XML 72 R63.htm IDEA: XBRL DOCUMENT
v3.23.2

Note 14 - Commitments and Contingencies - Personal Injury Liability Activity (Details) - USD ($) $ in Millions | 6 Months Ended |
--- | --- | ---
Jun. 30, 2023 | Jun. 30, 2022 | Dec. 31, 2022
Balance, Current | $ 267 |  | $ 242
Personal Injury [Member] |  |  |
Balance | 361 | $ 325 |
Current year accruals | 52 | 51 |
Changes in estimates for prior years | 31 | 36 |
Payments | (77) | (65) |
Balance | 367 | 347 |
Balance, Current | $ 98 | $ 70 |

X
- Definition Amount of expense (reversal of expense) which increases (decreases) the accrual for loss contingencies from revisions in estimates to existing obligations. + References No definition available. + Details
Name: | unp_LossContingencyAccrualCarryingValueChangeInPriorYears
Namespace Prefix: | unp_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of loss contingency liability. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 450 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org//1943274/2147483076/450-20-50-1 Reference 2: http://www.xbrl.org/2003/role/recommendedDisclosureRef -Topic 450 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 10 -Publisher FASB -URI https://asc.fasb.org//1943274/2147483076/450-20-50-10 + Details
Name: | us-gaap_LossContingencyAccrualAtCarryingValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of loss contingency liability expected to be resolved within one year or the normal operating cycle, if longer. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 450 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org//1943274/2147483076/450-20-50-1 + Details
Name: | us-gaap_LossContingencyAccrualCarryingValueCurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of cash outflow reducing loss contingency liability. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 450 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org//1943274/2147483076/450-20-50-1 + Details
Name: | us-gaap_LossContingencyAccrualPayments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount charged against operating income increasing loss contingency liability, after adjustments to reduce previously estimated charges. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 450 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org//1943274/2147483076/450-20-50-1 + Details
Name: | us-gaap_LossContingencyAccrualProvision
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_LossContingenciesByNatureOfContingencyAxis=unp_PersonalInjuryMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |