3.25.4 html 310 539 1 true 98 0 false 9 false false R1.htm 0000001 - Document - Cover Sheet http://www.up.com/role/Cover Cover Cover 1 false false R2.htm 0000002 - Document - Audit Information Sheet http://www.up.com/role/AuditInformation Audit Information Cover 2 false false R3.htm 9952151 - Statement - Consolidated Statements of Income Sheet http://www.up.com/role/ConsolidatedStatementsofIncome Consolidated Statements of Income Statements 3 false false R4.htm 9952152 - Statement - Consolidated Statements of Comprehensive Income Sheet http://www.up.com/role/ConsolidatedStatementsofComprehensiveIncome Consolidated Statements of Comprehensive Income Statements 4 false false R5.htm 9952153 - Statement - Consolidated Statements of Comprehensive Income (Parenthetical) Sheet http://www.up.com/role/ConsolidatedStatementsofComprehensiveIncomeParenthetical Consolidated Statements of Comprehensive Income (Parenthetical) Statements 5 false false R6.htm 9952154 - Statement - Consolidated Statements of Financial Position Sheet http://www.up.com/role/ConsolidatedStatementsofFinancialPosition Consolidated Statements of Financial Position Statements 6 false false R7.htm 9952155 - Statement - Consolidated Statements of Financial Position (Parenthetical) Sheet http://www.up.com/role/ConsolidatedStatementsofFinancialPositionParenthetical Consolidated Statements of Financial Position (Parenthetical) Statements 7 false false R8.htm 9952156 - Statement - Consolidated Statements of Cash Flows Sheet http://www.up.com/role/ConsolidatedStatementsofCashFlows Consolidated Statements of Cash Flows Statements 8 false false R9.htm 9952157 - Statement - Consolidated Statements of Changes in Common Shareholders' Equity Sheet http://www.up.com/role/ConsolidatedStatementsofChangesinCommonShareholdersEquity Consolidated Statements of Changes in Common Shareholders' Equity Statements 9 false false R10.htm 9952158 - Statement - Consolidated Statements of Changes in Common Shareholders' Equity (Parenthetical) Sheet http://www.up.com/role/ConsolidatedStatementsofChangesinCommonShareholdersEquityParenthetical Consolidated Statements of Changes in Common Shareholders' Equity (Parenthetical) Statements 10 false false R11.htm 9952159 - Disclosure - Nature of Operations Sheet http://www.up.com/role/NatureofOperations Nature of Operations Notes 11 false false R12.htm 9952160 - Disclosure - Significant Accounting Policies Sheet http://www.up.com/role/SignificantAccountingPolicies Significant Accounting Policies Notes 12 false false R13.htm 9952161 - Disclosure - Accounting Pronouncements Sheet http://www.up.com/role/AccountingPronouncements Accounting Pronouncements Notes 13 false false R14.htm 9952162 - Disclosure - Stock Options and Other Stock Plans Sheet http://www.up.com/role/StockOptionsandOtherStockPlans Stock Options and Other Stock Plans Notes 14 false false R15.htm 9952163 - Disclosure - Retirement Plans Sheet http://www.up.com/role/RetirementPlans Retirement Plans Notes 15 false false R16.htm 9952164 - Disclosure - Other Income Sheet http://www.up.com/role/OtherIncome Other Income Notes 16 false false R17.htm 9952165 - Disclosure - Income Taxes Sheet http://www.up.com/role/IncomeTaxes Income Taxes Notes 17 false false R18.htm 9952166 - Disclosure - Earnings Per Share Sheet http://www.up.com/role/EarningsPerShare Earnings Per Share Notes 18 false false R19.htm 9952167 - Disclosure - Accumulated Other Comprehensive Income/Loss Sheet http://www.up.com/role/AccumulatedOtherComprehensiveIncomeLoss Accumulated Other Comprehensive Income/Loss Notes 19 false false R20.htm 9952168 - Disclosure - Accounts Receivable Sheet http://www.up.com/role/AccountsReceivable Accounts Receivable Notes 20 false false R21.htm 9952169 - Disclosure - Properties Sheet http://www.up.com/role/Properties Properties Notes 21 false false R22.htm 9952170 - Disclosure - Accounts Payable and Other Current Liabilities Sheet http://www.up.com/role/AccountsPayableandOtherCurrentLiabilities Accounts Payable and Other Current Liabilities Notes 22 false false R23.htm 9952171 - Disclosure - Financial Instruments Sheet http://www.up.com/role/FinancialInstruments Financial Instruments Notes 23 false false R24.htm 9952172 - Disclosure - Debt Sheet http://www.up.com/role/Debt Debt Notes 24 false false R25.htm 9952173 - Disclosure - Variable Interest Entities Sheet http://www.up.com/role/VariableInterestEntities Variable Interest Entities Notes 25 false false R26.htm 9952174 - Disclosure - Leases Sheet http://www.up.com/role/Leases Leases Notes 26 false false R27.htm 9952175 - Disclosure - Commitments and Contingencies Sheet http://www.up.com/role/CommitmentsandContingencies Commitments and Contingencies Notes 27 false false R28.htm 9952176 - Disclosure - Share Repurchase Programs Sheet http://www.up.com/role/ShareRepurchasePrograms Share Repurchase Programs Notes 28 false false R29.htm 9952177 - Disclosure - Related Parties Sheet http://www.up.com/role/RelatedParties Related Parties Notes 29 false false R30.htm 9952178 - Disclosure - Pending Acquisition Sheet http://www.up.com/role/PendingAcquisition Pending Acquisition Notes 30 false false R31.htm 995445 - Disclosure - Insider Trading Arrangements Sheet http://xbrl.sec.gov/ecd/role/InsiderTradingArrangements Insider Trading Arrangements Notes 31 false false R32.htm 995447 - Disclosure - Insider Trading Policies and Procedures Sheet http://xbrl.sec.gov/ecd/role/InsiderTradingPoliciesProc Insider Trading Policies and Procedures Notes 32 false false R33.htm 995550 - Disclosure - Cybersecurity Risk Management and Strategy Disclosure Sheet http://xbrl.sec.gov/cyd/role/CybersecurityRiskManagementAndStrategyDisclosure Cybersecurity Risk Management and Strategy Disclosure Notes 33 false false R34.htm 9955511 - Disclosure - Significant Accounting Policies (Policies) Sheet http://www.up.com/role/SignificantAccountingPoliciesPolicies Significant Accounting Policies (Policies) Policies http://www.up.com/role/SignificantAccountingPolicies 34 false false R35.htm 9955512 - Disclosure - Nature of Operations (Tables) Sheet http://www.up.com/role/NatureofOperationsTables Nature of Operations (Tables) Tables http://www.up.com/role/NatureofOperations 35 false false R36.htm 9955513 - Disclosure - Significant Accounting Policies (Tables) Sheet http://www.up.com/role/SignificantAccountingPoliciesTables Significant Accounting Policies (Tables) Tables http://www.up.com/role/SignificantAccountingPolicies 36 false false R37.htm 9955514 - Disclosure - Stock Options and Other Stock Plans (Tables) Sheet http://www.up.com/role/StockOptionsandOtherStockPlansTables Stock Options and Other Stock Plans (Tables) Tables http://www.up.com/role/StockOptionsandOtherStockPlans 37 false false R38.htm 9955515 - Disclosure - Retirement Plans (Tables) Sheet http://www.up.com/role/RetirementPlansTables Retirement Plans (Tables) Tables http://www.up.com/role/RetirementPlans 38 false false R39.htm 9955516 - Disclosure - Other Income (Table) Sheet http://www.up.com/role/OtherIncomeTable Other Income (Table) Tables http://www.up.com/role/OtherIncome 39 false false R40.htm 9955517 - Disclosure - Income Taxes (Tables) Sheet http://www.up.com/role/IncomeTaxesTables Income Taxes (Tables) Tables http://www.up.com/role/IncomeTaxes 40 false false R41.htm 9955518 - Disclosure - Earnings Per Share (Tables) Sheet http://www.up.com/role/EarningsPerShareTables Earnings Per Share (Tables) Tables http://www.up.com/role/EarningsPerShare 41 false false R42.htm 9955519 - Disclosure - Accumulated Other Comprehensive Income/Loss (Tables) Sheet http://www.up.com/role/AccumulatedOtherComprehensiveIncomeLossTables Accumulated Other Comprehensive Income/Loss (Tables) Tables http://www.up.com/role/AccumulatedOtherComprehensiveIncomeLoss 42 false false R43.htm 9955520 - Disclosure - Properties (Tables) Sheet http://www.up.com/role/PropertiesTables Properties (Tables) Tables http://www.up.com/role/Properties 43 false false R44.htm 9955521 - Disclosure - Accounts Payable and Other Current Liabilities (Tables) Sheet http://www.up.com/role/AccountsPayableandOtherCurrentLiabilitiesTables Accounts Payable and Other Current Liabilities (Tables) Tables http://www.up.com/role/AccountsPayableandOtherCurrentLiabilities 44 false false R45.htm 9955522 - Disclosure - Debt (Tables) Sheet http://www.up.com/role/DebtTables Debt (Tables) Tables http://www.up.com/role/Debt 45 false false R46.htm 9955523 - Disclosure - Leases (Tables) Sheet http://www.up.com/role/LeasesTables Leases (Tables) Tables http://www.up.com/role/Leases 46 false false R47.htm 9955524 - Disclosure - Commitments and Contingencies (Tables) Sheet http://www.up.com/role/CommitmentsandContingenciesTables Commitments and Contingencies (Tables) Tables http://www.up.com/role/CommitmentsandContingencies 47 false false R48.htm 9955525 - Disclosure - Share Repurchase Programs (Tables) Sheet http://www.up.com/role/ShareRepurchaseProgramsTables Share Repurchase Programs (Tables) Tables http://www.up.com/role/ShareRepurchasePrograms 48 false false R49.htm 9955526 - Disclosure - Pending Acquisition (Tables) Sheet http://www.up.com/role/PendingAcquisitionTables Pending Acquisition (Tables) Tables http://www.up.com/role/PendingAcquisition 49 false false R50.htm 9955527 - Disclosure - Nature of Operations - Narrative (Details) Sheet http://www.up.com/role/NatureofOperationsNarrativeDetails Nature of Operations - Narrative (Details) Details 50 false false R51.htm 9955528 - Disclosure - Nature of Operations - Schedule of Freight and Other Revenues (Details) Sheet http://www.up.com/role/NatureofOperationsScheduleofFreightandOtherRevenuesDetails Nature of Operations - Schedule of Freight and Other Revenues (Details) Details 51 false false R52.htm 9955529 - Disclosure - Significant Accounting Policies - Schedule of Reconciliation of Cash, Cash Equivalents, and Restricted Cash (Details) Sheet http://www.up.com/role/SignificantAccountingPoliciesScheduleofReconciliationofCashCashEquivalentsandRestrictedCashDetails Significant Accounting Policies - Schedule of Reconciliation of Cash, Cash Equivalents, and Restricted Cash (Details) Details 52 false false R53.htm 9955530 - Disclosure - Significant Accounting Policies - Revenue Recognition (Details) Sheet http://www.up.com/role/SignificantAccountingPoliciesRevenueRecognitionDetails Significant Accounting Policies - Revenue Recognition (Details) Details 53 false false R54.htm 9955531 - Disclosure - Stock Options and Other Stock Plans - Narrative (Details) Sheet http://www.up.com/role/StockOptionsandOtherStockPlansNarrativeDetails Stock Options and Other Stock Plans - Narrative (Details) Details 54 false false R55.htm 9955532 - Disclosure - Stock Options and Other Stock Plans - Schedule of Stock Based Compensation Expense (Details) Sheet http://www.up.com/role/StockOptionsandOtherStockPlansScheduleofStockBasedCompensationExpenseDetails Stock Options and Other Stock Plans - Schedule of Stock Based Compensation Expense (Details) Details 55 false false R56.htm 9955533 - Disclosure - Stock Options and Other Stock Plans - Schedule of Annual Weighted Average Assumptions (Details) Sheet http://www.up.com/role/StockOptionsandOtherStockPlansScheduleofAnnualWeightedAverageAssumptionsDetails Stock Options and Other Stock Plans - Schedule of Annual Weighted Average Assumptions (Details) Details 56 false false R57.htm 9955534 - Disclosure - Stock Options and Other Stock Plans - Schedule of Stock Option Activity (Details) Sheet http://www.up.com/role/StockOptionsandOtherStockPlansScheduleofStockOptionActivityDetails Stock Options and Other Stock Plans - Schedule of Stock Option Activity (Details) Details 57 false false R58.htm 9955535 - Disclosure - Stock Options and Other Stock Plans - Schedule of Additional Information Regarding Stock Option Exercises (Details) Sheet http://www.up.com/role/StockOptionsandOtherStockPlansScheduleofAdditionalInformationRegardingStockOptionExercisesDetails Stock Options and Other Stock Plans - Schedule of Additional Information Regarding Stock Option Exercises (Details) Details 58 false false R59.htm 9955536 - Disclosure - Stock Options and Other Stock Plans - Schedule of Changes in Retention Awards (Details) Sheet http://www.up.com/role/StockOptionsandOtherStockPlansScheduleofChangesinRetentionAwardsDetails Stock Options and Other Stock Plans - Schedule of Changes in Retention Awards (Details) Details 59 false false R60.htm 9955537 - Disclosure - Stock Options and Other Stock Plans - Schedule of Changes in Performance Stock Unit Awards (Details) Sheet http://www.up.com/role/StockOptionsandOtherStockPlansScheduleofChangesinPerformanceStockUnitAwardsDetails Stock Options and Other Stock Plans - Schedule of Changes in Performance Stock Unit Awards (Details) Details 60 false false R61.htm 9955538 - Disclosure - Retirement Plans - Schedule of Funded Status (Details) Sheet http://www.up.com/role/RetirementPlansScheduleofFundedStatusDetails Retirement Plans - Schedule of Funded Status (Details) Details 61 false false R62.htm 9955539 - Disclosure - Retirement Plans - Narrative (Details) Sheet http://www.up.com/role/RetirementPlansNarrativeDetails Retirement Plans - Narrative (Details) Details 62 false false R63.htm 9955540 - Disclosure - Retirement Plans - Schedule of Amount Recognized in Financial Position (Details) Sheet http://www.up.com/role/RetirementPlansScheduleofAmountRecognizedinFinancialPositionDetails Retirement Plans - Schedule of Amount Recognized in Financial Position (Details) Details 63 false false R64.htm 9955541 - Disclosure - Retirement Plans - Schedule of Pre-Tax Changes in Other Comprehensive Income/Loss (Details) Sheet http://www.up.com/role/RetirementPlansScheduleofPreTaxChangesinOtherComprehensiveIncomeLossDetails Retirement Plans - Schedule of Pre-Tax Changes in Other Comprehensive Income/Loss (Details) Details 64 false false R65.htm 9955542 - Disclosure - Retirement Plans - Schedule of Underfunded Accumulated Benefit Obligation (Details) Sheet http://www.up.com/role/RetirementPlansScheduleofUnderfundedAccumulatedBenefitObligationDetails Retirement Plans - Schedule of Underfunded Accumulated Benefit Obligation (Details) Details 65 false false R66.htm 9955543 - Disclosure - Retirement Plans - Schedule of Weighted Average Assumptions (Details) Sheet http://www.up.com/role/RetirementPlansScheduleofWeightedAverageAssumptionsDetails Retirement Plans - Schedule of Weighted Average Assumptions (Details) Details 66 false false R67.htm 9955544 - Disclosure - Retirement Plans - Schedule of Net Periodic Pension Benefit/Cost (Details) Sheet http://www.up.com/role/RetirementPlansScheduleofNetPeriodicPensionBenefitCostDetails Retirement Plans - Schedule of Net Periodic Pension Benefit/Cost (Details) Details 67 false false R68.htm 9955545 - Disclosure - Retirement Plans - Schedule of Qualified and Non-Qualified Pension Plans (Details) Sheet http://www.up.com/role/RetirementPlansScheduleofQualifiedandNonQualifiedPensionPlansDetails Retirement Plans - Schedule of Qualified and Non-Qualified Pension Plans (Details) Details 68 false false R69.htm 9955546 - Disclosure - Retirement Plans - Schedule of Expected Benefit Payments (Details) Sheet http://www.up.com/role/RetirementPlansScheduleofExpectedBenefitPaymentsDetails Retirement Plans - Schedule of Expected Benefit Payments (Details) Details 69 false false R70.htm 9955547 - Disclosure - Retirement Plans - Schedule of Pension Plan Asset Allocation (Details) Sheet http://www.up.com/role/RetirementPlansScheduleofPensionPlanAssetAllocationDetails Retirement Plans - Schedule of Pension Plan Asset Allocation (Details) Details 70 false false R71.htm 9955548 - Disclosure - Retirement Plans - Schedule of Plan Asset Measured on a Recurring Basis (Details) Sheet http://www.up.com/role/RetirementPlansScheduleofPlanAssetMeasuredonaRecurringBasisDetails Retirement Plans - Schedule of Plan Asset Measured on a Recurring Basis (Details) Details 71 false false R72.htm 9955549 - Disclosure - Other Income (Details) Sheet http://www.up.com/role/OtherIncomeDetails Other Income (Details) Details http://www.up.com/role/OtherIncomeTable 72 false false R73.htm 9955550 - Disclosure - Income Taxes - Schedule of Income Tax Expense Components (Details) Sheet http://www.up.com/role/IncomeTaxesScheduleofIncomeTaxExpenseComponentsDetails Income Taxes - Schedule of Income Tax Expense Components (Details) Details 73 false false R74.htm 9955551 - Disclosure - Income Taxes - Schedule of Effective Income Tax Rate Reconciliation (Details) Sheet http://www.up.com/role/IncomeTaxesScheduleofEffectiveIncomeTaxRateReconciliationDetails Income Taxes - Schedule of Effective Income Tax Rate Reconciliation (Details) Details 74 false false R75.htm 9955552 - Disclosure - Income Taxes - Narrative (Details) Sheet http://www.up.com/role/IncomeTaxesNarrativeDetails Income Taxes - Narrative (Details) Details 75 false false R76.htm 9955553 - Disclosure - Income Taxes - Schedule of Deferred Income Tax Assets (Liabilities) (Details) Sheet http://www.up.com/role/IncomeTaxesScheduleofDeferredIncomeTaxAssetsLiabilitiesDetails Income Taxes - Schedule of Deferred Income Tax Assets (Liabilities) (Details) Details 76 false false R77.htm 9955554 - Disclosure - Income Taxes - Schedule of Unrecognized Tax Benefits Assets (Liabilities) (Details) Sheet http://www.up.com/role/IncomeTaxesScheduleofUnrecognizedTaxBenefitsAssetsLiabilitiesDetails Income Taxes - Schedule of Unrecognized Tax Benefits Assets (Liabilities) (Details) Details 77 false false R78.htm 9955555 - Disclosure - Earnings Per Share - Schedule of Reconciliation of Basic and Diluted (Details) Sheet http://www.up.com/role/EarningsPerShareScheduleofReconciliationofBasicandDilutedDetails Earnings Per Share - Schedule of Reconciliation of Basic and Diluted (Details) Details 78 false false R79.htm 9955556 - Disclosure - Earnings Per Share - Narrative (Details) Sheet http://www.up.com/role/EarningsPerShareNarrativeDetails Earnings Per Share - Narrative (Details) Details 79 false false R80.htm 9955557 - Disclosure - Accumulated Other Comprehensive Income/Loss (Details) Sheet http://www.up.com/role/AccumulatedOtherComprehensiveIncomeLossDetails Accumulated Other Comprehensive Income/Loss (Details) Details http://www.up.com/role/AccumulatedOtherComprehensiveIncomeLossTables 80 false false R81.htm 9955558 - Disclosure - Accounts Receivable (Details) Sheet http://www.up.com/role/AccountsReceivableDetails Accounts Receivable (Details) Details http://www.up.com/role/AccountsReceivable 81 false false R82.htm 9955559 - Disclosure - Properties - Schedule of Property and Equipment and Weighted Average Estimated Useful Life (Details) Sheet http://www.up.com/role/PropertiesScheduleofPropertyandEquipmentandWeightedAverageEstimatedUsefulLifeDetails Properties - Schedule of Property and Equipment and Weighted Average Estimated Useful Life (Details) Details 82 false false R83.htm 9955560 - Disclosure - Properties - Narrative (Details) Sheet http://www.up.com/role/PropertiesNarrativeDetails Properties - Narrative (Details) Details 83 false false R84.htm 9955561 - Disclosure - Accounts Payable and Other Current Liabilities (Details) Sheet http://www.up.com/role/AccountsPayableandOtherCurrentLiabilitiesDetails Accounts Payable and Other Current Liabilities (Details) Details http://www.up.com/role/AccountsPayableandOtherCurrentLiabilitiesTables 84 false false R85.htm 9955562 - Disclosure - Financial Instruments (Details) Sheet http://www.up.com/role/FinancialInstrumentsDetails Financial Instruments (Details) Details http://www.up.com/role/FinancialInstruments 85 false false R86.htm 9955563 - Disclosure - Debt - Schedule of Total Debt (Details) Sheet http://www.up.com/role/DebtScheduleofTotalDebtDetails Debt - Schedule of Total Debt (Details) Details 86 false false R87.htm 9955564 - Disclosure - Debt - Schedule of Aggregate Debt Maturities (Details) Sheet http://www.up.com/role/DebtScheduleofAggregateDebtMaturitiesDetails Debt - Schedule of Aggregate Debt Maturities (Details) Details 87 false false R88.htm 9955565 - Disclosure - Debt - Narrative (Details) Sheet http://www.up.com/role/DebtNarrativeDetails Debt - Narrative (Details) Details 88 false false R89.htm 9955566 - Disclosure - Debt - Schedule of Unsecured, Fixed-Rate Debt Securities Under Our Shelf Registration (Details) Sheet http://www.up.com/role/DebtScheduleofUnsecuredFixedRateDebtSecuritiesUnderOurShelfRegistrationDetails Debt - Schedule of Unsecured, Fixed-Rate Debt Securities Under Our Shelf Registration (Details) Details 89 false false R90.htm 9955567 - Disclosure - Variable Interest Entities (Details) Sheet http://www.up.com/role/VariableInterestEntitiesDetails Variable Interest Entities (Details) Details http://www.up.com/role/VariableInterestEntities 90 false false R91.htm 9955568 - Disclosure - Leases - Schedule of Leases Assets and Liabilities (Details) Sheet http://www.up.com/role/LeasesScheduleofLeasesAssetsandLiabilitiesDetails Leases - Schedule of Leases Assets and Liabilities (Details) Details 91 false false R92.htm 9955569 - Disclosure - Leases - Schedule of Lease Costs (Details) Sheet http://www.up.com/role/LeasesScheduleofLeaseCostsDetails Leases - Schedule of Lease Costs (Details) Details 92 false false R93.htm 9955570 - Disclosure - Leases - Schedule of Aggregate Lease Maturities (Details) Sheet http://www.up.com/role/LeasesScheduleofAggregateLeaseMaturitiesDetails Leases - Schedule of Aggregate Lease Maturities (Details) Details 93 false false R94.htm 9955571 - Disclosure - Leases - Schedule of Weighted Average Lease Term and Discount Rate (Details) Sheet http://www.up.com/role/LeasesScheduleofWeightedAverageLeaseTermandDiscountRateDetails Leases - Schedule of Weighted Average Lease Term and Discount Rate (Details) Details 94 false false R95.htm 9955572 - Disclosure - Leases - Schedule of Other Lease Information (Details) Sheet http://www.up.com/role/LeasesScheduleofOtherLeaseInformationDetails Leases - Schedule of Other Lease Information (Details) Details 95 false false R96.htm 9955573 - Disclosure - Commitments and Contingencies - Narrative (Details) Sheet http://www.up.com/role/CommitmentsandContingenciesNarrativeDetails Commitments and Contingencies - Narrative (Details) Details 96 false false R97.htm 9955574 - Disclosure - Commitments and Contingencies - Schedule of Personal Injury Liability Activity (Details) Sheet http://www.up.com/role/CommitmentsandContingenciesScheduleofPersonalInjuryLiabilityActivityDetails Commitments and Contingencies - Schedule of Personal Injury Liability Activity (Details) Details 97 false false R98.htm 9955575 - Disclosure - Commitments and Contingencies - Schedule of Environmental Liability Activity (Details) Sheet http://www.up.com/role/CommitmentsandContingenciesScheduleofEnvironmentalLiabilityActivityDetails Commitments and Contingencies - Schedule of Environmental Liability Activity (Details) Details 98 false false R99.htm 9955576 - Disclosure - Share Repurchase Programs - Narrative (Details) Sheet http://www.up.com/role/ShareRepurchaseProgramsNarrativeDetails Share Repurchase Programs - Narrative (Details) Details 99 false false R100.htm 9955577 - Disclosure - Share Repurchase Programs - Schedule of Share Repurchase Programs (Details) Sheet http://www.up.com/role/ShareRepurchaseProgramsScheduleofShareRepurchaseProgramsDetails Share Repurchase Programs - Schedule of Share Repurchase Programs (Details) Details 100 false false R101.htm 9955578 - Disclosure - Related Parties (Details) Sheet http://www.up.com/role/RelatedPartiesDetails Related Parties (Details) Details http://www.up.com/role/RelatedParties 101 false false R102.htm 9955579 - Disclosure - Pending Acquisition - Narrative (Details) Sheet http://www.up.com/role/PendingAcquisitionNarrativeDetails Pending Acquisition - Narrative (Details) Details 102 false false R103.htm 9955580 - Disclosure - Pending Acquisition - Schedule of Acquisition-Related Expense Associated with the Merger Agreement (Details) Sheet http://www.up.com/role/PendingAcquisitionScheduleofAcquisitionRelatedExpenseAssociatedwiththeMergerAgreementDetails Pending Acquisition - Schedule of Acquisition-Related Expense Associated with the Merger Agreement (Details) Details 103 false false All Reports Book All Reports unp-20251231.htm unp-20251231.xsd unp-20251231_cal.xml unp-20251231_def.xml unp-20251231_lab.xml unp-20251231_pre.xml unp-20251231_g1.jpg unp-20251231_g2.jpg unp-20251231_g3.jpg unp-20251231_g4.jpg unp-20251231_g5.jpg unp-20251231_g6.jpg unp-20251231_g7.jpg unp-20251231_g8.jpg http://fasb.org/srt/2025 http://fasb.org/us-gaap/2025 http://xbrl.sec.gov/cyd/2025 http://xbrl.sec.gov/dei/2025 http://xbrl.sec.gov/ecd/2025 true true