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Note 11 - Properties (Details Textual) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2020 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Number of Depreciable Asset Classes		60
Cost of Property Repairs and Maintenance		$ 2,100	$ 2,000	$ 2,300
Brazos Yard [Member] | Other Expense [Member]
Asset Impairment Charges, Total	$ 278
Railroad Transportation Equipment [Member]
Term of Depreciation Studies (Year)		3 years
Railroad Transportation Track Assets [Member]
Term of Depreciation Studies (Year)		6 years

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- Definition

Information on the number of depreciable asset classes.

+ References

No definition available.

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- Definition

Information on the term of depreciation studies to determine the estimated service lives of depreciable assets.

+ References

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- Definition

Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3602-108585

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 45
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=123351718&loc=d3e2420-110228

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- Definition

The aggregate costs of keeping the property in good condition but that do not appreciably prolong the life or increase the value of the property.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.2)
-URI http://asc.fasb.org/extlink&oid=123367319&loc=SL114868664-224227

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