Summarized Consolidating Financial Data - Consolidating Balance Sheet (Details) - USD ($) $ / shares in Units, $ in Millions	Jun. 26, 2015	Dec. 26, 2014	Jun. 27, 2014	Dec. 27, 2013
Current Assets:
Cash and Cash Equivalents	$ 438	$ 669	$ 573	$ 592
Short-term Investments	680	292
Accounts Receivable - Net	1,022	1,129
Receivable from Affiliates	0	0
Materials and Supplies	295	273
Deferred Income Taxes	132	141
Other Current Assets	102	68
Total Current Assets	2,669	2,572
Properties	40,313	39,343
Accumulated Depreciation	(11,063)	(10,759)
Properties - Net	29,250	28,584
Other Long-term Assets	492	541
Total Assets	33,777	33,053
Current Liabilities:
Accounts Payable	772	845
Labor and Fringe Benefits Payable	480	613
Payable to Affiliates	0	0
Casualty, Environmental and Other Reserves	146	142
Current Maturities of Long-term Debt	18	228
Income and Other Taxes Payable	243	163
Other Current Liabilities	119	116
Total Current Liabilities	1,778	2,107
Casualty, Environmental and Other Reserves	280	276
Long-term Debt	10,107	9,514
Deferred Income Taxes	8,897	8,858
Other Long-term Liabilities	1,138	1,122
Total Liabilities	22,200	21,877
Shareholders' Equity
Common Stock, $1 Par Value	984	992
Other Capital	118	92
Retained Earnings	11,117	10,734
Accumulated Other Comprehensive Loss	(656)	(666)
Noncontrolling Interest	14	24
Total Shareholders' Equity	11,577	11,176
Total Liabilities and Shareholders' Equity	$ 33,777	$ 33,053
Common stock, par value (in dollars per share)	$ 1	$ 1
Investments in Conrail
Current Assets:
Investment in Affiliates and Consolidated Subsidiaries	$ 787	$ 779
Affiliates and Other Companies
Current Assets:
Investment in Affiliates and Consolidated Subsidiaries	579	577
Investments in Consolidated Subsidiaries
Current Assets:
Investment in Affiliates and Consolidated Subsidiaries	0	0
CSX Corporation
Current Assets:
Cash and Cash Equivalents	233	510	407	439
Short-term Investments	670	250
Accounts Receivable - Net	2	2
Receivable from Affiliates	1,194	1,211
Materials and Supplies	0	0
Deferred Income Taxes	4	3
Other Current Assets	5	0
Total Current Assets	2,108	1,976
Properties	1	1
Accumulated Depreciation	(1)	(1)
Properties - Net	0	0
Other Long-term Assets	174	178
Total Assets	24,400	23,685
Current Liabilities:
Accounts Payable	108	106
Labor and Fringe Benefits Payable	34	38
Payable to Affiliates	3,125	3,053
Casualty, Environmental and Other Reserves	0	0
Current Maturities of Long-term Debt	0	200
Income and Other Taxes Payable	(320)	(150)
Other Current Liabilities	0	0
Total Current Liabilities	2,947	3,247
Casualty, Environmental and Other Reserves	0	0
Long-term Debt	9,301	8,705
Deferred Income Taxes	(164)	(172)
Other Long-term Liabilities	753	753
Total Liabilities	12,837	12,533
Shareholders' Equity
Common Stock, $1 Par Value	984	992
Other Capital	118	92
Retained Earnings	11,117	10,734
Accumulated Other Comprehensive Loss	(656)	(666)
Noncontrolling Interest	0	0
Total Shareholders' Equity	11,563	11,152
Total Liabilities and Shareholders' Equity	24,400	23,685
CSX Corporation \| Investments in Conrail
Current Assets:
Investment in Affiliates and Consolidated Subsidiaries	0	0
CSX Corporation \| Affiliates and Other Companies
Current Assets:
Investment in Affiliates and Consolidated Subsidiaries	(39)	(39)
CSX Corporation \| Investments in Consolidated Subsidiaries
Current Assets:
Investment in Affiliates and Consolidated Subsidiaries	22,157	21,570
CSX Transportation
Current Assets:
Cash and Cash Equivalents	144	100	103	91
Short-term Investments	0	0
Accounts Receivable - Net	175	206
Receivable from Affiliates	2,324	2,418
Materials and Supplies	295	272
Deferred Income Taxes	129	139
Other Current Assets	84	61
Total Current Assets	3,151	3,196
Properties	37,787	36,888
Accumulated Depreciation	(9,752)	(9,516)
Properties - Net	28,035	27,372
Other Long-term Assets	399	387
Total Assets	32,231	31,599
Current Liabilities:
Accounts Payable	638	707
Labor and Fringe Benefits Payable	411	511
Payable to Affiliates	495	514
Casualty, Environmental and Other Reserves	131	126
Current Maturities of Long-term Debt	18	29
Income and Other Taxes Payable	535	293
Other Current Liabilities	108	111
Total Current Liabilities	2,336	2,291
Casualty, Environmental and Other Reserves	224	213
Long-term Debt	806	809
Deferred Income Taxes	8,852	8,827
Other Long-term Liabilities	502	487
Total Liabilities	12,720	12,627
Shareholders' Equity
Common Stock, $1 Par Value	181	181
Other Capital	5,089	5,077
Retained Earnings	14,257	13,717
Accumulated Other Comprehensive Loss	(34)	(31)
Noncontrolling Interest	18	28
Total Shareholders' Equity	19,511	18,972
Total Liabilities and Shareholders' Equity	32,231	31,599
CSX Transportation \| Investments in Conrail
Current Assets:
Investment in Affiliates and Consolidated Subsidiaries	0	0
CSX Transportation \| Affiliates and Other Companies
Current Assets:
Investment in Affiliates and Consolidated Subsidiaries	646	644
CSX Transportation \| Investments in Consolidated Subsidiaries
Current Assets:
Investment in Affiliates and Consolidated Subsidiaries	0	0
Eliminations and Other
Current Assets:
Cash and Cash Equivalents	61	59	$ 63	$ 62
Short-term Investments	10	42
Accounts Receivable - Net	845	921
Receivable from Affiliates	(3,518)	(3,629)
Materials and Supplies	0	1
Deferred Income Taxes	(1)	(1)
Other Current Assets	13	7
Total Current Assets	(2,590)	(2,600)
Properties	2,525	2,454
Accumulated Depreciation	(1,310)	(1,242)
Properties - Net	1,215	1,212
Other Long-term Assets	(81)	(24)
Total Assets	(22,854)	(22,231)
Current Liabilities:
Accounts Payable	26	32
Labor and Fringe Benefits Payable	35	64
Payable to Affiliates	(3,620)	(3,567)
Casualty, Environmental and Other Reserves	15	16
Current Maturities of Long-term Debt	0	(1)
Income and Other Taxes Payable	28	20
Other Current Liabilities	11	5
Total Current Liabilities	(3,505)	(3,431)
Casualty, Environmental and Other Reserves	56	63
Long-term Debt	0	0
Deferred Income Taxes	209	203
Other Long-term Liabilities	(117)	(118)
Total Liabilities	(3,357)	(3,283)
Shareholders' Equity
Common Stock, $1 Par Value	(181)	(181)
Other Capital	(5,089)	(5,077)
Retained Earnings	(14,257)	(13,717)
Accumulated Other Comprehensive Loss	34	31
Noncontrolling Interest	(4)	(4)
Total Shareholders' Equity	(19,497)	(18,948)
Total Liabilities and Shareholders' Equity	(22,854)	(22,231)
Eliminations and Other \| Investments in Conrail
Current Assets:
Investment in Affiliates and Consolidated Subsidiaries	787	779
Eliminations and Other \| Affiliates and Other Companies
Current Assets:
Investment in Affiliates and Consolidated Subsidiaries	(28)	(28)
Eliminations and Other \| Investments in Consolidated Subsidiaries
Current Assets:
Investment in Affiliates and Consolidated Subsidiaries	$ (22,157)	$ (21,570)

Carrying value as of the balance sheet date of liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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- Definition

Amount due from customers or clients, within one year of the balance sheet date (or the normal operating cycle, whichever is longer), for goods or services (including trade receivables) that have been delivered or sold in the normal course of business, reduced to the estimated net realizable fair value by an allowance established by the entity of the amount it deems uncertain of collection.