Revenues - Schedule of Revenues Disaggregated by Lines of Business (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Disaggregation of Revenue [Line Items]
Revenue	$ 3,574	$ 3,701	$ 6,997	$ 7,382
Total Merchandise
Disaggregation of Revenue [Line Items]
Revenue	2,257	2,296	4,409	4,481
Chemicals
Disaggregation of Revenue [Line Items]
Revenue	701	722	1,399	1,415
Agricultural and Food Products
Disaggregation of Revenue [Line Items]
Revenue	418	406	826	813
Automotive
Disaggregation of Revenue [Line Items]
Revenue	320	336	591	629
Forest Products
Disaggregation of Revenue [Line Items]
Revenue	250	269	499	531
Metals and Equipment
Disaggregation of Revenue [Line Items]
Revenue	224	230	433	450
Minerals
Disaggregation of Revenue [Line Items]
Revenue	218	207	399	381
Fertilizers
Disaggregation of Revenue [Line Items]
Revenue	126	126	262	262
Intermodal
Disaggregation of Revenue [Line Items]
Revenue	491	506	984	1,012
Coal
Disaggregation of Revenue [Line Items]
Revenue	477	563	938	1,195
Trucking
Disaggregation of Revenue [Line Items]
Revenue	211	221	413	436
Other
Disaggregation of Revenue [Line Items]
Revenue	$ 138	$ 115	$ 253	$ 258