Summarized Consolidating Balance Sheet (Details) (USD $) In Millions, unless otherwise specified	Jun. 27, 2014	Dec. 27, 2013	Jun. 28, 2013	Dec. 28, 2012
Current Assets:
Cash and Cash Equivalents	$ 573	$ 592	$ 614	$ 784
Short-term Investments	216	487
Accounts Receivable - Net	1,062	1,052
Receivable from Affiliates	0	0
Materials and Supplies	275	252
Deferred Income Taxes	123	155
Other Current Assets	123	64
Total Current Assets	2,372	2,602
Properties	38,010	37,184
Accumulated Depreciation	(10,325)	(9,893)
Properties - Net	27,685	27,291
Other Long-term Assets	587	591
Total Assets	31,975	31,782
Current Liabilities:
Accounts Payable	900	957
Labor and Fringe Benefits Payable	490	587
Payable to Affiliates	0	0
Casualty, Environmental and Other Reserves	151	151
Current Maturities of Long-term Debt	899	533
Income and Other Taxes Payable	229	91
Other Current Liabilities	128	105
Total Current Liabilities	2,797	2,424
Casualty, Environmental and Other Reserves	289	300
Long-term Debt	8,410	9,022
Deferred Income Taxes	8,728	8,662
Other Long-term Liabilities	847	870
Total Liabilities	21,071	21,278
Shareholders' Equity
Common Stock $1 Par Value	1,000	1,009
Other Capital	70	61
Retained Earnings	10,304	9,936
Accumulated Other Comprehensive Loss	(492)	(523)
Noncontrolling Interest	22	21
Total Shareholders' Equity	10,904	10,504
Total Liabilities and Shareholders' Equity	31,975	31,782
Casualty, Environmental and Other [Member]
Current Liabilities:
Casualty, Environmental and Other Reserves	151	151
Casualty, Environmental and Other Reserves	289	300
Investments in Conrail
Current Assets:
Investment in Affiliates, Subsidiaries, and Joint Ventures	768	752
Affiliates and Other Companies
Current Assets:
Investment in Affiliates, Subsidiaries, and Joint Ventures	563	546
Investments in Consolidated Subsidiaries
Current Assets:
Investment in Affiliates, Subsidiaries, and Joint Ventures	0	0
CSX Corporation
Current Assets:
Cash and Cash Equivalents	407	439	441	481
Short-term Investments	195	472
Accounts Receivable - Net	5	3
Receivable from Affiliates	1,160	1,141
Materials and Supplies	0	0
Deferred Income Taxes	(8)	(5)
Other Current Assets	24	1
Total Current Assets	1,783	2,051
Properties	1	1
Accumulated Depreciation	(1)	(1)
Properties - Net	0	0
Other Long-term Assets	214	217
Total Assets	22,872	22,455
Current Liabilities:
Accounts Payable	102	110
Labor and Fringe Benefits Payable	34	38
Payable to Affiliates	3,317	3,298
Current Maturities of Long-term Debt	600	200
Income and Other Taxes Payable	(178)	(397)
Other Current Liabilities	0	0
Total Current Liabilities	3,875	3,249
Long-term Debt	7,709	8,308
Deferred Income Taxes	(66)	(64)
Other Long-term Liabilities	472	479
Total Liabilities	11,990	11,972
Shareholders' Equity
Common Stock $1 Par Value	1,000	1,009
Other Capital	70	61
Retained Earnings	10,304	9,936
Accumulated Other Comprehensive Loss	(492)	(523)
Noncontrolling Interest	0	0
Total Shareholders' Equity	10,882	10,483
Total Liabilities and Shareholders' Equity	22,872	22,455
CSX Corporation | Casualty, Environmental and Other [Member]
Current Liabilities:
Casualty, Environmental and Other Reserves	0	0
Casualty, Environmental and Other Reserves	0	0
CSX Corporation | Investments in Conrail
Current Assets:
Investment in Affiliates, Subsidiaries, and Joint Ventures	0	0
CSX Corporation | Affiliates and Other Companies
Current Assets:
Investment in Affiliates, Subsidiaries, and Joint Ventures	(39)	(39)
CSX Corporation | Investments in Consolidated Subsidiaries
Current Assets:
Investment in Affiliates, Subsidiaries, and Joint Ventures	20,914	20,226
CSX Transportation
Current Assets:
Cash and Cash Equivalents	103	91	115	235
Short-term Investments	0	0
Accounts Receivable - Net	168	240
Receivable from Affiliates	2,633	2,635
Materials and Supplies	275	252
Deferred Income Taxes	132	161
Other Current Assets	88	57
Total Current Assets	3,399	3,436
Properties	35,724	34,987
Accumulated Depreciation	(9,148)	(8,778)
Properties - Net	26,576	26,209
Other Long-term Assets	389	388
Total Assets	30,993	30,645
Current Liabilities:
Accounts Payable	769	809
Labor and Fringe Benefits Payable	417	491
Payable to Affiliates	443	535
Current Maturities of Long-term Debt	299	333
Income and Other Taxes Payable	400	479
Other Current Liabilities	118	103
Total Current Liabilities	2,582	2,886
Long-term Debt	701	714
Deferred Income Taxes	8,603	8,548
Other Long-term Liabilities	500	512
Total Liabilities	12,608	12,891
Shareholders' Equity
Common Stock $1 Par Value	181	181
Other Capital	5,077	5,077
Retained Earnings	13,137	12,514
Accumulated Other Comprehensive Loss	(36)	(43)
Noncontrolling Interest	26	25
Total Shareholders' Equity	18,385	17,754
Total Liabilities and Shareholders' Equity	30,993	30,645
CSX Transportation | Casualty, Environmental and Other [Member]
Current Liabilities:
Casualty, Environmental and Other Reserves	136	136
Casualty, Environmental and Other Reserves	222	231
CSX Transportation | Investments in Conrail
Current Assets:
Investment in Affiliates, Subsidiaries, and Joint Ventures	0	0
CSX Transportation | Affiliates and Other Companies
Current Assets:
Investment in Affiliates, Subsidiaries, and Joint Ventures	629	612
CSX Transportation | Investments in Consolidated Subsidiaries
Current Assets:
Investment in Affiliates, Subsidiaries, and Joint Ventures	0	0
Eliminations and Other
Current Assets:
Cash and Cash Equivalents	63	62	58	68
Short-term Investments	21	15
Accounts Receivable - Net	889	809
Receivable from Affiliates	(3,793)	(3,776)
Materials and Supplies	0	0
Deferred Income Taxes	(1)	(1)
Other Current Assets	11	6
Total Current Assets	(2,810)	(2,885)
Properties	2,285	2,196
Accumulated Depreciation	(1,176)	(1,114)
Properties - Net	1,109	1,082
Other Long-term Assets	(16)	(14)
Total Assets	(21,890)	(21,318)
Current Liabilities:
Accounts Payable	29	38
Labor and Fringe Benefits Payable	39	58
Payable to Affiliates	(3,760)	(3,833)
Current Maturities of Long-term Debt	0	0
Income and Other Taxes Payable	7	9
Other Current Liabilities	10	2
Total Current Liabilities	(3,660)	(3,711)
Long-term Debt	0	0
Deferred Income Taxes	191	178
Other Long-term Liabilities	(125)	(121)
Total Liabilities	(3,527)	(3,585)
Shareholders' Equity
Common Stock $1 Par Value	(181)	(181)
Other Capital	(5,077)	(5,077)
Retained Earnings	(13,137)	(12,514)
Accumulated Other Comprehensive Loss	36	43
Noncontrolling Interest	(4)	(4)
Total Shareholders' Equity	(18,363)	(17,733)
Total Liabilities and Shareholders' Equity	(21,890)	(21,318)
Eliminations and Other | Casualty, Environmental and Other [Member]
Current Liabilities:
Casualty, Environmental and Other Reserves	15	15
Casualty, Environmental and Other Reserves	67	69
Eliminations and Other | Investments in Conrail
Current Assets:
Investment in Affiliates, Subsidiaries, and Joint Ventures	768	752
Eliminations and Other | Affiliates and Other Companies
Current Assets:
Investment in Affiliates, Subsidiaries, and Joint Ventures	(27)	(27)
Eliminations and Other | Investments in Consolidated Subsidiaries
Current Assets:
Investment in Affiliates, Subsidiaries, and Joint Ventures	$ (20,914)	$ (20,226)