Revenues - Schedule of Revenues Disaggregated by Lines of Business (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Disaggregation of Revenue [Line Items]
Revenue	$ 3,482	$ 3,423
Total Merchandise
Disaggregation of Revenue [Line Items]
Revenue	2,188	2,152
Chemicals
Disaggregation of Revenue [Line Items]
Revenue	722	698
Agricultural and Food Products
Disaggregation of Revenue [Line Items]
Revenue	409	408
Automotive
Disaggregation of Revenue [Line Items]
Revenue	275	271
Forest Products
Disaggregation of Revenue [Line Items]
Revenue	229	249
Metals and Equipment
Disaggregation of Revenue [Line Items]
Revenue	220	209
Minerals
Disaggregation of Revenue [Line Items]
Revenue	192	181
Fertilizers
Disaggregation of Revenue [Line Items]
Revenue	141	136
Intermodal
Disaggregation of Revenue [Line Items]
Revenue	518	493
Coal
Disaggregation of Revenue [Line Items]
Revenue	458	461
Trucking
Disaggregation of Revenue [Line Items]
Revenue	202	202
Other
Disaggregation of Revenue [Line Items]
Revenue	$ 116	$ 115