RETIREMENT BENEFITS PLANS - Other Postretirement Benefits Plan Assumptions (Details) - Other postretirement benefits expense (income) |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2025 |
Dec. 31, 2024 |
Dec. 31, 2023 |
|
| Assumptions used to determine benefit obligation at year-end (as a percent) | |||
| Discount rate | 5.24% | 5.57% | 5.11% |
| Health care cost trend rate assumed for next year | 6.50% | 6.70% | 7.70% |
| Ultimate health care cost trend rate | 4.75% | 4.75% | 4.75% |
| Year ultimate health care cost trend rate is achieved | 2035 | 2034 | 2033 |
| Assumptions used to determine expense (as a percent) | |||
| Discount rate used to determine benefit obligation | 5.57% | 5.11% | 5.46% |
| Discount rate used to determine service cost | 5.84% | 5.25% | 5.53% |
| Discount rate used to determine interest cost | 5.29% | 4.96% | 5.32% |
| Initial health care cost trend rate | 6.70% | 7.70% | 7.10% |
| Ultimate health care cost trend rate | 4.75% | 4.75% | 4.75% |
| Year ultimate health care cost trend rate is achieved | 2034 | 2033 | 2031 |