Note 11 - Properties - Schedule of Property and Equipment Major Categories (Details) - USD ($) $ in Millions		Sep. 30, 2024		Dec. 31, 2023
Property, Plant and Equipment, Cost		$ 83,269		$ 81,733
Property, Plant and Equipment, Net		58,036		57,398
Property, Plant and Equipment, Accumulated Depreciation		25,233		24,335
Land [Member]
Property, Plant and Equipment, Cost		5,439		5,426
Property, Plant and Equipment, Net		5,439		5,426
Roadrail and Other Track Material [Member]
Property, Plant and Equipment, Cost		19,180		18,837
Property, Plant and Equipment, Net		11,611		11,493
Property, Plant and Equipment, Accumulated Depreciation		$ 7,569		$ 7,344
Property, Plant and Equipment, Useful Life (Year)		46 years		42 years
Road Ties [Member]
Property, Plant and Equipment, Cost		$ 12,268		$ 11,985
Property, Plant and Equipment, Net		8,215		8,090
Property, Plant and Equipment, Accumulated Depreciation		$ 4,053		$ 3,895
Property, Plant and Equipment, Useful Life (Year)		34 years		34 years
Road Ballast [Member]
Property, Plant and Equipment, Cost		$ 6,457		$ 6,345
Property, Plant and Equipment, Net		4,309		4,284
Property, Plant and Equipment, Accumulated Depreciation		$ 2,148		$ 2,061
Property, Plant and Equipment, Useful Life (Year)		34 years		34 years
Road, Other [Member]
Property, Plant and Equipment, Cost	[1]	$ 23,697		$ 23,175
Property, Plant and Equipment, Net		18,096	[1]	17,807
Property, Plant and Equipment, Accumulated Depreciation		$ 5,601	[1]	$ 5,368
Property, Plant and Equipment, Useful Life (Year)		47 years	[1]	47 years
Road [Member]
Property, Plant and Equipment, Cost		$ 61,602		$ 60,342
Property, Plant and Equipment, Net		42,231		41,674
Property, Plant and Equipment, Accumulated Depreciation		19,371		18,668
Equipment, Locomotives [Member]
Property, Plant and Equipment, Cost		9,561		9,295
Property, Plant and Equipment, Net		5,811		5,704
Property, Plant and Equipment, Accumulated Depreciation		$ 3,750		$ 3,591
Property, Plant and Equipment, Useful Life (Year)		18 years		18 years
Equipment, Freight Cars [Member]
Property, Plant and Equipment, Cost		$ 2,964		$ 2,765
Property, Plant and Equipment, Net		1,940		1,809
Property, Plant and Equipment, Accumulated Depreciation		$ 1,024		$ 956
Property, Plant and Equipment, Useful Life (Year)		23 years		23 years
Equipment, Work Equipment and Other [Member]
Property, Plant and Equipment, Cost		$ 1,191	[2]	$ 1,344
Property, Plant and Equipment, Net		719	[2]	798
Property, Plant and Equipment, Accumulated Depreciation		$ 472	[2]	$ 546
Property, Plant and Equipment, Useful Life (Year)		17 years	[2]	17 years
Equipment [Member]
Property, Plant and Equipment, Cost		$ 13,716		$ 13,404
Property, Plant and Equipment, Net		8,470		8,311
Property, Plant and Equipment, Accumulated Depreciation		5,246		5,093
Technology Equipment [Member]
Property, Plant and Equipment, Cost		1,423		1,388
Property, Plant and Equipment, Net		807		814
Property, Plant and Equipment, Accumulated Depreciation		$ 616		$ 574
Property, Plant and Equipment, Useful Life (Year)		12 years		12 years
Construction in Progress [Member]
Property, Plant and Equipment, Cost		$ 1,089		$ 1,173
Property, Plant and Equipment, Net		1,089		1,173
Property, Plant and Equipment, Accumulated Depreciation		$ 0		$ 0

[1] Other roadway includes grading, bridges and tunnels, signals, buildings, and other road assets.

[2] For retirements of depreciable railroad properties that do not occur in the normal course of business, a gain or loss may be recognized if the retirement meets each of the following three conditions: (a) is unusual, (b) is material in amount, and (c) varies significantly from the retirement profile identified through our depreciation studies. In the second quarter of 2024, we sold a large portion of an intermodal equipment asset class resulting in a $46 million gain recognized in other expense in our Condensed Consolidated Statements of Income.