Revenue from Contracts with Customers Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Disaggregation of Revenue [Line Items]
Revenues	$ 5,176	$ 6,021	$ 15,195	$ 17,676
Total freight revenues	4,912	5,723	14,396	16,763
Total other revenues	264	298	799	913
Consumer Products
Disaggregation of Revenue [Line Items]
Revenues	1,885	1,973	5,221	5,878
Industrial Products
Disaggregation of Revenue [Line Items]
Revenues	1,190	1,588	3,815	4,637
Agricultural Products
Disaggregation of Revenue [Line Items]
Revenues	1,186	1,166	3,402	3,500
Coal
Disaggregation of Revenue [Line Items]
Revenues	651	996	1,958	2,748
Non-rail logistics subsidiary
Disaggregation of Revenue [Line Items]
Revenues	175	199	497	595
Accessorial and other
Disaggregation of Revenue [Line Items]
Revenues	$ 89	$ 99	$ 302	$ 318