NET EARNINGS (LOSS) PER SHARE - Schedule of Earning (Loss) per share (Details) - shares shares in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Earnings Per Share Basic And Diluted [Line Items]
Basic	745,897	754,556	753,085
Dilutive potential common shares	0	2,271	3,581
Diluted	745,897	756,827	756,666
Stock options
Earnings Per Share Basic And Diluted [Line Items]
Dilutive potential common shares	0	1,310	2,571
Restricted stock units
Earnings Per Share Basic And Diluted [Line Items]
Dilutive potential common shares	0	566	582
Performance share units
Earnings Per Share Basic And Diluted [Line Items]
Dilutive potential common shares	0	395	428

Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of share based payment arrangements using the treasury stock method.

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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.

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Earnings per share basic and diluted.

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