| December 31 (In millions) | 2013 | 2012 | |||
| Unrecognized tax benefits | $ | 5,816 | $ | 5,445 | |
| Portion that, if recognized, would reduce tax expense and effective tax rate(a) | 4,307 | 4,032 | |||
| Accrued interest on unrecognized tax benefits | 975 | 961 | |||
| Accrued penalties on unrecognized tax benefits | 164 | 173 | |||
| Reasonably possible reduction to the balance of unrecognized tax benefits | |||||
| in succeeding 12 months | 0-900 | 0-800 | |||
| Portion that, if recognized, would reduce tax expense and effective tax rate(a) | 0-350 | 0-700 | |||
(a) Some portion of such reduction might be reported as discontinued operations.