Summarized Consolidating Income Statements (Details) (USD $)
In Millions, unless otherwise specified
 3 Months Ended 6 Months Ended
Jun. 29, 2012
Jul. 01, 2011
Jun. 29, 2012
Jul. 01, 2011
Consolidated Income Statement        
Revenue $ 3,012 $ 3,019 $ 5,978 $ 5,829
Expense 2,069 2,093 4,179 4,130
Operating Income 943 926 1,799 1,699
Equity in Earnings of Subsidiaries 0 0 0 0
Interest (Expense) / Benefit (139) (134) (283) (274)
Other Income - Net 5 0 9 5
Earnings Before Income Taxes 809 792 1,525 1,430
Income Tax (Expense) / Benefit (297) (286) (564) (529)
Net Earnings 512 506 961 901
Total Comprehensive Earnings 529 519 987 925
CSX Corporation
        
Consolidated Income Statement        
Revenue 0 0 0 0
Expense (89) (68) (176) (133)
Operating Income 89 68 176 133
Equity in Earnings of Subsidiaries 557 540 1,034 972
Interest (Expense) / Benefit (125) (121) (255) (247)
Other Income - Net (1) 1 (2) 3
Earnings Before Income Taxes 520 488 953 861
Income Tax (Expense) / Benefit (8) 18 8 40
Net Earnings 512 506 961 901
Total Comprehensive Earnings 529 519 987 925
CSX Transportation
        
Consolidated Income Statement        
Revenue 2,995 3,003 5,945 5,797
Expense 2,192 2,222 4,421 4,364
Operating Income 803 781 1,524 1,433
Equity in Earnings of Subsidiaries 0 2 (1) 3
Interest (Expense) / Benefit (17) (22) (36) (45)
Other Income - Net 1 0 4 2
Earnings Before Income Taxes 787 761 1,491 1,393
Income Tax (Expense) / Benefit (270) (275) (533) (516)
Net Earnings 517 486 958 877
Total Comprehensive Earnings 518 485 956 877
Eliminations and Other
        
Consolidated Income Statement        
Revenue 17 16 33 32
Expense (34) (61) (66) (101)
Operating Income 51 77 99 133
Equity in Earnings of Subsidiaries (557) (542) (1,033) (975)
Interest (Expense) / Benefit 3 9 8 18
Other Income - Net 5 (1) 7 0
Earnings Before Income Taxes (498) (457) (919) (824)
Income Tax (Expense) / Benefit (19) (29) (39) (53)
Net Earnings (517) (486) (958) (877)
Total Comprehensive Earnings $ (518) $ (485) $ (956) $ (877)