Revenues - Revenues Disaggregated by Lines of Business (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Disaggregation of Revenue [Line Items]
Revenue	$ 3,815	$ 2,990	$ 7,228	$ 5,803
Total Merchandise
Disaggregation of Revenue [Line Items]
Revenue	2,101	1,903	4,022	3,721
Chemicals
Disaggregation of Revenue [Line Items]
Revenue	666	606	1,284	1,186
Agricultural and Food Products
Disaggregation of Revenue [Line Items]
Revenue	412	370	799	719
Automotive
Disaggregation of Revenue [Line Items]
Revenue	268	216	495	452
Forest Products
Disaggregation of Revenue [Line Items]
Revenue	251	233	479	453
Metals and Equipment
Disaggregation of Revenue [Line Items]
Revenue	216	204	413	390
Minerals
Disaggregation of Revenue [Line Items]
Revenue	170	152	314	277
Fertilizers
Disaggregation of Revenue [Line Items]
Revenue	118	122	238	244
Intermodal
Disaggregation of Revenue [Line Items]
Revenue	602	511	1,129	979
Coal
Disaggregation of Revenue [Line Items]
Revenue	651	423	1,184	807
Trucking
Disaggregation of Revenue [Line Items]
Revenue	259	0	489	0
Other
Disaggregation of Revenue [Line Items]
Revenue	$ 202	$ 153	$ 404	$ 296