Note 11 - Properties (Details Textual) $ in Billions |
12 Months Ended | ||
|---|---|---|---|
|
Dec. 31, 2022
USD ($)
|
Dec. 31, 2021
USD ($)
|
Dec. 31, 2020
USD ($)
|
|
| Number of Depreciable Asset Classes | 60 | ||
| Cost of Property Repairs and Maintenance | $ 2.4 | $ 2.1 | $ 2.0 |
| Railroad Transportation Equipment [Member] | |||
| Term of Depreciation Studies (Year) | 3 years | ||
| Railroad Transportation Track Assets [Member] | |||
| Term of Depreciation Studies (Year) | 6 years | ||