Earnings or Loss Per Share (Notes)

3 Months Ended

Mar. 31, 2015

Earnings Per Share [Abstract]

Earnings or Loss Per Share

Earnings or Loss per Share

Basic earnings or loss per share is computed by dividing net income or loss attributable to common stockholders by the weighted average number of shares of common stock outstanding during the periods presented. Diluted earnings or loss per share is computed in a similar way but adjusted for the dilutive effect, if any, of the assumed exercise or conversion of dilutive instruments into common stock.

The following table presents the reconciliation of the denominators of basic and diluted earnings per share (in millions):

	Three Months Ended March 31, 2015
Weighted average shares outstanding, basic	131.4
Dilutive effect of stock options	0.5
Weighted average shares outstanding, diluted	131.9

For the three months ended March 31, 2015, the numerators of basic and diluted earnings or loss per share were the same because there were no expenses that would have been eliminated upon the assumed conversion of the stock options. For the three months ended March 31, 2014, the numerators and denominators of basic and diluted earnings or loss per share were the same because there were no instruments that could have been converted into common share during that period. No convertible instruments were excluded from diluted EPS in any period on the basis that they were anti-dilutive to the calculation.