Stock-based Compensation (Tables)

12 Months Ended

Dec. 31, 2022

Share-Based Payment Arrangement, Noncash Expense [Abstract]

Summary of Restricted Stock Awards Activity

The following is a summary of the RSU activity during the year ended December 31, 2022.

	RSUs
	(In millions)
Outstanding at the beginning of year	2
Granted	1
Vested	(1)
Forfeited	—
Outstanding at end of year	2

Summary of the Assumptions Used in the Monte Carlo Simulation to Determine the Grant-Date Fair Value

The following table summarizes the assumptions used in the Monte Carlo simulation to determine the grant-date fair value for the RSUs with market conditions granted during the years ended December 31, 2022, 2021 and 2020. 

	Years Ended December 31,
	2022		2021		2020
Risk-free rate	1.7	%	0.2	%	1.4	%
Expected volatility	31	%	30	%	19	%
Expected dividend rate	3.0	%	3.4	%	3.5	%

Summary of Restricted Stock Vested

The following table is a summary of the RSUs vested during the years ended December 31, 2022, 2021 and 2020.

Years Ended December 31,	Total Shares Vested	Fair Value on Vesting Date
	(In millions of shares)
2022	1	$	187
2021	1	199
2020	1	220

Stock Based Compensation Expense

The following table discloses the components of stock-based compensation expense.

	Years Ended December 31,
	2022		2021		2020
Stock-based compensation expense:
Site rental costs of operations	$	18	$	14	$	16
Services and other costs of operations	10		8		8
Selling, general and administrative expenses	128		109		109
Total stock-based compensation expense	$	156	$	131	$	133