Summarized Consolidating Balance Sheet (Details) (USD $) In Millions, unless otherwise specified	Mar. 28, 2014	Dec. 27, 2013	Mar. 29, 2013	Dec. 28, 2012
Current Assets
Cash and Cash Equivalents	$ 475	$ 592	$ 705	$ 784
Short-term Investments	248	487
Accounts Receivable - Net	1,073	1,052
Receivable from Affiliates	0	0
Materials and Supplies	259	252
Deferred Income Taxes	143	155
Other Current Assets	91	64
Total Current Assets	2,289	2,602
Properties	37,604	37,184
Accumulated Depreciation	(10,110)	(9,893)
Properties - Net	27,494	27,291
Other Long-term Assets	583	591
Total Assets	31,680	31,782
Current Liabilities:
Accounts Payable	975	957
Labor and Fringe Benefits Payable	404	587
Payable to Affiliates	0	0
Casualty, Environmental and Other Reserves	149	151
Current Maturities of Long-term Debt	325	533
Income and Other Taxes Payable	246	91
Other Current Liabilities	113	105
Total Current Liabilities	2,212	2,424
Casualty, Environmental and Other Reserves	285	300
Long-term Debt	9,021	9,022
Deferred Income Taxes	8,658	8,662
Other Long-term Liabilities	859	870
Total Liabilities	21,035	21,278
Shareholders' Equity
Common Stock $1 Par Value	1,004	1,009
Other Capital	65	61
Retained Earnings	10,062	9,936
Accumulated Other Comprehensive Loss	(507)	(523)
Noncontrolling Interest	21	21
Total Shareholders' Equity	10,645	10,504
Total Liabilities and Shareholders' Equity	31,680	31,782
Casualty, Environmental and Other [Member]
Current Liabilities:
Casualty, Environmental and Other Reserves	149	151
Casualty, Environmental and Other Reserves	285	300
Investments in Conrail
Current Assets
Investment in Affiliates, Subsidiaries, and Joint Ventures	756	752
Affiliates and Other Companies
Current Assets
Investment in Affiliates, Subsidiaries, and Joint Ventures	558	546
Investments in Consolidated Subsidiaries
Current Assets
Investment in Affiliates, Subsidiaries, and Joint Ventures	0	0
CSX Corporation
Current Assets
Cash and Cash Equivalents	321	439	445	481
Short-term Investments	230	472
Accounts Receivable - Net	3	3
Receivable from Affiliates	1,301	1,141
Materials and Supplies	0	0
Deferred Income Taxes	(11)	(5)
Other Current Assets	(1)	1
Total Current Assets	1,843	2,051
Properties	1	1
Accumulated Depreciation	(1)	(1)
Properties - Net	0	0
Other Long-term Assets	214	217
Total Assets	22,524	22,455
Current Liabilities:
Accounts Payable	190	110
Labor and Fringe Benefits Payable	33	38
Payable to Affiliates	3,063	3,298
Current Maturities of Long-term Debt	0	200
Income and Other Taxes Payable	(102)	(397)
Other Current Liabilities	0	0
Total Current Liabilities	3,184	3,249
Long-term Debt	8,308	8,308
Deferred Income Taxes	(70)	(64)
Other Long-term Liabilities	478	479
Total Liabilities	11,900	11,972
Shareholders' Equity
Common Stock $1 Par Value	1,004	1,009
Other Capital	65	61
Retained Earnings	10,062	9,936
Accumulated Other Comprehensive Loss	(507)	(523)
Noncontrolling Interest	0	0
Total Shareholders' Equity	10,624	10,483
Total Liabilities and Shareholders' Equity	22,524	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	20,506	20,226
CSX Transportation
Current Assets
Cash and Cash Equivalents	91	91	208	235
Short-term Investments	0	0
Accounts Receivable - Net	191	240
Receivable from Affiliates	2,323	2,635
Materials and Supplies	259	252
Deferred Income Taxes	155	161
Other Current Assets	86	57
Total Current Assets	3,105	3,436
Properties	35,377	34,987
Accumulated Depreciation	(8,965)	(8,778)
Properties - Net	26,412	26,209
Other Long-term Assets	388	388
Total Assets	30,529	30,645
Current Liabilities:
Accounts Payable	758	809
Labor and Fringe Benefits Payable	340	491
Payable to Affiliates	539	535
Current Maturities of Long-term Debt	325	333
Income and Other Taxes Payable	342	479
Other Current Liabilities	109	103
Total Current Liabilities	2,546	2,886
Long-term Debt	713	714
Deferred Income Taxes	8,541	8,548
Other Long-term Liabilities	506	512
Total Liabilities	12,524	12,891
Shareholders' Equity
Common Stock $1 Par Value	181	181
Other Capital	5,077	5,077
Retained Earnings	12,759	12,514
Accumulated Other Comprehensive Loss	(37)	(43)
Noncontrolling Interest	25	25
Total Shareholders' Equity	18,005	17,754
Total Liabilities and Shareholders' Equity	30,529	30,645
CSX Transportation | Casualty, Environmental and Other [Member]
Current Liabilities:
Casualty, Environmental and Other Reserves	133	136
Casualty, Environmental and Other Reserves	218	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	624	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	52	68
Short-term Investments	18	15
Accounts Receivable - Net	879	809
Receivable from Affiliates	(3,624)	(3,776)
Materials and Supplies	0	0
Deferred Income Taxes	(1)	(1)
Other Current Assets	6	6
Total Current Assets	(2,659)	(2,885)
Properties	2,226	2,196
Accumulated Depreciation	(1,144)	(1,114)
Properties - Net	1,082	1,082
Other Long-term Assets	(19)	(14)
Total Assets	(21,373)	(21,318)
Current Liabilities:
Accounts Payable	27	38
Labor and Fringe Benefits Payable	31	58
Payable to Affiliates	(3,602)	(3,833)
Current Maturities of Long-term Debt	0	0
Income and Other Taxes Payable	6	9
Other Current Liabilities	4	2
Total Current Liabilities	(3,518)	(3,711)
Long-term Debt	0	0
Deferred Income Taxes	187	178
Other Long-term Liabilities	(125)	(121)
Total Liabilities	(3,389)	(3,585)
Shareholders' Equity
Common Stock $1 Par Value	(181)	(181)
Other Capital	(5,077)	(5,077)
Retained Earnings	(12,759)	(12,514)
Accumulated Other Comprehensive Loss	37	43
Noncontrolling Interest	(4)	(4)
Total Shareholders' Equity	(17,984)	(17,733)
Total Liabilities and Shareholders' Equity	(21,373)	(21,318)
Eliminations and Other | Casualty, Environmental and Other [Member]
Current Liabilities:
Casualty, Environmental and Other Reserves	16	15
Casualty, Environmental and Other Reserves	67	69
Eliminations and Other | Investments in Conrail
Current Assets
Investment in Affiliates, Subsidiaries, and Joint Ventures	756	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	$ (20,506)	$ (20,226)