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Revenue from transporting cargo and freight to and from Mexico.

+ References

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- Definition

The approximate number of route miles linking Pacific Coast and Gulf Coast ports with the Midwest and eastern U.S. gateways and providing several corridors to key Mexican gateways.

+ References

No definition available.

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- Definition

Route miles owned by the Company.

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- Definition

Revenue from transporting cargo and freight between locations.

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- Definition

Revenues from the sale of other goods or rendering of other services, not elsewhere specified in the taxonomy; net of (reduced by) sales adjustments, returns, allowances, and discounts.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1(a),(d))

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Article 5

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- Definition

Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1)

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

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-Paragraph 1

-Article 5

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Nature Of Operations (Details) (USD $)	3 Months Ended								12 Months Ended
Nature Of Operations (Details) (USD $)	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting, Disclosure of Entity's Reportable Segments [Abstract]
Network route miles	31,974unp_NetworkRouteMiles								31,974unp_NetworkRouteMiles
Route miles owned	26,012unp_RouteMilesOwned								26,012unp_RouteMilesOwned
Commodity Group Information [Line Items]
Freight revenues									$ 22,560,000,000us-gaap_CargoAndFreightRevenue	$ 20,684,000,000us-gaap_CargoAndFreightRevenue	$ 19,686,000,000us-gaap_CargoAndFreightRevenue
Other revenues									1,428,000,000us-gaap_OtherSalesRevenueNet	1,279,000,000us-gaap_OtherSalesRevenueNet	1,240,000,000us-gaap_OtherSalesRevenueNet
Total operating revenues	6,153,000,000us-gaap_Revenues	6,182,000,000us-gaap_Revenues	6,015,000,000us-gaap_Revenues	5,638,000,000us-gaap_Revenues	5,630,000,000us-gaap_Revenues	5,573,000,000us-gaap_Revenues	5,470,000,000us-gaap_Revenues	5,290,000,000us-gaap_Revenues	23,988,000,000us-gaap_Revenues	21,963,000,000us-gaap_Revenues	20,926,000,000us-gaap_Revenues
Freight revenues - Mexico									2,300,000,000unp_MexicoCargoAndFreightRevenue	2,100,000,000unp_MexicoCargoAndFreightRevenue	1,900,000,000unp_MexicoCargoAndFreightRevenue
Agricultural Products [Member]
Commodity Group Information [Line Items]
Freight revenues									3,777,000,000	3,276,000,000	3,280,000,000
Automotive [Member]
Commodity Group Information [Line Items]
Freight revenues									2,103,000,000	2,077,000,000	1,807,000,000
Chemicals [Member]
Commodity Group Information [Line Items]
Freight revenues									3,664,000,000	3,501,000,000	3,238,000,000
Coal [Member]
Commodity Group Information [Line Items]
Freight revenues									4,127,000,000	3,978,000,000	3,912,000,000
Industrial Products [Member]
Commodity Group Information [Line Items]
Freight revenues									4,400,000,000	3,822,000,000	3,494,000,000
Intermodal [Member]
Commodity Group Information [Line Items]
Freight revenues									$ 4,489,000,000	$ 4,030,000,000	$ 3,955,000,000