Debt and Credit Agreements - Debt Issuance & Early Redemption of Long-term Debt (Details) (USD $)	1 Months Ended	9 Months Ended
	Jul. 31, 2014	Sep. 26, 2014	Sep. 27, 2013
Debt Instrument [Line Items]
Long-term Debt Issued		$ 1,000,000,000	$ 0
Early redemption premium	16,000,000
Early redemption of debt	663,000,000
Notes Payable [Member]
Debt Instrument [Line Items]
Long-term Debt Issued		1,000,000,000
Notes Payable [Member] | Redeemable Notes Due 2024 [Member]
Debt Instrument [Line Items]
Debt instrument face amount	550,000,000
Debt instrument stated rate (percentage)	3.40%
Notes Payable [Member] | Redeemable Notes Due 2054 [Member]
Debt Instrument [Line Items]
Debt instrument face amount	450,000,000
Debt instrument stated rate (percentage)	4.50%
Notes Payable [Member] | Secured Equipment Notes Due October 15, 2014 [Member]
Debt Instrument [Line Items]
Debt instrument face amount	263,000,000
Debt instrument stated rate (percentage)	8.375%
Notes Payable [Member] | CSX's Notes Payable Maturing April 1, 2015 [Member]
Debt Instrument [Line Items]
Debt instrument face amount	400,000,000
Debt instrument stated rate (percentage)	6.25%
Current Portion | Notes Payable [Member]
Debt Instrument [Line Items]
Long-term Debt Issued		0
Long-term Portion | Notes Payable [Member]
Debt Instrument [Line Items]
Long-term Debt Issued		$ 1,000,000,000