XML 65 R50.htm IDEA: XBRL DOCUMENT v3.24.0.1
Stock Based Compensation (Tables)
 12 Months Ended
Dec. 31, 2023
Share-Based Payment Arrangement [Abstract]  
Schedule of Future Compensation Future compensation amounts will be adjusted for any changes in estimated forfeitures:
($ in millions)
Stock Awards$35.6 
Stock options0.8 
Total unrecognized compensation cost$36.4 
Schedule of Stock Option Activity
The following summarizes option activity under the Stock Plan for the years ended December 31, 2023, 2022 and 2021 (in millions, except price per share and numbers of years):
OptionsWeighted Average Exercise PriceWeighted Average Remaining Contractual Term (years)Aggregate Intrinsic Value
Outstanding as of December 31, 20204.5 $27.17 
Granted0.1 31.48 
Exercised(0.4)19.53
Canceled/forfeited(0.3)30.34
Outstanding as of December 31, 20213.9 27.77 
Granted— — 
Exercised(0.1)16.14 
Canceled/forfeited(0.5)29.88 
Outstanding as of December 31, 20223.3 27.97 
Granted— — 
Exercised(0.5)21.01 
Canceled/forfeited(0.6)31.34 
Outstanding as of December 31, 20232.2 28.87 4.7$12.6 
Vested and expected to vest as of December 31, 20232.2 28.82 4.712.5 
Exercisable as of December 31, 20231.8 $28.38 4.5$11.4 
Options outstanding as of December 31, 2023 are summarized below (in millions; except price per share and numbers of years):
OutstandingExercisable
Exercise PriceNumber of OptionsAverage Exercise PriceAverage Remaining Life (in years)Number of OptionsAverage Exercise Price
$12.19 - $17.43
0.2 $17.16 1.80.2 $17.16 
$17.44 - $23.46
0.3 22.13 3.10.3 22.10 
$23.47 - $29.34
0.1 29.08 5.20.1 29.05 
$29.35 - $31.46
1.2 31.35 5.40.9 31.34 
$31.47 - $33.66
0.4 $33.44 5.40.3 $33.45 
Total shares2.2 1.8 
The following summarizes the aggregate intrinsic value of stock options exercised under the Stock Plan during the years ended December 31:

($ in millions)202320222021
Aggregate intrinsic value of stock options exercised$5.2 $1.0 $5.4 
Schedule of Assumptions Used
The fair value of each stock option granted was estimated on the date of grant using the Black-Scholes model for service condition awards with the following weighted average assumptions for the year ended December 31, 2021. There were no options granted during the years ended December 31, 2023 and 2022.
2021
Risk-free interest rate0.97 %
Volatility28.8 %
Dividend yield— %
Expected years until exercise6.5
Weighted average fair value at date of grant$9.75 
Schedule of Stock Unit Activity
The following summarizes information related to Stock Award activity under the Stock Plan for the years ended December 31, 2023, 2022 and 2021 (in millions; except price per share):
Number of Stock AwardsWeighted Average Grant-Date Fair Value
Unvested as of December 31, 20201.4 
Granted0.9 $33.43 
Vested(0.4)29.82 
Forfeited(0.1)31.64 
Unvested as of December 31, 20211.8 32.44 
Granted1.4 23.60 
Vested(0.6)31.29 
Forfeited(0.4)29.15 
Unvested as of December 31, 20222.2 27.39 
Granted1.4 26.39 
Vested(0.9)27.56 
Forfeited(0.3)26.56 
Unvested as of December 31, 20232.4 $26.87