Revenues - Revenues Disaggregated by Lines of Business (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Disaggregation of Revenue [Line Items]
Revenue	$ 3,681	$ 3,706
Total Merchandise
Disaggregation of Revenue [Line Items]
Revenue	2,185	2,163
Chemicals
Disaggregation of Revenue [Line Items]
Revenue	693	650
Agricultural and Food Products
Disaggregation of Revenue [Line Items]
Revenue	407	437
Automotive
Disaggregation of Revenue [Line Items]
Revenue	293	274
Forest Products
Disaggregation of Revenue [Line Items]
Revenue	262	261
Metals and Equipment
Disaggregation of Revenue [Line Items]
Revenue	220	239
Minerals
Disaggregation of Revenue [Line Items]
Revenue	174	173
Fertilizers
Disaggregation of Revenue [Line Items]
Revenue	136	129
Coal
Disaggregation of Revenue [Line Items]
Revenue	632	633
Intermodal
Disaggregation of Revenue [Line Items]
Revenue	506	499
Trucking
Disaggregation of Revenue [Line Items]
Revenue	215	233
Other
Disaggregation of Revenue [Line Items]
Revenue	$ 143	$ 178