The following tables summarize basic and dilutive earnings per share (in millions, except for per share amounts): | | | | | | | | | | Three Months Ended March 31, | | 2012 | | 2011 | Basic earnings per share | | | | Net income attributable to stockholders(a) | $ | 1,315 |
| | $ | 3,366 |
| Less: cumulative dividends on preferred stock and undistributed earnings allocated to Series B Preferred Stock participating security(b) | (311 | ) | | (215 | ) | Net income attributable to common stockholders | $ | 1,004 |
| | $ | 3,151 |
| Weighted-average common shares outstanding - basic | 1,572 |
| | 1,504 |
| Basic earnings per common share | $ | 0.64 |
| | $ | 2.09 |
| Diluted earnings per share | | | | Net income attributable to stockholders(a) | $ | 1,315 |
| | $ | 3,366 |
| Less: cumulative dividends on preferred stock and undistributed earnings allocated to Series B Preferred Stock participating security(c) | (305 | ) | | (215 | ) | Add: preferred dividends to holders of Series B Preferred Stock | — |
| | 59 |
| Net income attributable to common stockholders | $ | 1,010 |
| | $ | 3,210 |
| Weighted-average shares outstanding - diluted | | | | Weighted-average common shares outstanding - basic | 1,572 |
| | 1,504 |
| Dilutive effect of warrants | 116 |
| | 162 |
| Dilutive effect of conversion of Series B Preferred Stock | — |
| | 148 |
| Dilutive effect of restricted stock units (RSUs) | 4 |
| | 3 |
| Weighted-average common shares outstanding - diluted | 1,692 |
| | 1,817 |
| Diluted earnings per common share | $ | 0.60 |
| | $ | 1.77 |
|
__________ | | (a) | Includes earned but undeclared dividends of $26 million on our Series A Preferred Stock and $20 million on our Series B Preferred Stock in the three months ended March 31, 2012 and 2011. |
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