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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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Related Party Transactions - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 30, 2016	Dec. 25, 2015	Dec. 26, 2014
Related Party Transaction [Line Items]
Short term payable to related party	$ 0	$ 0
Corporate Joint Venture
Related Party Transaction [Line Items]
Difference between carrying amount and underlying equity	351
Interest expense	$ 6	6	$ 3
TTX Company
Related Party Transaction [Line Items]
Percentage economic interest in related party	20.00%
Equity method investments	$ 469
Accounts Payable \| Corporate Joint Venture
Related Party Transaction [Line Items]
Short term payable to related party	91	65
Accounts Payable \| TTX Company
Related Party Transaction [Line Items]
Short term payable to related party	47	40
Long-term Debt \| 2.89% CSXT promissory note due October 2044 \| Corporate Joint Venture
Related Party Transaction [Line Items]
Promissory note payable	$ 151	$ 151
Related party note, interest rate	2.89%
Voting interest in related party which is also an equity method investment \| Corporate Joint Venture
Related Party Transaction [Line Items]
Percentage economic interest in related party	50.00%
Economic interest in related party which is also an equity method investment \| Corporate Joint Venture
Related Party Transaction [Line Items]
Percentage economic interest in related party	42.00%