Summary of Significant Accounting Policies (Details) $ in Millions	12 Months Ended
	Dec. 31, 2022 USD ($) mi depreciableAssetClass	Dec. 31, 2021 USD ($)
Property, Plant and Equipment [Line Items]
Operating route miles \| mi	19,100
Employees covered by collective bargaining agreements	80.00%
Allowance for doubtful accounts \| $	$ 9	$ 8
Approximate number of depreciable asset classes used \| depreciableAssetClass	75
Equipment
Property, Plant and Equipment [Line Items]
Depreciation studies, period	3 years
Roadway
Property, Plant and Equipment [Line Items]
Depreciation studies, period	6 years
Intermodal
Property, Plant and Equipment [Line Items]
Market groups percent of total railway operating revenues	29.00%
Agriculture, Forest And Consumer Products
Property, Plant and Equipment [Line Items]
Market groups percent of total railway operating revenues	19.00%
Chemicals
Property, Plant and Equipment [Line Items]
Market groups percent of total railway operating revenues	17.00%
Metals and construction
Property, Plant and Equipment [Line Items]
Market groups percent of total railway operating revenues	13.00%
Coal
Property, Plant and Equipment [Line Items]
Market groups percent of total railway operating revenues	14.00%
Automotive
Property, Plant and Equipment [Line Items]
Market groups percent of total railway operating revenues	8.00%