Revenues - Revenues Disaggregated by Lines of Business (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Disaggregation of Revenue [Line Items]
Revenue	$ 3,699	$ 3,815	$ 7,405	$ 7,228
Total Merchandise
Disaggregation of Revenue [Line Items]
Revenue	2,196	2,101	4,359	4,022
Chemicals
Disaggregation of Revenue [Line Items]
Revenue	642	666	1,292	1,284
Agricultural and Food Products
Disaggregation of Revenue [Line Items]
Revenue	415	412	852	799
Automotive
Disaggregation of Revenue [Line Items]
Revenue	323	268	597	495
Forest Products
Disaggregation of Revenue [Line Items]
Revenue	257	251	518	479
Metals and Equipment
Disaggregation of Revenue [Line Items]
Revenue	240	216	479	413
Minerals
Disaggregation of Revenue [Line Items]
Revenue	191	170	364	314
Fertilizers
Disaggregation of Revenue [Line Items]
Revenue	128	118	257	238
Coal
Disaggregation of Revenue [Line Items]
Revenue	637	651	1,270	1,184
Intermodal
Disaggregation of Revenue [Line Items]
Revenue	492	602	991	1,129
Trucking
Disaggregation of Revenue [Line Items]
Revenue	227	259	460	489
Other
Disaggregation of Revenue [Line Items]
Revenue	$ 147	$ 202	$ 325	$ 404