A one-percentage point change in the assumed health care cost trend rate would have the following effects:
| (dollars in millions) | ||||||||
| One-Percentage Point | Increase | Decrease | ||||||
|
Effect on 2013 service and interest cost |
$ | 184 | $ | (150 | ) | |||
|
Effect on postretirement benefit obligation as of December 31, 2013 |
2,539 | (2,086 | ) | |||||