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Preferred and Common Stock (Tables) | 12 Months Ended
--- | ---
Dec. 31, 2018
Equity [Abstract] |
Schedule of Share Activity | Share Activity (number of shares)
| Common stock
| Treasury |  | Outstanding
Balance at end of 2015 | 81,051,103 |  |  | 1,310,160,141 |
Issued for stock-based compensation plans | (5,219,660 | ) |  | 5,302,128 |
Treasury stock retirement | (75,831,443 | ) |  | — |
Reverse Stock Split | — |  |  | (876,942,489 | )
Balance at end of 2016 | — |  |  | 438,519,780 |
Conversion of convertible notes | — |  |  | 39,242,706 |
Issued for stock-based compensation plans | — |  |  | 3,654,051 |
Balance at end of 2017 | — |  |  | 481,416,537 |
Issued for stock-based compensation plans | — |  |  | 1,854,180 |
Balance at end of 2018 | — |  |  | 483,270,717 |
Schedule of Activity for Stock Options and Stock Awards | The activity for stock options and stock awards during 2018 was as follows (options and awards in millions):
| Stock options |  | Stock awards
| Number of options |  | Weighted average exercise price |  | Number of awards |  | Weighted average FMV per award
Outstanding, January 1, 2018 | 11 |  |  | $ | 23.94 |  |  | 7 |  |  | $ | 21.49 |
Granted | 1 |  |  | 29.97 |  |  | 2 |  |  | 26.48 |
Exercised | (1 | ) |  | 18.95 |  |  | — |  |  | — |
Converted | — |  |  | — |  |  | (1 | ) |  | 32.75 |
Expired or forfeited | (1 | ) |  | 26.96 |  |  | (1 | ) |  | 21.10 |
Performance share adjustment | — |  |  | — |  |  | — |  |  | 18.47 |
Outstanding, December 31, 2018 | 10 |  |  | $ | 24.95 |  |  | 7 |  |  | $ | 21.13 |

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- Definition Tabular disclosure of the number and weighted-average exercise prices (or conversion ratios) for stock options and stock appreciation rights that were outstanding at the beginning and end of the year, exercisable at the end of the year, and the number of stock options and stock appreciation rights that were granted, exercised or converted, forfeited, and expired during the year. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
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