16. Earnings per Share

Basic earnings per share for all periods presented equals net income (loss) divided by the weighted average number of our shares outstanding during the period including participating securities. Diluted earnings (loss) per share is computed by dividing net income (loss) by the weighted average number of our shares outstanding during the period including participating securities, adjusted for the dilutive effect of our stock options, restricted shares and performance units.

The following discloses basic and diluted weighted average shares outstanding:



	Year Ended December 31,
(Shares in millions)	2018	2017	2016
Basic and Diluted Weighted Average Shares Outstanding	997	990	887

Our basic and diluted weighted average shares outstanding for the years ended December 31, 2018, 2017 and 2016, are equivalent due to the net loss attributable to shareholders. Diluted weighted average shares outstanding for the years ended December 31, 2018, 2017 and 2016, exclude potential shares for stock options, restricted shares, performance units, exchangeable notes, the warrant outstanding and the Employee Stock Purchase Plan (“ESPP”) as we have net losses for those periods and their inclusion would be anti-dilutive. The following table discloses the number of anti-dilutive shares excluded:



	Year Ended December 31,
(Shares in millions)	2018	2017	2016
Anti-dilutive Potential Shares	251	250	104