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Share-Based Compensation - Fair Value Options Granted and Assumptions (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021
Share-based Compensation |  |  |
Stock options granted, fair value | $ 0.0 | $ 1.8 | $ 2.0
Intrinsic value of options exercised | 0.2 | 1.2 | 13.4
Cash received for options exercised | 0.0 | $ 2.6 | $ 3.6
Intrinsic value of exercisable options outstanding | $ 1.9 |  |
Stock options granted, weighted average fair value (in dollars per share) |  | $ 47.84 | $ 54.19
Stock Options |  |  |
Share-based Compensation |  |  |
Shares available for future grant (in shares) | 1.1 |  |
Assumptions used to determine fair value of options granted |  |  |
Dividend yield |  | 0.00% | 0.00%
Expected volatility |  | 36.80% | 37.10%
Risk-free interest rate |  | 1.70% | 1.00%
Expected life of options (in years) |  | 5 years 8 months 12 days | 5 years 8 months 12 days
Forfeiture rate |  | 0.00% | 0.00%
Stock Options | Minimum |  |  |
Share-based Compensation |  |  |
Stock vesting period | 3 years |  |
Stock options, expiration period | 7 years |  |
Stock Options | Maximum |  |  |
Share-based Compensation |  |  |
Stock vesting period | 5 years |  |

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- Definition Represents the expected rate the entity will cancel the stock option awards due to nonfulfillment of certain conditions of equity-based compensation arrangements. + References No definition available. + Details
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- Definition Amount of cash inflow from exercise of option under share-based payment arrangement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 45 -Paragraph 14 -Subparagraph (a) -SubTopic 10 -Topic 230 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482740/230-10-45-14 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 50 -Paragraph 2A -Subparagraph (a) -SubTopic 10 -Topic 718 -Publisher FASB -URI https://asc.fasb.org//1943274/2147480429/718-10-50-2A + Details
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- Definition The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 718 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (f)(2)(iii) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480429/718-10-50-2 + Details
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- Definition The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 718 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (f)(2)(ii) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480429/718-10-50-2 + Details
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- Definition The risk-free interest rate assumption that is used in valuing an option on its own shares. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 718 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (f)(2)(iv) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480429/718-10-50-2 + Details
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- Definition The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org//1943274/2147480429/718-10-50-2 + Details
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- Definition The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 718 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (d)(1) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480429/718-10-50-2 + Details
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- Definition Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 718 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (a)(2) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480429/718-10-50-2 + Details
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