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Stock-Based Compensation - Summary of Changes in SARs Outstanding (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2021 | Dec. 31, 2020
Weighted Average Remaining Contractual Term (Years) |  |
Granted | 2 years 4 months 24 days |
Stock appreciation rights |  |
SARs |  |
Outstanding, Beginning Balance (in shares) | 1.0 |
Granted (in shares) | 0.2 |
Exercised (in shares) | (0.4) |
Outstanding, Ending Balance (in shares) | 0.8 | 1.0
Vested and exercisable, ending balance (in shares) | 0.3 |
Per Share Weighted Average Exercise Price |  |
Outstanding, Beginning Balance (in dollars per share) | $ 123.59 |
Granted (in dollars per share) | 180.64 |
Exercised (in dollars per share) | 103.53 |
Outstanding, Ending Balance (in dollars per share) | 145.36 | $ 123.59
Vested and exercisable, ending balance (in Dollars per share) | 125.20 |
Per Share Weighted Average Grant Date Fair Value |  |
Outstanding, Beginning Balance (in dollars per share) | 27.76 |
Granted (in dollars per share) | 49.13 |
Exercised (in Dollars per share) | 22.97 |
Outstanding, Ending Balance (in dollars per share) | 34.72 | $ 27.76
Vested and exercisable, ending balance (in Dollars per share) | $ 28.17 |
Weighted Average Remaining Contractual Term (Years) |  |
Weighted average remaining contractual terms | 4 years 5 months 12 days | 4 years 4 months 13 days
Granted | 6 years 1 month 9 days |
Weighted average remaining contractual terms vested and exercisable | 3 years 5 months 8 days |
Unvested SARs (in shares) | 0.8 | 1.0
Aggregate intrinsic value of outstanding shares | $ 156.1 |
Aggregate intrinsic value of shares vested and exercisable | $ 62.8 |
Stock appreciation rights | Unvested |  |
SARs |  |
Outstanding, Ending Balance (in shares) | 0.5 |
Weighted Average Remaining Contractual Term (Years) |  |
Unvested SARs (in shares) | 0.5 |

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- Definition The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2)(iii)(1) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
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