Property and Equipment, Net (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Property and Equipment, Gross	$ 91,672	$ 89,663
Less accumulated depreciation and amortization	(20,411)	(19,464)
Property and equipment, net	71,261	70,199
Right-of-use fixed assets	1,300	1,200
Finance Lease, Right-of-Use Asset, Accumulated Amortization	475	449
Interest costs capitalized	37	39	$ 28
Land for transportation purposes
Property, Plant and Equipment [Line Items]
Property and Equipment, Gross	7,108	7,068
Track structure
Property, Plant and Equipment [Line Items]
Property and Equipment, Gross	32,047	30,366
Other roadway a
Property, Plant and Equipment [Line Items]
Property and Equipment, Gross	34,938	34,257
Locomotives
Property, Plant and Equipment [Line Items]
Property and Equipment, Gross	9,995	10,627
Freight cars and other equipment
Property, Plant and Equipment [Line Items]
Property and Equipment, Gross	3,983	3,927
Computer hardware, software and other
Property, Plant and Equipment [Line Items]
Property and Equipment, Gross	1,788	1,703
Construction in progress
Property, Plant and Equipment [Line Items]
Property and Equipment, Gross	$ 1,813	$ 1,715
Minimum | Track structure
Property, Plant and Equipment [Line Items]
Useful life	15 years
Minimum | Other roadway a
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 a
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