Property and Equipment, Net (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Property, Plant and Equipment [Line Items]
Property and Equipment, Gross	$ 94,699	$ 91,672
Less accumulated depreciation and amortization	(22,327)	(20,411)
Property and equipment, net	72,372	71,261
Right-of-use fixed assets	1,300	1,300
Finance Lease, Right-of-Use Asset, Accumulated Amortization	503	475
Interest costs capitalized	37	37	$ 39
Land for transportation purposes
Property, Plant and Equipment [Line Items]
Property and Equipment, Gross	7,165	7,108
Track structure
Property, Plant and Equipment [Line Items]
Property and Equipment, Gross	33,823	32,047
Other Roadway
Property, Plant and Equipment [Line Items]
Property and Equipment, Gross	35,776	34,938
Locomotives
Property, Plant and Equipment [Line Items]
Property and Equipment, Gross	9,938	9,995
Freight cars and other equipment
Property, Plant and Equipment [Line Items]
Property and Equipment, Gross	4,044	3,983
Computer hardware, software and other
Property, Plant and Equipment [Line Items]
Property and Equipment, Gross	1,790	1,788
Construction in progress
Property, Plant and Equipment [Line Items]
Property and Equipment, Gross	$ 2,163	$ 1,813
Minimum | Track structure
Property, Plant and Equipment [Line Items]
Useful life	18 years
Minimum | Other Roadway
Property, Plant and Equipment [Line Items]
Useful life	10 years
Minimum | Locomotives
Property, Plant and Equipment [Line Items]
Useful life	8 years
Minimum | Freight cars and other equipment
Property, Plant and Equipment [Line Items]
Useful life	8 years
Minimum | Computer hardware, software and other
Property, Plant and Equipment [Line Items]
Useful life	6 years
Maximum | Track structure
Property, Plant and Equipment [Line Items]
Useful life	55 years
Maximum | Other Roadway
Property, Plant and Equipment [Line Items]
Useful life	100 years
Maximum | Locomotives
Property, Plant and Equipment [Line Items]
Useful life	38 years
Maximum | Freight cars and other equipment
Property, Plant and Equipment [Line Items]
Useful life	45 years
Maximum | Computer hardware, software and other
Property, Plant and Equipment [Line Items]
Useful life	15 years