Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2021

Share-based Payment Arrangement [Abstract]

Schedule of Number of Common Shares Reserved for Issuance

The number of common shares reserved for issuance are as follows: 

(in millions)	December 31,
	2021	2020
Shares available for granting 1	19.5	19.7
Options outstanding	0.3	0.5
Total shares reserved for issuance 2	19.8	20.2

1     Shares available for granting at December 31, 2021 and 2020 are under the 2019 Plan.

2     Shares reserved for issuance under the Director Deferred Stock Ownership Plan are not included in the total, but are less than 1.0 million at both December 31, 2021 and 2020.

Schedule of Stock-based Compensation Expense

Stock-based compensation expense and the corresponding tax benefit are as follows: 

(in millions)	Year Ended December 31,
	2021		2020		2019
Stock option expense	$	—	$	—	$	1
Restricted stock and unit awards expense	122		90		77
Total stock-based compensation expense	$	122	$	90	$	78
Tax benefit	$	20	$	15	$	13

Schedule of Stock Option Activity

Stock option activity is as follows: 

(in millions, except per award amounts)	Shares	Weighted average exercise price		Weighted-average remaining years of contractual term	Aggregate intrinsic value
Options outstanding as of December 31, 2020	0.5	$	60.46
Exercised	(0.2)	$	283.56
Forfeited and expired 1	—	$	39.94
Options outstanding as of December 31, 2021	0.3	$	67.14	1.99	$	113
Options exercisable as of December 31, 2021	0.3	$	67.14	1.99	$	113

1 There are less than 0.1 million shares forfeited and expired.

(in millions, except per award amounts)	Shares		Weighted-average grant-date fair value
Nonvested options outstanding as of December 31, 2020	—		$	111.96
Vested 1	—		$	111.96
Nonvested options outstanding as of December 31, 2021 2	—		$	—
Total unrecognized compensation expense related to nonvested options	$	—
Weighted-average years to be recognized over	0.0

1There are less than 0.1 million shares vested.

2There are no nonvested options outstanding as of December 31, 2021.

Schedule of Stock Option Exercises

Information regarding our stock option exercises is as follows: 

(in millions)	Year Ended December 31,
	2021		2020		2019
Net cash proceeds from the exercise of stock options	$	13	$	16	$	40
Total intrinsic value of stock option exercises	$	41	$	60	$	110
Income tax benefit realized from stock option exercises	$	11	$	13	$	33

Schedule of Restricted Stock and Unit Activity

Restricted stock and unit activity for performance and non-performance awards is as follows: 

(in millions, except per award amounts)	Shares		Weighted-average grant-date fair value
Nonvested shares as of December 31, 2020	0.6		$	227.67
Granted	0.4		$	296.49
Vested	(0.5)		$	219.85
Forfeited	—		$	263.18
Nonvested shares as of December 31, 2021	0.5		$	299.28
Total unrecognized compensation expense related to nonvested awards	$	101
Weighted-average years to be recognized over	1.7

	Year Ended December 31,
	2021		2020		2019
Weighted-average grant-date fair value per award	$	296.49	$	232.92	$	187.40
Total fair value of restricted stock and unit awards vested	$	243	$	134	$	153
Tax benefit relating to restricted stock activity	$	48	$	26	$	29