Amount of payable due to an entity that is affiliated with the reporting entity by means of direct or indirect ownership. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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Carrying amount as of the balance sheet date of obligations due all related parties. For classified balance sheets, represents the current portion of such liabilities (due within one year or within the normal operating cycle if longer).

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Difference between amount at which an investment accounted for under the equity method of accounting is carried (reported) on the balance sheet and amount of underlying equity in net assets the reporting Entity has in the investee.

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The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

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The amount for notes payable (written promise to pay), payable to related parties, which are due after one year (or one business cycle).

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Related Party Transactions (Narrative) (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Oct. 31, 2014	Dec. 25, 2015	Dec. 26, 2014	Dec. 27, 2013
Related Party Transaction [Line Items]
Short term payable to related party		$ 0	$ 0
Corporate Joint Venture [Member]
Related Party Transaction [Line Items]
Difference between carrying amount and underlying equity		353
Interest expense		$ 6	3	$ 4
TTX Company [Member]
Related Party Transaction [Line Items]
Percentage economic interest in related party		20.00%
Equity method investments		$ 443
Economic interest in related party which is also an equity method investment [Member] \| Corporate Joint Venture [Member]
Related Party Transaction [Line Items]
Percentage economic interest in related party		42.00%
Voting interest in related party which is also an equity method investment [Member] \| Corporate Joint Venture [Member]
Related Party Transaction [Line Items]
Percentage economic interest in related party		50.00%
CSXT Promissory Note Related Party October 2044 [Member]
Related Party Transaction [Line Items]
Accrued interest to related party	$ 3
Accounts Payable [Member] \| Corporate Joint Venture [Member]
Related Party Transaction [Line Items]
Short term payable to related party		$ 65	54
Accounts Payable [Member] \| TTX Company [Member]
Related Party Transaction [Line Items]
Short term payable to related party		40	35
Accounts Payable [Member] \| Related Party Accounts Payable Converted to a Note [Member] \| Corporate Joint Venture [Member]
Related Party Transaction [Line Items]
Short term payable to related party	125
Long-term Debt [Member] \| CSXT Promissory Note Related Party March 2035 [Member] \| Corporate Joint Venture [Member]
Related Party Transaction [Line Items]
Promissory note payable	$ 23
Related party note, interest rate	4.52%
Long-term Debt [Member] \| CSX Promissory Note Related Party October 2035 [Member] \| Corporate Joint Venture [Member]
Related Party Transaction [Line Items]
Promissory note payable	$ 73
Related party note, interest rate	4.40%
Long-term Debt [Member] \| CSXT Promissory Note Related Party October 2044 [Member] \| Corporate Joint Venture [Member]
Related Party Transaction [Line Items]
Promissory note payable		$ 151	$ 151
Related party note, interest rate	2.89%	2.89%
Long-term Debt [Member] \| Total Related Party Promissory Notes, October 2044 [Member] \| Corporate Joint Venture [Member]
Related Party Transaction [Line Items]
Promissory note payable	$ 224