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v3.22.1

Note 15 - Share Repurchase Programs (Tables) | 3 Months Ended
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Mar. 31, 2022
Notes Tables |
Share Repurchase Program [Table Text Block] |
|  | Number of Shares Purchased |  |  | Average Price Paid [a] |
|  | 2022 |  |  | 2021 |  |  | 2022 |  |  | 2021 |
First quarter [b] |  |  | 11,014,201 |  |  |  | 6,691,421 |  |  | $ | 249.95 |  |  | $ | 209.50 |

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- Definition Tabular disclosure of information related to share repurchase programs. + References No definition available. + Details
Name: | unp_ShareRepurchaseProgramTableTextBlock
Namespace Prefix: | unp_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

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- References No definition available. + Details
Name: | us-gaap_TableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration