XML 76 R52.htm IDEA: XBRL DOCUMENT
v3.22.0.1

Note 4 - Stock Options and Other Stock Plans - Additional Information Regarding Stock Option Exercises (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019
Intrinsic value of stock options exercised | $ 84 | $ 120 | $ 193
Cash received from option exercises | 58 | 95 | 130
Treasury shares repurchased for employee payroll taxes | (15) | (24) | (37)
Tax benefit realized from option exercises | 16 | 28 | 48
Aggregate grant-date fair value of stock options vested | $ 14 | $ 15 | $ 15

X
- Definition Represents the aggregate grant-date fair value of stock options vested during the period. + References No definition available. + Details
Name: | unp_AggregateGrantDateFairValueOfStockOptionsVested
Namespace Prefix: | unp_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Represents the amount of treasury shares repurchased for employee payroll taxes. + References No definition available. + Details
Name: | unp_TreasurySharesRepurchasedForEmployeePayrollTaxes
Namespace Prefix: | unp_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of tax benefit from exercise of option under share-based payment arrangement. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2A -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=120381028&loc=SL79508275-113901 + Details
Name: | us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromExerciseOfStockOptions
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of cash inflow from exercise of option under share-based payment arrangement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2A -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=120381028&loc=SL79508275-113901 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 14 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3255-108585 + Details
Name: | us-gaap_ProceedsFromStockOptionsExercised
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (d)(2) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration