| Federal, State and Foreign Tax |
| | | | | | | | | | | | |
| (Millions) | | 2013 | | 2012 | | 2011 |
| Gross UTB Balance at January 1 | | $ | 528 | | $ | 594 | | $ | 622 |
| | | | | | | | | | | |
| Additions based on tax positions related to the current year | | | 97 | | | 80 | | | 92 |
| Additions for tax positions of prior years | | | 158 | | | 114 | | | 69 |
| Reductions for tax positions of prior years | | | (29) | | | (120) | | | (123) |
| Settlements | | | (17) | | | (50) | | | 9 |
| Reductions due to lapse of applicable statute of limitations | | | (78) | | | (90) | | | (75) |
| | | | | | | | | | | | |
| Gross UTB Balance at December 31 | | $ | 659 | | $ | 528 | | $ | 594 |
| | | | | | | | | | | |
| Net UTB impacting the effective tax rate at December 31 | | $ | 262 | | $ | 185 | | $ | 295 |
