Share-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2023

Share-Based Payment Arrangement [Abstract]

Compensation Expense and Related Tax Benefit for All Share-Based Awards

The following schedule presents compensation expense and the related tax benefit for all share-based awards:

(In millions)	2023		2022		2021
Compensation expense	$	33	$	30	$	28
Reduction of income tax expense	9		11		11

Summary of Weighted Average Value at Grant Date and the Significant Assumptions Used in Applying the Black-Scholes Model for Options Granted

The following schedule summarizes the weighted average value at grant date and the significant assumptions used in applying the Black-Scholes model for options granted:

	2023			2022			2021
Weighted average value for options granted	$	11.23		$	15.16		$	7.86
Weighted average assumptions used:
Expected dividend yield	3.0		%	2.3		%	2.5		%
Expected volatility	27.0		%	27.0		%	25.0		%
Risk-free interest rate	4.00		%	1.98		%	0.47		%
Expected life (in years)	4.5			5.0			5.0

Summary of Stock Option Activity

The following schedule summarizes our stock option activity for the three years ended December 31, 2023:

	Number of shares	Weighted average exercise price
Balance at December 31, 2020	1,683,657	$	38.26
Granted	345,636	48.65
Exercised	(686,894)	31.08
Expired	(7,910)	42.16
Forfeited	(6,345)	48.04
Balance at December 31, 2021	1,328,144	44.60
Granted	201,932	73.02
Exercised	(256,004)	36.79
Expired	(8,912)	37.58
Forfeited	(2,794)	57.75
Balance at December 31, 2022	1,262,366	50.75
Granted	291,005	52.90
Exercised	(95,207)	29.67
Expired	(27,948)	35.41
Forfeited	(9,838)	57.07
Balance at December 31, 2023	1,420,378	52.83
Outstanding stock options exercisable as of:
December 31, 2023	891,884	$	50.36
December 31, 2022	729,411	46.02
December 31, 2021	693,883	41.54

Summary of Additional Selected Information on Stock Options

The following schedule presents additional selected information on stock options at December 31, 2023:

	Outstanding stock options						Exercisable stock options
Exercise price range	Number of shares	Weighted average exercise price			Weighted average remaining contractual life (years)		Number of shares	Weighted average exercise price
$4.15 to $19.99	5,223	$	6.41	1		0	5,223	$	6.41
$25.00 to $29.99	452	29.12				3.8	452	29.12
$40.00 to $44.99	73,077	44.18				0.2	73,077	44.18
$45.00 to $49.99	558,629	47.34				3.6	446,660	47.01
$50.00 to $59.99	587,155	52.78				3.8	301,194	52.67
$60.00 to $73.22	195,842	73.19				5.0	65,278	73.19
	1,420,378	52.83		1		3.7	891,884	50.36

1 The weighted average remaining contractual life excludes 5,223 stock options without a fixed expiration date that were assumed with the Amegy acquisition. They expire between the date of termination and one year from the date of termination, depending upon certain circumstances.

Summary of Nonvested Restricted Stock Activity

The following schedule summarizes our restricted stock activity for the three years ended December 31, 2023:

	Number of shares	Weighted average fair value
Nonvested restricted shares at December 31, 2020	57,396	$	44.20
Issued	26,083	39.16
Vested	(18,663)	43.89
Nonvested restricted shares at December 31, 2021	64,816	42.26
Issued	21,038	60.21
Vested	(25,105)	42.66
Nonvested restricted shares at December 31, 2022	60,749	48.31
Issued	—	—
Vested	(24,978)	46.31
Nonvested restricted shares at December 31, 2023	35,771	49.71

Summary of RSU Activity

The following schedule summarizes our RSU activity for the three years ended December 31, 2023:

	Number of restricted stock units	Weighted average fair value
Restricted stock units at December 31, 2020	1,242,321	$	46.31
Granted	578,056	47.02
Vested	(505,690)	46.51
Forfeited	(40,604)	47.97
Restricted stock units at December 31, 2021	1,274,083	46.49
Granted	433,674	68.07
Vested	(504,358)	47.83
Forfeited	(34,306)	56.58
Restricted stock units at December 31, 2022	1,169,093	53.62
Granted	727,019	48.85
Vested	(522,163)	48.71
Forfeited	(44,004)	56.19
Restricted stock units at December 31, 2023	1,329,945	52.88