Summarized Consolidating Financial Data (Balance Sheets) (Details) (USD $) In Millions, unless otherwise specified	Dec. 27, 2013		Dec. 28, 2012		Dec. 30, 2011		Dec. 31, 2010
Current Assets
Cash and Cash Equivalents	$ 592	[1]	$ 784	[1]	$ 783	[1]	$ 1,292	[1]
Short-term Investments	487	[1]	587	[1]
Accounts Receivable - Net	1,052	[1]	1,114	[1]	1,147	[1]
Receivable from Affiliates	0		0
Materials and Supplies	252	[1]	274	[1]
Deferred Income Taxes	155	[1]	119	[1]
Other Current Assets	64	[1]	75	[1]
Total Current Assets	2,602		2,953	[1]	2,953
Properties	37,184	[1]	35,279	[1]
Accumulated Depreciation	(9,893)	[1]	(9,229)	[1]
Properties - Net	27,291		26,050	[1]
Other Long-term Assets	591	[1]	514	[1]
Total Assets	31,782		30,723	[1]	29,491
Current Liabilities
Accounts Payable	957	[1]	948	[1]	954	[1]
Labor and Fringe Benefits Payable	587	[1]	468	[1]
Payable to Affiliates	0		0
Current Maturities of Long-term Debt	533	[1]	780	[1]
Income and Other Taxes Payable	91	[1]	169	[1]	210	[1]
Other Current Liabilities	105	[1]	140	[1]
Total Current Liabilities	2,424		2,645	[1]	2,575
Long-term Debt	9,022	[1]	9,052	[1]
Deferred Income Taxes	8,662	[1]	8,096	[1]
Other Long-term Liabilities	870	[1]	1,457	[1]
Total Liabilities	21,278		21,587	[1]	20,893
Common Stock, $1 Par Value	1,009	[1]	1,020	[1]
Other Capital	61	[1]	28	[1]
Retained Earnings	9,936	[1]	9,010	[1]	8,405	[1]
Accumulated Other Comprehensive Loss	(523)	[1]	(936)	[1]	(875)		(771)
Noncontrolling Minority Interest	21	[1]	14	[1]
Total Shareholders' Equity	10,504		9,136	[1]	8,598		8,798
Total Liabilities and Shareholders' Equity	31,782		30,723	[1]	29,491
Investments in Conrail
Current Assets
Investment in Affiliates, Subsidiaries, and Joint Ventures	752	[1]	695	[1]
Affiliates and Other Companies
Current Assets
Investment in Affiliates, Subsidiaries, and Joint Ventures	546	[1]	511	[1]
Investments in Consolidated Subsidiaries
Current Assets
Investment in Affiliates, Subsidiaries, and Joint Ventures	0		0
CSX Corporation
Current Assets
Cash and Cash Equivalents	439		481		549		1,100
Short-term Investments	472		555
Accounts Receivable - Net	3		3
Receivable from Affiliates	1,141		993
Materials and Supplies	0		0
Deferred Income Taxes	(5)		52
Other Current Assets	1		11
Total Current Assets	2,051		2,095
Properties	1		8
Accumulated Depreciation	(1)		(8)
Properties - Net	0		0
Other Long-term Assets	217		186
Total Assets	22,455		21,159
Current Liabilities
Accounts Payable	110		133
Labor and Fringe Benefits Payable	38		35
Payable to Affiliates	3,298		2,679
Current Maturities of Long-term Debt	200		700
Income and Other Taxes Payable	(397)		(262)
Other Current Liabilities	0		(1)
Total Current Liabilities	3,249		3,284
Long-term Debt	8,308		8,005
Deferred Income Taxes	(64)		(153)
Other Long-term Liabilities	479		901
Total Liabilities	11,972		12,037
Common Stock, $1 Par Value	1,009		1,020
Other Capital	61		28
Retained Earnings	9,936		9,010
Accumulated Other Comprehensive Loss	(523)		(936)
Noncontrolling Minority Interest	0		0
Total Shareholders' Equity	10,483		9,122
Total Liabilities and Shareholders' Equity	22,455		21,159
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	20,226		18,917
CSX Transportation
Current Assets
Cash and Cash Equivalents	91		235		154		118
Short-term Investments	0		0
Accounts Receivable - Net	240		579
Receivable from Affiliates	2,635		1,798
Materials and Supplies	252		274
Deferred Income Taxes	161		62
Other Current Assets	57		64
Total Current Assets	3,436		3,012
Properties	34,987		33,333
Accumulated Depreciation	(8,778)		(8,225)
Properties - Net	26,209		25,108
Other Long-term Assets	388		368
Total Assets	30,645		29,081
Current Liabilities
Accounts Payable	809		780
Labor and Fringe Benefits Payable	491		391
Payable to Affiliates	535		411
Current Maturities of Long-term Debt	333		80
Income and Other Taxes Payable	479		418
Other Current Liabilities	103		139
Total Current Liabilities	2,886		2,343
Long-term Debt	714		1,047
Deferred Income Taxes	8,548		8,131
Other Long-term Liabilities	512		656
Total Liabilities	12,891		12,433
Common Stock, $1 Par Value	181		181
Other Capital	5,077		5,672
Retained Earnings	12,514		10,874
Accumulated Other Comprehensive Loss	(43)		(102)
Noncontrolling Minority Interest	25		23
Total Shareholders' Equity	17,754		16,648
Total Liabilities and Shareholders' Equity	30,645		29,081
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	612		593
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	62		68		80		74
Short-term Investments	15		32
Accounts Receivable - Net	809		532
Receivable from Affiliates	(3,776)		(2,791)
Materials and Supplies	0		0
Deferred Income Taxes	(1)		5
Other Current Assets	6		0
Total Current Assets	(2,885)		(2,154)
Properties	2,196		1,938
Accumulated Depreciation	(1,114)		(996)
Properties - Net	1,082		942
Other Long-term Assets	(14)		(40)
Total Assets	(21,318)		(19,517)
Current Liabilities
Accounts Payable	38		35
Labor and Fringe Benefits Payable	58		42
Payable to Affiliates	(3,833)		(3,090)
Current Maturities of Long-term Debt	0		0
Income and Other Taxes Payable	9		13
Other Current Liabilities	2		2
Total Current Liabilities	(3,711)		(2,982)
Long-term Debt	0		0
Deferred Income Taxes	178		118
Other Long-term Liabilities	(121)		(100)
Total Liabilities	(3,585)		(2,883)
Common Stock, $1 Par Value	(181)		(181)
Other Capital	(5,077)		(5,672)
Retained Earnings	(12,514)		(10,874)
Accumulated Other Comprehensive Loss	43		102
Noncontrolling Minority Interest	(4)		(9)
Total Shareholders' Equity	(17,733)		(16,634)
Total Liabilities and Shareholders' Equity	(21,318)		(19,517)
Eliminations and Other | Investments in Conrail
Current Assets
Investment in Affiliates, Subsidiaries, and Joint Ventures	752		695
Eliminations and Other | Affiliates and Other Companies
Current Assets
Investment in Affiliates, Subsidiaries, and Joint Ventures	(27)		(43)
Eliminations and Other | Investments in Consolidated Subsidiaries
Current Assets
Investment in Affiliates, Subsidiaries, and Joint Ventures	(20,226)		(18,917)
Casualty, Environmental and Other [Member]
Current Liabilities
Loss Contingency, Accrual, Noncurrent	300		337
Loss Contingency, Accrual, Current	151		140
Casualty, Environmental and Other [Member] | CSX Corporation
Current Liabilities
Loss Contingency, Accrual, Noncurrent	0		0
Loss Contingency, Accrual, Current	0		0
Casualty, Environmental and Other [Member] | CSX Transportation
Current Liabilities
Loss Contingency, Accrual, Noncurrent	231		256
Loss Contingency, Accrual, Current	136		124
Casualty, Environmental and Other [Member] | Eliminations and Other
Current Liabilities
Loss Contingency, Accrual, Noncurrent	69		81
Loss Contingency, Accrual, Current	$ 15		$ 16

[1] See the revision of prior period financial statements in Note 1. Nature of Operations and Significant Accounting Policies.