Railway Operating Revenues (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	$ 2,085,000,000	$ 2,925,000,000	$ 4,710,000,000	$ 5,765,000,000
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%	4.00%	5.00%	4.00%
Merchandise
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	$ 1,307,000,000	$ 1,756,000,000	$ 2,979,000,000	$ 3,442,000,000
Merchandise | Agriculture, forest and consumer products
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	498,000,000	577,000,000	1,049,000,000	1,135,000,000
Merchandise | Chemicals
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	423,000,000	544,000,000	943,000,000	1,051,000,000
Merchandise | Metals and construction
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	293,000,000	384,000,000	660,000,000	754,000,000
Merchandise | Automotive
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	93,000,000	251,000,000	327,000,000	502,000,000
Intermodal
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	569,000,000	701,000,000	1,224,000,000	1,420,000,000
Coal
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	$ 209,000,000	$ 468,000,000	$ 507,000,000	$ 903,000,000