Railway Operating Revenues (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	$ 2,506,000,000	$ 2,841,000,000	$ 7,216,000,000	$ 8,606,000,000
Revenue, payment terms			15 days
Contract assets	0		$ 0		$ 0
Contract liabilities	$ 0		$ 0		$ 0
Accessorial Services
Disaggregation of Revenue [Line Items]
Accessorial services percent of total railway operating revenues	5.00%	5.00%	5.00%	5.00%
Merchandise
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	$ 1,556,000,000	$ 1,731,000,000	$ 4,535,000,000	$ 5,173,000,000
Merchandise | Agriculture, forest and consumer products
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	521,000,000	572,000,000	1,570,000,000	1,707,000,000
Merchandise | Chemicals
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	428,000,000	535,000,000	1,371,000,000	1,586,000,000
Merchandise | Metals and construction
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	337,000,000	377,000,000	997,000,000	1,131,000,000
Merchandise | Automotive
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	270,000,000	247,000,000	597,000,000	749,000,000
Intermodal
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	700,000,000	707,000,000	1,924,000,000	2,127,000,000
Coal
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	$ 250,000,000	$ 403,000,000	$ 757,000,000	$ 1,306,000,000