Commitments And Contingencies (Narrative) (Details) $ in Millions	12 Months Ended
Dec. 31, 2020 USD ($) site	Dec. 31, 2019 USD ($)
Commitments and Contingencies [Line Items]
Sites identified which we are or may be liable for remediation costs \| site	373
Sites subject of actions taken by the U.S. government \| site	29
Sites on the Superfund National Priorities List \| site	18
Personal Injury [Member]
Commitments and Contingencies [Line Items]
Percent of liability recorded related to asserted claims	94.00%
Percent of liability recorded related to unasserted claims	6.00%
Personal Injury [Member] \| Minimum [Member]
Commitments and Contingencies [Line Items]
Reasonably possible outcome of related claims	$ 270
Personal Injury [Member] \| Maximum [Member]
Commitments and Contingencies [Line Items]
Reasonably possible outcome of related claims	295
Guarantees [Member]
Commitments and Contingencies [Line Items]
Maximum potential amount of guarantee payments	10	$ 15
Recorded liability for fair value of guarantees	$ 0	$ 0
Expiration year of final guarantee	The final guarantee expires in 2022.

Percentage of the recorded liability related to asserted claims.

No definition available.

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- Definition

Percentage of the recorded liability related to unasserted claims.

+ References

No definition available.

+ Details

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- Definition

Sites identified at which Railroad is or may be liable for remediation costs associated with alleged contamination or for violations of environmental requirements.

+ References

No definition available.

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- Definition

Sites on the Superfund National Priorities List.

+ References

No definition available.

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- Definition

Sites subject of actions taken by the U.S. government.

+ References

No definition available.

+ Details

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- Definition

The current carrying amount of the liability for the freestanding or embedded guarantor's obligations under the guarantee or each group of similar guarantees.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=121555522&loc=d3e12069-110248

+ Details

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- Definition

Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries under recourse or collateralization provisions.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=121555522&loc=d3e12069-110248

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- Definition

Describe the approximate term of the guarantee or each group of similar guarantees.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=121555522&loc=d3e12069-110248

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- Definition

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.

+ References

No definition available.

+ Details

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- Definition

Reflects the estimated amount of loss from the specified contingency as of the balance sheet date.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121557415&loc=d3e14435-108349

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 9
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-URI http://asc.fasb.org/extlink&oid=121557415&loc=d3e14557-108349

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=121555522&loc=d3e12021-110248

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