benefit realized upon exercise	$	1	$	2
Number of shares exercised (1)	—		0.1
Vesting of restricted stock:
Fair value of shares vested	$	166	$	178
Tax benefit realized upon vesting	$	39	$	41
Number of shares vested	0.5		0.6
Vesting of performance-based restricted stock:
Fair value of shares vested	$	50	$	29
Tax benefit realized upon vesting	$	12	$	6
Number of shares vested	0.2		0.1

(1) The number of options exercised in 2022 was approximately 20 thousand.