| Property, Plant and Equipment [Table Text Block] |
| Millions, Except Estimated Useful Life | | | | | | Accumulated | | | Net Book | | | Estimated | |
| As of September 30, 2023 | | Cost | | | Depreciation | | | Value | | | Useful Life | |
| Land | | $ | 5,372 | | | $ | N/A | | | $ | 5,372 | | | | N/A | |
| Road: | | | | | | | | | | | | | | | | |
| Rail and other track material | | | 18,747 | | | | 7,280 | | | | 11,467 | | | | 42 | |
| Ties | | | 11,934 | | | | 3,844 | | | | 8,090 | | | | 34 | |
| Ballast | | | 6,320 | | | | 2,031 | | | | 4,289 | | | | 34 | |
| Other roadway [a] | | | 22,899 | | | | 5,269 | | | | 17,630 | | | | 47 | |
| Total road | | | 59,900 | | | | 18,424 | | | | 41,476 | | | | N/A | |
| Equipment: | | | | | | | | | | | | | | | | |
| Locomotives | | | 9,317 | | | | 3,667 | | | | 5,650 | | | | 18 | |
| Freight cars | | | 2,710 | | | | 945 | | | | 1,765 | | | | 23 | |
| Work equipment and other | | | 1,319 | | | | 527 | | | | 792 | | | | 17 | |
| Total equipment | | | 13,346 | | | | 5,139 | | | | 8,207 | | | | N/A | |
| Technology and other | | | 1,294 | | | | 559 | | | | 735 | | | | 12 | |
| Construction in progress | | | 1,220 | | | | - | | | | 1,220 | | | | N/A | |
| Total | | $ | 81,132 | | | $ | 24,122 | | | $ | 57,010 | | | | N/A | |
| Millions, Except Estimated Useful Life |
|
|
|
|
|
Accumulated |
|
|
Net Book |
|
|
Estimated |
|
| As of December 31, 2022 |
|
Cost |
|
|
Depreciation |
|
|
Value |
|
|
Useful Life |
|
| Land |
|
$ |
5,344 |
|
|
$ |
N/A |
|
|
$ |
5,344 |
|
|
|
N/A |
|
| Road: |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| Rail and other track material |
|
|
18,419 |
|
|
|
7,096 |
|
|
|
11,323 |
|
|
|
43 |
|
| Ties |
|
|
11,676 |
|
|
|
3,699 |
|
|
|
7,977 |
|
|
|
34 |
|
| Ballast |
|
|
6,222 |
|
|
|
1,950 |
|
|
|
4,272 |
|
|
|
34 |
|
| Other roadway [a] |
|
|
22,411 |
|
|
|
4,970 |
|
|
|
17,441 |
|
|
|
47 |
|
| Total road |
|
|
58,728 |
|
|
|
17,715 |
|
|
|
41,013 |
|
|
|
N/A |
|
| Equipment: |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| Locomotives |
|
|
9,166 |
|
|
|
3,606 |
|
|
|
5,560 |
|
|
|
18 |
|
| Freight cars |
|
|
2,562 |
|
|
|
898 |
|
|
|
1,664 |
|
|
|
23 |
|
| Work equipment and other |
|
|
1,253 |
|
|
|
473 |
|
|
|
780 |
|
|
|
17 |
|
| Total equipment |
|
|
12,981 |
|
|
|
4,977 |
|
|
|
8,004 |
|
|
|
N/A |
|
| Technology and other |
|
|
1,254 |
|
|
|
525 |
|
|
|
729 |
|
|
|
12 |
|
| Construction in progress |
|
|
948 |
|
|
|
- |
|
|
|
948 |
|
|
|
N/A |
|
| Total |
|
$ |
79,255 |
|
|
$ |
23,217 |
|
|
$ |
56,038 |
|
|
|
N/A |
|
|