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Share-Based Compensation (Tables) | 12 Months Ended
--- | ---
Dec. 31, 2012
Share-Based Compensation. |
Schedule of transactions of the Company's stock options |
|  | Stock Options |  | Weighted Average Exercise Price |  | Weighted Average Remaining Contractual Life (years) |
--- | --- | --- | --- | --- | --- | --- | ---
Unexercised options outstanding—January 1, 2012 |  |  | 5.1 |  | $ | 68.18 |  |  |  |
Options granted |  |  | 0.1 |  |  | 121.90 |  |  |  |
Options exercised |  |  | (1.4 | ) |  | 54.45 |  |  |  |
Options forfeited |  |  | 0.0 |  |  | 85.72 |  |  |  |
Unexercised options outstanding—December 31, 2012 |  |  | 3.8 |  |  | 74.04 |  |  | 4.1 |
Exercisable at December 31, 2012 |  |  | 2.5 |  |  | 68.64 |  |  | 3.6 |
Schedule of assumptions used to determine fair value of options granted |
|  | For the Years Ended December 31, |
--- | --- | --- | ---
|  | 2010 |  | 2011 |  | 2012 |
Dividend yield |  |  | 0.0 | % |  | 0.0 | % |  | 0.0 | %
Expected volatility(1) |  |  | 32.4 | % |  | 33.1 | % |  | 36.8 | %
Risk-free interest rate(2) |  |  | 1.6 | % |  | 1.3 | % |  | 0.7 | %
Expected life of options (in years)(3) |  |  | 4.5 |  |  | 4.8 |  |  | 5.0 |
Forfeiture rate(3) |  |  | 4.8 | % |  | 2.4 | % |  | 1.4 | %
(1) Based on historical and implied volatility. (2) Based on the U.S. Treasury yield curve in effect at the date of grant. (3) Based on the Company's historical data and expected exercise behavior.
Summary of transactions of the Company's restricted stock |
|  | Restricted Stock |  | Weighted Average Grant Date Value |
--- | --- | --- | --- | --- | ---
Units outstanding—January 1, 2012 |  |  | 0.4 |  | $ | 52.66 |
Units granted |  |  | 0.2 |  |  | 127.33 |
Units issued |  |  | (0.2 | ) |  | 48.54 |
Units forfeited |  |  | (0.0 | ) |  | 52.33 |
Units outstanding—December 31, 2012 |  |  | 0.4 |  |  | 84.53 |
Summary of recent share based compensation expense |
Period |  | Share-Based Compensation Expense |  | Tax Benefit |
--- | --- | --- | --- | --- | ---
2010 |  | $ | 19.5 |  | $ | 7.5 |
2011 |  |  | 30.3 |  |  | 11.6 |
2012 |  |  | 47.6 |  |  | 18.2 |

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- Definition Tabular disclosure of the changes in outstanding nonvested shares. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition Tabular disclosure of share-based compensation plans that may be presented in a single table for outstanding, vested and expected to vest, and exercisable awards. The information that may be disclosed in this table may include, but is not limited to, number of shares, weighted average exercise price, weighted average remaining contractual life, and aggregate intrinsic value. + 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://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (f)(2) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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