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Stock-Based Compensation Plans (Tables) | 3 Months Ended
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Mar. 31, 2021
Stock-Based Compensation Plans |
Stock-Based Compensation Disclosures (Table) | ​
​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | For the three months ended March 31,
​ |  | 2021 |  | 2020
​ | ​ | (in millions)
Compensation cost | ​ | $ | 31.1 | ​ | $ | 23.5
Related income tax benefit | ​ |  | 5.7 | ​ |  | 4.9
Capitalized as part of an asset | ​ |  | 0.5 | ​ |  | 0.4
​
Nonqualified Stock Options Fair Value (Table) | ​
​ | ​ | ​ | ​ | ​
​ | ​ | For the three months ended | ​
​ |  | March 31, 2021 | ​
​ | ​ | ​ | ​ | ​
Expected volatility |  | ​ | 34.2 | %
Expected term (in years) |  | ​ | 7.0 | ​
Risk-free interest rate |  | ​ | 1.2 | %
Expected dividend yield |  | ​ | 3.82 | %
Weighted average estimated fair value per common share |  | $ | 15.67 | ​
​

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- Definition Tabular disclosure of compensation-related costs for share-based compensation, including amounts charged to income and amount capitalized as part of an asset. + References No definition available. + Details
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- Definition Tabular disclosure of the significant assumptions used during the year to estimate the fair value of stock options, including, but not limited to: (a) expected term of share options and similar instruments, (b) expected volatility of the entity's shares, (c) expected dividends, (d) risk-free rate(s), and (e) discount for post-vesting restrictions. + 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 (f)(2) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
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