Earnings Per Share (Notes)

12 Months Ended

Dec. 31, 2020

Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]

Earnings Per Share [Text Block]

Basic earnings per share are based on the weighted average number of shares of common stock outstanding. Diluted earnings per share are based upon the weighted average number of shares of common stock outstanding plus all potentially dilutive securities that were assumed to be converted into common shares at the beginning of the period under the treasury stock method. This method requires that the effect of potentially dilutive common stock equivalents (stock options, SSARs, restricted stock or units, and performance stock units) be excluded from the calculation of diluted earnings per share for the periods in which losses from continuing operations are reported because the effect is anti-dilutive.

The following table sets forth the computation of basic and diluted earnings per share:

	Year ended December 31,
Share amounts in millions	2020	2019	2018
Denominator for basic earnings per share:
Weighted average common shares outstanding	111	123	143
Effect of dilutive securities:
Dilutive effect of employee stock plans	1	—	1
Dilutive potential common shares	112	123	144
Denominator for diluted earnings per share:
Adjusted weighted average shares	112	123	144

For the year ended December 31, 2019, approximately one million of the outstanding restricted stock and shares of common stock issuable upon exercise of outstanding stock option awards have been excluded from the calculation of diluted earnings per share because the net loss for the year ended December 31, 2019, causes such securities to be anti-dilutive.