Summarized Consolidating Income Statements (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 29, 2013	Mar. 30, 2012
Consolidated Income Statement
Revenue	$ 2,958	$ 2,966
Expense	2,083	2,110
Operating Income	875	856
Equity in Earnings of Subsidiaries	0	0
Interest (Expense) / Benefit	(147)	(144)
Other Income / (Expense) - Net	(3)	4
Earnings Before Income Taxes	725	716
Income Tax (Expense) / Benefit	(266)	(267)
Net Earnings	459	449
Total Comprehensive Earnings	476	458
CSX Corporation [Member]
Consolidated Income Statement
Revenue	0	0
Expense	(93)	(87)
Operating Income	93	87
Equity in Earnings of Subsidiaries	486	477
Interest (Expense) / Benefit	(134)	(130)
Other Income / (Expense) - Net	(1)	(1)
Earnings Before Income Taxes	444	433
Income Tax (Expense) / Benefit	15	16
Net Earnings	459	449
Total Comprehensive Earnings	476	458
CSX Transportation [Member]
Consolidated Income Statement
Revenue	2,941	2,950
Expense	2,217	2,229
Operating Income	724	721
Equity in Earnings of Subsidiaries	(1)	(1)
Interest (Expense) / Benefit	(17)	(19)
Other Income / (Expense) - Net	2	3
Earnings Before Income Taxes	708	704
Income Tax (Expense) / Benefit	(262)	(263)
Net Earnings	446	441
Total Comprehensive Earnings	446	438
Eliminations and Other [Member]
Consolidated Income Statement
Revenue	17	16
Expense	(41)	(32)
Operating Income	58	48
Equity in Earnings of Subsidiaries	(485)	(476)
Interest (Expense) / Benefit	4	5
Other Income / (Expense) - Net	(4)	2
Earnings Before Income Taxes	(427)	(421)
Income Tax (Expense) / Benefit	(19)	(20)
Net Earnings	(446)	(441)
Total Comprehensive Earnings	$ (446)	$ (438)