Stock-Based Compensation Plans (Tables)

12 Months Ended

Dec. 31, 2021

Share-based Payment Arrangement [Abstract]

Schedule of Share-based Compensation Activity

A summary of the 2021 RSUs, and PSUs granted to certain NEOs, employees, and the Board of Directors is presented below (shares/units in thousands):

Grant Year	Award Type	Number of Units Awarded(1)	Vesting Terms
2021	RSU	63	Vest equally over three service periods ending in 2024
2021	PSU	27	Three-year performance and service period ending in 2023
2021	RSU	5	One year service period ending in 2022

(1) PSUs presented are based on the target number of units for the original PSU grant.

Activity for Awards Made Outside of Share-Based Compensation Plans

Activity for our RSAs, RSUs, and PSUs is presented below (shares/units in thousands):

	PSUs			RSAs and RSUs			Total
(in thousands, except grant date values)	Number of Shares/Units	Weighted Average Grant Date Fair Value		Number of Shares/Units	Weighted Average Grant Date Fair Value		Number of Shares/Units	Weighted Average Grant Date Fair Value
Balance as of December 31, 2018	321	$	65.77	275	$	72.03	596	$	68.66
Granted	58	$	92.90	130	$	94.42	188	$	93.96
Performance adjustment(1)	87	$	55.75	—	$	—	87	$	55.75
Vested	(152)	$	55.75	(135)	$	68.15	(287)	$	61.57
Canceled/forfeited	—	$	—	(5)	$	77.59	(5)	$	77.59
Balance as of December 31, 2019	314	$	72.84	265	$	85.07	579	$	78.45
Granted	37	$	182.45	94	$	150.12	131	$	159.30
Performance adjustment(1)	41	$	90.73	—	$	—	41	$	90.73
Vested	(90)	$	90.73	(121)	$	90.01	(211)	$	90.32
Canceled/forfeited	—	$	—	(3)	$	121.39	(3)	$	121.39
Balance as of December 31, 2020	302	$	83.40	235	$	107.90	537	$	94.14
Granted	27	$	254.29	68	$	211.11	95	$	223.25
Performance adjustment(1)	258	$	68.87	—	$	—	258	$	68.87
Vested	(108)	$	92.90	(112)	$	121.77	(220)	$	107.63
Canceled/forfeited	—	$	—	(12)	$	160.42	(12)	$	160.42
Balance as of December 31, 2021	479	$	82.99	179	$	135.01	658	$	90.27

(1)Adjustment to number of target units awarded for PSUs based on achievement of underlying performance goals.

Summary of Unrecognized Stock-based Compensation Expense

A summary of total unrecognized stock-based compensation expense related to RSAs, RSUs, and PSUs (based on current performance estimates), at December 31, 2021 is presented below:

(in millions, except years)	December 31, 2021		Weighted Average Remaining Vesting Period (Years)
Unrecognized expense:
RSU	$	9.2	1.76
PSU	12.9		2.08
Total	$	22.1	1.94