Nature of Operations and Significant Accounting Policies - Narrative (Details) mi in Thousands, $ in Millions	Sep. 23, 2016 USD ($) state mi	Dec. 25, 2015 USD ($)
Background
Total number of rail route miles | mi	21
Number of states rail network serves | state	23
Allowance for Doubtful Accounts
Allowance for doubtful accounts	$ 29	$ 37
New Accounting Pronouncement, Early Adoption, Effect
Allowance for Doubtful Accounts
Deferred tax assets net, current		(126)
Deferred tax liabilities, net, current	$ 132	$ 126