Revenues - Schedule of Revenues Disaggregated by Lines of Business (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Disaggregation of Revenue [Line Items]
Revenues	$ 2,876	$ 2,869
Total Merchandise
Disaggregation of Revenue [Line Items]
Revenues	1,779	1,839
Chemicals
Disaggregation of Revenue [Line Items]
Revenues	557	566
Agricultural and Food Products
Disaggregation of Revenue [Line Items]
Revenues	307	332
Automotive
Disaggregation of Revenue [Line Items]
Revenues	304	316
Forest Products
Disaggregation of Revenue [Line Items]
Revenues	195	192
Metals and Equipment
Disaggregation of Revenue [Line Items]
Revenues	186	190
Fertilizers
Disaggregation of Revenue [Line Items]
Revenues	116	129
Minerals
Disaggregation of Revenue [Line Items]
Revenues	114	114
Total Coal
Disaggregation of Revenue [Line Items]
Revenues	503	522
Domestic Coal
Disaggregation of Revenue [Line Items]
Revenues	272	330
Export Coal
Disaggregation of Revenue [Line Items]
Revenues	231	192
Total Intermodal
Disaggregation of Revenue [Line Items]
Revenues	449	434
Domestic Intermodal
Disaggregation of Revenue [Line Items]
Revenues	294	291
International Intermodal
Disaggregation of Revenue [Line Items]
Revenues	155	143
Other
Disaggregation of Revenue [Line Items]
Revenues	$ 145	$ 74