| The following table presents the computation of basic and diluted earnings per share of common stock. | |
| | | | | | | | | | | | |
| ($ in millions except per share amounts) | | | | | | | | | | |
| | | | | | | | | | | | |
| For the year ended December 31: | | 2013 | | 2012 | | 2011 | |
| Weighted-average number of shares on which earnings | | | | | | | | | | |
| per share calculations are based | | | | | | | | | | |
| Basic | | | 1,094,486,604 | | | 1,142,508,521 | | | 1,196,951,006 | |
| Add—incremental shares under stock-based | | | | | | | | | | |
| | compensation plans | | | 6,751,240 | | | 10,868,426 | | | 14,241,131 | |
| Add—incremental shares associated with contingently | | | | | | | | | | |
| | issuable shares | | | 1,804,313 | | | 2,072,370 | | | 2,575,848 | |
| Assuming dilution | | | 1,103,042,156 | | | 1,155,449,317 | | | 1,213,767,985 | |
| Net income on which basic earnings per share is | | | | | | | | | | |
| calculated | | $ | 16,483 | | $ | 16,604 | | $ | 15,855 | |
| Less—net income applicable to contingently issuable | | | | | | | | | | |
| | shares | | | (1) | | | (1) | | | 0 | |
| Net income on which diluted earnings per share is | | | | | | | | | | |
| calculated | | $ | 16,483 | | $ | 16,603 | | $ | 15,855 | |
| Earnings/(loss) per share of common stock | | | | | | | | | | |
| Assuming dilution | | $ | 14.94 | | $ | 14.37 | | $ | 13.06 | |
| Basic | | $ | 15.06 | | $ | 14.53 | | $ | 13.25 | |
