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Stock Options and Other Stock Plans - Narrative (Details) - USD ($) $ in Thousands | 1 Months Ended | 12 Months Ended |  |  |  |  |
--- | --- | --- | --- | --- | --- | --- | ---
Feb. 29, 2024 | Dec. 31, 2024 | Dec. 31, 2023 | Dec. 31, 2022 | May 31, 2021 | May 31, 2013 | Apr. 30, 2000
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] |  |  |  |  |  |  |
Stock option (in shares) |  | 1,981,000 | 2,072,000 |  |  |  |
Number of shares available for grant (in shares) |  | 31,063,392 | 31,979,909 | 33,185,971 |  |  |
ESPP employee contribution annual limit |  | $ 15 |  |  |  |  |
Stock options |  |  |  |  |  |  |
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] |  |  |  |  |  |  |
Award expiration period (in years) |  | 10 years |  |  |  |  |
Award vesting period (in years) |  | 3 years |  |  |  |  |
Stock options outstanding (in shares) |  | 0 |  |  |  |  |
Unrecognized compensation expense |  | $ 15,000 |  |  |  |  |
Recognized weighted-average period (in years) |  | 9 months 18 days |  |  |  |  |
Retention awards |  |  |  |  |  |  |
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] |  |  |  |  |  |  |
Retention shares (in shares) |  | 915,000 | 996,000 |  |  |  |
Award vesting period (in years) |  | 4 years |  |  |  |  |
Unrecognized compensation expense |  | $ 70,000 |  |  |  |  |
Recognized weighted-average period (in years) |  | 1 year 1 month 6 days |  |  |  |  |
Performance Stock Unit Awards |  |  |  |  |  |  |
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] |  |  |  |  |  |  |
Retention shares (in shares) |  | 607,000 | 617,000 |  |  |  |
Unrecognized compensation expense |  | $ 15,000 |  |  |  |  |
Recognized weighted-average period (in years) |  | 1 year 1 month 6 days |  |  |  |  |
Share-based payment award, award requisite service period (in months) | 37 months |  |  |  |  |  |
Performance period (in years) | 3 years |  |  |  |  |  |
Performance Stock Unit Awards | Share-Based Payment Arrangement, Tranche One |  |  |  |  |  |  |
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] |  |  |  |  |  |  |
Award vesting rights (percent) | 66.67% |  |  |  |  |  |
Performance Stock Unit Awards | Share-Based Payment Arrangement, Tranche Two |  |  |  |  |  |  |
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] |  |  |  |  |  |  |
Award vesting rights (percent) | 33.33% |  |  |  |  |  |
Employee Stock |  |  |  |  |  |  |
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] |  |  |  |  |  |  |
Employer contribution match (as a percent) |  | 40.00% |  |  |  |  |
Maximum employee subscription rate |  | 5.00% |  |  |  |  |
Union Pacific Corporation 2000 Directors Plan |  |  |  |  |  |  |
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] |  |  |  |  |  |  |
Number of shares authorized (in shares) |  |  |  |  |  |  | 2,200,000
Retention shares granted to each non-employee director upon initial election to board (in shares) |  |  |  |  |  |  | 4,000
Outstanding, number (in shares) |  | 16,000 |  |  |  |  |
Union Pacific Corporation 2013 Stock Incentive Plan |  |  |  |  |  |  |
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] |  |  |  |  |  |  |
Number of shares authorized (in shares) |  |  |  |  |  | 78,000,000 |
Stock option (in shares) |  | 777,939 |  |  |  |  |
Retention shares (in shares) |  | 0 |  |  |  |  |
Union Pacific Corporation 2021 Stock Incentive Plan |  |  |  |  |  |  |
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] |  |  |  |  |  |  |
Number of shares authorized (in shares) |  |  |  |  | 23,000,000 |  |
Stock option (in shares) |  | 1,203,484 |  |  |  |  |
Retention shares (in shares) |  | 1,218,529 |  |  |  |  |
Union Pacific Corporation 2021 Employee Stock Purchase Plan |  |  |  |  |  |  |
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] |  |  |  |  |  |  |
Number of shares authorized (in shares) |  |  |  |  | 10,000,000 |  |
Shares issued in period (in shares) |  | 1,121,859 |  |  |  |  |

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