Other Information Net Income Attributable to Common Stockholders (Details) - shares shares in Millions |
3 Months Ended | |
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Mar. 31, 2016 |
Mar. 31, 2015 |
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| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||
| Basic weighted average shares outstanding | 99.0 | 101.1 |
| Diluted weighted average shares outstanding | 102.7 | 106.2 |
| Antidilutive securities excluded | 2.9 | 1.4 |
| Stock options | ||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||
| Effect of dilution: | 3.5 | 4.8 |
| Restricted shares | ||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||
| Effect of dilution: | 0.2 | 0.3 |
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- Definition Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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- Definition The sum of dilutive potential common shares or units used in the calculation of the diluted per-share or per-unit computation. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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