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Earnings Per Share (Tables) | 12 Months Ended
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Dec. 31, 2020
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Schedule Of Basic And Diluted Earnings Per Share | The following table presents the computation of basic and diluted earnings per share for the years ended December 31, 2020, 2019 and 2018:
|  | Years Ended December 31, |
In millions except per share amounts |  | 2020 |  |  | 2019 |  |  | 2018 |
Basic earnings per share: |  |  |  |  |  |  |  |  |  |  |  |
Net income (loss) available to common shareholders |  | $ | (578) |  |  | $ | (359) |  |  | $ | (296) |
Basic weighted average shares (1) |  |  | 59.1 |  |  |  | 81.0 |  |  |  | 89.0 |
Net income (loss) per basic common share |  | $ | (9.78) |  |  | $ | (4.43) |  |  | $ | (3.33) |
Diluted earnings per share: |  |  |  |  |  |  |  |  |  |  |  |
Net income (loss) available to common shareholders |  |  | (578) |  |  |  | (359) |  |  |  | (296) |
Diluted weighted average shares |  |  | 59.1 |  |  |  | 81.0 |  |  |  | 89.0 |
Net income (loss) per diluted common share |  | $ | (9.78) |  |  | $ | (4.43) |  |  | $ | (3.33) |
Potentially dilutive securities excluded from the diluted EPS because of antidilutive affect |  |  | 4.6 |  |  |  | 4.3 |  |  |  | 4.4 |
(1) Includes 0.9 million, 1.0 million and 0.8 million of participating securities that met the service condition and were eligible to receive nonforfeitable dividends or dividend equivalents for the years ended December 31, 2020, 2019 and 2018, respectively.

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