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Stock Options and Other Stock Plans (Details 2) (USD $)
In Millions, except Share data, unless otherwise specified |
12 Months Ended |
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Dec. 31, 2014
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| Stock Options [Member] | |
| Stock Option Activity [Abstract] | |
| Stock options, shares outstanding at January 1, 2014 | 7,443,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber / us-gaap_AwardTypeAxis = us-gaap_StockOptionMember |
| Stock options, shares granted | 989,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod / us-gaap_AwardTypeAxis = us-gaap_StockOptionMember |
| Stock options, shares exercised | (2,961,000)us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised / us-gaap_AwardTypeAxis = us-gaap_StockOptionMember |
| Stock options, shares forfeited or expired | (84,000)us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod / us-gaap_AwardTypeAxis = us-gaap_StockOptionMember |
| Stock options, shares outstanding at December 31, 2014 | 5,387,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber / us-gaap_AwardTypeAxis = us-gaap_StockOptionMember |
| Stock options, shares vested or expected to vest at December 31, 2014 | 5,325,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingNumber / us-gaap_AwardTypeAxis = us-gaap_StockOptionMember |
| Stock options, share options exercisable at December 31, 2014 | 3,350,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestExercisableNumber / us-gaap_AwardTypeAxis = us-gaap_StockOptionMember |
| Stock options weighted-average exercise price, outstanding at January 1, 2014 | $ 40.07us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice / us-gaap_AwardTypeAxis = us-gaap_StockOptionMember |
| Stock options weighted-average exercise price, granted | $ 87.56us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice / us-gaap_AwardTypeAxis = us-gaap_StockOptionMember |
| Stock options weighted-average exercise price, exercised | $ 30.59us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice / us-gaap_AwardTypeAxis = us-gaap_StockOptionMember |
| Stock options weighted-average exercise price, forfeited or expired | $ 68.48us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice / us-gaap_AwardTypeAxis = us-gaap_StockOptionMember |
| Stock options weighted-average exercise price, outstanding at December 31, 2014 | $ 53.56us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice / us-gaap_AwardTypeAxis = us-gaap_StockOptionMember |
| Stock options weighted-average exercise price, vested or expected to vest at December 31, 2014 | $ 53.30us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageExercisePrice / us-gaap_AwardTypeAxis = us-gaap_StockOptionMember |
| Stock options weighted-average exercise price, options exercisable at December 31, 2014 | $ 40.69us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice / us-gaap_AwardTypeAxis = us-gaap_StockOptionMember |
| Stock options weighted-average remaining contractual term in years, outstanding at January 1, 2014 | 5 years 10 months |
| Stock options weighted-average remaining contractual term in years, outstanding at December 31, 2014 | 5 years 10 months |
| Stock options weighted-average remaining contractual term in years, vested or expected to vest at December 31, 2014 | 5 years 10 months |
| Stock options weighted-average remaining contractual term in years, options exercisable at December 31, 2014 | 4 years 5 months |
| Stock options aggregate intrinsic value, outstanding at January 1, 2014 | $ 327us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue / us-gaap_AwardTypeAxis = us-gaap_StockOptionMember |
| Stock options aggregate intrinsic value, outstanding at December 31, 2014 | 353us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue / us-gaap_AwardTypeAxis = us-gaap_StockOptionMember |
| Stock options aggregate intrinsic value, vested or expected to vest at December 31, 2014 | 351us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingAggregateIntrinsicValue / us-gaap_AwardTypeAxis = us-gaap_StockOptionMember |
| Stock options aggregate intrinsic value, options exercisable at December 31, 2014 | 263us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1 / us-gaap_AwardTypeAxis = us-gaap_StockOptionMember |
| Contractual Term | Stock options are granted at the closing price on the date of grant, have ten-year contractual terms |
| Stock options, years until vest | 3 years |
| Stock options, subject to performance or market-based vesting conditions | None |
| Unrecognized Compensation Expense [Abstract] | |
| Unrecognized compensation expense | 15us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized / us-gaap_AwardTypeAxis = us-gaap_StockOptionMember |
| Expected weighted average period (in years) of nonvested stock options to be recognized | 1 year |
| Retention Awards [Member] | |
| Awards Activity [Abstract] | |
| Awards, shares nonvested at January 1, 2014 | 3,712,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber / us-gaap_AwardTypeAxis = unp_RetentionAwardsMember |
| Awards, shares granted | 871,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod / us-gaap_AwardTypeAxis = unp_RetentionAwardsMember |
| Awards, shares vested | (1,080,000)us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod / us-gaap_AwardTypeAxis = unp_RetentionAwardsMember |
| Awards, shares forfeited | (100,000)us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod / us-gaap_AwardTypeAxis = unp_RetentionAwardsMember |
| Awards, shares nonvested at December 31, 2014 | 3,403,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber / us-gaap_AwardTypeAxis = unp_RetentionAwardsMember |
| Awards weighted-average grant-date fair value, nonvested at January 1, 2014 | $ 49.02us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue / us-gaap_AwardTypeAxis = unp_RetentionAwardsMember |
| Awards weighted-average grant-date fair value, granted | $ 88.14us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue / us-gaap_AwardTypeAxis = unp_RetentionAwardsMember |
| Awards weighted-average grant-date fair value, vested | $ 31.33us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue / us-gaap_AwardTypeAxis = unp_RetentionAwardsMember |
| Awards weighted-average grant-date fair value, forfeited | $ 57.82us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue / us-gaap_AwardTypeAxis = unp_RetentionAwardsMember |
| Awards weighted-average grant-date fair value, nonvested at December 31, 2014 | $ 64.39us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue / us-gaap_AwardTypeAxis = unp_RetentionAwardsMember |
| Unrecognized Compensation Expense [Abstract] | |
| Unrecognized compensation expense | 87us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized / us-gaap_AwardTypeAxis = unp_RetentionAwardsMember |
| Expected weighted average period (in years) of nonvested stock options to be recognized | 1 year 7 months |
| Performance Retention Awards [Member] | |
| Awards Activity [Abstract] | |
| Awards, shares nonvested at January 1, 2014 | 1,888,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber / us-gaap_AwardTypeAxis = unp_PerformanceRetentionAwardsMember |
| Awards, shares granted | 456,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod / us-gaap_AwardTypeAxis = unp_PerformanceRetentionAwardsMember |
| Awards, shares vested | (661,000)us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod / us-gaap_AwardTypeAxis = unp_PerformanceRetentionAwardsMember |
| Awards, shares forfeited | (100,000)us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod / us-gaap_AwardTypeAxis = unp_PerformanceRetentionAwardsMember |
| Awards, shares nonvested at December 31, 2014 | 1,583,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber / us-gaap_AwardTypeAxis = unp_PerformanceRetentionAwardsMember |
| Awards weighted-average grant-date fair value, nonvested at January 1, 2014 | $ 53.70us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue / us-gaap_AwardTypeAxis = unp_PerformanceRetentionAwardsMember |
| Awards weighted-average grant-date fair value, granted | $ 83.06us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue / us-gaap_AwardTypeAxis = unp_PerformanceRetentionAwardsMember |
| Awards weighted-average grant-date fair value, vested | $ 44.94us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue / us-gaap_AwardTypeAxis = unp_PerformanceRetentionAwardsMember |
| Awards weighted-average grant-date fair value, forfeited | $ 61.36us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue / us-gaap_AwardTypeAxis = unp_PerformanceRetentionAwardsMember |
| Awards weighted-average grant-date fair value, nonvested at December 31, 2014 | $ 65.33us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue / us-gaap_AwardTypeAxis = unp_PerformanceRetentionAwardsMember |
| Unrecognized Compensation Expense [Abstract] | |
| Unrecognized compensation expense | $ 36us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized / us-gaap_AwardTypeAxis = unp_PerformanceRetentionAwardsMember |
| Expected weighted average period (in years) of nonvested stock options to be recognized | 1 year |
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- Definition
The number of stock options outstanding that are subject to performance or market-based vesting conditions before giving the employee the legal right to convert the award to shares. No definition available.
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- Definition
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term, Beginning of Period. No definition available.
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- Details
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- Definition
Unrecognized cost of unvested share-based compensation awards. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Details
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- Definition
The weighted average fair value of nonvested awards on equity-based plans excluding option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, revenue or profit achievement stock award plan) for which the employer is contingently obligated to issue equity instruments or transfer assets to an employee who has not yet satisfied service or performance criteria necessary to gain title to proceeds from the sale of the award or underlying shares or units. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
Weighted average remaining contractual term for vested portions of options outstanding and currently exercisable or convertible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
For presentations that combine terminations, the number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan or that expired. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
Weighted average price of options that were either forfeited or expired. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
Net number of share options (or share units) granted during the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
Number of options outstanding, including both vested and non-vested options. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Details
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- Definition
Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
The number of exercisable share options (fully vested and expected to vest) that may be converted as of the balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
Amount by which the current fair value of the underlying stock exceeds the exercise price of fully vested and expected to vest options outstanding. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
As of the balance sheet date, the number of shares into which fully vested and expected to vest stock options outstanding can be converted under the option plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
As of the balance sheet date, the weighted-average exercise price for outstanding stock options that are fully vested or expected to vest. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
Weighted average remaining contractual term for fully vested and expected to vest options outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
Description of pertinent provisions of equity-based compensation awards that have actual or potential impact upon the company's financial statements. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
Weighted average price at which option holders acquired shares when converting their stock options into shares. No definition available.
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- Definition
Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options. No definition available.
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- Definition
Number of share options (or share units) exercised during the current period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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