Revenues - Revenues Disaggregated by Lines of Business (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Disaggregation of Revenue [Line Items]
Revenue	$ 3,572	$ 3,895	$ 10,977	$ 11,123
Total Merchandise
Disaggregation of Revenue [Line Items]
Revenue	2,112	2,143	6,471	6,165
Chemicals
Disaggregation of Revenue [Line Items]
Revenue	646	678	1,938	1,962
Agricultural and Food Products
Disaggregation of Revenue [Line Items]
Revenue	376	428	1,228	1,227
Automotive
Disaggregation of Revenue [Line Items]
Revenue	308	274	905	769
Forest Products
Disaggregation of Revenue [Line Items]
Revenue	243	264	761	743
Metals and Equipment
Disaggregation of Revenue [Line Items]
Revenue	225	211	704	624
Minerals
Disaggregation of Revenue [Line Items]
Revenue	190	180	554	494
Fertilizers
Disaggregation of Revenue [Line Items]
Revenue	124	108	381	346
Coal
Disaggregation of Revenue [Line Items]
Revenue	594	624	1,864	1,808
Intermodal
Disaggregation of Revenue [Line Items]
Revenue	517	604	1,508	1,733
Trucking
Disaggregation of Revenue [Line Items]
Revenue	218	251	678	740
Other
Disaggregation of Revenue [Line Items]
Revenue	$ 131	$ 273	$ 456	$ 677