Railway Operating Revenues - Schedule of Account Receivables (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accounts receivable – net	$ 1,039	$ 1,009
Trade Accounts Receivable
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accounts receivable – net	767	740
Other Receivables
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accounts receivable – net	272	269
Other Noncurrent Receivables
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accounts receivable, net, noncurrent	$ 55	$ 55