ESPP employee contribution annual limit.

No definition available.

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- Definition

Represents the performance period of share-based payment awards.

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No definition available.

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- Definition

Represents the number of retention shares or retention stock units granted to each non-employee director upon his or her initial election to the Board of Directors.

+ References

No definition available.

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Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

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Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

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Estimated period over which an employee is required to provide service in exchange for the equity-based payment award, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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- Definition

Discount rate from fair value on purchase date that participants pay for shares.

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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.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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- Definition

The highest percentage of annual salary that an employee is permitted to utilize with respect to the plan.

+ References

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- Definition

Number of equity instruments other than options outstanding, including both vested and non-vested instruments.

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- Definition

Number of shares authorized for issuance under share-based payment arrangement.

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The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

+ References

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- Definition

Number of options outstanding, including both vested and non-vested options.

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- Definition

Number of shares issued under share-based payment arrangement.

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- Definition

Percentage of vesting of award under share-based payment arrangement.

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- Definition

Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Stock Options and Other Stock Plans - Narrative (Details) - USD ($) $ in Thousands			1 Months Ended	12 Months Ended
	Jun. 10, 2025	Jun. 09, 2025	Feb. 28, 2025	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023	May 31, 2021	May 31, 2013	Apr. 30, 2000
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Stock option (in shares)				2,095,000	1,981,000
Number of shares available for grant (in shares)				29,874,539	31,063,392	31,979,909
ESPP employee contribution annual limit				$ 15
Stock options
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Award expiration period (in years)				10 years
Award vesting period (in years)				3 years
Unrecognized compensation expense				$ 10,000
Recognized weighted-average period (in years)				8 months 12 days
Retention awards
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Retention shares (in shares)				878,000	915,000
Award vesting period (in years)				4 years
Unrecognized compensation expense				$ 50,000
Recognized weighted-average period (in years)				9 months 18 days
Performance stock unit awards
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Retention shares (in shares)				619,000	607,000
Unrecognized compensation expense				$ 11,000
Recognized weighted-average period (in years)				1 year
Share-based payment award, award requisite service period (in months)			37 months
Performance period (in years)			3 years
Performance stock unit awards \| Share-Based Payment Arrangement, Tranche One
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Award vesting rights (percent)			66.67%
Performance stock unit awards \| Share-Based Payment Arrangement, Tranche Two
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Award vesting rights (percent)			33.33%
Employee stock
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Employer contribution match (as a percent)	20.00%	40.00%
Maximum employee subscription rate				5.00%
Union Pacific Corporation 2000 Directors Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of shares authorized (in shares)									2,200,000
Retention shares granted to each non-employee director upon initial election to board (in shares)									4,000
Outstanding, number (in shares)				16,000
Union Pacific Corporation 2013 Stock Incentive Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of shares authorized (in shares)								78,000,000
Stock option (in shares)				501,049
Retention shares (in shares)				0
Union Pacific Corporation 2021 Stock Incentive Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of shares authorized (in shares)							23,000,000
Stock option (in shares)				1,593,585
Retention shares (in shares)				1,187,093
Union Pacific Corporation 2021 Employee Stock Purchase Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of shares authorized (in shares)							10,000,000
Shares issued in period (in shares)				1,537,960