Revenues - Schedule of Revenues Disaggregated by Lines of Business (Details) - USD ($) $ in Millions	3 Months Ended			6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023		Jun. 30, 2024		Jun. 30, 2023
Disaggregation of Revenue [Line Items]
Revenue	$ 3,701	$ 3,699	[1]	$ 7,382	[1]	$ 7,405	[1]
Total Merchandise
Disaggregation of Revenue [Line Items]
Revenue	2,296	2,196		4,481		4,359
Chemicals
Disaggregation of Revenue [Line Items]
Revenue	722	642		1,415		1,292
Agricultural and Food Products
Disaggregation of Revenue [Line Items]
Revenue	406	415		813		852
Automotive
Disaggregation of Revenue [Line Items]
Revenue	336	323		629		597
Forest Products
Disaggregation of Revenue [Line Items]
Revenue	269	257		531		518
Metals and Equipment
Disaggregation of Revenue [Line Items]
Revenue	230	240		450		479
Minerals
Disaggregation of Revenue [Line Items]
Revenue	207	191		381		364
Fertilizers
Disaggregation of Revenue [Line Items]
Revenue	126	128		262		257
Coal
Disaggregation of Revenue [Line Items]
Revenue	563	637		1,195		1,270
Intermodal
Disaggregation of Revenue [Line Items]
Revenue	506	492		1,012		991
Trucking
Disaggregation of Revenue [Line Items]
Revenue	221	227		436		460
Other
Disaggregation of Revenue [Line Items]
Revenue	$ 115	$ 147		$ 258		$ 325

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