Revenues - Schedule of Revenues Disaggregated by Lines of Business (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023		Sep. 30, 2024		Sep. 30, 2023
Disaggregation of Revenue [Line Items]
Revenue	$ 3,619	$ 3,572	[1]	$ 11,001	[1]	$ 10,977	[1]
Total Merchandise
Disaggregation of Revenue [Line Items]
Revenue	2,231	2,112		6,712		6,471
Chemicals
Disaggregation of Revenue [Line Items]
Revenue	727	646		2,142		1,938
Agricultural and Food Products
Disaggregation of Revenue [Line Items]
Revenue	416	376		1,229		1,228
Automotive
Disaggregation of Revenue [Line Items]
Revenue	301	308		930		905
Forest Products
Disaggregation of Revenue [Line Items]
Revenue	259	243		790		761
Metals and Equipment
Disaggregation of Revenue [Line Items]
Revenue	208	225		658		704
Minerals
Disaggregation of Revenue [Line Items]
Revenue	202	190		583		554
Fertilizers
Disaggregation of Revenue [Line Items]
Revenue	118	124		380		381
Coal
Disaggregation of Revenue [Line Items]
Revenue	553	594		1,748		1,864
Intermodal
Disaggregation of Revenue [Line Items]
Revenue	509	517		1,521		1,508
Trucking
Disaggregation of Revenue [Line Items]
Revenue	214	218		650		678
Other
Disaggregation of Revenue [Line Items]
Revenue	$ 112	$ 131		$ 370		$ 456

[1] See Note 11, Revision of Prior Period Financial Statements.