CSX (CSX) 10-K 10 Feb 16 2015 FY Annual report Financial data

Document And Entity Information

Document And Entity Information - USD ($) $ in Billions	12 Months Ended
	Dec. 25, 2015	Jan. 22, 2016	Jun. 26, 2015
Document and Entity Information [Abstract]
Entity Registrant Name	CSX CORP
Entity Central Index Key	277,948
Current Fiscal Year End Date	--12-25
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$ 33
Entity Common Stock, Shares Outstanding		963,150,011
Document Fiscal Year Focus	2,015
Document Fiscal Period Focus	FY
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 25, 2015

CONSOLIDATED INCOME STATEMENTS

CONSOLIDATED INCOME STATEMENTS - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 25, 2015	Dec. 26, 2014	Dec. 27, 2013
Income Statement [Abstract]
Revenue	$ 11,811	$ 12,669	$ 12,026
Expense
Labor and Fringe	3,290	3,377	3,138
Materials, Supplies and Other	2,336	2,484	2,275
Fuel	957	1,616	1,656
Depreciation	1,208	1,151	1,104
Equipment and Other Rents	436	428	380
Total Expense	8,227	9,056	8,553
Operating Income	3,584	3,613	3,473
Interest Expense	(544)	(545)	(562)
Other Income - Net	98	(24)	11
Earnings Before Income Taxes	3,138	3,044	2,922
Income Tax Expense	(1,170)	(1,117)	(1,058)
Net Earnings	$ 1,968	$ 1,927	$ 1,864
Net Earnings Per Share, Basic
Net Earnings Per Share, Basic (dollars per share)	$ 2	$ 1.93	$ 1.83
Net Earnings Per Common Share, Assuming Dilution
Net Earnings Per Share, Assuming Dilution (dollars per share)	$ 2	$ 1.92	$ 1.83
Average Common Shares Outstanding, Basic (shares)	983	1,001	1,019
Average Common Shares Outstanding, Assuming Dilution (shares)	984	1,002	1,019
Common Stock Dividends (dollars per share)	$ 0.70	$ 0.63	$ 0.59

CONSOLIDATED COMPREHENSIVE INCO

CONSOLIDATED COMPREHENSIVE INCOME STATEMENTS - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 25, 2015	Sep. 25, 2015	Jun. 26, 2015	Mar. 27, 2015	Dec. 26, 2014	Sep. 26, 2014	Jun. 27, 2014	Mar. 28, 2014	Dec. 25, 2015	Dec. 26, 2014	Dec. 27, 2013
Net Earnings	$ 466	$ 507	$ 553	$ 442	$ 491	$ 509	$ 529	$ 398	$ 1,968	$ 1,927	$ 1,864
Other Comprehensive Income (Loss), Net of Tax									1	(143)	413
Comprehensive Earnings									1,969	1,784	2,277
Pension and Other Post-Employment Benefits
Other Comprehensive Income (Loss), Net of Tax									10	(149)	389
Other
Other Comprehensive Income (Loss), Net of Tax									$ (9)	$ 6	$ 24

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions	Dec. 25, 2015	Dec. 26, 2014	Dec. 27, 2013	Dec. 28, 2012
Current Assets:
Cash and Cash Equivalents	$ 628	$ 669	$ 592	$ 784
Short-term Investments	810	292
Accounts Receivable - Net	982	1,129
Materials and Supplies	350	273
Deferred Income Taxes	126	141
Other Current Assets	70	68
Total Current Assets	2,966	2,572
Noncurrent Assets
Properties	41,574	39,343
Accumulated Depreciation	(11,400)	(10,759)
Properties - Net	30,174	28,584
Other Long-term Assets	505	541
Total Assets	35,039	33,053
Current Liabilities:
Accounts Payable	764	845
Labor and Fringe Benefits Payable	490	613
Casualty, Environmental and Other Reserves	131	142
Current Maturities of Long-term Debt	20	228
Income and Other Taxes Payable	108	163
Other Current Liabilities	439	116
Total Current Liabilities	1,952	2,107
Noncurrent Liabilities
Casualty, Environmental and Other Reserves	269	276
Long-term Debt	10,683	9,514
Deferred Income Taxes	9,305	8,858
Other Long-term Liabilities	1,162	1,122
Total Liabilities	23,371	21,877
Shareholders' Equity:
Common Stock, $1 Par Value	966	992
Other Capital	113	92
Retained Earnings	11,238	10,734
Accumulated Other Comprehensive Loss	(665)	(666)	(523)	(936)
Noncontrolling Minority Interest	16	24
Total Shareholders' Equity	11,668	11,176	$ 10,504	$ 9,136
Total Liabilities and Shareholders' Equity	35,039	33,053
Investments in Conrail
Noncurrent Assets
Investment in Affiliates, Subsidiaries and Other	803	779
Affiliates and Other Companies
Noncurrent Assets
Investment in Affiliates, Subsidiaries and Other	$ 591	$ 577

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 25, 2015	Dec. 26, 2014
Statement of Financial Position [Abstract]
Common stock par value (dollars per share)	$ 1	$ 1

CONSOLIDATED CASH FLOW STATEMEN

CONSOLIDATED CASH FLOW STATEMENTS - USD ($) $ in Millions	12 Months Ended
	Dec. 25, 2015	Dec. 26, 2014	Dec. 27, 2013
OPERATING ACTIVITIES
Net Earnings	$ 1,968	$ 1,927	$ 1,864
Adjustments to Reconcile Net Earnings to Net Cash
Depreciation	1,208	1,151	1,104
Deferred Income Taxes	456	298	300
Gain on Property Dispositions	(90)	(11)	(70)
Other Operating Activities	22	14	(35)
Changes in Operating Assets and Liabilities:
Accounts Receivable	149	(119)	(6)
Other Current Assets	(84)	(26)	36
Accounts Payable	(79)	1	28
Income and Other Taxes Payable	(62)	74	(67)
Other Current Liabilities	(118)	34	113
Net Cash Provided by Operating Activities	3,370	3,343	3,267
INVESTING ACTIVITIES
Property Additions	(2,562)	(2,449)	(2,313)
Purchase of Short-term Investments	(1,739)	(1,433)	(1,256)
Proceeds from Sales of Short-term Investments	1,225	1,674	1,401
Proceeds from Property Dispositions	147	62	53
Other Investing Activities	37	(37)	(112)
Net Cash Used in Investing Activities	(2,892)	(2,183)	(2,227)
FINANCING ACTIVITIES
Long-term Debt Issued	1,200	1,000	500
Long-term Debt Repaid	(229)	(933)	(780)
Dividends Paid	(686)	(629)	(600)
Stock Options Exercised	0	0	9
Shares Repurchased	(804)	(517)	(353)
Other Financing Activities	0	(4)	(8)
Net Cash Used in Financing Activities	(519)	(1,083)	(1,232)
Net (Decrease) Increase in Cash and Cash Equivalents	(41)	77	(192)
CASH AND CASH EQUIVALENTS
Cash and Cash Equivalents at Beginning of Period	669	592	784
Cash and Cash Equivalents at End of Period	628	669	592
SUPPLEMENTAL CASH FLOW INFORMATION
Interest Paid - Net of Amounts Capitalized	566	575	595
Income Taxes Paid	768	741	824
Seller Financed Assets	$ 307	$ 0	$ 0

CONSOLIDATED STATEMENTS OF CHAN

CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Millions	Total	Common Shares Outstanding	Common Stock and Other Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)		Non- controlling Interest
Accumulated other comprehensive loss, tax					$ 266
Common Shares Outstanding, beginning balance at Dec. 28, 2012		1,020,485
Shareholders' Equity, beginning balance at Dec. 28, 2012	$ 9,136		$ 1,048	$ 9,010	(936)	[1]	$ 14
Comprehensive Earnings:
Net Earnings	1,864			1,864
Other Comprehensive Income (Loss)	413				413	[1]
Comprehensive Earnings	2,277
Common stock dividends	$ (600)			(600)			0
Share Repurchases (shares)	(14,000)	(13,791)
Share Repurchases	$ (353)		(14)	(339)
Bond Conversions (shares)		1
Bond Conversions	0		0
Stock Option Exercises and Other (shares)		2,165
Stock Option Exercises and Other	44		36	1			7
Common Shares Outstanding, ending balance at Dec. 27, 2013		1,008,860
Shareholders' Equity, ending balance at Dec. 27, 2013	10,504		1,070	9,936	(523)	[1]	21
Accumulated other comprehensive loss, tax					354
Comprehensive Earnings:
Net Earnings	1,927			1,927
Other Comprehensive Income (Loss)	(143)				(143)	[1]
Comprehensive Earnings	1,784
Common stock dividends	$ (629)			(629)			0
Share Repurchases (shares)	(17,000)	(17,010)
Share Repurchases	$ (517)		(17)	(500)
Bond Conversions (shares)		134
Bond Conversions	1		1
Other (shares)		(393)
Other	33		30	0			3
Common Shares Outstanding, ending balance at Dec. 26, 2014		991,591
Shareholders' Equity, ending balance at Dec. 26, 2014	11,176		1,084	10,734	(666)	[1]	24
Accumulated other comprehensive loss, tax					347
Comprehensive Earnings:
Net Earnings	1,968			1,968
Other Comprehensive Income (Loss)	1				1	[1]
Comprehensive Earnings	1,969
Common stock dividends	$ (686)			(686)			0
Share Repurchases (shares)	(26,000)	(26,359)
Share Repurchases	$ (804)		(26)	(778)
Bond Conversions (shares)		13
Bond Conversions	0		0
Other (shares)		269
Other	13		21	0			(8)
Common Shares Outstanding, ending balance at Dec. 25, 2015		965,514
Shareholders' Equity, ending balance at Dec. 25, 2015	$ 11,668		$ 1,079	$ 11,238	$ (665)	[1]	$ 16
[1]	Accumulated Other Comprehensive Loss year-end balances shown above are net of tax. The associated taxes were $266 million, $354 million and $347 million for 2013, 2014 and 2015, respectively. For additional information see Note 14, Other Comprehensive Income.

CONSOLIDATED STATEMENTS OF CHA8

CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY (Parenthetical) - $ / shares	12 Months Ended
	Dec. 25, 2015	Dec. 26, 2014	Dec. 27, 2013
Statement of Stockholders' Equity [Abstract]
Common Stock Dividends (dollars per share)	$ 0.70	$ 0.63	$ 0.59

Nature of Operations and Signif

Nature of Operations and Significant Accounting Policies	12 Months Ended
	Dec. 25, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of Operations and Significant Accounting Policies	Nature of Operations and Significant Accounting Policies Business CSX Corporation (“CSX”), together with its subsidiaries (the “Company”), based in Jacksonville, Florida, is one of the nation's leading transportation companies. The Company provides rail-based transportation services including traditional rail service and the transport of intermodal containers and trailers. The Company’s number of employees was approximately 29,000 as of December 2015 , which includes approximately 24,000 union employees. Most of the Company’s employees provide or support transportation services. CSX Transportation, Inc. CSX’s principal operating subsidiary, CSX Transportation, Inc. (“CSXT”), provides an important link to the transportation supply chain through its approximately 21,000 route mile rail network, which serves major population centers in 23 states east of the Mississippi River, the District of Columbia and the Canadian provinces of Ontario and Quebec. It has access to over 70 ocean, river and lake port terminals along the Atlantic and Gulf Coasts, the Mississippi River, the Great Lakes and the St. Lawrence Seaway. The Company’s intermodal business, also part of CSXT, links customers to railroads via trucks and terminals. CSXT also serves thousands of production and distribution facilities through track connections to approximately 240 short-line and regional railroads. Lines of Business During 2015 , the Company services generated $11.8 billion of revenue and served three primary lines of business: • The merchandise business shipped nearly 2.9 million carloads and generated 62% of revenue and 42% of volume in 2015 . The Company’s merchandise business is comprised of shipments in the following diverse markets: agricultural products, phosphates and fertilizers, food and consumer, chemicals, automotive, metals, forest products, minerals and waste and equipment. • The coal business shipped about 1.1 million carloads and accounted for 19% of revenue and 16% of volume in 2015 . The Company transports domestic coal, coke and iron ore to electricity-generating power plants, steel manufacturers and industrial plants as well as export coal to deep-water port facilities. Roughly one-third of export coal and the majority of the domestic coal that the Company transports is used for generating electricity. • The intermodal business accounted for 15% of revenue and 42% of volume in 2015 . The intermodal business combines the superior economics of rail transportation with the short-haul flexibility of trucks and offers a cost advantage over long-haul trucking. Through a network of more than 50 terminals, the intermodal business serves all major markets east of the Mississippi River and transports mainly manufactured consumer goods in containers, providing customers with truck-like service for longer shipments. Other revenue accounted for 4% of the Company’s total revenue in 2015 . This revenue category includes revenue from regional subsidiary railroads, demurrage, revenue for customer volume commitments not met, switching and other incidental charges. Revenue from regional railroads includes shipments by railroads that the Company does not directly operate. Demurrage represents charges assessed when freight cars are held beyond a specified period of time. Switching revenue is primarily generated when CSXT switches cars for a customer or another railroad. NOTE 1. Nature of Operations and Significant Accounting Policies, continued Other Entities In addition to CSXT, the Company’s subsidiaries include CSX Intermodal Terminals, Inc. (“CSX Intermodal Terminals”), Total Distribution Services, Inc. (“TDSI”), Transflo Terminal Services, Inc. (“Transflo”), CSX Technology, Inc. (“CSX Technology”) and other subsidiaries. CSX Intermodal Terminals owns and operates a system of intermodal terminals, predominantly in the eastern United States and also performs drayage services (the pickup and delivery of intermodal shipments) for certain customers and trucking dispatch operations. TDSI serves the automotive industry with distribution centers and storage locations. Transflo connects non-rail served customers to the many benefits of rail by transferring products from rail to trucks. The biggest Transflo markets are chemicals and agriculture, which includes shipments of plastics and ethanol. CSX Technology and other subsidiaries provide support services for the Company. CSX’s other holdings include CSX Real Property, Inc., a subsidiary responsible for the Company’s operating and non-operating real estate sales, leasing, acquisition and management and development activities. These activities are classified in either operating income or other income - net depending upon the nature of the activity. Results of these activities fluctuate with the timing of real estate transactions. Basis of Presentation In the opinion of management, the accompanying consolidated financial statements contain all normal, recurring adjustments necessary to fairly present the financial position of CSX and its subsidiaries at December 25, 2015 and December 26, 2014 , and the consolidated statements of income, comprehensive income, cash flows and changes in shareholders’ equity for fiscal years 2015 , 2014 and 2013 . In addition, management has evaluated and disclosed all material events occurring subsequent to the date of the financial statements up to the date this annual report is filed on Form 10-K. Fiscal Year CSX follows a 52/53 week fiscal reporting calendar. This fiscal calendar allows every quarter to consistently end on a Friday and typically, to be of equal duration ( 13 weeks), resulting in a 52 week fiscal year. To maintain this type of reporting calendar every fifth or sixth year (depending on the Gregorian calendar and when leap year falls), an extra week will be included in the fourth quarter (a 14-week fiscal quarter) and, therefore, that full fiscal year will have 53 weeks. The next 53 week fiscal year will be 2016, which will end on December 30, 2016. Fiscal years 2015, 2014 and 2013 each consisted of 52 weeks ending on December 25, 2015 , December 26, 2014 and December 27, 2013 , respectively. Except as otherwise specified, references to full year indicate CSX’s fiscal periods ended on these dates. Principles of Consolidation The consolidated financial statements include results of operations of CSX and subsidiaries over which CSX has majority ownership or financial control. All significant intercompany accounts and transactions have been eliminated. Most investments in companies that were not majority-owned were carried at cost (if less than 20% owned and the Company has no significant influence) or were accounted for under the equity method (if the Company has significant influence but does not have control). These investments are reported within Investment in Conrail or Affiliates and Other Investments on the consolidated balance sheets. Cash and Cash Equivalents On a daily basis, cash in excess of current operating requirements is invested in various highly liquid investments having a typical maturity date of three months or less at the date of acquisition. These investments are carried at cost, which approximated market value, and are classified as cash equivalents. NOTE 1. Nature of Operations and Significant Accounting Policies, continued Investments Investments in instruments with original maturities greater than three months but will mature in less than one year were classified as short-term investments. Investments with original maturities greater than one year are classified within other long-term assets. Allowance for Doubtful Accounts The Company maintains an allowance for doubtful accounts on uncollectible amounts related to freight receivables, government reimbursement receivables, claims for damages and other various receivables. The allowance is based upon the credit worthiness of customers, historical experience, the age of the receivable and current market and economic conditions. Uncollectible amounts are charged against the allowance account. Allowance for doubtful accounts of $37 million and $41 million is included in the consolidated balance sheets as of December 2015 and December 2014 , respectively. Materials and Supplies Materials and supplies in the consolidated balance sheets are carried at average costs and consist primarily of fuel and parts used in the repair and maintenance of CSXT’s freight car and locomotive fleets, equipment and track structure. Goodwill Goodwill represents purchase price in excess of fair value and is related to affiliates of CSXT, primarily P&L Transportation, Inc. Goodwill of $63 million is recorded in other long-term assets in the consolidated balance sheets as of December 2015 and December 2014 , respectively. Revenue and Expense Recognition The Company recognizes freight revenue using Free-On-Board Origin pursuant to the Revenue Recognition Topic in the Accounting Standards Codification ("ASC"). Accounting guidance in this topic provides for the allocation of revenue between reporting periods based on relative transit time in each reporting period. Expenses are recognized as incurred. The certain key estimates included in the recognition and measurement of revenue and related accounts receivable under the policies described above are as follows: • revenue associated with shipments in transit is recognized ratably over transit time and is based on average cycle times to move commodities and products from their origin to their final destination or interchange; • adjustments to revenue for billing corrections, billing discounts and bad debts or to accounts receivable for allowances for doubtful accounts; • adjustments to revenue for overcharge claims filed by customers, which are based on historical cash paid to customers for rate overcharges as a percentage of total billing; • incentive-based refunds to customers, which are primarily based on customers achieving certain volume thresholds and are recorded as a reduction to revenue on the basis of management’s best estimate of the projected liability (this estimate is based on historical activity, current volume levels and a forecast of future volume). NOTE 1. Nature of Operations and Significant Accounting Policies, continued The Company regularly updates the estimates described above based on historical experience and current conditions. All other revenue, such as demurrage, switching and other incidental charges are recorded upon completion of the service. New Accounting Pronouncements In November 2015, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU"), Balance Sheet Classification of Deferred Taxes , which requires that all deferred income taxes be classified as noncurrent in the balance sheet, rather than being separated into current and noncurrent amounts. This standard is effective for annual reporting periods beginning after December 15, 2016 and will not have a material effect on the Company's financial condition, results of operations or liquidity. In July 2015, the FASB issued ASU, Plan Accounting: Defined Benefit Pension Plans (Topic 960), Defined Contribution Pension Plans (Topic 962) and Health and Welfare Benefit Plans (Topic 965): I. Fully Benefit-Responsive Investment Contracts; II. Plan Investment Disclosures; III. Measurement Date Practical Expedient . This three-part update simplifies current benefit plan accounting and requires benefit plans to disaggregate their investments measured using fair value by general type, among other changes. This update is effective for fiscal years beginning after December 15, 2015 and early adoption is permitted. Parts I and III of this update are not applicable to CSX. This update only affects disclosures related to fair value measurement. Adoption does not have an effect on the Company's pension plan net assets available for benefits or its changes in net assets available for benefits. In May 2015, the FASB issued ASU, Disclosures for Investments in Certain Entities That Calculate Net Asset Value per Share (or Its Equivalent). This update eliminates the requirement to categorize investments within the fair value hierarchy if their fair value is measured using the net asset value per share practical expedient. This update requires that investments measured using the net asset value per share be disclosed as a reconciling item between the statement of net assets available for benefits and the fair value hierarchy disclosure. This update is effective for fiscal years beginning after December 15, 2015 and early adoption is permitted. This update only affects disclosures related to fair value measurement. Adoption does not have an effect on the Company's pension plan net assets available for benefits or its changes in net assets available for benefits. In April 2015, the FASB issued ASU, Interest - Imputation of Interest , which changes the financial statement presentation of debt issuance costs to be a direct reduction to long-term debt, rather than presented as a long-term asset. The amortization of debt issuance costs will continue to be included in interest expense. This standard is effective for annual reporting periods beginning after December 15, 2015 and will not have a material effect on the Company's financial condition, results of operations or liquidity. NOTE 1. Nature of Operations and Significant Accounting Policies, continued In May 2014, the FASB issued ASU, Revenue from Contracts with Customers , which supersedes previous revenue recognition guidance. The new standard requires that a company recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration the company expects to receive in exchange for those goods or services. Companies will need to use more judgment and estimates than under the guidance currently in effect, including estimating the amount of variable revenue to recognize over each identified performance obligation. Additional disclosures will be required to help users of financial statements understand the nature, amount and timing of revenue and cash flows arising from contracts. In July 2015, the FASB approved a one-year deferral of the effective date. This standard will now become effective for CSX beginning with the first quarter 2018 and can be adopted either retrospectively to each prior reporting period presented or as a cumulative effect adjustment as of the date of adoption. The Company is currently evaluating the impact of adopting this new guidance on the consolidated financial statements. Use of Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires that management make estimates in reporting the amounts of certain assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amount of certain revenues and expenses during the reporting period. Actual results may differ from those estimates. Critical accounting estimates using management judgment are made for the following areas: • casualty, environmental and legal reserves (see Note 5, Casualty, Environmental and Other Reserves); • pension and post-retirement medical plan accounting (see Note 8, Employee Benefit Plans); • depreciation policies for assets under the group-life method (see Note 6, Properties); and • income taxes (see Note 11, Income Taxes). Other Items Share Repurchases In April 2015, the Company announced a new $2 billion share repurchase program, which is expected to be completed by April 2017. Management's assessment of market conditions and other factors guide the timing and volume of repurchases. Future share repurchases are expected to be funded by cash on hand, cash generated from operations and debt issuances. During 2015 , 2014 and 2013 , CSX repurchased $804 million , or 26 million shares, $517 million or 17 million shares, and $353 million , or 14 million shares, respectively, of common stock. In accordance with the Equity Topic in the ASC, the Company elected to allocate the excess of repurchase price over par value and record in retained earnings. Generally, retained earnings is only impacted by net earnings and dividends. Workforce Reduction Plans, Separation & Other Costs Union agreements In November 2015, CSX finalized a union agreement that will improve efficiency across the CSX network. This agreement allows certain employees impacted by work transitions to voluntarily separate from the Company with enhanced benefits and will provide relocation benefits for employees not electing to separate. As a result, approximately 300 union employees will be impacted. Separation benefits will be paid from general corporate funds. NOTE 1. Nature of Operations and Significant Accounting Policies, continued Facility closures In October 2015, CSX closed facilities in Erwin, Tennessee and Corbin, Kentucky as a result of the decline in coal movements in these regions. These closures impacted approximately 500 positions. The Company recorded a charge resulting from separation, relocation and furlough costs, as well as asset impairment charges related to the facility closures. Separation benefits will be paid from general corporate funds. Management streamlining In 2014, the Company announced a workforce reduction plan to streamline the organization. The initiative reduced management workforce by approximately 300 positions through a voluntary separation program with enhanced benefits as well as a subsequent involuntary severance program during the fourth quarter of 2014 and the first quarter of 2015. The majority of separation benefits were paid from CSX’s qualified pension plans, while the remainder was paid from general corporate funds. The Company recorded a charge for each of the initiatives above as shown in the table below. These amounts are recognized in labor and fringe and materials, supplies and other on the consolidated statements of income. Workforce Reduction Plans, Separation & Other Costs (Dollars in millions) 2015 2014 Union agreements $ 28 $ — Facility closures 19 — Management streamlining 4 39 Total costs $ 51 $ 39

Earnings Per Share

Earnings Per Share	12 Months Ended
	Dec. 25, 2015
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per Share The following table sets forth the computation of basic earnings per share and earnings per share, assuming dilution: Fiscal Years 2015 2014 2013 Numerator (Dollars in Millions) : Net Earnings $ 1,968 $ 1,927 $ 1,864 Dividend Equivalents on Restricted Stock (1 ) (1 ) — Net Earnings, Attributable to Common Shareholders $ 1,967 $ 1,926 $ 1,864 Denominator (Units in Millions) : Average Common Shares Outstanding 983 1,001 1,019 Other Potentially Dilutive Common Shares 1 1 — Average Common Shares Outstanding, Assuming Dilution 984 1,002 1,019 Net Earnings Per Share, Basic $ 2.00 $ 1.93 $ 1.83 Net Earnings Per Share, Assuming Dilution $ 2.00 $ 1.92 $ 1.83 NOTE 2. Earnings Per Share, continued Basic earnings per share is based on the weighted-average number of shares of common stock outstanding. Earnings per share, assuming dilution, is based on the weighted-average number of shares of common stock equivalents outstanding adjusted for the effects of common stock that may be issued as a result of potentially dilutive instruments. CSX's potentially dilutive instruments are made up of employee stock options and equity awards, which include long-term incentive awards. The Earnings Per Share Topic in the ASC requires CSX to include additional shares in the computation of earnings per share, assuming dilution. The additional shares included in diluted earnings per share represent the number of shares that would be issued if all of the above potentially dilutive instruments were converted into CSX common stock. When calculating diluted earnings per share, the Earnings Per Share Topic in the ASC requires CSX to include the potential shares that would be outstanding if all outstanding stock options were exercised. This number is different from outstanding stock options, which is included in Note 4, Stock Plans and Share-Based Compensation, because it is offset by shares CSX could repurchase using the proceeds from these hypothetical exercises to obtain the common stock equivalent. Outstanding stock options were excluded from the diluted earnings per share calculation as the effect of their inclusion currently would be anti-dilutive.

Shareholders' Equity

Shareholders' Equity	12 Months Ended
	Dec. 25, 2015
Stockholders' Equity Note [Abstract]
Stockholders' Equity	Shareholders’ Equity Common and preferred stock consists of the following: Common Stock, $1 Par Value December 2015 (Units in Millions) Common Shares Authorized 1,800 Common Shares Issued and Outstanding 966 Preferred Stock Preferred Shares Authorized 25 Preferred Shares Issued and Outstanding — Holders of common stock are entitled to one vote on all matters requiring a vote for each share held. Preferred stock is senior to common stock with respect to dividends and upon liquidation of CSX.

Stock Plans and Share-Based Com

Stock Plans and Share-Based Compensation	12 Months Ended
	Dec. 25, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock Plans and Share-Based Compensation	Stock Plans and Share-Based Compensation Under CSX's share-based compensation plans, awards primarily consist of performance grants, restricted stock awards, restricted stock units and stock grants for directors. Awards granted under the various programs are determined and approved by the Compensation Committee of the Board of Directors or, in certain circumstances, by the Chief Executive Officer for awards to management employees other than senior executives. The Board of Directors approves awards granted to the Company’s non-management directors upon recommendation of the Governance Committee. The Compensation-Stock Compensation Topic in the ASC requires the cash flows resulting from income tax deductions in excess of compensation costs to be classified as financing cash flows. This requirement resulted in reduced net operating cash flows and increased net financing cash flows of approximately $4 million , $3 million and $13 million for fiscal years 2015 , 2014 and 2013 , respectively. It also requires the disclosure of total compensation costs for share-based payment arrangements and the related tax benefits recognized in income. Share-based compensation expense is measured at the fair market value of the Company’s stock on the grant date and is recognized on a straight-line basis over the service period of the respective award. Total pre-tax expense associated with share-based compensation and its related income tax benefit is shown in the table below. Fiscal Years (Dollars in Millions) 2015 2014 2013 Share-Based Compensation Expense $ 12 $ 33 $ 14 Income Tax Benefit 4 13 6 Stock Options During fourth quarter 2015 , the Company granted 2.5 million in stock options to certain members of management. The fair value of stock options on the date of grant was $5.31 which was estimated using the Black-Scholes valuation model. Stock options have been granted with 10 -year terms and vest three years after the date of grant. The exercise price for options granted equals the closing market price of the underlying stock on the date of grant. Restricted Stock Grants Restricted stock grants consist of units and awards. Restricted stock units are granted as part of the Company's long-term incentive plan, with each unit being equivalent to one share of CSX stock and vest over three years. Restricted stock awards generally vest over an employment period of up to five years. The following table provides information about outstanding restricted stock units and awards combined. As of December 2015 , unrecognized compensation expense for these awards and units was approximately $13 million , which will be expensed over a weighted-average remaining period of 2 years. NOTE 4. Stock Plans and Share-Based Compensation, continued Fiscal Years 2015 2014 2013 Restricted Stock Units and Awards Outstanding (Thousands) (a) 1,157 1,383 1,462 Weighted-Average Fair Value at Grant Date $ 28.66 $ 25.03 $ 23.89 Restricted Stock Units and Awards Expense (Millions) (a) $ 11 $ 11 $ 10 Unvested Restricted Stock Units and Awards Outstanding (Thousands) 406 601 705 Weighted-Average Fair Value of Unvested Units and Awards Outstanding $ 31.35 $ 26.40 $ 24.17 (a) Time-based restricted stock units were granted to certain employees under the respective Long-term Incentive Plans in the amount of 312,000 , 371,000 , and 524,000 in 2015 , 2014 and 2013 , respectively, as described below. These units vest over three years , therefore only a partial amount of expense was recognized in 2015 , 2014 , and 2013 , respectively. Long-term Incentive Plans The CSX Long-term Incentive Plans (“LTIP”) were adopted under the 2010 CSX Stock and Incentive Award Plan. The objective of these long-term incentive plans is to motivate and reward certain employees for achieving and exceeding certain financial and strategic initiatives. Grants were made in performance units, with each unit being equivalent to one share of CSX common stock, and payouts will be made in CSX common stock. The payout range for participants will be between 0% and 200% of the target awards depending on Company performance against predetermined goals for each three -year cycle. In 2013 , 2014 and 2015 , target performance units were granted to certain employees under three separate LTIP plans covering three -year cycles: the 2013-2015 (“2013-2015 LTIP”) , 2014-2016 (“2014-2016 LTIP”) and 2015-2017 (“2015-2017 LTIP”) plans (collectively, the “plans”). The key financial targets for the plans will be based on the achievement of goals related to both operating ratio and return on assets (tax-adjusted operating income divided by net property) excluding non-recurring items as disclosed in the Company's financial statements. The three-year cumulative operating ratio and average return on assets over the performance period will each comprise 50% of the payout and are measured independently of the other. The plans state that payouts for certain executive officers are subject to downward adjustment by up to 30% based upon total shareholder return relative to specified comparable groups. The total benefit recognized due to the plans was $1 million for fiscal year 2015 reflecting adjustments for reduced award payouts. The expense incurred due to the plans was $19 million and $2 million for fiscal years 2014 and 2013 , respectively. LTIP Plan (Plan Ended In) 2015 2016 2017 Number of target units outstanding (Thousands) (a) 1,317 1,115 826 Weighted-average fair value at grant date (a) $ 25.90 $ 28.60 $ 35.94 Payout Range 0% - 200% 0% - 200% 0% - 200% (a) Number of target units granted and weighted-average fair value calculations above include the value of both initial grants and subsequent, smaller grants issued at different prices based on grant date fair value to new or promoted employees not previously included. NOTE 4. Stock Plans and Share-Based Compensation, continued Restricted Stock Units As part of the 2013-2015, 2014-2016 and 2015-2017 LTIP plans, 524 thousand , 371 thousand and 312 thousand restricted stock units, respectively, were granted. The restricted stock units vest three years after the date of grant. Participants receive cash dividend equivalents on the unvested shares during the restriction period. These awards are time-based and are not based upon CSX’s attainment of operational targets. The restricted stock units and expenses are included in the information as shown within the Restricted Stock Grants section above. As of December 2015 , there was $7 million of total unrecognized compensation cost related to these plans that is expected to be recognized over a weighted-average period of approximately 2 years. The activity related to each of the outstanding long-term incentive plans is summarized as follows: LTIP Plan (Plan Ended In) Weighted-Average Fair Value at Grant Date (Units Outstanding, in Thousands) 2015 2016 2017 Unvested at December 27, 2013 1,318 — — $ 25.32 Granted in 2014 52 1,144 — 28.11 Forfeited in 2014 (40 ) (25 ) — 26.33 Unvested at December 26, 2014 1,330 1,119 — 26.66 Granted in 2015 63 134 935 35.45 Forfeited in 2015 (76 ) (138 ) (109 ) 30.06 Vested at December 25, 2015 1,317 — — 25.90 Unvested at December 25, 2015 — 1,115 826 $ 31.73 Stock Awards for Directors CSX’s non-management directors receive an annual retainer of $90,000 to be paid quarterly in cash, unless the director chooses to receive the retainer in the form of CSX common stock. Additionally, non-management directors receive an annual grant of common stock in the amount of approximately $150,000 , with the number of shares to be granted based on the average closing price of CSX stock in the months of November, December and January. The following table provides information about shares issued to directors. Fiscal Years 2015 2014 2013 Shares Issued to Directors (Thousands) 62 79 105 Expense (Millions) $ 2 $ 2 $ 2 Weighted Average Grant Date Stock Price $ 34.59 $ 28.01 $ 23.12 The directors may elect to defer receipt of their fees, in accordance with Internal Revenue Code ("IRC") Section 409A. Deferred cash amounts were credited to an account and invested in a choice of eight investment selections, including a CSX common stock equivalent fund. Distributions are made in accordance with elections made by the directors, consistent with the terms of the Directors' Deferred Compensation Plan.

Casualty, Environmental and Oth

Casualty, Environmental and Other Reserves	12 Months Ended
	Dec. 25, 2015
Casualty, Environmental and Other Reserves [Abstract]
Casualty, Environmental and Other Reserves	Casualty, Environmental and Other Reserves Activity related to casualty, environmental and other reserves is as follows: Casualty Environmental Other (Dollars in Millions) Reserves Reserves Reserves Total December 28, 2012 $ 325 $ 88 $ 64 $ 477 Charged to Expense 54 48 38 140 Payments (99 ) (36 ) (31 ) (166 ) December 27, 2013 280 100 71 451 Charged to Expense (a) 89 57 30 176 Payments (104 ) (63 ) (42 ) (209 ) December 26, 2014 265 94 59 418 Charged to Expense 60 45 37 142 Payments (56 ) (57 ) (47 ) (160 ) December 25, 2015 $ 269 $ 82 $ 49 $ 400 (a) Increase in expense in 2014 is primarily due to the resolution of personal injury claims for prior years. These reserves are considered critical accounting estimates due to the need for significant management judgment. They are provided for in the consolidated balance sheets as shown in the table below. December 2015 December 2014 (Dollars in Millions) Current Long-term Total Current Long-term Total Casualty: Personal Injury $ 57 $ 147 $ 204 $ 68 $ 123 $ 191 Asbestos 9 44 53 5 51 56 Occupational 3 9 12 3 15 18 Total Casualty $ 69 $ 200 $ 269 $ 76 $ 189 $ 265 Environmental 42 40 82 48 46 94 Other 20 29 49 18 41 59 Total $ 131 $ 269 $ 400 $ 142 $ 276 $ 418 These liabilities are accrued when estimable and probable in accordance with the Contingencies Topic in the ASC. Actual settlements and claims received could differ and final outcome of these matters cannot be predicted with certainty. Considering the legal defenses currently available, the liabilities that have been recorded and other factors, it is the opinion of management that none of these items individually, when finally resolved, will have a material effect on the Company's financial condition, results of operations or liquidity. Should a number of these items occur in the same period, however, they could have a material effect on the Company's financial condition, results of operations or liquidity in that particular period. NOTE 5. Casualty, Environmental and Other Reserves, continued Casualty Casualty reserves of $265 million and $269 million for 2014 and 2015 , respectively, represent accruals for personal injury, asbestos and occupational injury claims. The Company's self-insured retention amount for these claims is $50 million per occurrence. Currently, no individual claim is expected to exceed the self-insured retention amount. In accordance with the Contingencies Topic in the ASC, to the extent the value of an individual claim exceeds the self-insured retention amount, the Company would present the liability on a gross basis with a corresponding receivable for insurance recoveries. These reserves fluctuate based upon the timing of payments as well as changes in estimate. Actual results may vary from estimates due to the number, type and severity of the injury, costs of medical treatments and uncertainties in litigation. Most of the Company's casualty claims relate to CSXT unless otherwise noted below. Defense and processing costs, which historically have been insignificant and are anticipated to be insignificant in the future, are not included in the recorded liabilities. During 2015, 2014 and 2013, there were no significant changes in estimate recorded to adjust casualty reserves. Personal Injury Personal injury reserves represent liabilities for employee work-related and third-party injuries. Work-related injuries for CSXT employees are primarily subject to FELA. In addition to FELA liabilities, employees of other current or former CSX subsidiaries are covered by various state workers’ compensation laws, the Federal Longshore and Harbor Workers’ Compensation Program or the Maritime Jones Act. CSXT retains an independent actuary to assist management in assessing the value of personal injury claims. An analysis is performed by the actuary quarterly and is reviewed by management. The methodology used by the actuary includes a development factor to reflect growth or reduction in the value of these personal injury claims. It is based largely on CSXT's historical claims and settlement experience. Asbestos & Occupational The Company is party to a number of asbestos claims by employees alleging exposure to asbestos in the workplace. The greatest possible exposure for employees resulted from work conducted in and around steam locomotive engines that were largely phased out beginning around the 1950s. Other types of exposures, however, including exposure from locomotive component parts and building materials, continued until these exposures were substantially eliminated by 1985. Additionally, the Company has retained liability for asbestos claims filed against its previously owned international container shipping business. Diseases associated with asbestos typically have long latency periods (amount of time between exposure to asbestos and the onset of the disease) which can range from 10 to 40 years after exposure. Management reviews asserted asbestos claims quarterly. Since exposure to asbestos has been substantially eliminated, unasserted or incurred but not reported ("IBNR") asbestos claims are analyzed by a third-party specialist and reviewed by management annually. In 2014, management extended the forecast period from 7 years to 10 years. Based on a review of historical settlement trends, management concluded that ten years is the most probable time period in which unasserted asbestos claim filings and claim values can be estimated. The Company does not believe there is sufficient data to justify a projection period longer than 10 years at this time. The change in the forecast period resulted in an immaterial increase in the asbestos reserves during 2014. Approximately 20% of the recorded undiscounted liability is related to asserted claims and approximately 80% is related to unasserted claims as of December 25, 2015. NOTE 5. Casualty, Environmental and Other Reserves, continued CSXT’s historical claim filings, settlement amounts, and dismissal rates are analyzed to determine future anticipated claim filing rates and average settlement values for asbestos claims reserves. The potentially exposed population is estimated by using CSXT’s employment records and industry data. From this analysis, the specialist estimates the IBNR claims liabilities. Occupational claims arise from allegations of exposure to certain materials in the workplace, such as solvents, soaps, chemicals (collectively referred to as “irritants”) and diesel fuels (like exhaust fumes) or allegations of chronic physical injuries resulting from work conditions, such as repetitive stress injuries, carpal tunnel syndrome and hearing loss. A summary of asbestos claims activity is as follows: Fiscal Years 2015 2014 Asserted Asbestos Claims Open Claims - Beginning of Year 177 251 New Claims Filed 77 106 Claims Settled (64 ) (95 ) Claims Dismissed (30 ) (85 ) Open Claims - End of Year 160 177 Environmental Environmental reserves were $94 million and $82 million for 2014 and 2015 , respectively. The Company is a party to various proceedings related to environmental issues, including administrative and judicial proceedings involving private parties and regulatory agencies. The Company has been identified as a potentially responsible party at approximately 242 environmentally impaired sites. Many of these are, or may be, subject to remedial action under the federal Comprehensive Environmental Response, Compensation and Liability Act of 1980 ("CERCLA"), also known as the Superfund Law, or similar state statutes. Most of these proceedings arose from environmental conditions on properties used for ongoing or discontinued railroad operations. A number of these proceedings, however, are based on allegations that the Company, or its predecessors, sent hazardous substances to facilities owned or operated by others for treatment, recycling or disposal. In addition, some of the Company’s land holdings were leased to others for commercial or industrial uses that may have resulted in releases of hazardous substances or other regulated materials onto the property and could give rise to proceedings against the Company. In any such proceedings, the Company is subject to environmental clean-up and enforcement actions under the Superfund Law, as well as similar state laws that may impose joint and several liability for clean-up and enforcement costs on current and former owners and operators of a site without regard to fault or the legality of the original conduct. These costs could be substantial. NOTE 5. Casualty, Environmental and Other Reserves, continued In accordance with the Asset Retirement and Environmental Obligations Topic in the ASC, the Company reviews its role with respect to each site identified at least quarterly, giving consideration to a number of factors such as: • type of clean-up required; • nature of the Company’s alleged connection to the location (e.g., generator of waste sent to the site or owner or operator of the site); • extent of the Company’s alleged connection (e.g., volume of waste sent to the location and other relevant factors); and • number, connection and financial viability of other named and unnamed potentially responsible parties at the location. Based on the review process, the Company has recorded amounts to cover contingent anticipated future environmental remediation costs with respect to each site to the extent such costs are estimable and probable. The recorded liabilities for estimated future environmental costs are undiscounted. The liability includes future costs for remediation and restoration of sites as well as any significant ongoing monitoring costs, but excludes any anticipated insurance recoveries. Payments related to these liabilities are expected to be made over the next several years. Environmental remediation costs are included in materials, supplies and other on the consolidated income statement. Currently, the Company does not possess sufficient information to reasonably estimate the amounts of additional liabilities, if any, on some sites until completion of future environmental studies. In addition, conditions that are currently unknown could, at any given location, result in additional exposure, the amount and materiality of which cannot presently be reasonably estimated. Based upon information currently available, however, the Company believes its environmental reserves accurately reflect the estimated cost of remedial actions currently required. Other Other reserves of $59 million and $49 million for 2014 and 2015 , respectively, include liabilities for various claims, such as property, automobile and general liability. Also included in other reserves are longshoremen disability claims related to a previously owned international shipping business (these claims are in runoff) as well as claims for current port employees.

Properties

Properties	12 Months Ended
	Dec. 25, 2015
Property, Plant and Equipment [Abstract]
Properties	Properties A detail of the Company’s net properties are as follows: (Dollars in Millions) Accumulated Net Book Annual Depreciation Depreciation Estimated Useful December 2015 Cost Depreciation Value Rate Method Life Road Rail and Other Track Material $ 7,150 $ (1,414 ) $ 5,736 2.5% Group Life Ties 5,077 (1,147 ) 3,930 3.7% Group Life Grading 2,533 (479 ) 2,054 1.4% Group Life Ballast 2,793 (802 ) 1,991 2.7% Group Life Bridges, Trestles, and Culverts 2,238 (283 ) 1,955 1.6% Group Life Signals and Interlockers 2,315 (416 ) 1,899 4.0% Group Life Buildings 1,152 (424 ) 728 2.5% Group Life Other 4,306 (1,793 ) 2,513 4.2% Group Life Total Road 27,564 (6,758 ) 20,806 8-90 Years Equipment Locomotive 5,673 (2,461 ) 3,212 3.6% Group Life Freight Cars 3,362 (1,018 ) 2,344 3.2% Group Life Work Equipment and Other 2,073 (1,154 ) 919 7.1% Group Life Total Equipment 11,108 (4,633 ) 6,475 3-38 Years Land 1,858 — 1,858 N/A N/A N/A Construction In Progress 1,003 — 1,003 N/A N/A N/A Other 41 (9 ) 32 N/A Straight Line 4-30 Years Total Properties $ 41,574 $ (11,400 ) $ 30,174 NOTE 6. Properties, continued (Dollars in Millions) Accumulated Net Book Annual Depreciation Depreciation Estimated Useful December 2014 Cost Depreciation Value Rate Method Life Road Rail and Other Track Material $ 6,771 $ (1,400 ) $ 5,371 2.5% Group Life Ties 4,807 (1,060 ) 3,747 3.7% Group Life Grading 2,460 (481 ) 1,979 1.4% Group Life Ballast 2,693 (679 ) 2,014 2.7% Group Life Bridges, Trestles, and Culverts 2,119 (278 ) 1,841 1.6% Group Life Signals and Interlockers 2,103 (356 ) 1,747 4.0% Group Life Buildings 1,102 (377 ) 725 2.5% Group Life Other 4,070 (1,517 ) 2,553 4.2% Group Life Total Road 26,125 (6,148 ) 19,977 8-90 Years Equipment Locomotive 5,036 (2,325 ) 2,711 3.6% Group Life Freight Cars 3,244 (1,169 ) 2,075 3.2% Group Life Work Equipment and Other 1,828 (1,032 ) 796 7.1% Group Life Total Equipment 10,108 (4,526 ) 5,582 3-38 Years Land 1,875 — 1,875 N/A N/A N/A Construction In Progress 1,196 — 1,196 N/A N/A N/A Other 39 (85 ) (46 ) N/A Straight Line 4-30 Years Total Properties $ 39,343 $ (10,759 ) $ 28,584 Railroad Assets The Company depreciates its rail assets, including main-line track, locomotives and freight cars, using the group-life method of accounting. Assets depreciated under the group-life method of accounting comprise 86% of total fixed assets of $42 billion on a gross basis as of December 2015 . All other depreciable assets of the Company are depreciated on a straight-line basis. The group-life method aggregates assets with similar lives and characteristics into groups and depreciates each of these groups as a whole. When using the group-life method, an underlying assumption is that each group of assets, as a whole, is used and depreciated to the end of its recoverable life. The Company currently utilizes more than 130 different depreciable asset categories to account for depreciation expense for the railroad assets that are depreciated under the group-life method of accounting. Examples of depreciable asset categories include 18 different categories for crossties due to the different combinations of density classifications and asset types. By utilizing various depreciable categories, the Company can more accurately account for the use of its assets. All assets of the Company are depreciated on a time or life basis. The Company believes the group-life method of depreciation closely approximates the straight-line method of depreciation. Additionally, due to the nature of most of its assets (e.g. track is one contiguous, connected asset) the Company believes that this is the most effective way to properly depreciate its assets. NOTE 6. Properties, continued Under the group-life method of accounting, the service lives and salvage values for each group of assets are determined by completing periodic depreciation studies and applying management’s assumptions regarding the service lives of its properties. A depreciation study (also referred to as a life study) is the periodic review of asset service lives, salvage values, accumulated depreciation, and other related factors for group assets conducted by a third-party specialist, analyzed by the Company’s management and approved by the Surface Transportation Board (“STB”), the regulatory board that has broad jurisdiction over railroad practices. The STB requires depreciation studies be performed for equipment assets generally every three years and for road (e.g. bridges and signals) and track (e.g. rail, ties and ballast) assets generally every six years. The Company believes the frequency currently required by the STB provides adequate review of asset service lives and that a more frequent review would not result in a material change due to the long-lived nature of most of the assets. In 2014, the Company completed a depreciation study for its road and track assets. In 2012, the Company completed a depreciation study for its equipment assets and a technical update (an update to the prior depreciation study) for its road and track assets. The Company plans to complete the next depreciation study for road and track assets in 2020 and for equipment assets in 2016. The results of the depreciation study process determine the service lives for each asset group under the group-life method. Road assets, including main-line track, have estimated service lives ranging from eight years for system roadway machinery to 90 years for grading (construction of protection for the roadway, tracks and embankments). Equipment assets, including locomotives and freight cars, have estimated service lives ranging from three years for technology assets to 38 years for work equipment. Changes in asset service lives due to the results of the depreciation studies are applied on a prospective basis and could significantly impact future periods’ depreciation expense, and thus, the Company's results of operations. There are several factors taken into account during the depreciation study and they include: • statistical analysis of historical life and salvage data for each group of property; • statistical analysis of historical retirements for each group of property; • evaluation of current operations; • evaluation of technological advances and maintenance schedules; • previous assessment of the condition of the assets; • management's outlook on the future use of certain asset groups; • expected net salvage to be received upon retirement; and • comparison of assets to the same asset groups with other companies. NOTE 6. Properties, continued For retirements or disposals of depreciable rail assets that occur in the ordinary course of business, the asset cost (net of salvage value or sales proceeds) is charged to accumulated depreciation and no gain or loss is recognized. As individual assets within a specific group are retired or disposed of, resulting gains and losses are recorded in accumulated depreciation. This practice is consistent with accounting treatment normally prescribed under the group-life method. As part of the depreciation study, an assessment of the recorded amount of accumulated depreciation is made to determine if it is deficient (or in excess) of the appropriate amount indicated by the study. Any such deficiency (or excess), including any deferred gains or losses, is amortized as a component of depreciation expense over the remaining service life of the asset group until the next required depreciation study. Since the overall assumption with the group-life method of accounting is that the assets within the group on average have the same service life and characteristics, it is therefore concluded that the deferred gains and losses offset over time. Since the rail network is one contiguous, connected network it is impractical to maintain specific identification records for these assets. For road assets (such as rail and track related items), CSX utilizes a first-in, first-out approach to asset retirements. The historical cost of these replaced assets is estimated using inflation indices published by the Bureau of Labor Statistics applied to the replacement value based on the age of the retired asset. The indices are used because they closely correlate with the major cost of the materials comprising the applicable road assets. Equipment assets (such as locomotives and freight cars) are specifically identified at retirement. When an equipment asset is retired that has been depreciated using the group-life method, the cost is reduced from the cost base and recorded in accumulated depreciation. In the event that large groups of assets are removed from service as a result of unusual acts or sales, resulting gains and losses are recognized immediately. These acts are not considered to be in the normal course of business and are therefore recognized when incurred. Examples of such acts would be the major destruction of assets due to significant storm damage (e.g. major hurricanes), the sale of a rail line segment or the disposal of an entire class of assets (e.g. disposal of all refrigerated freight cars). Abnormal operating gains were $23 million in 2015 primarily related to the sale of an operating rail line segment. There were no abnormal operating gains or losses in 2014 . Abnormal operating gains of $65 million in 2013 were related to a deferred gain from the 2011 sale of an operating rail line segment as well as a non-monetary exchange of easements and rail assets. Recent experience with depreciation studies has resulted in depreciation rate changes, which did not materially affect the Company’s annual depreciation expense of $1.2 billion , $1.2 billion and $1.1 billion for 2015 , 2014 and 2013 , respectively. In general, changes in depreciation rates result from updated average asset service lives as determined during depreciation studies. Non-Railroad Assets, Capital Leases and Land The majority of non-railroad property is depreciated using the straight-line method on a per asset basis. The depreciable lives of this property are periodically reviewed by the Company and any changes are applied on a prospective basis. Amortization expense recorded under capital leases is included in depreciation expense on the consolidated income statements. For retirements or disposals of non-railroad depreciable assets and all dispositions of land, the resulting gains or losses are recognized in earnings at the time of disposal. During 2015, the Company recognized a gain of $59 million related to the sale of non-operating easements, which is recognized in other income on the consolidated statements of income. (For additional information regarding cost reimbursements related to this sale, see Note 10, Other Income.) These gains and losses were not material for any other period presented. NOTE 6. Properties, continued Impairment Review Properties and other long-lived assets are reviewed for impairment annually or whenever events or business conditions indicate the carrying amount of such assets may not be fully recoverable. Initial assessments of recoverability are based on estimates of undiscounted future net cash flows associated with an asset or a group of assets in accordance with the Property, Plant, and Equipment Topic in the ASC. Where impairment is indicated, the assets are evaluated and their carrying amount is reduced to fair value based on discounted net cash flows or other estimates of fair value. Capital Expenditures The Company’s capital investment includes purchased or self-constructed assets and property additions that substantially extend the service life or increase the utility of those assets. Indirect costs that can be specifically traced to capital projects are also capitalized. The Company is committed to maintaining and improving its existing infrastructure and expanding its network for long-term growth. Rail operations are capital intensive and CSX accounts for these costs in accordance with GAAP and the Company’s capitalization policy. All properties are stated at historical cost less an allowance for accumulated depreciation. The Company’s largest category of capital investment is the replacement of track assets and the acquisition or construction of new assets that enable CSX to enhance its operations or provide new capacity offerings to its customers. These construction projects are typically completed by CSXT employees. Costs for track asset replacement and capacity projects that are capitalized include: • labor costs, because many of the assets are self-constructed; • costs to purchase or construct new track or to prepare ground for the laying of track; • welding (rail, field and plant) which are processes used to connect segments of rail; • new ballast, which is gravel and crushed stone that holds track in line; • fuels and lubricants associated with tie, rail and surfacing work which is the process of raising track to a designated elevation over an extended distance; • cross, switch and bridge ties which are the braces that support the rails on a track; • gauging which is the process of standardizing the distance between rails; • handling costs associated with installing ties or ballast; • usage charge of machinery and equipment utilized in construction or installation; and • other track materials. The primary cost in self-constructed track replacement work is labor. CSXT engineering employees directly charge their labor to the track replacement project (the capitalized depreciable property). These employees concurrently perform deconstruction and installation of track material. Because of this concurrent process, CSX must estimate the amount of labor that is related to deconstruction versus installation. Through analysis of CSXT’s track replacement process, CSX determined that approximately 20% of labor costs associated with track material installation is related to the deconstruction of old track and 80% is associated with the installation of new track. NOTE 6. Properties, continued Capital investment related to locomotives and freight cars comprises the second largest category of the Company’s capital assets. This category includes purchase costs of locomotives and freight cars as well as certain equipment leases that are considered to be capital leases in accordance with the Leases Topic in the ASC. In addition, costs to modify or rebuild these assets are capitalized if the investment incurred extends the asset’s service life or improves utilization. Improvement projects must meet specified dollar thresholds to be capitalized and are reviewed by management to determine proper accounting treatment. Routine repairs and maintenance costs, for all asset categories, are expensed as incurred.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 25, 2015
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Lease Commitments The Company has various lease agreements with other parties with terms up to 30 years. Non-cancelable, long-term leases may include provisions for maintenance, options to purchase and options to extend the terms. The Company uses the straight-line method to recognize rent expense associated with operating leases that include escalations over their terms. These amounts are shown in the table below. Fiscal Years (Dollars in Millions) 2015 2014 2013 Rent Expense on Operating Leases $ 66 $ 61 $ 60 At December 2015 , minimum rentals on land, buildings, track and equipment under operating leases are disclosed in the table below. Also, payments to Conrail for leases on shared rail infrastructure are included in these amounts. (See Note 12, Related Party Transactions). (Dollars in Millions) Operating Sublease Net Lease Years Leases Income Commitments 2016 $ 76 $ (3 ) $ 73 2017 69 (3 ) 66 2018 55 (2 ) 53 2019 53 (2 ) 51 2020 35 (2 ) 33 Thereafter 167 (8 ) 159 Total $ 455 $ (20 ) $ 435 Purchase Commitments CSXT has a commitment under a long-term maintenance program that currently covers 50% of CSXT’s fleet of locomotives. The agreement is based on the maintenance cycle for each locomotive. Under CSXT’s current obligations, the agreement will expire no earlier than 2031 . The costs expected to be incurred throughout the duration of the agreement fluctuate as locomotives are placed into or removed from service, or as required maintenance schedules are revised. The table below includes both active and inactive locomotives covered under this agreement. NOTE 7. Commitments and Contingencies, continued The following table summarizes the number of locomotives covered and CSXT’s payments under the long-term maintenance program. Fiscal Years (Dollars in Millions) 2015 2014 2013 Amounts Paid $ 233 $ 247 $ 287 Number of Locomotives 2,310 1,886 1,886 Annual payments related to the locomotive purchase obligations, including amounts that would be payable under the long-term maintenance program, are estimated in the table below. The amount of the ultimate purchase commitment depends upon the model of locomotive acquired and the timing of delivery. Additionally, the Company has various other commitments to purchase technology, communications, railcar maintenance and other services from various suppliers. Total annual payments under all of these purchase commitments are also estimated in the table below. (Dollars in Millions) Locomotive & Maintenance Payments Other Commitments Total 2016 $ 570 $ 110 $ 680 2017 561 74 635 2018 287 20 307 2019 306 17 323 2020 316 12 328 Thereafter 4,515 64 4,579 Total $ 6,555 $ 297 $ 6,852 Insurance The Company maintains numerous insurance programs with substantial limits for property damage (which includes business interruption) and third-party liability. A certain amount of risk is retained by the Company on each of the property and liability programs. The Company has a $25 million retention per occurrence for the non-catastrophic property program (such as a derailment) and a $50 million retention per occurrence for the liability and catastrophic property programs (such as hurricanes and floods). While the Company believes its insurance coverage is adequate, future claims could exceed existing insurance coverage or insurance may not continue to be available at commercially reasonable rates. NOTE 7. Commitments and Contingencies, continued Legal The Company is involved in litigation incidental to its business and is a party to a number of legal actions and claims, various governmental proceedings and private civil lawsuits, including, but not limited to, those related to fuel surcharge practices, environmental and hazardous material exposure matters, FELA and labor claims by current or former employees, other personal injury or property claims and disputes and complaints involving certain transportation rates and charges. Some of the legal proceedings include claims for compensatory as well as punitive damages and others are, or are purported to be, class actions. While the final outcome of these matters cannot be predicted with certainty, considering, among other things, the legal defenses available and liabilities that have been recorded along with applicable insurance, it is currently the opinion of management that none of these pending items will have a material adverse effect on the Company's financial condition, results of operations or liquidity. An unexpected adverse resolution of one or more of these items, however, could have a material adverse effect on the Company's financial condition, results of operations or liquidity in that particular period. The Company is able to estimate a range of possible loss for certain legal proceedings for which a loss is reasonably possible in excess of reserves established. The Company has estimated this range to be $2 million to $78 million in aggregate at December 25, 2015 . This estimated aggregate range is based upon currently available information and is subject to significant judgment and a variety of assumptions. Accordingly, the Company's estimate will change from time to time, and actual losses may vary significantly from the current estimate. Fuel Surcharge Antitrust Litigation In May 2007, class action lawsuits were filed against CSXT and three other U.S.-based Class I railroads alleging that the defendants' fuel surcharge practices relating to contract and unregulated traffic resulted from an illegal conspiracy in violation of antitrust laws. In November 2007, the class action lawsuits were consolidated in federal court in the District of Columbia, where they are now pending. The suit seeks treble damages allegedly sustained by purported class members as well as attorneys' fees and other relief. Plaintiffs are expected to allege damages at least equal to the fuel surcharges at issue. In June 2012, the District Court certified the case as a class action. The decision was not a ruling on the merits of plaintiffs' claims, but rather a decision to allow the plaintiffs to seek to prove the case as a class. The defendant railroads petitioned the U.S. Court of Appeals for the D.C. Circuit for permission to appeal the District Court's class certification decision. In August 2013, the D.C. Circuit issued a decision vacating the class certification decision and remanded the case to the District Court to reconsider its class certification decision. The District Court remand proceedings are underway. Although a class certification hearing had been scheduled for November 2015, it has been postponed pending the U.S. Supreme Court’s decision on a class certification issue in an unrelated case. The District Court has delayed proceedings on the merits of the case pending the outcome of the class certification remand proceedings. CSXT believes that its fuel surcharge practices were arrived at and applied lawfully and that the case is without merit. Accordingly, the Company intends to defend itself vigorously. However, penalties for violating antitrust laws can be severe, and an unexpected adverse decision on the merits could have a material adverse effect on the Company's financial condition, results of operations or liquidity in that particular period. NOTE 7. Commitments and Contingencies, continued Environmental CSXT has indemnified Pharmacia LLC (formerly known as Monsanto Company) for certain liabilities associated with real estate located in Kearny, New Jersey along the Lower Passaic River (the “Property”). The Property, which was formerly owned by Pharmacia, is now owned by CSXT. CSXT's indemnification and defense duties arise with respect to several matters. CSXT, on behalf of Pharmacia, is conducting a Remedial Investigation and Feasibility Study of the 17 -mile Lower Passaic River Study Area with approximately 55 other parties pursuant to an Administrative Settlement Agreement and Order on Consent with the U.S. Environmental Protection Agency ("EPA"). The EPA, using its CERCLA authority, seeks cleanup and removal costs and other damages associated with the presence of hazardous substances in the Lower Passaic River Study Area. In April 2014, the EPA announced its proposed plan to remediate the lower 8 miles of the Lower Passaic River, which was based on a Focused Feasibility Study. After review of public comments, EPA is expected to issue its cleanup plan for the lower eight miles of the Lower Passaic River in 2016. CSXT is also defending and indemnifying Pharmacia in a cooperative natural resource damages assessment process related to the Property . Based on currently available information, the Company does not believe any remediation costs potentially allocable to CSXT would be material to the Company's financial condition, results of operations or liquidity.

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 25, 2015
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Abstract]
Employee Benefit Plans	Employee Benefit Plans The Company sponsors defined benefit pension plans principally for salaried, management personnel. For employees hired prior to January 1, 2003 , the plans provide eligible employees with retirement benefits based predominantly on years of service and compensation rates near retirement. For employees hired in 2003 or thereafter, benefits are determined based on a cash balance formula, which provides benefits by utilizing interest and pay credits based upon age, service and compensation. In addition to these plans, the Company sponsors a post-retirement medical plan and a life insurance plan that provide benefits to full-time, salaried, management employees, hired prior to January 1, 2003 , upon their retirement if certain eligibility requirements are met. Eligible retirees who are age 65 years or older (Medicare-eligible) are covered by a health reimbursement arrangement, which is an employer-funded account that can be used for reimbursement of eligible medical expenses. Eligible retirees younger than 65 years (non-Medicare eligible) are covered by a self-insured program partially funded by participating retirees. The life insurance plan is non-contributory. The Company engages independent actuaries to compute the amounts of liabilities and expenses relating to these plans subject to the assumptions that the Company selects. These amounts are reviewed by management. In order to perform this valuation, the actuaries are provided with the details of the population covered at the beginning of the year, summarized in the table below, and projects that population forward to the end of the year . NOTE 8. Employee Benefit Plans, continued Summary of Participants as of January 1, 2015 Pension Plans Post-retirement Medical Plan Active Employees 5,234 1,212 Retirees and Beneficiaries 11,777 12,957 Other (a) 3,781 69 Total 20,792 14,238 (a) For pension plans, the other category consists mostly of terminated but vested former employees. For post-retirement plans, the other category consists of employees on long-term disability that have not yet retired. The benefit obligation for these plans represents the liability of the Company for current and retired employees and is affected primarily by the following: • service cost (benefits attributed to employee service during the period); • interest cost (interest on the liability due to the passage of time); • actuarial gains/losses (experience during the year different from that assumed and changes in plan assumptions); and • benefits paid to participants. Cash Flows Plan assets are amounts that have been segregated and restricted to provide qualified pension plan benefits and include amounts contributed by the Company and amounts earned from invested contributions, net of benefits paid. Qualified pension plan obligations are funded in accordance with regulatory requirements and with an objective of meeting minimum funding requirements necessary to avoid restrictions on flexibility of plan operation and benefit payments. The Company funds the cost of the post-retirement medical and life insurance benefits as well as nonqualified pension benefits on a pay-as-you go basis. No contributions were made during 2013, 2014 and 2015. No contributions to the Company's qualified pension plans are expected in 2016 . Future expected benefit payments are as follows: Expected Cash Flows (Dollars in Millions) Pension Benefits Post-retirement Benefits 2016 $ 187 $ 36 2017 188 34 2018 188 31 2019 183 29 2020 183 27 2021-2025 917 107 Total $ 1,846 $ 264 NOTE 8. Employee Benefit Plans, continued Plan Assets The CSX Investment Committee (the “Investment Committee”), whose members were selected by the Chief Financial Officer and approved by the Chief Executive Officer, is responsible for oversight and investment of plan assets. The Investment Committee utilizes an investment asset allocation strategy that is monitored on an ongoing basis and that is updated periodically in consideration of plan or employee changes, or changing market conditions. These studies provide an extensive modeling of asset investment return in conjunction with projected plan liabilities and seek to evaluate how to maximize return within the constraints of acceptable risk. The current asset allocation targets 70% equity investments and 30% fixed income investments and cash. Within equity, a further target is currently established for 42% of total plan assets in domestic equity and 28% in international equity. Allocations are evaluated for levels within 3% of targeted allocations and are adjusted quarterly as necessary. The distribution of pension plan assets as of the measurement date is shown in the table below, and these assets are netted against the pension liabilities on the balance sheet. December 2015 December 2014 Percent of Percent of (Dollars in Millions) Amount Total Assets Amount Total Assets Equity $ 1,626 70 % $ 1,715 68 % Fixed Income 641 28 740 30 Cash and Cash Equivalents 42 2 49 2 Total $ 2,309 100 % $ 2,504 100 % Under the supervision of the Investment Committee, individual investments or fund managers are selected in accordance with standards of prudence applicable to asset diversification and investment suitability. The Company also selects fund managers with differing investment styles and benchmarks their investment returns against appropriate indices. Fund investment performance is continuously monitored. Acceptable performance is determined in the context of the long-term return objectives of the fund and appropriate asset class benchmarks. Within the Company's equity funds, the U.S. stock segment includes diversification among large and small capitalization stocks. The international stock segment is diversified in a similar manner as well as in developed versus emerging markets stocks. Guidelines established with individual managers limit investment by industry sectors, individual stock issuer concentration and the use of derivatives and CSX securities. Fixed income securities guidelines established with individual managers specify the types of allowable investments, such as government, corporate and asset-backed bonds, targets certain allocation ranges for domestic and foreign investments and limits the use of certain derivatives. Additionally, guidelines stipulate minimum credit quality constraints and any prohibited securities. For detailed information regarding the fair value of pension assets, see Note 13, Fair Value Measurements. NOTE 8. Employee Benefit Plans, continued Benefit Obligation, Plan Assets and Funded Status Changes in benefit obligation and the fair value of plan assets for the 2015 and 2014 calendar plan years are as follows: Pension Benefits Post-retirement Benefits Plan Year Plan Year Plan Year Plan Year (Dollars in Millions) 2015 2014 2015 2014 Actuarial Present Value of Benefit Obligation Accumulated Benefit Obligation $ 2,672 $ 2,849 N/A N/A Projected Benefit Obligation 2,860 3,002 $ 314 $ 340 Change in Projected Benefit Obligation: Projected Benefit Obligation at Beginning of Plan Year $ 3,002 $ 2,679 $ 340 $ 350 Service Cost 45 44 2 3 Interest Cost 116 123 12 13 Plan Participants' Contributions — — 7 7 Workforce Reduction Program/Curtailment 7 27 — 8 Actuarial Loss (Gain) (110 ) 333 (7 ) (8 ) Benefits Paid (200 ) (204 ) (40 ) (33 ) Benefit Obligation at End of Plan Year $ 2,860 $ 3,002 $ 314 $ 340 Change in Plan Assets: Fair Value of Plan Assets at Beginning of Plan Year $ 2,504 $ 2,500 $ — $ — Actual Return on Plan Assets (9 ) 195 — — Non-qualified Employer Contributions 14 13 33 26 Plan Participants' Contributions — — 7 7 Benefits Paid (200 ) (204 ) (40 ) (33 ) Fair Value of Plan Assets at End of Plan Year 2,309 2,504 — — Funded Status at End of Plan Year $ (551 ) $ (498 ) $ (314 ) $ (340 ) For qualified plan funding purposes, assets and discounted liabilities are measured in accordance with the Employee Retirement Income Security Act ("ERISA"), as well as other related provisions of the IRC and related regulations. Under these funding provisions and the alternative measurements available thereunder, the Company estimates its unfunded obligation for qualified plans on an annual basis. In accordance with Compensation-Retirement Benefits Topic in the ASC, an employer must recognize the funded status of a pension or other post-retirement benefit plan by recording a liability (underfunded plan) or asset (overfunded plan) for the difference between the projected benefit obligation (or the accumulated post-retirement benefit obligation for a post-retirement benefit plan) and the fair value of plan assets at the plan measurement date. Amounts related to pension and post-retirement benefits recorded in other long-term assets, labor and fringe benefits payable and other long-term liabilities on the balance sheet are as follows: NOTE 8. Employee Benefit Plans, continued Pension Benefits Post-retirement Benefits December December December December (Dollars in Millions) 2015 2014 2015 2014 Amounts Recorded in Consolidated Balance Sheets: Long-term Assets (a) $ 9 $ 9 $ — $ — Current Liabilities (15 ) (15 ) (36 ) (37 ) Long-term Liabilities (545 ) (492 ) (278 ) (303 ) Net Amount Recognized in Consolidated Balance Sheets $ (551 ) $ (498 ) $ (314 ) $ (340 ) (a) Long-term assets as of December 2015 and 2014 relate to one of the qualified pension plans whose assets exceed projected benefit obligations. The funded status, or amount by which the benefit obligation exceeds the fair value of plan assets, represents a liability. At December 2015 , the status of CSX plans only with a net liability is disclosed below. The total fair value of all plans as of December 2015 was $2.3 billion , which includes the qualified pension plans with net assets. Aggregate Aggregate (Dollars in Millions) Fair Value Projected Benefit Obligations in Excess of Plan Assets of Plan Assets Benefit Obligation Projected Benefit Obligation $ 2,273 $ (2,833 ) Accumulated Benefit Obligation 2,273 (2,645 ) NOTE 8. Employee Benefit Plans, continued Net Benefit Expense The following table describes the components of expense/(income) related to net benefit expense recorded in labor and fringe on the income statement. Pension Benefits Fiscal Years Post-retirement Benefits Fiscal Years (Dollars in Millions) 2015 2014 2013 2015 2014 2013 Service Cost $ 45 $ 44 $ 49 $ 2 $ 3 $ 3 Interest Cost 116 123 108 12 13 13 Expected Return on Plan Assets (162 ) (166 ) (162 ) — — — Amortization of Net Loss 70 57 100 4 5 14 Amortization of Prior Service Cost — — — (1 ) (1 ) (1 ) Net Periodic Benefit Expense 69 58 95 17 20 29 Special Termination Benefits - Workforce Reduction Program/Curtailment (a) 7 27 — — 8 — Settlement Gain (b) (2 ) (1 ) (2 ) — — — Total Expense $ 74 $ 84 $ 93 $ 17 $ 28 $ 29 (a) Special termination benefits are charges in 2015 and 2014 that resulted from a management workforce reduction program initiated in 2014. For further information regarding the program, see Note 1. Nature of Operations and Significant Accounting Policies. (b) Settlement gains were recognized as one of the pension plan's lump-sum payments to retirees with insignificant balances exceeded the sum of the service cost and interest cost recognized. The gain is the recognition of a portion of its accumulated other comprehensive income related to that plan. Pension and Other Post-Employment Benefits Adjustments The following table shows the pre-tax change in other comprehensive loss (income) attributable to the components of net expense and the change in benefit obligation for CSX for pension and other post-employment benefits. (Dollars in Millions) Pension Benefits Post-retirement Benefits Components of Other Comprehensive December December December December Loss (Income) 2015 2014 2015 2014 Recognized in the balance sheet Losses (Gains) $ 60 $ 305 $ (7 ) $ (8 ) Expense (Income) recognized in the income statement Amortization of net losses (a) $ 70 $ 57 $ 4 $ 5 Settlement gain (2 ) (1 ) — — Amortization of prior service costs — — (1 ) (1 ) (a) Amortization of net losses estimated to be expensed for 2016 is approximately $48 million and $2 million for pension benefits and post-retirement benefits, respectively. NOTE 8. Employee Benefit Plans, continued As of December 2015 , the balances of pre-tax amounts to be amortized that are included in accumulated other comprehensive loss (a component of shareholders’ equity) are as follows: Pension Benefits Post-retirement Benefits Losses $ 900 $ 49 Prior Service Costs (Credits) — — Total $ 900 $ 49 Assumptions The expected long-term average rate of return on plan assets reflects the average rate of earnings expected on the funds invested, or to be invested, to provide for benefits included in the projected benefit obligation. In estimating that rate, the Company gives appropriate consideration to the returns being earned by the plan assets in the funds and the rates of return expected to be available for reinvestment as well as the current and projected asset mix of the funds. Management balances market expectations obtained from various investment managers and economists with both market and actual plan historical returns to develop a reasonable estimate of the expected long-term rate of return on assets. This assumption is reviewed annually and adjusted as deemed appropriate. Weighted-average assumptions used in accounting for the plans were as follows: Pension Benefits Post-retirement Benefits 2015 2014 2015 2014 Expected Long-term Return on Plan Assets: Benefit Cost for Plan Year 7.25 % 7.50 % N/A N/A Benefit Obligation at End of Plan Year 7.00 % 7.25 % N/A N/A Discount Rates: Benefit Cost for Plan Year 4.00 % 4.75 % 3.60 % 4.25 % Benefit Obligation at End of Plan Year 4.30 % 4.00 % 3.85 % 3.60 % Salary Scale Inflation 4.60 % 4.10 % N/A N/A The impact of the health care cost trend rate is immaterial to the post-retirement benefit cost and obligation due to the plan's health reimbursement arrangement that covers Medicare-eligible retirees. Other Plans Under collective bargaining agreements, the Company participates in a multi-employer benefit plan, which provides certain post-retirement health care and life insurance benefits to eligible contract employees. Premiums under this plan are expensed as incurred and amounted to $32 million , $37 million and $41 million in 2015 , 2014 and 2013 , respectively. The Company maintains savings plans for virtually all full-time salaried employees and certain employees covered by collective bargaining agreements. Expense associated with these plans was $36 million , $41 million and $37 million for 2015 , 2014 and 2013 , respectively.

Debt and Credit Agreements

Debt and Credit Agreements	12 Months Ended
	Dec. 25, 2015
Debt Disclosure [Abstract]
Debt and Credit Agreements	Debt and Credit Agreements Debt at December 2015 and December 2014 is shown in the table below. For information regarding the fair value of debt, see Note 13, Fair Value Measurements. Maturity at December Average Interest Rates at December December December (Dollars in Millions) 2015 2015 2015 2014 Notes 2017-2054 5.2% $ 10,445 $ 9,456 Equipment Obligations (a) 2016-2023 6.3% 250 277 Capital Leases 2016-2026 15.0% 7 8 Convertible Debentures 2021 1.0% 1 1 Subtotal Long-term Debt (including current portion) $ 10,703 $ 9,742 Less Debt Due within One Year (20 ) (228 ) Long-term Debt (excluding current portion) $ 10,683 $ 9,514 (a) These obligations are secured by an interest in certain railroad equipment. Debt Issuance & Early Redemption of Long-term Debt During 2015, CSX issued $600 million of 3.95% notes due 2050 and $600 million of 3.35% notes due 2025 . These notes are included in the consolidated balance sheets under long-term debt and may be redeemed by the Company at any time at the applicable redemption premium. Proceeds were used for general corporate purposes, which may include repurchases of CSX’s common stock, capital investment, working capital requirements, improvements in productivity and other cost reductions at CSX’s major transportation units. During 2014, CSX issued $550 million of 3.40% notes due 2024 and $450 million of 4.50% notes due 2054 . The net proceeds of the 2014 issuances were used to redeem $263 million of CSXT's 8.375% secured equipment obligations that otherwise would have matured on October 15, 2014 and $400 million of CSX Corporation’s 6.25% unsecured notes that otherwise would have matured April 1, 2015 . Proceeds were used for general corporate purposes, which may include repurchases of CSX’s common stock, capital investment, working capital requirements, improvements in productivity and other cost reductions at CSX’s major transportation units. CSX recognized $16 million of other expense in 2014 for the early redemption premium related to $663 million of note repayments. For more information regarding a non-cash debt transaction with a related party, see Note 12. Related Party Transactions. Long-term Debt Maturities (Dollars in Millions) Maturities as of Fiscal Years Ending December 2015 2016 $ 20 2017 632 2018 619 2019 518 2020 745 Thereafter 8,169 Total Long-term Debt Maturities (including current portion) $ 10,703 NOTE 9. Debt and Credit Agreements, continued Credit Facilities During 2015, CSX replaced its existing $1 billion unsecured, revolving credit facility backed by a diverse syndicate of banks which was set to expire in September 2016 . This new facility expires in May 2020 , and as of the date of this filing, the Company has no outstanding balances under this facility. The facility allows borrowings at floating (LIBOR-based) interest rates, plus a spread, depending upon CSX's senior unsecured debt ratings. LIBOR is the London Interbank Offered Rate which is a daily reference rate based on the interest rates at which banks offer to lend unsecured funds. Commitment fees and interest rates payable under the facility were similar to fees and rates available to comparably rated investment-grade borrowers. At December 2015, CSX was in compliance with all covenant requirements under the facilities. Receivables Securitization Facility The Company has a receivables securitization facility with a three -year term expiring in June 2017. The purpose of this facility is to provide an alternative to commercial paper and a low cost source of short-term liquidity of up to $250 million , depending on eligible receivables balances. Under the terms of this facility, CSXT transfers eligible third-party receivables to CSX Trade Receivables, LLC ("CSX Trade Receivables"), a bankruptcy-remote special purpose subsidiary. A separate subsidiary of CSX services the receivables. Upon transfer, the receivables become assets of CSX Trade Receivables and are not available to the creditors of CSX or any of its other subsidiaries. In the event CSX Trade Receivables draws under this facility, the Company will record an equivalent amount of debt on its consolidated financial statements. As of the date of this filing, the Company has no outstanding balances under this facility.

Other Income - Net

Other Income - Net	12 Months Ended
	Dec. 25, 2015
Other Income and Expenses [Abstract]
Other Income - Net	Other Income - Net The Company derives income from items that are not considered operating activities. Income from these items is reported net of related expense. Income from real estate operations includes the results of the Company’s non-operating real estate sales, leasing, acquisition and management and development activities and may fluctuate as a function of timing of real estate sales. Miscellaneous income (expense) includes equity earnings or losses, investment gains and losses and other non-operating activities and may fluctuate due to timing. Other income – net consisted of the following: Fiscal Years (Dollars in Millions) 2015 2014 2013 Interest Income $ 6 $ 5 $ 8 Income from Real Estate Operations (a) 83 23 23 Miscellaneous Income (Expense) (b) 9 (52 ) (20 ) Total Other Income (Expense) - Net $ 98 $ (24 ) $ 11 Gross Revenue from Real Estate Operations included above $ 104 $ 47 $ 48 (a) Income from real estate operations increased from 2014 to 2015 primarily due to a $59 million gain on a sale of non-operating easements. For additional information, see Note 6, Properties. (b) Miscellaneous income increased from 2014 to 2015 primarily due to a reimbursement of environmental costs of $21 million related to the sale above. Additionally, 2015 environmental costs were $21 million lower than 2014, and prior year costs of $16 million associated with the early redemption of long-term debt did not repeat in the current year.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 25, 2015
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Earnings before income taxes of $3.1 billion , $3.0 billion and $2.9 billion for fiscal years 2015 , 2014 and 2013 , respectively, represent earnings from domestic operations. The breakdown of income tax expense between current and deferred is as follows: Fiscal Years (Dollars in Millions) 2015 2014 2013 Current: Federal $ 619 $ 729 $ 671 State 95 90 87 Subtotal Current 714 819 758 Deferred: Federal 414 291 285 State 42 7 15 Subtotal Deferred 456 298 300 Total $ 1,170 $ 1,117 $ 1,058 Income tax expense reconciled to the tax computed at statutory rates is presented in the table below. The Company recorded a tax benefit of $4 million , $31 million and $42 million in 2015, 2014 and 2013, respectively, primarily as a result of federal and state legislative changes as well as the resolution of other federal and state tax matters. Each year's benefit is included in the state income tax and other lines in the table below. Fiscal Years (Dollars In Millions) 2015 2014 2013 Federal Income Taxes $ 1,098 35.0 % $ 1,066 35.0 % $ 1,023 35.0 % State Income Taxes 86 2.7 % 61 2.0 % 65 2.2 % Other (14 ) (0.4 )% (10 ) (0.3 )% (30 ) (1.0 )% Income Tax Expense/Rate $ 1,170 37.3 % $ 1,117 36.7 % $ 1,058 36.2 % In September 2013, the IRS issued final regulations governing the income tax treatment of the acquisition, disposition and repair of tangible property. The regulations were effective beginning in 2014. These new regulations did not have a material impact on the financial statements. The significant components of deferred income tax assets and liabilities include: 2015 2014 (Dollars in Millions) Assets Liabilities Assets Liabilities Pension Plans $ 207 $ — $ 188 $ — Other Employee Benefit Plans 258 — 306 — Accelerated Depreciation — 9,614 — 9,133 Other 261 291 256 334 Total $ 726 $ 9,905 $ 750 $ 9,467 Net Deferred Income Tax Liabilities $ 9,179 $ 8,717 NOTE 11. Income Taxes, continued The primary factors in the change in year-end net deferred income tax liability balances include: • annual provision for deferred income tax expense and • accumulated other comprehensive loss. The Company files a consolidated federal income tax return, which includes its principal domestic subsidiaries. Income tax incurred on the operations of the Company are subject to U.S. federal income tax as well as income tax of multiple state jurisdictions. CSX participated in a contemporaneous IRS audit of tax year 2015 . Federal examinations of original federal income tax returns for all years through 2014 are resolved. As of December 2015 , 2014 and 2013 , the Company had approximately $23 million , $21 million and $23 million , respectively, of total unrecognized tax benefits. Net tax benefits of $15 million , $13 million and $15 million in 2015 , 2014 and 2013 , respectively, could favorably impact the effective income tax rate in each year. The Company does not expect that unrecognized tax benefits as of December 2015 for various state and federal income tax matters will significantly change over the next 12 months. The final outcome of these uncertain tax positions is not yet determinable. The change to the total gross unrecognized tax benefits and prior year audit resolutions of the Company during the fiscal year ended December 2015 is reconciled in the table below. Uncertain Tax Positions: Fiscal Year (Dollars in Millions) 2015 2014 2013 Balance at beginning of the year $ 21 $ 23 $ 24 Additions based on tax positions related to current year 1 2 2 Additions based on tax positions related to prior years 4 3 5 Reductions based on tax positions related to prior years — — (6 ) Settlements with taxing authorities 1 — — Lapse of statute of limitations (4 ) (7 ) (2 ) Balance at end of the year $ 23 $ 21 $ 23 CSX’s continuing practice is to recognize net interest and penalties related to income tax matters in income tax expense. Included in the consolidated income statements are expense of $2 million in 2015 , expense of $1 million in 2014 and benefits of $1 million in 2013 , respectively, for changes to reserves for interest and penalties for all prior year tax positions. The Company had $4 million , $1 million and $2 million accrued for interest and penalties at 2015 , 2014 and 2013 , respectively, for all prior year tax positions.

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 25, 2015
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions Conrail Through a limited liability company, CSX and Norfolk Southern Corporation (“NS”) jointly own Conrail. CSX has a 42% economic interest and 50% voting interest in the jointly-owned entity, and NS has the remainder of the economic and voting interests. Pursuant to the Investments-Equity Method and Joint Venture Topic in the ASC, CSX applies the equity method of accounting to its investment in Conrail. Conrail owns rail infrastructure and operates for the joint benefit of CSX and NS. This is known as the shared asset area. Conrail charges fees for right-of-way usage, equipment rentals and transportation, switching and terminal service charges in the shared asset area. These expenses are included in materials, supplies and other on the consolidated income statements. Future minimum lease payments due to Conrail under the shared asset area agreements are shown in the table below. (Dollars in Millions) Conrail Shared Years Asset Agreement 2016 $ 26 2017 26 2018 26 2019 26 2020 26 Thereafter 98 Total $ 228 Also, included in materials, supplies and other are CSX’s 42% share of Conrail’s income and its amortization of the fair value write-up arising from the acquisition of Conrail and certain other adjustments. The amortization primarily represents the additional after-tax depreciation expense related to the write-up of Conrail’s fixed assets when the original purchase price, from the 1997 acquisition of Conrail, was allocated based on fair value. This write-up of fixed assets resulted in a difference between CSX's investment in Conrail and its share of Conrail's underlying net equity, which is $353 million as of December 2015 . The following table details the related Conrail amounts included in materials, supplies and other in the Company’s consolidated income statements: Fiscal Years (Dollars in Millions) 2015 2014 2013 Rents, fees and services $ 123 $ 124 $ 115 Purchase price amortization and other 4 4 4 Equity earnings of Conrail (33 ) (31 ) (35 ) Total Conrail Expense $ 94 $ 97 $ 84 NOTE 12. Related Party Transactions, continued As required by the Related Party Disclosures Topic in the ASC, the Company has identified amounts below owed to Conrail, or its subsidiaries, representing liabilities under the operating, equipment and shared area agreements with Conrail. The Company also executed two promissory notes with a subsidiary of Conrail which were included in long-term debt on the consolidated balance sheets. Interest expense from these promissory notes was $6 million , $3 million and $4 million for 2015 , 2014 and 2013 , respectively. December December (Dollars in Millions) 2015 2014 Balance Sheet Information: CSX payable to Conrail $ 65 $ 54 Promissory notes payable to Conrail subsidiary 2.89% CSX promissory note due October 2044 73 73 2.89% CSXT promissory note due October 2044 151 151 In October 2014, the Company converted its existing short term payable balance of approximately $125 million for operation of the shared asset area as well as its $23 million , 4.52% note due 2035 and its $73 million , 4.40% note due 2035 plus accrued interest of $3 million , into $224 million , 2.89% notes due 2044 . The transaction was non-cash in nature. TTX Company TTX Company ("TTX") is a privately-held corporation engaged in the business of providing its owner-railroads with standardized fleets of intermodal, automotive and general use railcars at time and mileage rates. CSX owns about 20% of TTX's common stock, and the remaining is owned by the other leading North American railroads and their affiliates. CSX's investment in TTX is $443 million and is included in affiliates and other companies in the consolidated balance sheet. Pursuant to the Investments-Equity Method topic in the ASC, CSX applies the equity method of accounting to its investment in TTX. As required by the Related Party Disclosures Topic in the ASC, the following table discloses amounts related to TTX that are included in equipment and other rents in the Company’s consolidated income statements. Also included below is balance sheet information related to CSX's payable to TTX, which represents car rental liabilities. Fiscal Years (Dollars in Millions) 2015 2014 2013 Income statement information: Car hire rents $ 218 $ 207 $ 180 Equity earnings of TTX (20 ) (21 ) (13 ) Total TTX expense $ 198 $ 186 $ 167 December December Balance sheet information: 2015 2014 CSX payable to TTX $ 40 $ 35

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 25, 2015
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements The Financial Instruments Topic in the ASC requires disclosures about fair value of financial instruments in annual reports as well as in quarterly reports. For CSX, this statement applies to certain investments, pension plan assets and long-term debt. Also, the Fair Value Measurements and Disclosures Topic in the ASC clarifies the definition of fair value for financial reporting, establishes a framework for measuring fair value and requires additional disclosures about the use of fair value measurements. Various inputs are considered when determining the value of the Company's investments, pension plan assets and long-term debt. The inputs or methodologies used for valuing securities are not necessarily an indication of the risk associated with investing in these securities. These inputs are summarized in the three broad levels listed below. • Level 1 – observable market inputs that are unadjusted quoted prices for identical assets or liabilities in active markets • Level 2 – other significant observable inputs (including quoted prices for similar securities, interest rates, credit risk, etc.) • Level 3 – significant unobservable inputs (including the Company’s own assumptions about the assumptions market participants would use in determining the fair value of investments) The valuation methods described below may produce a fair value calculation that may not be indicative of net realizable value or reflective of future fair values. Furthermore, while the Company believes its valuation methods are appropriate and consistent with other market participants, the use of different methodologies or assumptions to determine the fair value of certain financial instruments could result in a different fair value measurement at the reporting date. Investments The Company's investment assets, valued with assistance from a third-party trustee, consist of certificates of deposits, commercial paper, corporate bonds, government securities and auction rate securities and are carried at fair value on the consolidated balance sheet per the Fair Value Measurements and Disclosures Topic in the ASC. There are several valuation methodologies used for those assets as described below. • Certificates of Deposit and Commercial Paper (Level 2): Valued at amortized cost, which approximates fair value. • Corporate Bonds and Government Securities (Level 2): Valued using broker quotes that utilize observable market inputs. • Auction Rate Securities (Level 3): Valued using pricing models for which the assumptions utilize management’s estimates of market participant assumptions, because there is currently no active market for trading. The Company's investment assets are carried at fair value on the consolidated balance sheets as summarized in the table below. Additionally, the amortized cost basis of these investments was $920 million and $453 million as of December 25, 2015 and December 26, 2014 , respectively. NOTE 13. Fair Value Measurements, continued Fiscal Years 2015 2014 (Dollars in Millions) Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total Certificates of Deposit and Commercial Paper $ — $ 810 $ — $ 810 $ — $ 250 $ — $ 250 Corporate Bonds — 73 — 73 — 141 — 141 Government Securities — 32 — 32 — 51 — 51 Auction Rate Securities — — 4 4 — — 11 11 Total investments at fair value $ — $ 915 $ 4 $ 919 $ — $ 442 $ 11 $ 453 These investments have the following maturities and are represented on the consolidated balance sheet within short-term investments for investments with maturities within one year or less, and other long-term assets for investments with maturities greater than one year: (Dollars in Millions) December 2015 December 2014 Less than 1 year $ 810 $ 292 1 - 2 years 9 45 2 - 5 years 27 100 Greater than 5 years 73 16 Total investments at fair value $ 919 $ 453 Long-term Debt Long-term debt is reported at carrying amount on the consolidated balance sheets and is the Company's only financial instrument with fair values significantly different from their carrying amounts. The majority of the Company's long-term debt is valued with assistance from a third party that utilizes closing transactions, market quotes or market values of comparable debt. For those instruments not valued by the third party, the fair value has been estimated by applying market rates of similar instruments to the scheduled contractual debt payments and maturities. These market rates are provided by the same third party. All of the inputs used to determine the fair value of the Company's long-term debt are Level 2 inputs. The fair value of outstanding debt fluctuates with changes in a number of factors. Such factors include, but are not limited to, interest rates, market conditions, values of similar financial instruments, size of the transaction, cash flow projections and comparable trades. Fair value will exceed carrying value when the current market interest rate is lower than the interest rate at which the debt was originally issued. The fair value of a company's debt is a measure of its current value under present market conditions. It does not impact the financial statements under current accounting rules. NOTE 13. Fair Value Measurements, continued The fair value and carrying value of the Company's long-term debt is as follows: (Dollars in Millions) December 2015 December 2014 Long-term Debt (Including Current Maturities): Fair Value $ 11,340 $ 11,042 Carrying Value 10,703 9,742 Pension Plan Assets Pension plan assets are reported at fair value on the consolidated balance sheet. The Investment Committee targets an allocation of pension assets to be generally 70% equity and 30% fixed income. There are several valuation methodologies used for those assets as described below. Investments in the fair value hierarchy • Common stock (Level 1): Valued at the closing price reported on the active market on which the individual securities are traded on the last day of the year and classified in level 1 of the fair value hierarchy • Mutual funds (Level 1) : Valued at the net asset value of shares held at year end based on quoted market prices determined in an active market. These assets are classified in level 1 of the fair value hierarchy. • Corporate bonds, government securities, asset-backed securities and derivatives (Level 2): Valued using price evaluations reflecting the bid and/or ask sides of the market for a similar investment at year end. Asset-backed securities include commercial mortgage-backed securities and collateralized mortgage obligations. These assets are classified in level 2 of the fair value hierarchy. Investments measured at net asset value • Partnerships: Net asset value of private equity is based on the fair market values associated with the underlying investments at year end. These funds have redemption restrictions that require advanced notice of 15 business days. • Common collective trust funds: This class consists of private funds that invest in government and corporate securities and various short-term debt instruments and are measured at net asset value to estimate the fair value of the investments. The net asset value of the investments is determined by reference to the fair value of the underlying securities, which are valued primarily through the use of directly or indirectly observable inputs. These funds have redemption restrictions that require advanced notice of up to 15 business days. The pension plan assets at fair value by level, within the fair value hierarchy, as of calendar plan years 2015 and 2014 are shown in the table below. For additional information related to pension assets, see Note 8, Employee Benefit Plans. NOTE 13. Fair Value Measurements, continued Fiscal Years 2015 2014 (Dollars in Millions) Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total Common Stock $ 738 $ — $ — $ 738 $ 787 $ — $ — $ 787 Mutual funds 15 — — 15 20 — — 20 Cash equivalents 8 — — 8 1 — — 1 Corporate bonds — 480 — 480 — 539 — 539 Government securities — 132 — 132 — 164 — 164 Asset-backed securities — 14 — 14 — 15 — 15 Derivatives and other — 6 — 6 — 2 — 2 Total investments in the fair value hierarchy $ 761 $ 632 $ — $ 1,393 $ 808 $ 720 $ — $ 1,528 Investments measured at net asset value (a) n/a n/a n/a $ 916 n/a n/a n/a $ 976 Investments at fair value $ 761 $ 632 $ — $ 2,309 $ 808 $ 720 $ — $ 2,504 (a) Investments measured at net asset value represent certain investments that have been measured at net asset value per share (or its equivalent) and are thus are not classified in the fair value hierarchy. In accordance with ASC 820, Fair Value Measurements, the fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the pension assets disclosed in Note 8, Employee Benefit Plans.

Other Comprehensive Income _ (L

Other Comprehensive Income / (Loss)	12 Months Ended
	Dec. 25, 2015
Equity [Abstract]
Other Comprehensive Income / (Loss)	Other Comprehensive Income / (Loss) CSX reports comprehensive earnings or loss in accordance with the Comprehensive Income Topic in the ASC in the Consolidated Comprehensive Income Statement. Total comprehensive earnings are defined as all changes in shareholders' equity during a period, other than those resulting from investments by and distributions to shareholders (e.g. issuance of equity securities and dividends). Generally, for CSX, total comprehensive earnings equal net earnings plus or minus adjustments for pension and other post-retirement liabilities. Total comprehensive earnings represent the activity for a period net of tax and were $2.0 billion , $1.8 billion and $2.3 billion for 2015 , 2014 and 2013 , respectively. While total comprehensive earnings is the activity in a period and is largely driven by net earnings in that period, accumulated other comprehensive income or loss (“AOCI”) represents the cumulative balance of other comprehensive income, net of tax, as of the balance sheet date. For CSX, AOCI is primarily the cumulative balance related to pension and other post-retirement benefit adjustments and CSX's share of AOCI of equity method investees. Changes in the AOCI balance by component are shown in the table below. Amounts reclassified in pension and other post-employment benefits to net earnings relate to the amortization of actuarial losses and are included in labor and fringe on the consolidated income statements. See Note 8. Employee Benefit Plans for further information. Other primarily represents CSX's share of AOCI of equity method investees. Amounts reclassified in other to net earnings are included in materials, supplies and other on the consolidated income statements. NOTE 14. Other Comprehensive Income / (Loss), continued Pension and Other Post-Employment Benefits Other Accumulated Other Comprehensive Income (Loss) (Dollars in millions) Balance December 28, 2012 - Net of Tax $ (851 ) $ (85 ) $ (936 ) Other Comprehensive Income Income Before Reclassifications 510 24 534 Amounts Reclassified to Net Earnings 111 (2 ) 109 Tax (Expense) Benefit (232 ) 2 (230 ) Total Other Comprehensive Income 389 24 413 Balance December 27, 2013 - Net of Tax (462 ) (61 ) (523 ) Other Comprehensive (Loss) Income (Loss) Income Before Reclassifications (297 ) 4 (293 ) Amounts Reclassified to Net Earnings 60 2 62 Tax Benefit 88 — 88 Total Other Comprehensive (Loss) Income (149 ) 6 (143 ) Balance December 26, 2014 - Net of Tax (611 ) (55 ) (666 ) Other Comprehensive Income (Loss) Loss Before Reclassifications (53 ) (8 ) (61 ) Amounts Reclassified to Net Earnings 71 (2 ) 69 Tax (Expense) Benefit (8 ) 1 (7 ) Total Other Comprehensive Income (Loss) 10 (9 ) 1 Balance December 25, 2015 - Net of Tax $ (601 ) $ (64 ) $ (665 )

Quarterly Financial Data (Unaud

Quarterly Financial Data (Unaudited)	12 Months Ended
	Dec. 25, 2015
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Data (Unaudited)	Quarterly Financial Data (Unaudited) Pursuant to Article 3 of the SEC’s Regulation S-X, the following are selected quarterly financial data: Fiscal Year Ended December 2015 Quarters (Dollars in Millions, Except Per Share Amounts) 1st 2nd 3rd 4th Full Year Revenue $ 3,027 $ 3,064 $ 2,939 $ 2,781 $ 11,811 Operating Income 843 1,017 933 791 3,584 Net Earnings 442 553 507 466 1,968 Earnings Per Share, Basic $ 0.45 $ 0.56 $ 0.52 $ 0.48 $ 2.00 Earnings Per Share, Assuming Dilution 0.45 0.56 0.52 0.48 2.00 Fiscal Year Ended December 2014 Revenue $ 3,012 $ 3,244 $ 3,221 $ 3,192 $ 12,669 Operating Income 739 997 976 901 3,613 Net Earnings 398 529 509 491 1,927 Earnings Per Share, Basic $ 0.40 $ 0.53 $ 0.51 $ 0.49 $ 1.93 Earnings Per Share, Assuming Dilution 0.40 0.53 0.51 0.49 1.92

Summarized Consolidating Financ

Summarized Consolidating Financial Data	12 Months Ended
	Dec. 25, 2015
Summarized Consolidating Financial Data [Abstract]
Summarized Consolidating Financial Data	Summarized Consolidating Financial Data In 2007, CSXT, a wholly-owned subsidiary of CSX Corporation, sold secured equipment notes maturing in 2023 in a registered public offering. CSX has fully and unconditionally guaranteed the notes. In connection with the notes, the Company is providing the following condensed consolidating financial information in accordance with SEC disclosure requirements. Each entity in the consolidating financial information follows the same accounting policies as described in the consolidated financial statements, except for the use of the equity method of accounting to reflect ownership interests in subsidiaries which are eliminated upon consolidation and the allocation of certain expenses of CSX incurred for the benefit of its subsidiaries. Condensed consolidating financial information for the obligor, CSXT, and parent guarantor, CSX, is shown in the tables below. NOTE 16. Summarized Consolidating Financial Data, continued Consolidating Income Statements (Dollars in Millions) Fiscal Year Ended December 2015 CSX Corporation CSX Transportation Eliminations and Other CSX Consolidated Revenue $ — $ 11,733 $ 78 $ 11,811 Expense (589 ) 8,922 (106 ) 8,227 Operating Income 589 2,811 184 3,584 Equity in Earnings of Subsidiaries 1,949 — (1,949 ) — Interest Expense (539 ) (33 ) 28 (544 ) Other Income - Net (4 ) 111 (9 ) 98 Earnings Before Income Taxes 1,995 2,889 (1,746 ) 3,138 Income Tax Expense (27 ) (1,083 ) (60 ) (1,170 ) Net Earnings $ 1,968 $ 1,806 $ (1,806 ) $ 1,968 Total Comprehensive Earnings $ 1,969 $ 1,806 $ (1,806 ) $ 1,969 Fiscal Year Ended December 2014 Revenue $ — $ 12,590 $ 79 $ 12,669 Expense (427 ) 9,585 (102 ) 9,056 Operating Income 427 3,005 181 3,613 Equity in Earnings of Subsidiaries 1,996 1 (1,997 ) — Interest Expense (520 ) (46 ) 21 (545 ) Other Income - Net (19 ) (4 ) (1 ) (24 ) Earnings Before Income Taxes 1,884 2,956 (1,796 ) 3,044 Income Tax Benefit (Expense) 43 (1,093 ) (67 ) (1,117 ) Net Earnings $ 1,927 $ 1,863 $ (1,863 ) $ 1,927 Total Comprehensive Earnings $ 1,784 $ 1,875 $ (1,875 ) $ 1,784 Fiscal Year Ended December 2013 Revenue $ — $ 11,950 $ 76 $ 12,026 Expense (371 ) 9,091 (167 ) 8,553 Operating Income 371 2,859 243 3,473 Equity in Earnings of Subsidiaries 1,964 (1 ) (1,963 ) — Interest Expense (516 ) (62 ) 16 (562 ) Other Income - Net (7 ) (2 ) 20 11 Earnings Before Income Taxes 1,812 2,794 (1,684 ) 2,922 Income Tax Benefit (Expense) 52 (1,028 ) (82 ) (1,058 ) Net Earnings $ 1,864 $ 1,766 $ (1,766 ) $ 1,864 Total Comprehensive Earnings $ 2,277 $ 1,825 $ (1,825 ) $ 2,277 NOTE 16. Summarized Consolidating Financial Data, continued Consolidating Balance Sheets (Dollars in Millions) As of December 25, 2015 CSX Corporation CSX Transportation Eliminations and Other CSX ASSETS Current Assets: Cash and Cash Equivalents $ 444 $ 175 $ 9 $ 628 Short-term Investments 810 — — 810 Accounts Receivable - Net 1 198 783 982 Receivable from Affiliates 1,092 2,038 (3,130 ) — Materials and Supplies — 350 — 350 Deferred Income Taxes 10 117 (1 ) 126 Other Current Assets (59 ) 120 9 70 Total Current Assets 2,298 2,998 (2,330 ) 2,966 Properties 1 38,964 2,609 41,574 Accumulated Depreciation (1 ) (10,016 ) (1,383 ) (11,400 ) Properties - Net — 28,948 1,226 30,174 Investments in Conrail — — 803 803 Affiliates and Other Companies (39 ) 658 (28 ) 591 Investment in Consolidated Subsidiaries 22,755 — (22,755 ) — Other Long-term Assets 176 399 (70 ) 505 Total Assets $ 25,190 $ 33,003 $ (23,154 ) $ 35,039 LIABILITIES AND SHAREHOLDERS' EQUITY Current Liabilities: Accounts Payable $ 108 $ 626 $ 30 $ 764 Labor and Fringe Benefits Payable 36 407 47 490 Payable to Affiliates 2,954 437 (3,391 ) — Casualty, Environmental and Other Reserves — 115 16 131 Current Maturities of Long-term Debt 1 19 — 20 Income and Other Taxes Payable (87 ) 183 12 108 Other Current Liabilities — 437 2 439 Total Current Liabilities 3,012 2,224 (3,284 ) 1,952 Casualty, Environmental and Other Reserves — 219 50 269 Long-term Debt 9,900 783 — 10,683 Deferred Income Taxes (178 ) 9,258 225 9,305 Other Long-term Liabilities 804 484 (126 ) 1,162 Total Liabilities 13,538 12,968 (3,135 ) 23,371 Shareholders' Equity: Common Stock, $1 Par Value 966 181 (181 ) 966 Other Capital 113 5,091 (5,091 ) 113 Retained Earnings 11,238 14,774 (14,774 ) 11,238 Accumulated Other Comprehensive Loss (665 ) (31 ) 31 (665 ) Noncontrolling Minority Interest — 20 (4 ) 16 Total Shareholders' Equity 11,652 20,035 (20,019 ) 11,668 Total Liabilities and Shareholders' Equity $ 25,190 $ 33,003 $ (23,154 ) $ 35,039 NOTE 16. Summarized Consolidating Financial Data, continued Consolidating Balance Sheets (Dollars in Millions) As of December 26, 2014 CSX Corporation CSX Transportation Eliminations and Other CSX ASSETS Current Assets Cash and Cash Equivalents $ 510 $ 100 $ 59 $ 669 Short-term Investments 250 — 42 292 Accounts Receivable - Net 2 206 921 1,129 Receivable from Affiliates 1,211 2,418 (3,629 ) — Materials and Supplies — 272 1 273 Deferred Income Taxes 3 139 (1 ) 141 Other Current Assets — 61 7 68 Total Current Assets 1,976 3,196 (2,600 ) 2,572 Properties 1 36,888 2,454 39,343 Accumulated Depreciation (1 ) (9,516 ) (1,242 ) (10,759 ) Properties - Net — 27,372 1,212 28,584 Investments in Conrail — — 779 779 Affiliates and Other Companies (39 ) 644 (28 ) 577 Investment in Consolidated Subsidiaries 21,570 — (21,570 ) — Other Long-term Assets 178 387 (24 ) 541 Total Assets $ 23,685 $ 31,599 $ (22,231 ) $ 33,053 LIABILITIES AND SHAREHOLDERS' EQUITY Current Liabilities Accounts Payable $ 106 $ 707 $ 32 $ 845 Labor and Fringe Benefits Payable 38 511 64 613 Payable to Affiliates 3,053 514 (3,567 ) — Casualty, Environmental and Other Reserves — 126 16 142 Current Maturities of Long-term Debt 200 29 (1 ) 228 Income and Other Taxes Payable (150 ) 293 20 163 Other Current Liabilities — 111 5 116 Total Current Liabilities 3,247 2,291 (3,431 ) 2,107 Casualty, Environmental and Other Reserves — 213 63 276 Long-term Debt 8,705 809 — 9,514 Deferred Income Taxes (172 ) 8,827 203 8,858 Other Long-term Liabilities 753 487 (118 ) 1,122 Total Liabilities 12,533 12,627 (3,283 ) 21,877 Shareholders' Equity Common Stock, $1 Par Value 992 181 (181 ) 992 Other Capital 92 5,077 (5,077 ) 92 Retained Earnings 10,734 13,717 (13,717 ) 10,734 Accumulated Other Comprehensive Loss (666 ) (31 ) 31 (666 ) Noncontrolling Minority Interest — 28 (4 ) 24 Total Shareholders' Equity 11,152 18,972 (18,948 ) 11,176 Total Liabilities and Shareholders' Equity $ 23,685 $ 31,599 $ (22,231 ) $ 33,053 NOTE 16. Summarized Consolidating Financial Data, continued Consolidating Cash Flow Statements (Dollars in Millions) Fiscal Year Ended December 2015 CSX Corporation CSX Transportation Eliminations and Other CSX Operating Activities Net Cash Provided by (Used in) Operating Activities $ 983 $ 2,974 $ (587 ) $ 3,370 Investing Activities Property Additions — (2,400 ) (162 ) (2,562 ) Purchases of Short-term Investments (1,734 ) — (5 ) (1,739 ) Proceeds from Sales of Short-term Investments 1,175 — 50 1,225 Proceeds from Property Dispositions — 147 — 147 Other Investing Activities (10 ) 132 (85 ) 37 Net Cash Provided by (Used in) Investing Activities (569 ) (2,121 ) (202 ) (2,892 ) Financing Activities Long-term Debt Issued 1,200 — — 1,200 Long-term Debt Repaid (200 ) (29 ) — (229 ) Dividends Paid (686 ) (750 ) 750 (686 ) Stock Options Exercised — — — — Shares Repurchased (804 ) — — (804 ) Other Financing Activities 10 1 (11 ) — Net Cash Provided by (Used in) Financing Activities (480 ) (778 ) 739 (519 ) Net Decrease in Cash and Cash Equivalents (66 ) 75 (50 ) (41 ) Cash and Cash Equivalents at Beginning of Period 510 100 59 669 Cash and Cash Equivalents at End of Period $ 444 $ 175 $ 9 $ 628 NOTE 16. Summarized Consolidating Financial Data, continued Consolidating Cash Flow Statements (Dollars in Millions) Fiscal Year Ended December 2014 CSX Corporation CSX Transportation Eliminations and Other CSX Operating Activities Net Cash Provided by (Used in) Operating Activities $ 583 $ 3,278 $ (518 ) $ 3,343 Investing Activities Property Additions — (2,192 ) (257 ) (2,449 ) Purchases of Short-term Investments (1,419 ) — (14 ) (1,433 ) Proceeds from Sales of Short-term Investments 1,642 — 32 1,674 Proceeds from Property Dispositions — 62 — 62 Other Investing Activities — (128 ) 91 (37 ) Net Cash Provided by (Used in) Investing Activities 223 (2,258 ) (148 ) (2,183 ) Financing Activities Long-term Debt Issued 1,000 — — 1,000 Long-term Debt Repaid (600 ) (333 ) — (933 ) Dividends Paid (629 ) (660 ) 660 (629 ) Stock Options Exercised — — — — Shares Repurchased (517 ) — — (517 ) Other Financing Activities 11 (18 ) 3 (4 ) Net Cash Provided by (Used in) Financing Activities (735 ) (1,011 ) 663 (1,083 ) Net (Decrease) Increase in Cash and Cash Equivalents 71 9 (3 ) 77 Cash and Cash Equivalents at Beginning of Period 439 91 62 592 Cash and Cash Equivalents at End of Period $ 510 $ 100 $ 59 $ 669 NOTE 16. Summarized Consolidating Financial Data, continued Consolidating Cash Flow Statements (Dollars in Millions) Fiscal Year Ended December 2013 CSX Corporation CSX Transportation Eliminations and Other CSX Operating Activities Net Cash Provided by (Used in) Operating Activities $ 1,004 $ 3,005 $ (742 ) $ 3,267 Investing Activities Property Additions — (2,053 ) (260 ) (2,313 ) Purchases of Short-term Investments (1,251 ) — (5 ) (1,256 ) Proceeds from Sales of Short-term Investments 1,335 — 66 1,401 Proceeds from Property Dispositions — 53 — 53 Other Investing Activities (134 ) (315 ) 337 (112 ) Net Cash Provided by (Used in) Investing Activities (50 ) (2,315 ) 138 (2,227 ) Financing Activities Long-term Debt Issued 500 — — 500 Long-term Debt Repaid (700 ) (80 ) — (780 ) Dividends Paid (600 ) (730 ) 730 (600 ) Stock Options Exercised 9 — — 9 Shares Repurchased (353 ) — — (353 ) Other Financing Activities 148 (24 ) (132 ) (8 ) Net Cash Provided by (Used in) Financing Activities (996 ) (834 ) 598 (1,232 ) Net (Decrease) Increase in Cash and Cash Equivalents (42 ) (144 ) (6 ) (192 ) Cash and Cash Equivalents at Beginning of Period 481 235 68 784 Cash and Cash Equivalents at End of Period $ 439 $ 91 $ 62 $ 592

Nature of Operations and Sign25

Nature of Operations and Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 25, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	In the opinion of management, the accompanying consolidated financial statements contain all normal, recurring adjustments necessary to fairly present the financial position of CSX and its subsidiaries at December 25, 2015 and December 26, 2014 , and the consolidated statements of income, comprehensive income, cash flows and changes in shareholders’ equity for fiscal years 2015 , 2014 and 2013 . In addition, management has evaluated and disclosed all material events occurring subsequent to the date of the financial statements up to the date this annual report is filed on Form 10-K.
Fiscal Year	CSX follows a 52/53 week fiscal reporting calendar. This fiscal calendar allows every quarter to consistently end on a Friday and typically, to be of equal duration ( 13 weeks), resulting in a 52 week fiscal year. To maintain this type of reporting calendar every fifth or sixth year (depending on the Gregorian calendar and when leap year falls), an extra week will be included in the fourth quarter (a 14-week fiscal quarter) and, therefore, that full fiscal year will have 53 weeks. The next 53 week fiscal year will be 2016, which will end on December 30, 2016. Fiscal years 2015, 2014 and 2013 each consisted of 52 weeks ending on December 25, 2015 , December 26, 2014 and December 27, 2013 , respectively. Except as otherwise specified, references to full year indicate CSX’s fiscal periods ended on these dates
Principles of Consolidation	The consolidated financial statements include results of operations of CSX and subsidiaries over which CSX has majority ownership or financial control. All significant intercompany accounts and transactions have been eliminated. Most investments in companies that were not majority-owned were carried at cost (if less than 20% owned and the Company has no significant influence) or were accounted for under the equity method (if the Company has significant influence but does not have control). These investments are reported within Investment in Conrail or Affiliates and Other Investments on the consolidated balance sheets.
Cash, Cash Equivalents and Investments	On a daily basis, cash in excess of current operating requirements is invested in various highly liquid investments having a typical maturity date of three months or less at the date of acquisition. These investments are carried at cost, which approximated market value, and are classified as cash equivalents. NOTE 1. Nature of Operations and Significant Accounting Policies, continued Investments Investments in instruments with original maturities greater than three months but will mature in less than one year were classified as short-term investments. Investments with original maturities greater than one year are classified within other long-term assets.
Allowance for Doubtful Accounts	The Company maintains an allowance for doubtful accounts on uncollectible amounts related to freight receivables, government reimbursement receivables, claims for damages and other various receivables. The allowance is based upon the credit worthiness of customers, historical experience, the age of the receivable and current market and economic conditions. Uncollectible amounts are charged against the allowance account.
Materials and Supplies	Materials and supplies in the consolidated balance sheets are carried at average costs and consist primarily of fuel and parts used in the repair and maintenance of CSXT’s freight car and locomotive fleets, equipment and track structure.
Goodwill	Goodwill represents purchase price in excess of fair value and is related to affiliates of CSXT, primarily P&L Transportation, Inc. Goodwill of $63 million is recorded in other long-term assets in the consolidated balance sheets as of December 2015 and December 2014 , respectively.
Revenue and Expense Recognition	The Company recognizes freight revenue using Free-On-Board Origin pursuant to the Revenue Recognition Topic in the Accounting Standards Codification ("ASC"). Accounting guidance in this topic provides for the allocation of revenue between reporting periods based on relative transit time in each reporting period. Expenses are recognized as incurred. The certain key estimates included in the recognition and measurement of revenue and related accounts receivable under the policies described above are as follows: • revenue associated with shipments in transit is recognized ratably over transit time and is based on average cycle times to move commodities and products from their origin to their final destination or interchange; • adjustments to revenue for billing corrections, billing discounts and bad debts or to accounts receivable for allowances for doubtful accounts; • adjustments to revenue for overcharge claims filed by customers, which are based on historical cash paid to customers for rate overcharges as a percentage of total billing; • incentive-based refunds to customers, which are primarily based on customers achieving certain volume thresholds and are recorded as a reduction to revenue on the basis of management’s best estimate of the projected liability (this estimate is based on historical activity, current volume levels and a forecast of future volume). NOTE 1. Nature of Operations and Significant Accounting Policies, continued The Company regularly updates the estimates described above based on historical experience and current conditions. All other revenue, such as demurrage, switching and other incidental charges are recorded upon completion of the service.
New Accounting Pronouncements	In November 2015, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU"), Balance Sheet Classification of Deferred Taxes , which requires that all deferred income taxes be classified as noncurrent in the balance sheet, rather than being separated into current and noncurrent amounts. This standard is effective for annual reporting periods beginning after December 15, 2016 and will not have a material effect on the Company's financial condition, results of operations or liquidity. In July 2015, the FASB issued ASU, Plan Accounting: Defined Benefit Pension Plans (Topic 960), Defined Contribution Pension Plans (Topic 962) and Health and Welfare Benefit Plans (Topic 965): I. Fully Benefit-Responsive Investment Contracts; II. Plan Investment Disclosures; III. Measurement Date Practical Expedient . This three-part update simplifies current benefit plan accounting and requires benefit plans to disaggregate their investments measured using fair value by general type, among other changes. This update is effective for fiscal years beginning after December 15, 2015 and early adoption is permitted. Parts I and III of this update are not applicable to CSX. This update only affects disclosures related to fair value measurement. Adoption does not have an effect on the Company's pension plan net assets available for benefits or its changes in net assets available for benefits. In May 2015, the FASB issued ASU, Disclosures for Investments in Certain Entities That Calculate Net Asset Value per Share (or Its Equivalent). This update eliminates the requirement to categorize investments within the fair value hierarchy if their fair value is measured using the net asset value per share practical expedient. This update requires that investments measured using the net asset value per share be disclosed as a reconciling item between the statement of net assets available for benefits and the fair value hierarchy disclosure. This update is effective for fiscal years beginning after December 15, 2015 and early adoption is permitted. This update only affects disclosures related to fair value measurement. Adoption does not have an effect on the Company's pension plan net assets available for benefits or its changes in net assets available for benefits. In April 2015, the FASB issued ASU, Interest - Imputation of Interest , which changes the financial statement presentation of debt issuance costs to be a direct reduction to long-term debt, rather than presented as a long-term asset. The amortization of debt issuance costs will continue to be included in interest expense. This standard is effective for annual reporting periods beginning after December 15, 2015 and will not have a material effect on the Company's financial condition, results of operations or liquidity. NOTE 1. Nature of Operations and Significant Accounting Policies, continued In May 2014, the FASB issued ASU, Revenue from Contracts with Customers , which supersedes previous revenue recognition guidance. The new standard requires that a company recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration the company expects to receive in exchange for those goods or services. Companies will need to use more judgment and estimates than under the guidance currently in effect, including estimating the amount of variable revenue to recognize over each identified performance obligation. Additional disclosures will be required to help users of financial statements understand the nature, amount and timing of revenue and cash flows arising from contracts. In July 2015, the FASB approved a one-year deferral of the effective date. This standard will now become effective for CSX beginning with the first quarter 2018 and can be adopted either retrospectively to each prior reporting period presented or as a cumulative effect adjustment as of the date of adoption. The Company is currently evaluating the impact of adopting this new guidance on the consolidated financial statements.
Use of Estimates	The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires that management make estimates in reporting the amounts of certain assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amount of certain revenues and expenses during the reporting period. Actual results may differ from those estimates. Critical accounting estimates using management judgment are made for the following areas: • casualty, environmental and legal reserves (see Note 5, Casualty, Environmental and Other Reserves); • pension and post-retirement medical plan accounting (see Note 8, Employee Benefit Plans); • depreciation policies for assets under the group-life method (see Note 6, Properties); and • income taxes (see Note 11, Income Taxes).
Other Items - Share Repurchases	In accordance with the Equity Topic in the ASC, the Company elected to allocate the excess of repurchase price over par value and record in retained earnings. Generally, retained earnings is only impacted by net earnings and dividends.
Earnings Per Share	Basic earnings per share is based on the weighted-average number of shares of common stock outstanding. Earnings per share, assuming dilution, is based on the weighted-average number of shares of common stock equivalents outstanding adjusted for the effects of common stock that may be issued as a result of potentially dilutive instruments. CSX's potentially dilutive instruments are made up of employee stock options and equity awards, which include long-term incentive awards. The Earnings Per Share Topic in the ASC requires CSX to include additional shares in the computation of earnings per share, assuming dilution. The additional shares included in diluted earnings per share represent the number of shares that would be issued if all of the above potentially dilutive instruments were converted into CSX common stock. When calculating diluted earnings per share, the Earnings Per Share Topic in the ASC requires CSX to include the potential shares that would be outstanding if all outstanding stock options were exercised. This number is different from outstanding stock options, which is included in Note 4, Stock Plans and Share-Based Compensation, because it is offset by shares CSX could repurchase using the proceeds from these hypothetical exercises to obtain the common stock equivalent. Outstanding stock options were excluded from the diluted earnings per share calculation as the effect of their inclusion currently would be anti-dilutive.
Share-based Compensation Expense	Share-based compensation expense is measured at the fair market value of the Company’s stock on the grant date and is recognized on a straight-line basis over the service period of the respective award.
Casualty Reserves	In accordance with the Contingencies Topic in the ASC, to the extent the value of an individual claim exceeds the self-insured retention amount, the Company would present the liability on a gross basis with a corresponding receivable for insurance recoveries. These reserves fluctuate based upon the timing of payments as well as changes in estimate. Actual results may vary from estimates due to the number, type and severity of the injury, costs of medical treatments and uncertainties in litigation. Most of the Company's casualty claims relate to CSXT unless otherwise noted below. Defense and processing costs, which historically have been insignificant and are anticipated to be insignificant in the future, are not included in the recorded liabilities.
Asset Retirement and Environmental Obligations	In accordance with the Asset Retirement and Environmental Obligations Topic in the ASC, the Company reviews its role with respect to each site identified at least quarterly, giving consideration to a number of factors such as: • type of clean-up required; • nature of the Company’s alleged connection to the location (e.g., generator of waste sent to the site or owner or operator of the site); • extent of the Company’s alleged connection (e.g., volume of waste sent to the location and other relevant factors); and • number, connection and financial viability of other named and unnamed potentially responsible parties at the location.
Property and Equipment Depreciation	The Company depreciates its rail assets, including main-line track, locomotives and freight cars, using the group-life method of accounting. Assets depreciated under the group-life method of accounting comprise 86% of total fixed assets of $42 billion on a gross basis as of December 2015 . All other depreciable assets of the Company are depreciated on a straight-line basis. The group-life method aggregates assets with similar lives and characteristics into groups and depreciates each of these groups as a whole. When using the group-life method, an underlying assumption is that each group of assets, as a whole, is used and depreciated to the end of its recoverable life.
Impairment Review of Property and Other Long-lived Assets	Properties and other long-lived assets are reviewed for impairment annually or whenever events or business conditions indicate the carrying amount of such assets may not be fully recoverable. Initial assessments of recoverability are based on estimates of undiscounted future net cash flows associated with an asset or a group of assets in accordance with the Property, Plant, and Equipment Topic in the ASC. Where impairment is indicated, the assets are evaluated and their carrying amount is reduced to fair value based on discounted net cash flows or other estimates of fair value.

Nature of Operations and Sign26

Nature of Operations and Significant Accounting Policies Nature of Operations and Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 25, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Restructuring and Related Costs	These amounts are recognized in labor and fringe and materials, supplies and other on the consolidated statements of income. Workforce Reduction Plans, Separation & Other Costs (Dollars in millions) 2015 2014 Union agreements $ 28 $ — Facility closures 19 — Management streamlining 4 39 Total costs $ 51 $ 39

Earnings Per Share (Tables)

Earnings Per Share (Tables)	12 Months Ended
	Dec. 25, 2015
Earnings Per Share [Abstract]
Computation of basic and diluted earnings per share	The following table sets forth the computation of basic earnings per share and earnings per share, assuming dilution: Fiscal Years 2015 2014 2013 Numerator (Dollars in Millions) : Net Earnings $ 1,968 $ 1,927 $ 1,864 Dividend Equivalents on Restricted Stock (1 ) (1 ) — Net Earnings, Attributable to Common Shareholders $ 1,967 $ 1,926 $ 1,864 Denominator (Units in Millions) : Average Common Shares Outstanding 983 1,001 1,019 Other Potentially Dilutive Common Shares 1 1 — Average Common Shares Outstanding, Assuming Dilution 984 1,002 1,019 Net Earnings Per Share, Basic $ 2.00 $ 1.93 $ 1.83 Net Earnings Per Share, Assuming Dilution $ 2.00 $ 1.92 $ 1.83

Shareholders' Equity (Tables)

Shareholders' Equity (Tables)	12 Months Ended
	Dec. 25, 2015
Stockholders' Equity Note [Abstract]
Schedule of common and preferred stock	Common and preferred stock consists of the following: Common Stock, $1 Par Value December 2015 (Units in Millions) Common Shares Authorized 1,800 Common Shares Issued and Outstanding 966 Preferred Stock Preferred Shares Authorized 25 Preferred Shares Issued and Outstanding —

Stock Plans and Share-Based C29

Stock Plans and Share-Based Compensation (Tables)	12 Months Ended
	Dec. 25, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of share-based compensation and related income tax benefit	Total pre-tax expense associated with share-based compensation and its related income tax benefit is shown in the table below. Fiscal Years (Dollars in Millions) 2015 2014 2013 Share-Based Compensation Expense $ 12 $ 33 $ 14 Income Tax Benefit 4 13 6
Schedule of outstanding restricted stock units and awards	The following table provides information about outstanding restricted stock units and awards combined. As of December 2015 , unrecognized compensation expense for these awards and units was approximately $13 million , which will be expensed over a weighted-average remaining period of 2 years. NOTE 4. Stock Plans and Share-Based Compensation, continued Fiscal Years 2015 2014 2013 Restricted Stock Units and Awards Outstanding (Thousands) (a) 1,157 1,383 1,462 Weighted-Average Fair Value at Grant Date $ 28.66 $ 25.03 $ 23.89 Restricted Stock Units and Awards Expense (Millions) (a) $ 11 $ 11 $ 10 Unvested Restricted Stock Units and Awards Outstanding (Thousands) 406 601 705 Weighted-Average Fair Value of Unvested Units and Awards Outstanding $ 31.35 $ 26.40 $ 24.17 (a) Time-based restricted stock units were granted to certain employees under the respective Long-term Incentive Plans in the amount of 312,000 , 371,000 , and 524,000 in 2015 , 2014 and 2013 , respectively, as described below. These units vest over three years , therefore only a partial amount of expense was recognized in 2015 , 2014 , and 2013 , respectively.
Schedule of target units granted and weighted-average fair value calculations	LTIP Plan (Plan Ended In) 2015 2016 2017 Number of target units outstanding (Thousands) (a) 1,317 1,115 826 Weighted-average fair value at grant date (a) $ 25.90 $ 28.60 $ 35.94 Payout Range 0% - 200% 0% - 200% 0% - 200% (a) Number of target units granted and weighted-average fair value calculations above include the value of both initial grants and subsequent, smaller grants issued at different prices based on grant date fair value to new or promoted employees not previously included.
Schedule of outstanding long-term incentive plans	The activity related to each of the outstanding long-term incentive plans is summarized as follows: LTIP Plan (Plan Ended In) Weighted-Average Fair Value at Grant Date (Units Outstanding, in Thousands) 2015 2016 2017 Unvested at December 27, 2013 1,318 — — $ 25.32 Granted in 2014 52 1,144 — 28.11 Forfeited in 2014 (40 ) (25 ) — 26.33 Unvested at December 26, 2014 1,330 1,119 — 26.66 Granted in 2015 63 134 935 35.45 Forfeited in 2015 (76 ) (138 ) (109 ) 30.06 Vested at December 25, 2015 1,317 — — 25.90 Unvested at December 25, 2015 — 1,115 826 $ 31.73
Schedule of shares issued to directors	The following table provides information about shares issued to directors. Fiscal Years 2015 2014 2013 Shares Issued to Directors (Thousands) 62 79 105 Expense (Millions) $ 2 $ 2 $ 2 Weighted Average Grant Date Stock Price $ 34.59 $ 28.01 $ 23.12

Casualty, Environmental and O30

Casualty, Environmental and Other Reserves (Tables)	12 Months Ended
	Dec. 25, 2015
Casualty, Environmental and Other Reserves [Abstract]
Casualty, environmental and other reserves	Activity related to casualty, environmental and other reserves is as follows: Casualty Environmental Other (Dollars in Millions) Reserves Reserves Reserves Total December 28, 2012 $ 325 $ 88 $ 64 $ 477 Charged to Expense 54 48 38 140 Payments (99 ) (36 ) (31 ) (166 ) December 27, 2013 280 100 71 451 Charged to Expense (a) 89 57 30 176 Payments (104 ) (63 ) (42 ) (209 ) December 26, 2014 265 94 59 418 Charged to Expense 60 45 37 142 Payments (56 ) (57 ) (47 ) (160 ) December 25, 2015 $ 269 $ 82 $ 49 $ 400 (a) Increase in expense in 2014 is primarily due to the resolution of personal injury claims for prior years. These reserves are considered critical accounting estimates due to the need for significant management judgment. They are provided for in the consolidated balance sheets as shown in the table below. December 2015 December 2014 (Dollars in Millions) Current Long-term Total Current Long-term Total Casualty: Personal Injury $ 57 $ 147 $ 204 $ 68 $ 123 $ 191 Asbestos 9 44 53 5 51 56 Occupational 3 9 12 3 15 18 Total Casualty $ 69 $ 200 $ 269 $ 76 $ 189 $ 265 Environmental 42 40 82 48 46 94 Other 20 29 49 18 41 59 Total $ 131 $ 269 $ 400 $ 142 $ 276 $ 418
Schedule of Claims Activity	A summary of asbestos claims activity is as follows: Fiscal Years 2015 2014 Asserted Asbestos Claims Open Claims - Beginning of Year 177 251 New Claims Filed 77 106 Claims Settled (64 ) (95 ) Claims Dismissed (30 ) (85 ) Open Claims - End of Year 160 177

Properties (Tables)

Properties (Tables)	12 Months Ended
	Dec. 25, 2015
Property, Plant and Equipment [Abstract]
Schedule of net properties	A detail of the Company’s net properties are as follows: (Dollars in Millions) Accumulated Net Book Annual Depreciation Depreciation Estimated Useful December 2015 Cost Depreciation Value Rate Method Life Road Rail and Other Track Material $ 7,150 $ (1,414 ) $ 5,736 2.5% Group Life Ties 5,077 (1,147 ) 3,930 3.7% Group Life Grading 2,533 (479 ) 2,054 1.4% Group Life Ballast 2,793 (802 ) 1,991 2.7% Group Life Bridges, Trestles, and Culverts 2,238 (283 ) 1,955 1.6% Group Life Signals and Interlockers 2,315 (416 ) 1,899 4.0% Group Life Buildings 1,152 (424 ) 728 2.5% Group Life Other 4,306 (1,793 ) 2,513 4.2% Group Life Total Road 27,564 (6,758 ) 20,806 8-90 Years Equipment Locomotive 5,673 (2,461 ) 3,212 3.6% Group Life Freight Cars 3,362 (1,018 ) 2,344 3.2% Group Life Work Equipment and Other 2,073 (1,154 ) 919 7.1% Group Life Total Equipment 11,108 (4,633 ) 6,475 3-38 Years Land 1,858 — 1,858 N/A N/A N/A Construction In Progress 1,003 — 1,003 N/A N/A N/A Other 41 (9 ) 32 N/A Straight Line 4-30 Years Total Properties $ 41,574 $ (11,400 ) $ 30,174 NOTE 6. Properties, continued (Dollars in Millions) Accumulated Net Book Annual Depreciation Depreciation Estimated Useful December 2014 Cost Depreciation Value Rate Method Life Road Rail and Other Track Material $ 6,771 $ (1,400 ) $ 5,371 2.5% Group Life Ties 4,807 (1,060 ) 3,747 3.7% Group Life Grading 2,460 (481 ) 1,979 1.4% Group Life Ballast 2,693 (679 ) 2,014 2.7% Group Life Bridges, Trestles, and Culverts 2,119 (278 ) 1,841 1.6% Group Life Signals and Interlockers 2,103 (356 ) 1,747 4.0% Group Life Buildings 1,102 (377 ) 725 2.5% Group Life Other 4,070 (1,517 ) 2,553 4.2% Group Life Total Road 26,125 (6,148 ) 19,977 8-90 Years Equipment Locomotive 5,036 (2,325 ) 2,711 3.6% Group Life Freight Cars 3,244 (1,169 ) 2,075 3.2% Group Life Work Equipment and Other 1,828 (1,032 ) 796 7.1% Group Life Total Equipment 10,108 (4,526 ) 5,582 3-38 Years Land 1,875 — 1,875 N/A N/A N/A Construction In Progress 1,196 — 1,196 N/A N/A N/A Other 39 (85 ) (46 ) N/A Straight Line 4-30 Years Total Properties $ 39,343 $ (10,759 ) $ 28,584

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 25, 2015
Commitments and Contingencies Disclosure [Abstract]
Schedule of rent expense associated with operating leases	The Company uses the straight-line method to recognize rent expense associated with operating leases that include escalations over their terms. These amounts are shown in the table below. Fiscal Years (Dollars in Millions) 2015 2014 2013 Rent Expense on Operating Leases $ 66 $ 61 $ 60
Schedule of minimum rentals and commitments under operating leases	At December 2015 , minimum rentals on land, buildings, track and equipment under operating leases are disclosed in the table below. Also, payments to Conrail for leases on shared rail infrastructure are included in these amounts. (See Note 12, Related Party Transactions). (Dollars in Millions) Operating Sublease Net Lease Years Leases Income Commitments 2016 $ 76 $ (3 ) $ 73 2017 69 (3 ) 66 2018 55 (2 ) 53 2019 53 (2 ) 51 2020 35 (2 ) 33 Thereafter 167 (8 ) 159 Total $ 455 $ (20 ) $ 435
Schedule of number of locomotives and payments under long-term maintenance program	The following table summarizes the number of locomotives covered and CSXT’s payments under the long-term maintenance program. Fiscal Years (Dollars in Millions) 2015 2014 2013 Amounts Paid $ 233 $ 247 $ 287 Number of Locomotives 2,310 1,886 1,886
Schedule of annual payments under long-term maintenance program	Total annual payments under all of these purchase commitments are also estimated in the table below. (Dollars in Millions) Locomotive & Maintenance Payments Other Commitments Total 2016 $ 570 $ 110 $ 680 2017 561 74 635 2018 287 20 307 2019 306 17 323 2020 316 12 328 Thereafter 4,515 64 4,579 Total $ 6,555 $ 297 $ 6,852

Employee Benefit Plans (Tables)

Employee Benefit Plans (Tables)	12 Months Ended
	Dec. 25, 2015
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Abstract]
Schedule of summary of participants	In order to perform this valuation, the actuaries are provided with the details of the population covered at the beginning of the year, summarized in the table below, and projects that population forward to the end of the year . NOTE 8. Employee Benefit Plans, continued Summary of Participants as of January 1, 2015 Pension Plans Post-retirement Medical Plan Active Employees 5,234 1,212 Retirees and Beneficiaries 11,777 12,957 Other (a) 3,781 69 Total 20,792 14,238 (a) For pension plans, the other category consists mostly of terminated but vested former employees. For post-retirement plans, the other category consists of employees on long-term disability that have not yet retired.
Schedule of future expected benefit payments	Future expected benefit payments are as follows: Expected Cash Flows (Dollars in Millions) Pension Benefits Post-retirement Benefits 2016 $ 187 $ 36 2017 188 34 2018 188 31 2019 183 29 2020 183 27 2021-2025 917 107 Total $ 1,846 $ 264
Schedule of allocation of plan assets	The distribution of pension plan assets as of the measurement date is shown in the table below, and these assets are netted against the pension liabilities on the balance sheet. December 2015 December 2014 Percent of Percent of (Dollars in Millions) Amount Total Assets Amount Total Assets Equity $ 1,626 70 % $ 1,715 68 % Fixed Income 641 28 740 30 Cash and Cash Equivalents 42 2 49 2 Total $ 2,309 100 % $ 2,504 100 %
Schedule of changes in benefit obligation and fair value of plan assets	Changes in benefit obligation and the fair value of plan assets for the 2015 and 2014 calendar plan years are as follows: Pension Benefits Post-retirement Benefits Plan Year Plan Year Plan Year Plan Year (Dollars in Millions) 2015 2014 2015 2014 Actuarial Present Value of Benefit Obligation Accumulated Benefit Obligation $ 2,672 $ 2,849 N/A N/A Projected Benefit Obligation 2,860 3,002 $ 314 $ 340 Change in Projected Benefit Obligation: Projected Benefit Obligation at Beginning of Plan Year $ 3,002 $ 2,679 $ 340 $ 350 Service Cost 45 44 2 3 Interest Cost 116 123 12 13 Plan Participants' Contributions — — 7 7 Workforce Reduction Program/Curtailment 7 27 — 8 Actuarial Loss (Gain) (110 ) 333 (7 ) (8 ) Benefits Paid (200 ) (204 ) (40 ) (33 ) Benefit Obligation at End of Plan Year $ 2,860 $ 3,002 $ 314 $ 340 Change in Plan Assets: Fair Value of Plan Assets at Beginning of Plan Year $ 2,504 $ 2,500 $ — $ — Actual Return on Plan Assets (9 ) 195 — — Non-qualified Employer Contributions 14 13 33 26 Plan Participants' Contributions — — 7 7 Benefits Paid (200 ) (204 ) (40 ) (33 ) Fair Value of Plan Assets at End of Plan Year 2,309 2,504 — — Funded Status at End of Plan Year $ (551 ) $ (498 ) $ (314 ) $ (340 )
Schedule of amount recognized in balance sheet	Amounts related to pension and post-retirement benefits recorded in other long-term assets, labor and fringe benefits payable and other long-term liabilities on the balance sheet are as follows: NOTE 8. Employee Benefit Plans, continued Pension Benefits Post-retirement Benefits December December December December (Dollars in Millions) 2015 2014 2015 2014 Amounts Recorded in Consolidated Balance Sheets: Long-term Assets (a) $ 9 $ 9 $ — $ — Current Liabilities (15 ) (15 ) (36 ) (37 ) Long-term Liabilities (545 ) (492 ) (278 ) (303 ) Net Amount Recognized in Consolidated Balance Sheets $ (551 ) $ (498 ) $ (314 ) $ (340 ) (a) Long-term assets as of December 2015 and 2014 relate to one of the qualified pension plans whose assets exceed projected benefit obligations.
Benefit obligations in excess of plan assets	At December 2015 , the status of CSX plans only with a net liability is disclosed below. The total fair value of all plans as of December 2015 was $2.3 billion , which includes the qualified pension plans with net assets. Aggregate Aggregate (Dollars in Millions) Fair Value Projected Benefit Obligations in Excess of Plan Assets of Plan Assets Benefit Obligation Projected Benefit Obligation $ 2,273 $ (2,833 ) Accumulated Benefit Obligation 2,273 (2,645 )
Schedule of net benefit expense	The following table describes the components of expense/(income) related to net benefit expense recorded in labor and fringe on the income statement. Pension Benefits Fiscal Years Post-retirement Benefits Fiscal Years (Dollars in Millions) 2015 2014 2013 2015 2014 2013 Service Cost $ 45 $ 44 $ 49 $ 2 $ 3 $ 3 Interest Cost 116 123 108 12 13 13 Expected Return on Plan Assets (162 ) (166 ) (162 ) — — — Amortization of Net Loss 70 57 100 4 5 14 Amortization of Prior Service Cost — — — (1 ) (1 ) (1 ) Net Periodic Benefit Expense 69 58 95 17 20 29 Special Termination Benefits - Workforce Reduction Program/Curtailment (a) 7 27 — — 8 — Settlement Gain (b) (2 ) (1 ) (2 ) — — — Total Expense $ 74 $ 84 $ 93 $ 17 $ 28 $ 29 (a) Special termination benefits are charges in 2015 and 2014 that resulted from a management workforce reduction program initiated in 2014. For further information regarding the program, see Note 1. Nature of Operations and Significant Accounting Policies. (b) Settlement gains were recognized as one of the pension plan's lump-sum payments to retirees with insignificant balances exceeded the sum of the service cost and interest cost recognized. The gain is the recognition of a portion of its accumulated other comprehensive income related to that plan
Schedule of pre-tax change in other comprehensive loss (income)	The following table shows the pre-tax change in other comprehensive loss (income) attributable to the components of net expense and the change in benefit obligation for CSX for pension and other post-employment benefits. (Dollars in Millions) Pension Benefits Post-retirement Benefits Components of Other Comprehensive December December December December Loss (Income) 2015 2014 2015 2014 Recognized in the balance sheet Losses (Gains) $ 60 $ 305 $ (7 ) $ (8 ) Expense (Income) recognized in the income statement Amortization of net losses (a) $ 70 $ 57 $ 4 $ 5 Settlement gain (2 ) (1 ) — — Amortization of prior service costs — — (1 ) (1 ) (a) Amortization of net losses estimated to be expensed for 2016 is approximately $48 million and $2 million for pension benefits and post-retirement benefits, respectively.
Schedule of pre-tax amounts to be amortized that included in accumulated other comprehensive loss	As of December 2015 , the balances of pre-tax amounts to be amortized that are included in accumulated other comprehensive loss (a component of shareholders’ equity) are as follows: Pension Benefits Post-retirement Benefits Losses $ 900 $ 49 Prior Service Costs (Credits) — — Total $ 900 $ 49
Schedule of weighted-average assumptions used	Weighted-average assumptions used in accounting for the plans were as follows: Pension Benefits Post-retirement Benefits 2015 2014 2015 2014 Expected Long-term Return on Plan Assets: Benefit Cost for Plan Year 7.25 % 7.50 % N/A N/A Benefit Obligation at End of Plan Year 7.00 % 7.25 % N/A N/A Discount Rates: Benefit Cost for Plan Year 4.00 % 4.75 % 3.60 % 4.25 % Benefit Obligation at End of Plan Year 4.30 % 4.00 % 3.85 % 3.60 % Salary Scale Inflation 4.60 % 4.10 % N/A N/A

Debt and Credit Agreements (Tab

Debt and Credit Agreements (Tables)	12 Months Ended
	Dec. 25, 2015
Debt Disclosure [Abstract]
Schedule of long-term debt instruments	Debt at December 2015 and December 2014 is shown in the table below. For information regarding the fair value of debt, see Note 13, Fair Value Measurements. Maturity at December Average Interest Rates at December December December (Dollars in Millions) 2015 2015 2015 2014 Notes 2017-2054 5.2% $ 10,445 $ 9,456 Equipment Obligations (a) 2016-2023 6.3% 250 277 Capital Leases 2016-2026 15.0% 7 8 Convertible Debentures 2021 1.0% 1 1 Subtotal Long-term Debt (including current portion) $ 10,703 $ 9,742 Less Debt Due within One Year (20 ) (228 ) Long-term Debt (excluding current portion) $ 10,683 $ 9,514 (a) These obligations are secured by an interest in certain railroad equipment.
Schedule of long-term debt maturities	Long-term Debt Maturities (Dollars in Millions) Maturities as of Fiscal Years Ending December 2015 2016 $ 20 2017 632 2018 619 2019 518 2020 745 Thereafter 8,169 Total Long-term Debt Maturities (including current portion) $ 10,703

Other Income - Net (Tables)

Other Income - Net (Tables)	12 Months Ended
	Dec. 25, 2015
Other Income and Expenses [Abstract]
Schedule of Other Income - Net	Other income – net consisted of the following: Fiscal Years (Dollars in Millions) 2015 2014 2013 Interest Income $ 6 $ 5 $ 8 Income from Real Estate Operations (a) 83 23 23 Miscellaneous Income (Expense) (b) 9 (52 ) (20 ) Total Other Income (Expense) - Net $ 98 $ (24 ) $ 11 Gross Revenue from Real Estate Operations included above $ 104 $ 47 $ 48 (a) Income from real estate operations increased from 2014 to 2015 primarily due to a $59 million gain on a sale of non-operating easements. For additional information, see Note 6, Properties. (b) Miscellaneous income increased from 2014 to 2015 primarily due to a reimbursement of environmental costs of $21 million related to the sale above. Additionally, 2015 environmental costs were $21 million lower than 2014, and prior year costs of $16 million associated with the early redemption of long-term debt did not repeat in the current year.

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 25, 2015
Income Tax Disclosure [Abstract]
Schedule of breakdown of income tax expense between current and deferred	The breakdown of income tax expense between current and deferred is as follows: Fiscal Years (Dollars in Millions) 2015 2014 2013 Current: Federal $ 619 $ 729 $ 671 State 95 90 87 Subtotal Current 714 819 758 Deferred: Federal 414 291 285 State 42 7 15 Subtotal Deferred 456 298 300 Total $ 1,170 $ 1,117 $ 1,058
Schedule of income tax expense reconciled to tax computed at statutory rates	Each year's benefit is included in the state income tax and other lines in the table below. Fiscal Years (Dollars In Millions) 2015 2014 2013 Federal Income Taxes $ 1,098 35.0 % $ 1,066 35.0 % $ 1,023 35.0 % State Income Taxes 86 2.7 % 61 2.0 % 65 2.2 % Other (14 ) (0.4 )% (10 ) (0.3 )% (30 ) (1.0 )% Income Tax Expense/Rate $ 1,170 37.3 % $ 1,117 36.7 % $ 1,058 36.2 %
Schedule of significant components of deferred income tax assets and liabilities	The significant components of deferred income tax assets and liabilities include: 2015 2014 (Dollars in Millions) Assets Liabilities Assets Liabilities Pension Plans $ 207 $ — $ 188 $ — Other Employee Benefit Plans 258 — 306 — Accelerated Depreciation — 9,614 — 9,133 Other 261 291 256 334 Total $ 726 $ 9,905 $ 750 $ 9,467 Net Deferred Income Tax Liabilities $ 9,179 $ 8,717
Schedule of change to total gross unrecognized tax benefits	The change to the total gross unrecognized tax benefits and prior year audit resolutions of the Company during the fiscal year ended December 2015 is reconciled in the table below. Uncertain Tax Positions: Fiscal Year (Dollars in Millions) 2015 2014 2013 Balance at beginning of the year $ 21 $ 23 $ 24 Additions based on tax positions related to current year 1 2 2 Additions based on tax positions related to prior years 4 3 5 Reductions based on tax positions related to prior years — — (6 ) Settlements with taxing authorities 1 — — Lapse of statute of limitations (4 ) (7 ) (2 ) Balance at end of the year $ 23 $ 21 $ 23

Related Party Transactions (Tab

Related Party Transactions (Tables)	12 Months Ended
	Dec. 25, 2015
Related Party Transaction [Line Items]
Future minimum lease payments	At December 2015 , minimum rentals on land, buildings, track and equipment under operating leases are disclosed in the table below. Also, payments to Conrail for leases on shared rail infrastructure are included in these amounts. (See Note 12, Related Party Transactions). (Dollars in Millions) Operating Sublease Net Lease Years Leases Income Commitments 2016 $ 76 $ (3 ) $ 73 2017 69 (3 ) 66 2018 55 (2 ) 53 2019 53 (2 ) 51 2020 35 (2 ) 33 Thereafter 167 (8 ) 159 Total $ 455 $ (20 ) $ 435
Corporate Joint Venture [Member]
Related Party Transaction [Line Items]
Future minimum lease payments	Future minimum lease payments due to Conrail under the shared asset area agreements are shown in the table below. (Dollars in Millions) Conrail Shared Years Asset Agreement 2016 $ 26 2017 26 2018 26 2019 26 2020 26 Thereafter 98 Total $ 228
Schedule of related party in the consolidated income statement components	The following table details the related Conrail amounts included in materials, supplies and other in the Company’s consolidated income statements: Fiscal Years (Dollars in Millions) 2015 2014 2013 Rents, fees and services $ 123 $ 124 $ 115 Purchase price amortization and other 4 4 4 Equity earnings of Conrail (33 ) (31 ) (35 ) Total Conrail Expense $ 94 $ 97 $ 84
Schedule of related party consolidated balance sheet components	As required by the Related Party Disclosures Topic in the ASC, the Company has identified amounts below owed to Conrail, or its subsidiaries, representing liabilities under the operating, equipment and shared area agreements with Conrail. The Company also executed two promissory notes with a subsidiary of Conrail which were included in long-term debt on the consolidated balance sheets. Interest expense from these promissory notes was $6 million , $3 million and $4 million for 2015 , 2014 and 2013 , respectively. December December (Dollars in Millions) 2015 2014 Balance Sheet Information: CSX payable to Conrail $ 65 $ 54 Promissory notes payable to Conrail subsidiary 2.89% CSX promissory note due October 2044 73 73 2.89% CSXT promissory note due October 2044 151 151
TTX Company [Member]
Related Party Transaction [Line Items]
Schedule of related party in the consolidated income statement components	Fiscal Years (Dollars in Millions) 2015 2014 2013 Income statement information: Car hire rents $ 218 $ 207 $ 180 Equity earnings of TTX (20 ) (21 ) (13 ) Total TTX expense $ 198 $ 186 $ 167
Schedule of related party consolidated balance sheet components	December December Balance sheet information: 2015 2014 CSX payable to TTX $ 40 $ 35

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 25, 2015
Fair Value Disclosures [Abstract]
Schedule of fair value of investment assets	The Company's investment assets are carried at fair value on the consolidated balance sheets as summarized in the table below. Additionally, the amortized cost basis of these investments was $920 million and $453 million as of December 25, 2015 and December 26, 2014 , respectively. NOTE 13. Fair Value Measurements, continued Fiscal Years 2015 2014 (Dollars in Millions) Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total Certificates of Deposit and Commercial Paper $ — $ 810 $ — $ 810 $ — $ 250 $ — $ 250 Corporate Bonds — 73 — 73 — 141 — 141 Government Securities — 32 — 32 — 51 — 51 Auction Rate Securities — — 4 4 — — 11 11 Total investments at fair value $ — $ 915 $ 4 $ 919 $ — $ 442 $ 11 $ 453
Schedule of investment maturities	These investments have the following maturities and are represented on the consolidated balance sheet within short-term investments for investments with maturities within one year or less, and other long-term assets for investments with maturities greater than one year: (Dollars in Millions) December 2015 December 2014 Less than 1 year $ 810 $ 292 1 - 2 years 9 45 2 - 5 years 27 100 Greater than 5 years 73 16 Total investments at fair value $ 919 $ 453
Schedule of fair value and carrying value of long-term debt	The fair value and carrying value of the Company's long-term debt is as follows: (Dollars in Millions) December 2015 December 2014 Long-term Debt (Including Current Maturities): Fair Value $ 11,340 $ 11,042 Carrying Value 10,703 9,742
Schedule of pension plan assets at fair value by level	The pension plan assets at fair value by level, within the fair value hierarchy, as of calendar plan years 2015 and 2014 are shown in the table below. For additional information related to pension assets, see Note 8, Employee Benefit Plans. NOTE 13. Fair Value Measurements, continued Fiscal Years 2015 2014 (Dollars in Millions) Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total Common Stock $ 738 $ — $ — $ 738 $ 787 $ — $ — $ 787 Mutual funds 15 — — 15 20 — — 20 Cash equivalents 8 — — 8 1 — — 1 Corporate bonds — 480 — 480 — 539 — 539 Government securities — 132 — 132 — 164 — 164 Asset-backed securities — 14 — 14 — 15 — 15 Derivatives and other — 6 — 6 — 2 — 2 Total investments in the fair value hierarchy $ 761 $ 632 $ — $ 1,393 $ 808 $ 720 $ — $ 1,528 Investments measured at net asset value (a) n/a n/a n/a $ 916 n/a n/a n/a $ 976 Investments at fair value $ 761 $ 632 $ — $ 2,309 $ 808 $ 720 $ — $ 2,504 (a) Investments measured at net asset value represent certain investments that have been measured at net asset value per share (or its equivalent) and are thus are not classified in the fair value hierarchy. In accordance with ASC 820, Fair Value Measurements, the fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the pension assets disclosed in Note 8, Employee Benefit Plans.

Other Comprehensive Income _ 39

Other Comprehensive Income / (Loss) (Tables)	12 Months Ended
	Dec. 25, 2015
Equity [Abstract]
Changes in the AOCI balance by component	Changes in the AOCI balance by component are shown in the table below. Amounts reclassified in pension and other post-employment benefits to net earnings relate to the amortization of actuarial losses and are included in labor and fringe on the consolidated income statements. See Note 8. Employee Benefit Plans for further information. Other primarily represents CSX's share of AOCI of equity method investees. Amounts reclassified in other to net earnings are included in materials, supplies and other on the consolidated income statements. NOTE 14. Other Comprehensive Income / (Loss), continued Pension and Other Post-Employment Benefits Other Accumulated Other Comprehensive Income (Loss) (Dollars in millions) Balance December 28, 2012 - Net of Tax $ (851 ) $ (85 ) $ (936 ) Other Comprehensive Income Income Before Reclassifications 510 24 534 Amounts Reclassified to Net Earnings 111 (2 ) 109 Tax (Expense) Benefit (232 ) 2 (230 ) Total Other Comprehensive Income 389 24 413 Balance December 27, 2013 - Net of Tax (462 ) (61 ) (523 ) Other Comprehensive (Loss) Income (Loss) Income Before Reclassifications (297 ) 4 (293 ) Amounts Reclassified to Net Earnings 60 2 62 Tax Benefit 88 — 88 Total Other Comprehensive (Loss) Income (149 ) 6 (143 ) Balance December 26, 2014 - Net of Tax (611 ) (55 ) (666 ) Other Comprehensive Income (Loss) Loss Before Reclassifications (53 ) (8 ) (61 ) Amounts Reclassified to Net Earnings 71 (2 ) 69 Tax (Expense) Benefit (8 ) 1 (7 ) Total Other Comprehensive Income (Loss) 10 (9 ) 1 Balance December 25, 2015 - Net of Tax $ (601 ) $ (64 ) $ (665 )

Quarterly Financial Data (Una40

Quarterly Financial Data (Unaudited) (Tables)	12 Months Ended
	Dec. 25, 2015
Quarterly Financial Information Disclosure [Abstract]
Schedule of quarterly financial data	Pursuant to Article 3 of the SEC’s Regulation S-X, the following are selected quarterly financial data: Fiscal Year Ended December 2015 Quarters (Dollars in Millions, Except Per Share Amounts) 1st 2nd 3rd 4th Full Year Revenue $ 3,027 $ 3,064 $ 2,939 $ 2,781 $ 11,811 Operating Income 843 1,017 933 791 3,584 Net Earnings 442 553 507 466 1,968 Earnings Per Share, Basic $ 0.45 $ 0.56 $ 0.52 $ 0.48 $ 2.00 Earnings Per Share, Assuming Dilution 0.45 0.56 0.52 0.48 2.00 Fiscal Year Ended December 2014 Revenue $ 3,012 $ 3,244 $ 3,221 $ 3,192 $ 12,669 Operating Income 739 997 976 901 3,613 Net Earnings 398 529 509 491 1,927 Earnings Per Share, Basic $ 0.40 $ 0.53 $ 0.51 $ 0.49 $ 1.93 Earnings Per Share, Assuming Dilution 0.40 0.53 0.51 0.49 1.92

Summarized Consolidating Fina41

Summarized Consolidating Financial Data (Tables)	12 Months Ended
	Dec. 25, 2015
Summarized Consolidating Financial Data [Abstract]
Consolidating Income Statement	Consolidating Income Statements (Dollars in Millions) Fiscal Year Ended December 2015 CSX Corporation CSX Transportation Eliminations and Other CSX Consolidated Revenue $ — $ 11,733 $ 78 $ 11,811 Expense (589 ) 8,922 (106 ) 8,227 Operating Income 589 2,811 184 3,584 Equity in Earnings of Subsidiaries 1,949 — (1,949 ) — Interest Expense (539 ) (33 ) 28 (544 ) Other Income - Net (4 ) 111 (9 ) 98 Earnings Before Income Taxes 1,995 2,889 (1,746 ) 3,138 Income Tax Expense (27 ) (1,083 ) (60 ) (1,170 ) Net Earnings $ 1,968 $ 1,806 $ (1,806 ) $ 1,968 Total Comprehensive Earnings $ 1,969 $ 1,806 $ (1,806 ) $ 1,969 Fiscal Year Ended December 2014 Revenue $ — $ 12,590 $ 79 $ 12,669 Expense (427 ) 9,585 (102 ) 9,056 Operating Income 427 3,005 181 3,613 Equity in Earnings of Subsidiaries 1,996 1 (1,997 ) — Interest Expense (520 ) (46 ) 21 (545 ) Other Income - Net (19 ) (4 ) (1 ) (24 ) Earnings Before Income Taxes 1,884 2,956 (1,796 ) 3,044 Income Tax Benefit (Expense) 43 (1,093 ) (67 ) (1,117 ) Net Earnings $ 1,927 $ 1,863 $ (1,863 ) $ 1,927 Total Comprehensive Earnings $ 1,784 $ 1,875 $ (1,875 ) $ 1,784 Fiscal Year Ended December 2013 Revenue $ — $ 11,950 $ 76 $ 12,026 Expense (371 ) 9,091 (167 ) 8,553 Operating Income 371 2,859 243 3,473 Equity in Earnings of Subsidiaries 1,964 (1 ) (1,963 ) — Interest Expense (516 ) (62 ) 16 (562 ) Other Income - Net (7 ) (2 ) 20 11 Earnings Before Income Taxes 1,812 2,794 (1,684 ) 2,922 Income Tax Benefit (Expense) 52 (1,028 ) (82 ) (1,058 ) Net Earnings $ 1,864 $ 1,766 $ (1,766 ) $ 1,864 Total Comprehensive Earnings $ 2,277 $ 1,825 $ (1,825 ) $ 2,277
Consolidating Balance Sheets	Consolidating Balance Sheets (Dollars in Millions) As of December 25, 2015 CSX Corporation CSX Transportation Eliminations and Other CSX ASSETS Current Assets: Cash and Cash Equivalents $ 444 $ 175 $ 9 $ 628 Short-term Investments 810 — — 810 Accounts Receivable - Net 1 198 783 982 Receivable from Affiliates 1,092 2,038 (3,130 ) — Materials and Supplies — 350 — 350 Deferred Income Taxes 10 117 (1 ) 126 Other Current Assets (59 ) 120 9 70 Total Current Assets 2,298 2,998 (2,330 ) 2,966 Properties 1 38,964 2,609 41,574 Accumulated Depreciation (1 ) (10,016 ) (1,383 ) (11,400 ) Properties - Net — 28,948 1,226 30,174 Investments in Conrail — — 803 803 Affiliates and Other Companies (39 ) 658 (28 ) 591 Investment in Consolidated Subsidiaries 22,755 — (22,755 ) — Other Long-term Assets 176 399 (70 ) 505 Total Assets $ 25,190 $ 33,003 $ (23,154 ) $ 35,039 LIABILITIES AND SHAREHOLDERS' EQUITY Current Liabilities: Accounts Payable $ 108 $ 626 $ 30 $ 764 Labor and Fringe Benefits Payable 36 407 47 490 Payable to Affiliates 2,954 437 (3,391 ) — Casualty, Environmental and Other Reserves — 115 16 131 Current Maturities of Long-term Debt 1 19 — 20 Income and Other Taxes Payable (87 ) 183 12 108 Other Current Liabilities — 437 2 439 Total Current Liabilities 3,012 2,224 (3,284 ) 1,952 Casualty, Environmental and Other Reserves — 219 50 269 Long-term Debt 9,900 783 — 10,683 Deferred Income Taxes (178 ) 9,258 225 9,305 Other Long-term Liabilities 804 484 (126 ) 1,162 Total Liabilities 13,538 12,968 (3,135 ) 23,371 Shareholders' Equity: Common Stock, $1 Par Value 966 181 (181 ) 966 Other Capital 113 5,091 (5,091 ) 113 Retained Earnings 11,238 14,774 (14,774 ) 11,238 Accumulated Other Comprehensive Loss (665 ) (31 ) 31 (665 ) Noncontrolling Minority Interest — 20 (4 ) 16 Total Shareholders' Equity 11,652 20,035 (20,019 ) 11,668 Total Liabilities and Shareholders' Equity $ 25,190 $ 33,003 $ (23,154 ) $ 35,039 NOTE 16. Summarized Consolidating Financial Data, continued Consolidating Balance Sheets (Dollars in Millions) As of December 26, 2014 CSX Corporation CSX Transportation Eliminations and Other CSX ASSETS Current Assets Cash and Cash Equivalents $ 510 $ 100 $ 59 $ 669 Short-term Investments 250 — 42 292 Accounts Receivable - Net 2 206 921 1,129 Receivable from Affiliates 1,211 2,418 (3,629 ) — Materials and Supplies — 272 1 273 Deferred Income Taxes 3 139 (1 ) 141 Other Current Assets — 61 7 68 Total Current Assets 1,976 3,196 (2,600 ) 2,572 Properties 1 36,888 2,454 39,343 Accumulated Depreciation (1 ) (9,516 ) (1,242 ) (10,759 ) Properties - Net — 27,372 1,212 28,584 Investments in Conrail — — 779 779 Affiliates and Other Companies (39 ) 644 (28 ) 577 Investment in Consolidated Subsidiaries 21,570 — (21,570 ) — Other Long-term Assets 178 387 (24 ) 541 Total Assets $ 23,685 $ 31,599 $ (22,231 ) $ 33,053 LIABILITIES AND SHAREHOLDERS' EQUITY Current Liabilities Accounts Payable $ 106 $ 707 $ 32 $ 845 Labor and Fringe Benefits Payable 38 511 64 613 Payable to Affiliates 3,053 514 (3,567 ) — Casualty, Environmental and Other Reserves — 126 16 142 Current Maturities of Long-term Debt 200 29 (1 ) 228 Income and Other Taxes Payable (150 ) 293 20 163 Other Current Liabilities — 111 5 116 Total Current Liabilities 3,247 2,291 (3,431 ) 2,107 Casualty, Environmental and Other Reserves — 213 63 276 Long-term Debt 8,705 809 — 9,514 Deferred Income Taxes (172 ) 8,827 203 8,858 Other Long-term Liabilities 753 487 (118 ) 1,122 Total Liabilities 12,533 12,627 (3,283 ) 21,877 Shareholders' Equity Common Stock, $1 Par Value 992 181 (181 ) 992 Other Capital 92 5,077 (5,077 ) 92 Retained Earnings 10,734 13,717 (13,717 ) 10,734 Accumulated Other Comprehensive Loss (666 ) (31 ) 31 (666 ) Noncontrolling Minority Interest — 28 (4 ) 24 Total Shareholders' Equity 11,152 18,972 (18,948 ) 11,176 Total Liabilities and Shareholders' Equity $ 23,685 $ 31,599 $ (22,231 ) $ 33,053
Consolidating Cash Flow Statements	Consolidating Cash Flow Statements (Dollars in Millions) Fiscal Year Ended December 2015 CSX Corporation CSX Transportation Eliminations and Other CSX Operating Activities Net Cash Provided by (Used in) Operating Activities $ 983 $ 2,974 $ (587 ) $ 3,370 Investing Activities Property Additions — (2,400 ) (162 ) (2,562 ) Purchases of Short-term Investments (1,734 ) — (5 ) (1,739 ) Proceeds from Sales of Short-term Investments 1,175 — 50 1,225 Proceeds from Property Dispositions — 147 — 147 Other Investing Activities (10 ) 132 (85 ) 37 Net Cash Provided by (Used in) Investing Activities (569 ) (2,121 ) (202 ) (2,892 ) Financing Activities Long-term Debt Issued 1,200 — — 1,200 Long-term Debt Repaid (200 ) (29 ) — (229 ) Dividends Paid (686 ) (750 ) 750 (686 ) Stock Options Exercised — — — — Shares Repurchased (804 ) — — (804 ) Other Financing Activities 10 1 (11 ) — Net Cash Provided by (Used in) Financing Activities (480 ) (778 ) 739 (519 ) Net Decrease in Cash and Cash Equivalents (66 ) 75 (50 ) (41 ) Cash and Cash Equivalents at Beginning of Period 510 100 59 669 Cash and Cash Equivalents at End of Period $ 444 $ 175 $ 9 $ 628 NOTE 16. Summarized Consolidating Financial Data, continued Consolidating Cash Flow Statements (Dollars in Millions) Fiscal Year Ended December 2014 CSX Corporation CSX Transportation Eliminations and Other CSX Operating Activities Net Cash Provided by (Used in) Operating Activities $ 583 $ 3,278 $ (518 ) $ 3,343 Investing Activities Property Additions — (2,192 ) (257 ) (2,449 ) Purchases of Short-term Investments (1,419 ) — (14 ) (1,433 ) Proceeds from Sales of Short-term Investments 1,642 — 32 1,674 Proceeds from Property Dispositions — 62 — 62 Other Investing Activities — (128 ) 91 (37 ) Net Cash Provided by (Used in) Investing Activities 223 (2,258 ) (148 ) (2,183 ) Financing Activities Long-term Debt Issued 1,000 — — 1,000 Long-term Debt Repaid (600 ) (333 ) — (933 ) Dividends Paid (629 ) (660 ) 660 (629 ) Stock Options Exercised — — — — Shares Repurchased (517 ) — — (517 ) Other Financing Activities 11 (18 ) 3 (4 ) Net Cash Provided by (Used in) Financing Activities (735 ) (1,011 ) 663 (1,083 ) Net (Decrease) Increase in Cash and Cash Equivalents 71 9 (3 ) 77 Cash and Cash Equivalents at Beginning of Period 439 91 62 592 Cash and Cash Equivalents at End of Period $ 510 $ 100 $ 59 $ 669 NOTE 16. Summarized Consolidating Financial Data, continued Consolidating Cash Flow Statements (Dollars in Millions) Fiscal Year Ended December 2013 CSX Corporation CSX Transportation Eliminations and Other CSX Operating Activities Net Cash Provided by (Used in) Operating Activities $ 1,004 $ 3,005 $ (742 ) $ 3,267 Investing Activities Property Additions — (2,053 ) (260 ) (2,313 ) Purchases of Short-term Investments (1,251 ) — (5 ) (1,256 ) Proceeds from Sales of Short-term Investments 1,335 — 66 1,401 Proceeds from Property Dispositions — 53 — 53 Other Investing Activities (134 ) (315 ) 337 (112 ) Net Cash Provided by (Used in) Investing Activities (50 ) (2,315 ) 138 (2,227 ) Financing Activities Long-term Debt Issued 500 — — 500 Long-term Debt Repaid (700 ) (80 ) — (780 ) Dividends Paid (600 ) (730 ) 730 (600 ) Stock Options Exercised 9 — — 9 Shares Repurchased (353 ) — — (353 ) Other Financing Activities 148 (24 ) (132 ) (8 ) Net Cash Provided by (Used in) Financing Activities (996 ) (834 ) 598 (1,232 ) Net (Decrease) Increase in Cash and Cash Equivalents (42 ) (144 ) (6 ) (192 ) Cash and Cash Equivalents at Beginning of Period 481 235 68 784 Cash and Cash Equivalents at End of Period $ 439 $ 91 $ 62 $ 592

Nature of Operations and Sign42

Nature of Operations and Significant Accounting Policies (Business) (Details) mi in Thousands, employees in Thousands, carloads in Millions, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 25, 2015USD ($)employeesterminalsrailroadsstateport_terminalsmi	Sep. 25, 2015USD ($)	Jun. 26, 2015USD ($)	Mar. 27, 2015USD ($)	Dec. 26, 2014USD ($)	Sep. 26, 2014USD ($)	Jun. 27, 2014USD ($)	Mar. 28, 2014USD ($)	Dec. 25, 2015USD ($)employeesterminalsrailroadsstatecarloadsport_terminalsmi	Dec. 26, 2014USD ($)	Dec. 27, 2013USD ($)
Revenue from External Customer [Line Items]
Number of employees | employees	29								29
Number of union employees | employees									24
Number of rail route miles | mi	21								21
Rail network states number | state	23								23
Number of short-line and regional railroads served | railroads	240								240
Revenue | $	$ 2,781	$ 2,939	$ 3,064	$ 3,027	$ 3,192	$ 3,221	$ 3,244	$ 3,012	$ 11,811	$ 12,669	$ 12,026
Minimum [Member]
Revenue from External Customer [Line Items]
Number of ocean, river and lake ports serviced (more than) | port_terminals	70								70
Merchandise business [Member]
Revenue from External Customer [Line Items]
Number of carloads | carloads									2.9
Percentage of total revenue									62.00%
Percentage of total volume									42.00%
Coal business [Member]
Revenue from External Customer [Line Items]
Number of carloads | carloads									1.1
Percentage of total revenue									19.00%
Percentage of total volume									16.00%
Intermodal business [Member]
Revenue from External Customer [Line Items]
Percentage of total revenue									15.00%
Percentage of total volume									42.00%
Number of terminals (more than) | terminals	50								50
Other business [Member]
Revenue from External Customer [Line Items]
Percentage of total revenue									4.00%

Nature of Operations and Sign43

Nature of Operations and Significant Accounting Policies (Nature of Operations) (Details) $ in Millions	1 Months Ended			12 Months Ended
	Nov. 30, 2015employee	Oct. 31, 2015employee	Nov. 30, 2014employee	Dec. 25, 2015USD ($)	Dec. 26, 2014USD ($)	Dec. 27, 2013
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of weeks in fiscal reporting calendar				P52W	P52W	P52W
Number of weeks in fiscal quarter				P13W
Cost method, maximum percentage				20.00%
Cash equivalents, maximum maturity period				3 months
Short-term investments, minimum maturity period				3 months
Short-term investments, maximum maturity period				1 year
Allowance for doubtful accounts				$ 37	$ 41
Goodwill				63	63
Restructuring Cost and Reserve [Line Items]
Restructuring charges incurred				51	39
Workforce Reduction Plan [Member]
Restructuring Cost and Reserve [Line Items]
Number of positions reduced | employee			300
Workforce Reduction Plan [Member] | Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges incurred				4	39
Erwin, Tennessee and Corbin, Kentucky Facilities [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges incurred				19	0
Number of positions reduced | employee		500
Union Agreement [Member]
Restructuring Cost and Reserve [Line Items]
Number of positions reduced | employee	300
Union Agreement [Member] | Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges incurred				$ 28	$ 0

Nature of Operations and Sign44

Nature of Operations and Significant Accounting Policies (Other Items - Share Repurchases) (Details) - USD ($) shares in Millions	12 Months Ended
	Dec. 25, 2015	Dec. 26, 2014	Dec. 27, 2013	Apr. 30, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Share repurchase program				$ 2,000,000,000
Shares acquired, repurchase amount	$ 804,000,000	$ 517,000,000	$ 353,000,000
Stock repurchased, shares	26	17	14

Earnings Per Share (Details)

Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 25, 2015	Sep. 25, 2015	Jun. 26, 2015	Mar. 27, 2015	Dec. 26, 2014	Sep. 26, 2014	Jun. 27, 2014	Mar. 28, 2014	Dec. 25, 2015	Dec. 26, 2014	Dec. 27, 2013
Numerator:
Net Earnings	$ 466	$ 507	$ 553	$ 442	$ 491	$ 509	$ 529	$ 398	$ 1,968	$ 1,927	$ 1,864
Dividend Equivalents on Restricted Stock									(1)	(1)	0
Net Earnings, Attributable to Common Shareholders									$ 1,967	$ 1,926	$ 1,864
Denominator:
Average Common Shares Outstanding (in shares)									983	1,001	1,019
Other Potentially Dilutive Common Shares (in shares)									1	1	0
Average Common Shares Outstanding, Assuming Dilution (in shares)									984	1,002	1,019
Net Earnings Per Share, Basic (dollars per share)	$ 0.48	$ 0.52	$ 0.56	$ 0.45	$ 0.49	$ 0.51	$ 0.53	$ 0.40	$ 2	$ 1.93	$ 1.83
Net Earnings Per Share, Assuming Dilution (dollars per share)	$ 0.48	$ 0.52	$ 0.56	$ 0.45	$ 0.49	$ 0.51	$ 0.53	$ 0.40	$ 2	$ 1.92	$ 1.83

Shareholders' Equity (Details)

Shareholders' Equity (Details) - $ / shares	12 Months Ended
	Dec. 25, 2015	Dec. 26, 2014
Class of Stock [Line Items]
Common stock par value (dollars per share)	$ 1	$ 1
Common Stock [Member]
Class of Stock [Line Items]
Common Shares Authorized	1,800,000,000
Common Shares Issued	966,000,000
Common Shares Outstanding	966,000,000
Number of votes for each share held	1
Preferred Stock [Member]
Class of Stock [Line Items]
Preferred Shares Authorized	25,000,000
Preferred Shares Issued	0
Preferred Shares Outstanding	0

Stock Plans and Share-Based C47

Stock Plans and Share-Based Compensation (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 25, 2015	Dec. 26, 2014	Dec. 27, 2013
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Net financing cash flows	$ 4	$ 3	$ 13
Share-Based Compensation Expense	12	33	14
Income Tax Benefit	$ 4	$ 13	$ 6

Stock Plans and Share-Based C48

Stock Plans and Share-Based Compensation (Stock Options) (Details) shares in Millions	12 Months Ended
	Dec. 25, 2015$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted | shares	2.5
Fair value of stock options granted | $ / shares	$ 5.31
Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award term	10
Award vesting period	3 years

Stock Plans and Share-Based C49

Stock Plans and Share-Based Compensation (Restricted Stock Grants) (Details) - USD ($) $ / shares in Units, $ in Millions		12 Months Ended
		Dec. 25, 2015	Dec. 26, 2014	Dec. 27, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-Based Compensation Expense		$ 12	$ 33	$ 14
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period		5 years
Unrecognized compensation cost		$ 13
Expected weighted average period of recognition for unrecognized compensation cost (in years)		2 years
Restricted stock units and awards outstanding	[1]	1,157,000	1,383,000	1,462,000
Weighted-average fair value at grant date (dollars per share)		$ 28.66	$ 25.03	$ 23.89
Share-Based Compensation Expense	[1]	$ 11	$ 11	$ 10
Unvested restricted stock units and awards outstanding (in shares)		406,000	601,000	705,000
Weighted-average fair value of unvested units and awards outstanding (dollars per share)		$ 31.35	$ 26.40	$ 24.17
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance unit equivalent of CSX stock, in shares		1
Award vesting period		3 years
Long-term Incentive Plans [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-Based Compensation Expense		$ (1)	$ 19	$ 2
Long-term Incentive Plans [Member] | Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period		3 years
Unrecognized compensation cost		$ 7
Expected weighted average period of recognition for unrecognized compensation cost (in years)		2 years
Weighted-average fair value at grant date (dollars per share)		$ 35.45	$ 28.11
Weighted-average fair value of unvested units and awards outstanding (dollars per share)		$ 31.73	$ 26.66	$ 25.32
Time-based restricted stock units granted (in shares)		312,000	371,000	524,000
[1]	Time-based restricted stock units were granted to certain employees under the respective Long-term Incentive Plans in the amount of 312,000, 371,000, and 524,000 in 2015, 2014 and 2013, respectively, as described below. These units vest over three years, therefore only a partial amount of expense was recognized in 2015, 2014, and 2013, respectively.

Stock Plans and Share-Based C50

Stock Plans and Share-Based Compensation (Long-term Incentive Plans) (Details) $ / shares in Units, $ in Millions		12 Months Ended
		Dec. 25, 2015USD ($)plan$ / sharesshares	Dec. 26, 2014USD ($)	Dec. 27, 2013USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total (benefit) expense | $		$ 12	$ 33	$ 14
Long-term Incentive Plans [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of payout subject to reduction (up to)		30.00%
Total (benefit) expense | $		$ (1)	$ 19	$ 2
Long-term Incentive Plans [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payout Range		0.00%
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Payout Range		0.00%
Long-term Incentive Plans [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payout Range		200.00%
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Payout Range		200.00%
Performance Units [Member] | Long-term Incentive Plans [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance unit equivalent of CSX stock, in shares		1
Plan duration		3 years
Number of plans | plan		3
Payout percentage cumulative period		3 years
Percentage payout on operating ratio		50.00%
Percentage payout on average return on assets		50.00%
Performance Units [Member] | Long Term Incentive Plan - 2014 [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Number of target units outstanding	[1]	1,317,000
Weighted-average fair value at grant date (dollars per share) | $ / shares	[1]	$ 25.90
Performance Units [Member] | Long Term Incentive Plan - 2014 [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payout Range		0.00%
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Payout Range		0.00%
Performance Units [Member] | Long Term Incentive Plan - 2014 [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payout Range		200.00%
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Payout Range		200.00%
Performance Units [Member] | Long Term Incentive Plan - 2015 [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Number of target units outstanding	[1]	1,115,000
Weighted-average fair value at grant date (dollars per share) | $ / shares	[1]	$ 28.60
Performance Units [Member] | Long Term Incentive Plan - 2015 [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payout Range		0.00%
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Payout Range		0.00%
Performance Units [Member] | Long Term Incentive Plan - 2015 [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payout Range		200.00%
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Payout Range		200.00%
Performance Units [Member] | Long Term Incentive Plan - 2016 [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Number of target units outstanding	[1]	826,000
Weighted-average fair value at grant date (dollars per share) | $ / shares	[1]	$ 35.94
Performance Units [Member] | Long Term Incentive Plan - 2016 [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payout Range		0.00%
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Payout Range		0.00%
Performance Units [Member] | Long Term Incentive Plan - 2016 [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payout Range		200.00%
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Payout Range		200.00%
[1]	Number of target units granted and weighted-average fair value calculations above include the value of both initial grants and subsequent, smaller grants issued at different prices based on grant date fair value to new or promoted employees not previously included.

Stock Plans and Share-Based C51

Stock Plans and Share-Based Compensation (Restricted Stock Units) (Details) - Restricted Stock Units (RSUs) [Member] - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	12 Months Ended
	Dec. 25, 2015	Dec. 26, 2014	Dec. 27, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	3 years
Long Term Incentive Plan - 2014 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	63	52
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Unvested, Units Outstanding, beginning balance	1,330	1,318
Granted (in shares)	63	52
Forfeited (in shares)	(76)	(40)
Vested (in shares)	1,317
Unvested, Units Outstanding, beginning balance	0	1,330	1,318
Long Term Incentive Plan - 2015 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	134	1,144
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Unvested, Units Outstanding, beginning balance	1,119	0
Granted (in shares)	134	1,144
Forfeited (in shares)	(138)	(25)
Vested (in shares)	0
Unvested, Units Outstanding, beginning balance	1,115	1,119	0
Long Term Incentive Plan - 2016 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	935	0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Unvested, Units Outstanding, beginning balance	0	0
Granted (in shares)	935	0
Forfeited (in shares)	(109)	0
Vested (in shares)	0
Unvested, Units Outstanding, beginning balance	826	0	0
Long-term Incentive Plans [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected weighted average period of recognition for unrecognized compensation cost (in years)	2 years
Granted (in shares)	312	371	524
Award vesting period	3 years
Unrecognized compensation cost	$ 7
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Granted (in shares)	312	371	524
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Unvested, Weighted-Average Fair Value at Grant Date, beginning balance (dollars per share)	$ 26.66	$ 25.32
Granted, Weighted-Average Fair Value at Grant Date (dollars per share)	35.45	28.11
Forfeited, Weighted-Average Fair Value at Grant Date (dollars per share)	30.06	26.33
Vested, Weighted-Average Fair Value at Grant Date (dollars per share)	25.90
Unvested, Weighted-Average Fair Value at Grant Date, beginning balance (dollars per share)	$ 31.73	$ 26.66	$ 25.32

Stock Plans and Share-Based C52

Stock Plans and Share-Based Compensation (Stock Awards for Directors) (Details) - USD ($) $ / shares in Units, shares in Thousands	12 Months Ended
	Dec. 25, 2015	Dec. 26, 2014	Dec. 27, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-Based Compensation Expense	$ 12,000,000	$ 33,000,000	$ 14,000,000
Non-management Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual retainer to be paid to non-management directors, cash option	90,000
Annual retainer to be paid to non-management directors, common stock option	$ 150,000
Shares Issued to Directors	62	79	105
Share-Based Compensation Expense	$ 2,000,000	$ 2,000,000	$ 2,000,000
Weighted Average Grant Date Stock Price (dollars per share)	$ 34.59	$ 28.01	$ 23.12

Casualty, Environmental and O53

Casualty, Environmental and Other Reserves (Casualty, Environmental and Other Reserves Activity) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 25, 2015	Dec. 26, 2014		Dec. 27, 2013
Casualty Reserves [Member]
Loss Contingency Accrual [Roll Forward]
Balance at beginning of period	$ 265	$ 280		$ 325
Charged to Expense	60	89	[1]	54
Payments	(56)	(104)		(99)
Balance end of period	269	265		280
Environmental Reserves [Member]
Loss Contingency Accrual [Roll Forward]
Balance at beginning of period	94	100		88
Charged to Expense	45	57	[1]	48
Payments	(57)	(63)		(36)
Balance end of period	82	94		100
Other Reserves [Member]
Loss Contingency Accrual [Roll Forward]
Balance at beginning of period	59	71		64
Charged to Expense	37	30	[1]	38
Payments	(47)	(42)		(31)
Balance end of period	49	59		71
Casualty, Environmental and Other [Member]
Loss Contingency Accrual [Roll Forward]
Balance at beginning of period	418	451		477
Charged to Expense	142	176	[1]	140
Payments	(160)	(209)		(166)
Balance end of period	$ 400	$ 418		$ 451
[1]	Increase in expense in 2014 is primarily due to the resolution of personal injury claims for prior years.

Casualty, Environmental and O54

Casualty, Environmental and Other Reserves (Loss Contingencies Accrual) (Details) - USD ($) $ in Millions	Dec. 25, 2015	Dec. 26, 2014	Dec. 27, 2013	Dec. 28, 2012
Contingencies [Line Items]
Current	$ 131	$ 142
Long-term	269	276
Casualty [Member]
Contingencies [Line Items]
Current	69	76
Long-term	200	189
Total	269	265	$ 280	$ 325
Personal Injury [Member]
Contingencies [Line Items]
Current	57	68
Long-term	147	123
Total	204	191
Asbestos [Member]
Contingencies [Line Items]
Current	9	5
Long-term	44	51
Total	53	56
Occupational [Member]
Contingencies [Line Items]
Current	3	3
Long-term	9	15
Total	12	18
Environmental [Member]
Contingencies [Line Items]
Current	42	48
Long-term	40	46
Total	82	94	100	88
Other Reserves [Member]
Contingencies [Line Items]
Current	20	18
Long-term	29	41
Total	49	59	71	64
Casualty, Environmental and Other [Member]
Contingencies [Line Items]
Current	131	142
Long-term	269	276
Total	$ 400	$ 418	$ 451	$ 477

Casualty, Environmental and O55

Casualty, Environmental and Other Reserves (Casualty) (Details) - Casualty [Member]	12 Months Ended
	Dec. 25, 2015USD ($)claim	Dec. 26, 2014USD ($)	Dec. 27, 2013USD ($)	Dec. 28, 2012USD ($)
Loss Contingencies [Line Items]
Reserves	$ 269,000,000	$ 265,000,000	$ 280,000,000	$ 325,000,000
Self-insured retention amount per injury	$ 50,000,000
Individual claims expected to exceed self-insured retention amount | claim	0
Change in estimate recorded to adjust reserves	$ 0	$ 0	$ 0

Casualty, Environmental and O56

Casualty, Environmental and Other Reserves (Asbestos and Occupational Claims) (Details) $ in Millions	12 Months Ended
	Dec. 25, 2015USD ($)claim	Dec. 26, 2014USD ($)claim
Loss Contingency, Claims Quantities [Roll Forward]
Asserted Claims Percentage	20.00%
Unasserted Claims Percentage	80.00%
Occupational Casualty and Asbestos Issues [Member]
Loss Contingency, Claims Quantities [Roll Forward]
Open Claims - Beginning of Year	177	251
New Claims Filed	77	106
Claims Settled	(64)	(95)
Claims Dismissed	(30)	(85)
Open Claims - End of Year	160	177
Asbestos [Member]
Loss Contingencies [Line Items]
Loss contingency, latency period (in years)	10 years
Total liability | $	$ 53	$ 56
Asbestos Casualty [Member]
Loss Contingencies [Line Items]
Loss Contingency, Prior Estimate, Period	7 years
Time period for estimating probable claims (in years)	10 years
Minimum [Member] | Asbestos [Member]
Loss Contingencies [Line Items]
Loss contingency, latency period (in years)	10 years
Maximum [Member] | Asbestos [Member]
Loss Contingencies [Line Items]
Loss contingency, latency period (in years)	40 years

Casualty, Environmental and O57

Casualty, Environmental and Other Reserves (Environmental and Other) (Details) $ in Millions	Dec. 25, 2015USD ($)site	Dec. 26, 2014USD ($)	Dec. 27, 2013USD ($)	Dec. 28, 2012USD ($)
Environmental Reserves [Member]
Contingencies [Line Items]
Reserves	$ 82	$ 94	$ 100	$ 88
Environmental impaired site | site	242
Other Reserves [Member]
Contingencies [Line Items]
Reserves	$ 49	$ 59	$ 71	$ 64

Properties (Detail of Net Prope

Properties (Detail of Net Properties) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 25, 2015	Dec. 26, 2014
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	$ 41,574	$ 39,343
Accumulated Depreciation	(11,400)	(10,759)
Properties - Net	30,174	28,584
Road - Total [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	27,564	26,125
Accumulated Depreciation	(6,758)	(6,148)
Properties - Net	20,806	19,977
Road - Rail and Other Track Material [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	7,150	6,771
Accumulated Depreciation	(1,414)	(1,400)
Properties - Net	$ 5,736	$ 5,371
Annual Depreciation Rate	2.50%	2.50%
Depreciation Method		Group Life
Road - Ties [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	$ 5,077	$ 4,807
Accumulated Depreciation	(1,147)	(1,060)
Properties - Net	$ 3,930	$ 3,747
Annual Depreciation Rate	3.70%	3.70%
Depreciation Method		Group Life
Road - Grading [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	$ 2,533	$ 2,460
Accumulated Depreciation	(479)	(481)
Properties - Net	$ 2,054	$ 1,979
Annual Depreciation Rate	1.40%	1.40%
Depreciation Method		Group Life
Road - Ballast [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	$ 2,793	$ 2,693
Accumulated Depreciation	(802)	(679)
Properties - Net	$ 1,991	$ 2,014
Annual Depreciation Rate	2.70%	2.70%
Depreciation Method		Group Life
Road - Bridges, Trestles, and Culverts [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	$ 2,238	$ 2,119
Accumulated Depreciation	(283)	(278)
Properties - Net	$ 1,955	$ 1,841
Annual Depreciation Rate	1.60%	1.60%
Depreciation Method		Group Life
Road - Signals and Interlockers [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	$ 2,315	$ 2,103
Accumulated Depreciation	(416)	(356)
Properties - Net	$ 1,899	$ 1,747
Annual Depreciation Rate	4.00%	4.00%
Depreciation Method		Group Life
Road - Buildings [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	$ 1,152	$ 1,102
Accumulated Depreciation	(424)	(377)
Properties - Net	$ 728	$ 725
Annual Depreciation Rate	2.50%	2.50%
Depreciation Method		Group Life
Road - Other [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	$ 4,306	$ 4,070
Accumulated Depreciation	(1,793)	(1,517)
Properties - Net	$ 2,513	$ 2,553
Annual Depreciation Rate	4.20%	4.20%
Depreciation Method		Group Life
Total Equipment [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	$ 11,108	$ 10,108
Accumulated Depreciation	(4,633)	(4,526)
Properties - Net	6,475	5,582
Equipment - Locomotive [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	5,673	5,036
Accumulated Depreciation	(2,461)	(2,325)
Properties - Net	$ 3,212	$ 2,711
Annual Depreciation Rate	3.60%	3.60%
Depreciation Method		Group Life
Equipment - Freight Cars [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	$ 3,362	$ 3,244
Accumulated Depreciation	(1,018)	(1,169)
Properties - Net	$ 2,344	$ 2,075
Annual Depreciation Rate	3.20%	3.20%
Depreciation Method		Group Life
Equipment - Work Equipment and Other [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	$ 2,073	$ 1,828
Accumulated Depreciation	(1,154)	(1,032)
Properties - Net	$ 919	$ 796
Annual Depreciation Rate	7.10%	7.10%
Depreciation Method		Group Life
Land [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	$ 1,858	$ 1,875
Properties - Net	1,858	1,875
Construction in Progress [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	1,003	1,196
Properties - Net	1,003	1,196
Other properties [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	41	39
Accumulated Depreciation	(9)	(85)
Properties - Net	$ 32	$ (46)
Depreciation Method		Straight Line
Minimum [Member] | Road - Total [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Estimated useful life	8 years	8 years
Minimum [Member] | Road - Other [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Estimated useful life	8 years
Minimum [Member] | Total Equipment [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Estimated useful life	3 years	3 years
Minimum [Member] | Other properties [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Estimated useful life	4 years	4 years
Maximum [Member] | Road - Total [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Estimated useful life	90 years	90 years
Maximum [Member] | Road - Grading [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Estimated useful life	90 years
Maximum [Member] | Total Equipment [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Estimated useful life	38 years	38 years
Maximum [Member] | Equipment - Work Equipment and Other [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Estimated useful life	38 years
Maximum [Member] | Other properties [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Estimated useful life	30 years	30 years

Properties (Railroad Assets, No

Properties (Railroad Assets, Non-Railroad Assets, and Capital Expenditure) (Details)	12 Months Ended
	Dec. 25, 2015USD ($)categories	Dec. 26, 2014USD ($)	Dec. 27, 2013USD ($)
Railroad Assets [Abstract]
Percentage of assets depreciated under the group-life method	86.00%
Total fixed assets	$ 41,574,000,000	$ 39,343,000,000
Annual depreciation expense	$ 1,208,000,000	1,151,000,000	$ 1,104,000,000
Capital Expenditures [Abstract]
Percentage of labor costs relating to the deconstruction of old track (In hundredths)	20.00%
Percentage of labor costs relating to the installation of new track (In hundredths)	80.00%
Minimum [Member]
Railroad Assets [Abstract]
Number of depreciable asset categories for railroad assets | categories	130
Road - Ties [Member]
Railroad Assets [Abstract]
Total fixed assets	$ 5,077,000,000	4,807,000,000
Number of depreciable asset categories for railroad assets | categories	18
Total Equipment [Member]
Railroad Assets [Abstract]
Total fixed assets	$ 11,108,000,000	$ 10,108,000,000
Life studies, frequency period	3 years
Total Equipment [Member] | Minimum [Member]
Railroad Assets [Abstract]
Estimated useful life	3 years	3 years
Total Equipment [Member] | Maximum [Member]
Railroad Assets [Abstract]
Estimated useful life	38 years	38 years
Road - Total [Member]
Railroad Assets [Abstract]
Total fixed assets	$ 27,564,000,000	$ 26,125,000,000
Life studies, frequency period	6 years
Road - Total [Member] | Minimum [Member]
Railroad Assets [Abstract]
Estimated useful life	8 years	8 years
Road - Total [Member] | Maximum [Member]
Railroad Assets [Abstract]
Estimated useful life	90 years	90 years
Technology Equipment [Member] | Minimum [Member]
Railroad Assets [Abstract]
Estimated useful life	3 years
Abnormal gain (loss) on operating property [Member]
Railroad Assets [Abstract]
Abnormal gains and losses	$ 23,000,000	$ 0	$ 65,000,000
Gain (loss) on non-operating property [Member]
Railroad Assets [Abstract]
Abnormal gains and losses	$ 59,000,000

Commitments and Contingencies60

Commitments and Contingencies (Lease Commitments) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 25, 2015	Dec. 26, 2014	Dec. 27, 2013
Operating Leased Assets [Line Items]
Maximum lease term (up to)	30 years
Operating Leases [Abstract]
2,016	$ 76
2,017	69
2,018	55
2,019	53
2,020	35
Thereafter	167
Total	455
Sublease Income [Abstract]
2,016	(3)
2,017	(3)
2,018	(2)
2,019	(2)
2,020	(2)
Thereafter	(8)
Total	(20)
Net Lease Commitments [Abstract]
2,016	73
2,017	66
2,018	53
2,019	51
2,020	33
Thereafter	159
Total	435
Rent Expense on Operating Leases [Member]
Operating Leases, Rent Expense, Net [Abstract]
Rent Expense on Operating Leases	$ 66	$ 61	$ 60

Commitments and Contingencies61

Commitments and Contingencies (Purchase Commitments) (Details) $ in Millions	12 Months Ended
	Dec. 25, 2015USD ($)locomotives	Dec. 26, 2014USD ($)locomotives	Dec. 27, 2013USD ($)locomotives
Unrecorded Unconditional Purchase Obligation [Line Items]
Percentage of locomotive fleet under long-term maintenance program	50.00%
Amounts Paid	$ 233	$ 247	$ 287
Number of Locomotives | locomotives	2,310	1,886	1,886
Unrecorded Unconditional Purchase Obligation [Abstract]
2,016	$ 680
2,017	635
2,018	307
2,019	323
2,020	328
Thereafter	4,579
Total	6,852
Locomotive & Maintenance Payments [Member]
Unrecorded Unconditional Purchase Obligation [Abstract]
2,016	570
2,017	561
2,018	287
2,019	306
2,020	316
Thereafter	4,515
Total	6,555
Other Commitments [Member]
Unrecorded Unconditional Purchase Obligation [Abstract]
2,016	110
2,017	74
2,018	20
2,019	17
2,020	12
Thereafter	64
Total	$ 297

Commitments and Contingencies62

Commitments and Contingencies (Insurance and Legal) (Details)	1 Months Ended
	May. 31, 2007entity	Dec. 25, 2015USD ($)
Insurance
Non-catastrophic property deductible		$ 25,000,000
Casualty and catastrophic property deductible		50,000,000
Pending Litigation [Member]
Loss Contingency, Estimate [Abstract]
Minimum range of possible loss for legal proceedings		2,000,000
Maximum range of possible loss for legal proceedings		$ 78,000,000
Fuel Surcharge Antitrust Litigation [Member]
Loss Contingency, Estimate [Abstract]
Number of other U.S.-based entities mentioned in class action lawsuit | entity	3

Commitments and Contingencies63

Commitments and Contingencies (Environmental Matters) (Details) - Environmental Litigation [Member]	1 Months Ended	12 Months Ended
	Apr. 30, 2014mi	Dec. 25, 2015counterpartymi
Loss Contingencies [Line Items]
Number of miles pertaining to Passaic River tidal reach required to be studied by EPA		17
Number of potentially responsible parties in connection with environmental liability | counterparty		55
Number of miles under study	8

Employee Benefit Plans (Summary

Employee Benefit Plans (Summary of Participants) (Details)	Dec. 25, 2015employees
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Active Employees	5,234
Retirees and Beneficiaries	11,777
Other	3,781	[1]
Total	20,792
Post-retirement Medical Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Active Employees	1,212
Retirees and Beneficiaries	12,957
Other	69	[1]
Total	14,238
[1]	For pension plans, the other category consists mostly of terminated but vested former employees. For post-retirement plans, the other category consists of employees on long-term disability that have not yet retired.

Employee Benefit Plans (Future

Employee Benefit Plans (Future Expected Benefit Payments) (Details)	12 Months Ended
	Dec. 25, 2015USD ($)
Defined Benefit Plan Disclosure [Line Items]
Significant expected contributions	$ 0
Pension Benefits [Member]
Defined Benefit Plan, Estimated Future Benefit Payments [Abstract]
2,016	187,000,000
2,017	188,000,000
2,018	188,000,000
2,019	183,000,000
2,020	183,000,000
2021-2025	917,000,000
Total	1,846,000,000
Post-retirement Benefits [Member]
Defined Benefit Plan, Estimated Future Benefit Payments [Abstract]
2,016	36,000,000
2,017	34,000,000
2,018	31,000,000
2,019	29,000,000
2,020	27,000,000
2021-2025	107,000,000
Total	$ 264,000,000

Employee Benefit Plans (Plan As

Employee Benefit Plans (Plan Assets) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 25, 2015	Dec. 26, 2014
Defined Benefit Plan Disclosure [Line Items]
Amount	$ 2,309	$ 2,504
Percent of Total Assets	100.00%	100.00%
Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Targeted and established equity allocation (in hundredths)	70.00%
Targeted allocation of total plan assets in domestic equity (in hundredths)	42.00%
Targeted allocation of total plan assets in international equity (in hundredths)	28.00%
Percentage within which the planned allocation is managed (in hundredths)	3.00%
Amount	$ 1,626	$ 1,715
Percent of Total Assets	70.00%	68.00%
Fixed Income [Member]
Defined Benefit Plan Disclosure [Line Items]
Targeted and established equity allocation (in hundredths)	30.00%
Amount	$ 641	$ 740
Percent of Total Assets	28.00%	30.00%
Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Amount	$ 42	$ 49
Percent of Total Assets	2.00%	2.00%

Employee Benefit Plans (Benefit

Employee Benefit Plans (Benefit Obligation and Fair Value of Plan Assets) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 25, 2015	Dec. 26, 2014	Dec. 27, 2013	Dec. 25, 2015	Dec. 26, 2014
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets at Beginning of Plan Year	$ 2,504
Fair Value of Plan Assets at End of Plan Year	2,309	$ 2,504
Pension Benefits [Member]
Actuarial Present Value of Benefit Obligation [Abstract]
Accumulated Benefit Obligation				$ 2,672	$ 2,849
Projected Benefit Obligation	3,002	2,679	$ 2,679	2,860	3,002
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Projected Benefit Obligation at Beginning of Plan Year	3,002	2,679
Service Cost	45	44	49
Interest Cost	116	123	108
Plan Participants' Contributions	0	0
Workforce Reduction Program/Curtailment	7	27
Actuarial Loss (Gain)	(110)	333
Benefits Paid	(200)	(204)
Benefit Obligation at End of Plan Year	2,860	3,002	2,679
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets at Beginning of Plan Year	2,504	2,500
Actual Return on Plan Assets	(9)	195
Plan Participants' Contributions	0	0
Benefits Paid	(200)	(204)
Fair Value of Plan Assets at End of Plan Year	2,309	2,504	2,500
Funded Status at End of Plan Year				(551)	(498)
Post-retirement Benefits [Member]
Actuarial Present Value of Benefit Obligation [Abstract]
Projected Benefit Obligation	340	350	350	314	340
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Projected Benefit Obligation at Beginning of Plan Year	340	350
Service Cost	2	3	3
Interest Cost	12	13	13
Plan Participants' Contributions	7	7
Workforce Reduction Program/Curtailment	0	8
Actuarial Loss (Gain)	(7)	(8)
Benefits Paid	(40)	(33)
Benefit Obligation at End of Plan Year	314	340	350
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets at Beginning of Plan Year	0	0
Actual Return on Plan Assets	0	0
Plan Participants' Contributions	7	7
Benefits Paid	(40)	(33)
Fair Value of Plan Assets at End of Plan Year	0	0	$ 0
Funded Status at End of Plan Year				$ (314)	$ (340)
Non-qualified Employer Contributions [Member] | Pension Benefits [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Non-qualified Employer Contributions	14	13
Non-qualified Employer Contributions [Member] | Post-retirement Benefits [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Non-qualified Employer Contributions	$ 33	$ 26

Employee Benefit Plans (Amounts

Employee Benefit Plans (Amounts Recorded in Consolidated Balance Sheets) (Details) - USD ($) $ in Millions		Dec. 25, 2015	Dec. 26, 2014
Pension Benefits [Member]
Amounts Recorded in Consolidated Balance Sheets [Abstract]
Long-term Assets	[1]	$ 9	$ 9
Current Liabilities		(15)	(15)
Long-term Liabilities		(545)	(492)
Net Amount Recognized in Consolidated Balance Sheets		(551)	(498)
Post-retirement Benefits [Member]
Amounts Recorded in Consolidated Balance Sheets [Abstract]
Long-term Assets		0	0
Current Liabilities		(36)	(37)
Long-term Liabilities		(278)	(303)
Net Amount Recognized in Consolidated Balance Sheets		$ (314)	$ (340)
[1]	Long-term assets as of December 2015 and 2014 relate to one of the qualified pension plans whose assets exceed projected benefit obligations.

Employee Benefit Plans (Benef69

Employee Benefit Plans (Benefit Obligations in Excess of Plan Assets) (Details) - USD ($) $ in Millions	Dec. 25, 2015	Dec. 26, 2014
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Abstract]
Total fair value of all plans	$ 2,309	$ 2,504
Projected Benefit Obligation
Aggregate Fair Value of Plan Assets	2,273
Aggregate Projected Benefit Obligation	(2,833)
Accumulated Benefit Obligation
Aggregate Fair Value of Plan Assets	2,273
Aggregate Projected Benefit Obligation	$ (2,645)

Employee Benefit Plans (Net Ben

Employee Benefit Plans (Net Benefit Expense) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 25, 2015	Dec. 26, 2014	Dec. 27, 2013
Pension Benefits [Member]
Components of expense/ (income) related to net benefit expense [Abstract]
Service Cost	$ 45	$ 44	$ 49
Interest Cost	116	123	108
Expected Return on Plan Assets	(162)	(166)	(162)
Amortization of Net Loss	70	57	100
Amortization of Prior Service Cost	0	0	0
Net Periodic Benefit Expense	69	58	95
Special Termination Benefits - Workforce Reduction Program/Curtailment	7	27	0
Settlement Gain	(2)	(1)	(2)
Total Expense	74	84	93
Post-retirement Benefits [Member]
Components of expense/ (income) related to net benefit expense [Abstract]
Service Cost	2	3	3
Interest Cost	12	13	13
Expected Return on Plan Assets	0	0	0
Amortization of Net Loss	4	5	14
Amortization of Prior Service Cost	(1)	(1)	(1)
Net Periodic Benefit Expense	17	20	29
Special Termination Benefits - Workforce Reduction Program/Curtailment	0	8	0
Settlement Gain	0	0	0
Total Expense	$ 17	$ 28	$ 29

Employee Benefit Plans (Pre-Tax

Employee Benefit Plans (Pre-Tax Change in Other Comprehensive Loss (Income) and Accumulated Other Comprehensive Loss) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 25, 2015	Dec. 26, 2014	Dec. 27, 2013
Pension Benefits [Member]
Components of other comprehensive loss (income) [Abstract]
Losses (Gains)	$ 60	$ 305
Expense (Income) recognized in income statement [Abstract]
Amortization of net losses	70	57	$ 100
Settlement gain	(2)	(1)	(2)
Amortization of prior service costs	0	0	0
Estimated amount to be expensed in the future period	48
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax [Abstract]
Losses	900
Prior Service Costs (Credits)	0
Total	900
Post-retirement Benefits [Member]
Components of other comprehensive loss (income) [Abstract]
Losses (Gains)	(7)	(8)
Expense (Income) recognized in income statement [Abstract]
Amortization of net losses	4	5	14
Settlement gain	0	0	0
Amortization of prior service costs	(1)	$ (1)	$ (1)
Estimated amount to be expensed in the future period	2
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax [Abstract]
Losses	49
Prior Service Costs (Credits)	0
Total	$ 49

Employee Benefit Plans (Weighte

Employee Benefit Plans (Weighted-Average Assumptions) (Details)	12 Months Ended
	Dec. 25, 2015	Dec. 26, 2014
Pension Benefits [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Benefit Cost for Plan Year	7.25%	7.50%
Benefit Obligation at End of Plan Year	7.00%	7.25%
Benefit Cost for Plan Year	4.00%	4.75%
Benefit Obligation at End of Plan Year	4.30%	4.00%
Salary Scale Inflation	4.60%	4.10%
Post-retirement Benefits [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Benefit Cost for Plan Year	3.60%	4.25%
Benefit Obligation at End of Plan Year	3.85%	3.60%

Employee Benefit Plans (Medicar

Employee Benefit Plans (Medicare Prescription Drug and Other Plans) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 25, 2015	Dec. 26, 2014	Dec. 27, 2013
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Abstract]
Amount of premium expenses incurred under the plan	$ 32	$ 37	$ 41
Expense associated with savings plans	$ 36	$ 41	$ 37

Debt and Credit Agreements (Lon

Debt and Credit Agreements (Long-term Debt Instruments) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 25, 2015	Dec. 26, 2014
Debt Instrument [Line Items]
Subtotal Long-term Debt (including current portion)	$ 10,703	$ 9,742
Less Debt Due within One Year	(20)	(228)
Long-term Debt (excluding current portion)	$ 10,683	9,514
Notes [Member]
Debt Instrument [Line Items]
Average Interest Rates (in hundredths)	5.20%
Subtotal Long-term Debt (including current portion)	$ 10,445	9,456
Equipment Obligations [Member]
Debt Instrument [Line Items]
Average Interest Rates (in hundredths)	6.30%
Subtotal Long-term Debt (including current portion)	$ 250	277
Capital Leases [Member]
Debt Instrument [Line Items]
Average Interest Rates (in hundredths)	15.00%
Subtotal Long-term Debt (including current portion)	$ 7	8
Convertible Debt [Member]
Debt Instrument [Line Items]
Average Interest Rates (in hundredths)	1.00%
Subtotal Long-term Debt (including current portion)	$ 1	$ 1

Debt and Credit Agreements (Deb

Debt and Credit Agreements (Debt Issuance and Early Redemption of Long-term Debt) (Details) - USD ($)	12 Months Ended
	Dec. 26, 2014	Dec. 25, 2015
Debt Instrument [Line Items]
Other expense recognized for early redemption premium	$ 16,000,000
Early redemption amount	663,000,000
Unsecured Debt [Member] | Three Point Nine Five Percent Notes Due 2050 [Member]
Debt Instrument [Line Items]
Face amount of debt issued		$ 600,000,000
Notes issued, interest rate		3.95%
Unsecured Debt [Member] | Three Point Three Five Percent Notes Due 2025 [Member] [Domain]
Debt Instrument [Line Items]
Face amount of debt issued		$ 600,000,000
Notes issued, interest rate		3.35%
Unsecured Debt [Member] | Three Point Four Percent Notes Due 2024 [Member]
Debt Instrument [Line Items]
Face amount of debt issued	$ 550,000,000
Notes issued, interest rate	3.40%
Unsecured Debt [Member] | Four Point Five Percent Notes Due 2054 [Member]
Debt Instrument [Line Items]
Face amount of debt issued	$ 450,000,000
Notes issued, interest rate	4.50%
Unsecured Debt [Member] | CSX's Notes Payable Maturing April 1, 2015 [Member]
Debt Instrument [Line Items]
Face amount of debt issued	$ 400,000,000
Notes issued, interest rate	6.25%
Equipment Obligations [Member] | Secured Equipment Notes Due October 15, 2014 [Member]
Debt Instrument [Line Items]
Face amount of debt issued	$ 263,000,000
Notes issued, interest rate	8.375%

Debt and Credit Agreements (L76

Debt and Credit Agreements (Long-term Debt Maturities) (Details) - USD ($) $ in Millions	Dec. 25, 2015	Dec. 26, 2014
Maturities of Long-term Debt [Abstract]
2,016	$ 20	$ 228
2,017	632
2,018	619
2,019	518
2,020	745
Thereafter	8,169
Total Long-term Debt Maturities (including current portion)	$ 10,703

Debt and Credit Agreements (Cre

Debt and Credit Agreements (Credit Facilities and Receivable Securitization Facility) (Details)	12 Months Ended
	Dec. 25, 2015USD ($)
Unsecured Revolving Credit Facility, Current [Member]
Line of Credit Facility [Line Item]
Line of credit facility, current borrowing capacity	$ 1,000,000,000
Line of credit facility, amount outstanding	0
Accounts Receivable Securitization Credit Facility [Member]
Line of Credit Facility [Line Item]
Line of credit facility, current borrowing capacity	250,000,000
Line of credit facility, amount outstanding	$ 0
Line of credit facility, total expiration period	3 years

Other Income - Net (Details)

Other Income - Net (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 25, 2015	Dec. 26, 2014	Dec. 27, 2013
Property, Plant and Equipment [Line Items]
Interest Income	$ 6	$ 5	$ 8
Income from Real Estate Operations (a)	83	23	23
Miscellaneous Income (Expense)	9	(52)	(20)
Total Other Income (Expense) - Net	98	(24)	11
Gross Revenue from Real Estate Operations included above	104	47	$ 48
Reimbursement of environmental clean-ups costs	21
Environmental cleanup costs		21
Other expense recognized for early redemption premium		$ 16
Gain (loss) on non-operating property [Member]
Property, Plant and Equipment [Line Items]
Gain on sale of non-operating easements	$ 59

Income Taxes (Income Tax Expens

Income Taxes (Income Tax Expense) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 25, 2015	Dec. 26, 2014	Dec. 27, 2013
Earnings From Continuing Operations [Abstract]
Earnings before income taxes	$ 3,138	$ 3,044	$ 2,922
Current:
Federal	619	729	671
State	95	90	87
Subtotal Current	714	819	758
Deferred:
Federal	414	291	285
State	42	7	15
Subtotal Deferred	456	298	300
Income Tax Expense (Benefit)	$ 1,170	$ 1,117	$ 1,058

Income Taxes (Income Tax Reconc

Income Taxes (Income Tax Reconciliation) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 25, 2015	Dec. 26, 2014	Dec. 27, 2013
Reconciliation between the statutory income tax rate and the effective income tax rate [Abstract]
Federal Income Taxes	$ 1,098	$ 1,066	$ 1,023
State Income Taxes Expense (Benefit)	86	61	65
Other	(14)	(10)	(30)
Income Tax Expense (Benefit)	$ 1,170	$ 1,117	$ 1,058
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Federal Income Taxes	35.00%	35.00%	35.00%
State Income Taxes	2.70%	2.00%	2.20%
Other	(0.40%)	(0.30%)	(1.00%)
Income Tax Rate	37.30%	36.70%	36.20%
Federal and State Legislative [Member]
Reconciliation between the statutory income tax rate and the effective income tax rate [Abstract]
State Income Taxes Expense (Benefit)	$ (4)	$ (31)	$ (42)

Income Taxes (Deferred Income T

Income Taxes (Deferred Income Tax Assets and Liabilities) (Details) - USD ($) $ in Millions	Dec. 25, 2015	Dec. 26, 2014
Components of Deferred Tax Assets [Abstract]
Pension Plans	$ 207	$ 188
Other Employee Benefit Plans	258	306
Other	261	256
Total	726	750
Components of Deferred Tax Liabilities [Abstract]
Accelerated Depreciation	9,614	9,133
Other	291	334
Total	9,905	9,467
Net Deferred Income Tax Liabilities	$ 9,179	$ 8,717

Income Taxes (Unrecognized Tax

Income Taxes (Unrecognized Tax Benefits) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 25, 2015	Dec. 26, 2014	Dec. 27, 2013
Income Tax Disclosure [Abstract]
Amount of unrecognized tax benefits that may favorably effect the effective income tax rate	$ 15	$ 13	$ 15
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at beginning of the year	21	23	24
Additions based on tax positions related to current year	1	2	2
Additions based on tax positions related to prior years	4	3	5
Reductions based on tax positions related to prior years	0	0	(6)
Settlements with taxing authorities	1	0	0
Lapse of statute of limitations	(4)	(7)	(2)
Balance at end of the year	$ 23	$ 21	$ 23

Income Taxes (Income Taxes Unce

Income Taxes (Income Taxes Uncertainties) (Details) - USD ($) $ in Millions	Dec. 25, 2015	Dec. 26, 2014	Dec. 27, 2013
Income Tax Uncertainties [Abstract]
Reduction (Increase) to income tax reserves due to interest and penalties of prior year tax positions	$ (2)	$ (1)	$ 1
Previously recorded liabilities for interest and penalties of prior period tax positions	$ 4	$ 1	$ 2

Related Party Transactions (Nar

Related Party Transactions (Narrative) (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Oct. 31, 2014	Dec. 25, 2015	Dec. 26, 2014	Dec. 27, 2013
Related Party Transaction [Line Items]
Short term payable to related party		$ 0	$ 0
Corporate Joint Venture [Member]
Related Party Transaction [Line Items]
Difference between carrying amount and underlying equity		353
Interest expense		$ 6	3	$ 4
TTX Company [Member]
Related Party Transaction [Line Items]
Percentage economic interest in related party		20.00%
Equity method investments		$ 443
Economic interest in related party which is also an equity method investment [Member] | Corporate Joint Venture [Member]
Related Party Transaction [Line Items]
Percentage economic interest in related party		42.00%
Voting interest in related party which is also an equity method investment [Member] | Corporate Joint Venture [Member]
Related Party Transaction [Line Items]
Percentage economic interest in related party		50.00%
CSXT Promissory Note Related Party October 2044 [Member]
Related Party Transaction [Line Items]
Accrued interest to related party	$ 3
Accounts Payable [Member] | Corporate Joint Venture [Member]
Related Party Transaction [Line Items]
Short term payable to related party		$ 65	54
Accounts Payable [Member] | TTX Company [Member]
Related Party Transaction [Line Items]
Short term payable to related party		40	35
Accounts Payable [Member] | Related Party Accounts Payable Converted to a Note [Member] | Corporate Joint Venture [Member]
Related Party Transaction [Line Items]
Short term payable to related party	125
Long-term Debt [Member] | CSXT Promissory Note Related Party March 2035 [Member] | Corporate Joint Venture [Member]
Related Party Transaction [Line Items]
Promissory note payable	$ 23
Related party note, interest rate	4.52%
Long-term Debt [Member] | CSX Promissory Note Related Party October 2035 [Member] | Corporate Joint Venture [Member]
Related Party Transaction [Line Items]
Promissory note payable	$ 73
Related party note, interest rate	4.40%
Long-term Debt [Member] | CSXT Promissory Note Related Party October 2044 [Member] | Corporate Joint Venture [Member]
Related Party Transaction [Line Items]
Promissory note payable		$ 151	$ 151
Related party note, interest rate	2.89%	2.89%
Long-term Debt [Member] | Total Related Party Promissory Notes, October 2044 [Member] | Corporate Joint Venture [Member]
Related Party Transaction [Line Items]
Promissory note payable	$ 224

Related Party Transactions (Fut

Related Party Transactions (Future Lease Payment under Asset Agreement) (Details) $ in Millions	Dec. 25, 2015USD ($)
Related Party Transaction [Line Items]
2,016	$ 76
2,017	69
2,018	55
2,019	53
2,020	35
Thereafter	167
Total	455
Corporate Joint Venture [Member]
Related Party Transaction [Line Items]
2,016	26
2,017	26
2,018	26
2,019	26
2,020	26
Thereafter	98
Total	$ 228

Related Party Transactions (Con

Related Party Transactions (Consolidated Income Statements Components) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 25, 2015	Dec. 26, 2014	Dec. 27, 2013
Related Party Amounts Consolidated Income Statements [Abstract]
Equity earnings	$ 0	$ 0	$ 0
TTX Company [Member] | Materials, Supplies and Other [Member]
Related Party Amounts Consolidated Income Statements [Abstract]
Car Hire Rents	218	207	180
Equity earnings	(20)	(21)	(13)
Total	198	186	167
Corporate Joint Venture [Member] | Materials, Supplies and Other [Member]
Related Party Amounts Consolidated Income Statements [Abstract]
Rents, fees and services	123	124	115
Purchase price amortization and other	4	4	4
Equity earnings	(33)	(31)	(35)
Total	$ 94	$ 97	$ 84

Related Party Transactions (C87

Related Party Transactions (Consolidated Balance Sheets Components) (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Oct. 31, 2014	Dec. 25, 2015	Dec. 26, 2014
Related Party Transaction [Line Items]
Payable to Affiliates		$ 0	$ 0
TTX Company [Member] | Accounts Payable [Member]
Related Party Transaction [Line Items]
Payable to Affiliates		40	35
Corporate Joint Venture [Member] | Accounts Payable [Member]
Related Party Transaction [Line Items]
Payable to Affiliates		65	54
Corporate Joint Venture [Member] | Long-term Debt [Member] | CSX Promissory Note Related Party October 2044 [Member]
Related Party Transaction [Line Items]
Promissory notes payable to Conrail subsidiary		$ 73	73
Related party note, interest rate		2.89%
Corporate Joint Venture [Member] | Long-term Debt [Member] | CSXT Promissory Note Related Party October 2044 [Member]
Related Party Transaction [Line Items]
Promissory notes payable to Conrail subsidiary		$ 151	$ 151
Related party note, interest rate	2.89%	2.89%

Fair Value Measurements (Invest

Fair Value Measurements (Investments and Long-term Debt) (Details) - USD ($) $ in Millions	Dec. 25, 2015	Dec. 26, 2014
Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments at fair value	$ 919	$ 453
Less than 1 year	810	292
1 - 2 years	9	45
2 - 5 years	27	100
Greater than 5 years	73	16
Fair Value [Member] | Certificates of Deposit and Commercial Paper [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments at fair value	810	250
Fair Value [Member] | Corporate Bonds [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments at fair value	73	141
Fair Value [Member] | Government securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments at fair value	32	51
Fair Value [Member] | Auction Rate Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments at fair value	4	11
Fair Value [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments at fair value	0	0
Fair Value [Member] | Level 1 [Member] | Certificates of Deposit and Commercial Paper [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments at fair value	0	0
Fair Value [Member] | Level 1 [Member] | Corporate Bonds [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments at fair value	0	0
Fair Value [Member] | Level 1 [Member] | Government securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments at fair value	0	0
Fair Value [Member] | Level 1 [Member] | Auction Rate Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments at fair value	0	0
Fair Value [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments at fair value	915	442
Long-term Debt (Including Current Maturities)	11,340	11,042
Fair Value [Member] | Level 2 [Member] | Certificates of Deposit and Commercial Paper [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments at fair value	810	250
Fair Value [Member] | Level 2 [Member] | Corporate Bonds [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments at fair value	73	141
Fair Value [Member] | Level 2 [Member] | Government securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments at fair value	32	51
Fair Value [Member] | Level 2 [Member] | Auction Rate Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments at fair value	0	0
Fair Value [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments at fair value	4	11
Fair Value [Member] | Level 3 [Member] | Certificates of Deposit and Commercial Paper [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments at fair value	0	0
Fair Value [Member] | Level 3 [Member] | Corporate Bonds [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments at fair value	0	0
Fair Value [Member] | Level 3 [Member] | Government securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments at fair value	0	0
Fair Value [Member] | Level 3 [Member] | Auction Rate Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments at fair value	4	11
Carrying Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized cost basis of investments	920	453
Carrying Value [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt (Including Current Maturities)	$ 10,703	$ 9,742

Fair Value Measurements (Pensio

Fair Value Measurements (Pension Plan Assets) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 25, 2015	Dec. 26, 2014
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	$ 2,309	$ 2,504
Defined Benefit Plan, Fair Value of Plan Assets Excluding Assets Measured at NAV	1,393	1,528
Alternative Investments, Fair Value Disclosure	$ 916	976
Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Investment committee equity target allocation percentage of pension assets	70.00%
Pension plan assets at fair value	$ 1,626	1,715
Common Stock [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	$ 738	787
Fixed Income [Member]
Defined Benefit Plan Disclosure [Line Items]
Investment committee equity target allocation percentage of pension assets	30.00%
Pension plan assets at fair value	$ 641	740
Mutual funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	15	20
Cash equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	8	1
Corporate bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	480	539
Government securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	132	164
Asset-backed securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	14	15
Derivatives and other [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	6	2
Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	761	808
Defined Benefit Plan, Fair Value of Plan Assets Excluding Assets Measured at NAV	761	808
Level 1 [Member] | Common Stock [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	738	787
Level 1 [Member] | Mutual funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	15	20
Level 1 [Member] | Cash equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	8	1
Level 1 [Member] | Corporate bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	0	0
Level 1 [Member] | Government securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	0	0
Level 1 [Member] | Asset-backed securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	0	0
Level 1 [Member] | Derivatives and other [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	0	0
Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	632	720
Defined Benefit Plan, Fair Value of Plan Assets Excluding Assets Measured at NAV	632	720
Level 2 [Member] | Common Stock [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	0	0
Level 2 [Member] | Mutual funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	0	0
Level 2 [Member] | Cash equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	0	0
Level 2 [Member] | Corporate bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	480	539
Level 2 [Member] | Government securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	132	164
Level 2 [Member] | Asset-backed securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	14	15
Level 2 [Member] | Derivatives and other [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	6	2
Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	0	0
Defined Benefit Plan, Fair Value of Plan Assets Excluding Assets Measured at NAV	0	0
Level 3 [Member] | Common Stock [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	0	0
Level 3 [Member] | Mutual funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	0	0
Level 3 [Member] | Cash equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	0	0
Level 3 [Member] | Corporate bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	0	0
Level 3 [Member] | Government securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	0	0
Level 3 [Member] | Asset-backed securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	0	0
Level 3 [Member] | Derivatives and other [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	$ 0	$ 0

Other Comprehensive Income _ 90

Other Comprehensive Income / (Loss) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 25, 2015	Dec. 26, 2014	Dec. 27, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]
Comprehensive earnings	$ 1,969	$ 1,784	$ 2,277
Other Comprehensive Income (Loss):
Beginning Balance	(666)	(523)	(936)
(Loss) Income Before Reclassifications	(61)	(293)	534
Amounts Reclassified to Net Earnings	69	62	109
Tax (Expense) Benefit	(7)	88	(230)
Total Other Comprehensive (Loss) Income	1	(143)	413
Ending Balance	(665)	(666)	(523)
Pension and Other Post-Employment Benefits [Member]
Other Comprehensive Income (Loss):
Beginning Balance	(611)	(462)	(851)
(Loss) Income Before Reclassifications	(53)	(297)	510
Amounts Reclassified to Net Earnings	71	60	111
Tax (Expense) Benefit	(8)	88	(232)
Total Other Comprehensive (Loss) Income	10	(149)	389
Ending Balance	(601)	(611)	(462)
Other
Other Comprehensive Income (Loss):
Beginning Balance	(55)	(61)	(85)
(Loss) Income Before Reclassifications	(8)	4	24
Amounts Reclassified to Net Earnings	(2)	2	(2)
Tax (Expense) Benefit	1	0	2
Total Other Comprehensive (Loss) Income	(9)	6	24
Ending Balance	$ (64)	$ (55)	$ (61)

Quarterly Financial Data (Una91

Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 25, 2015	Sep. 25, 2015	Jun. 26, 2015	Mar. 27, 2015	Dec. 26, 2014	Sep. 26, 2014	Jun. 27, 2014	Mar. 28, 2014	Dec. 25, 2015	Dec. 26, 2014	Dec. 27, 2013
Selected Quarterly Financial Information [Abstract]
Revenue	$ 2,781	$ 2,939	$ 3,064	$ 3,027	$ 3,192	$ 3,221	$ 3,244	$ 3,012	$ 11,811	$ 12,669	$ 12,026
Operating Income	791	933	1,017	843	901	976	997	739	3,584	3,613	3,473
Net Earnings	$ 466	$ 507	$ 553	$ 442	$ 491	$ 509	$ 529	$ 398	$ 1,968	$ 1,927	$ 1,864
Earnings Per Share, Basic (dollars per share)	$ 0.48	$ 0.52	$ 0.56	$ 0.45	$ 0.49	$ 0.51	$ 0.53	$ 0.40	$ 2	$ 1.93	$ 1.83
Earnings Per Share, Assuming Dilution (dollars per share)	$ 0.48	$ 0.52	$ 0.56	$ 0.45	$ 0.49	$ 0.51	$ 0.53	$ 0.40	$ 2	$ 1.92	$ 1.83

Summarized Consolidating Fina92

Summarized Consolidating Financial Data (Income Statements) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 25, 2015	Sep. 25, 2015	Jun. 26, 2015	Mar. 27, 2015	Dec. 26, 2014	Sep. 26, 2014	Jun. 27, 2014	Mar. 28, 2014	Dec. 25, 2015	Dec. 26, 2014	Dec. 27, 2013
Consolidated Income Statement
Revenue	$ 2,781	$ 2,939	$ 3,064	$ 3,027	$ 3,192	$ 3,221	$ 3,244	$ 3,012	$ 11,811	$ 12,669	$ 12,026
Expense									8,227	9,056	8,553
Operating Income	791	933	1,017	843	901	976	997	739	3,584	3,613	3,473
Equity in Earnings of Subsidiaries									0	0	0
Interest Expense									(544)	(545)	(562)
Other Income - Net									98	(24)	11
Earnings Before Income Taxes									3,138	3,044	2,922
Income Tax Benefit (Expense)									(1,170)	(1,117)	(1,058)
Net Earnings	$ 466	$ 507	$ 553	$ 442	$ 491	$ 509	$ 529	$ 398	1,968	1,927	1,864
Total Comprehensive Earnings									1,969	1,784	2,277
CSX Corporation
Consolidated Income Statement
Revenue									0	0	0
Expense									(589)	(427)	(371)
Operating Income									589	427	371
Equity in Earnings of Subsidiaries									1,949	1,996	1,964
Interest Expense									(539)	(520)	(516)
Other Income - Net									(4)	(19)	(7)
Earnings Before Income Taxes									1,995	1,884	1,812
Income Tax Benefit (Expense)									(27)	43	52
Net Earnings									1,968	1,927	1,864
Total Comprehensive Earnings									1,969	1,784	2,277
CSX Transportation
Consolidated Income Statement
Revenue									11,733	12,590	11,950
Expense									8,922	9,585	9,091
Operating Income									2,811	3,005	2,859
Equity in Earnings of Subsidiaries									0	1	(1)
Interest Expense									(33)	(46)	(62)
Other Income - Net									111	(4)	(2)
Earnings Before Income Taxes									2,889	2,956	2,794
Income Tax Benefit (Expense)									(1,083)	(1,093)	(1,028)
Net Earnings									1,806	1,863	1,766
Total Comprehensive Earnings									1,806	1,875	1,825
Eliminations and Other
Consolidated Income Statement
Revenue									78	79	76
Expense									(106)	(102)	(167)
Operating Income									184	181	243
Equity in Earnings of Subsidiaries									(1,949)	(1,997)	(1,963)
Interest Expense									28	21	16
Other Income - Net									(9)	(1)	20
Earnings Before Income Taxes									(1,746)	(1,796)	(1,684)
Income Tax Benefit (Expense)									(60)	(67)	(82)
Net Earnings									(1,806)	(1,863)	(1,766)
Total Comprehensive Earnings									$ (1,806)	$ (1,875)	$ (1,825)

Summarized Consolidating Fina93

Summarized Consolidating Financial Data (Balance Sheets) (Details) - USD ($) $ in Millions	Dec. 25, 2015	Dec. 26, 2014	Dec. 27, 2013	Dec. 28, 2012
Current Assets:
Cash and Cash Equivalents	$ 628	$ 669	$ 592	$ 784
Short-term Investments	810	292
Accounts Receivable - Net	982	1,129
Receivable from Affiliates	0	0
Materials and Supplies	350	273
Deferred Income Taxes	126	141
Other Current Assets	70	68
Total Current Assets	2,966	2,572
Properties	41,574	39,343
Accumulated Depreciation	(11,400)	(10,759)
Properties - Net	30,174	28,584
Other Long-term Assets	505	541
Total Assets	35,039	33,053
Current Liabilities:
Accounts Payable	764	845
Labor and Fringe Benefits Payable	490	613
Payable to Affiliates	0	0
Casualty, Environmental and Other Reserves	131	142
Current Maturities of Long-term Debt	20	228
Income and Other Taxes Payable	108	163
Other Current Liabilities	439	116
Total Current Liabilities	1,952	2,107
Casualty, Environmental and Other Reserves	269	276
Long-term Debt	10,683	9,514
Deferred Income Taxes	9,305	8,858
Other Long-term Liabilities	1,162	1,122
Total Liabilities	23,371	21,877
Shareholders' Equity:
Common Stock, $1 Par Value	966	992
Other Capital	113	92
Retained Earnings	11,238	10,734
Accumulated Other Comprehensive Loss	(665)	(666)	(523)	(936)
Noncontrolling Minority Interest	16	24
Total Shareholders' Equity	11,668	11,176	10,504	9,136
Total Liabilities and Shareholders' Equity	35,039	33,053
Investments in Conrail
Current Assets:
Investment in Affiliates, Subsidiaries and Other	803	779
Affiliates and Other Companies
Current Assets:
Investment in Affiliates, Subsidiaries and Other	591	577
Investment in Consolidated Subsidiaries
Current Assets:
Investment in Affiliates, Subsidiaries and Other	0	0
CSX Corporation
Current Assets:
Cash and Cash Equivalents	444	510	439	481
Short-term Investments	810	250
Accounts Receivable - Net	1	2
Receivable from Affiliates	1,092	1,211
Materials and Supplies	0	0
Deferred Income Taxes	10	3
Other Current Assets	(59)	0
Total Current Assets	2,298	1,976
Properties	1	1
Accumulated Depreciation	(1)	(1)
Properties - Net	0	0
Other Long-term Assets	176	178
Total Assets	25,190	23,685
Current Liabilities:
Accounts Payable	108	106
Labor and Fringe Benefits Payable	36	38
Payable to Affiliates	2,954	3,053
Casualty, Environmental and Other Reserves	0	0
Current Maturities of Long-term Debt	1	200
Income and Other Taxes Payable	(87)	(150)
Other Current Liabilities	0	0
Total Current Liabilities	3,012	3,247
Casualty, Environmental and Other Reserves	0	0
Long-term Debt	9,900	8,705
Deferred Income Taxes	(178)	(172)
Other Long-term Liabilities	804	753
Total Liabilities	13,538	12,533
Shareholders' Equity:
Common Stock, $1 Par Value	966	992
Other Capital	113	92
Retained Earnings	11,238	10,734
Accumulated Other Comprehensive Loss	(665)	(666)
Noncontrolling Minority Interest	0	0
Total Shareholders' Equity	11,652	11,152
Total Liabilities and Shareholders' Equity	25,190	23,685
CSX Corporation | Investments in Conrail
Current Assets:
Investment in Affiliates, Subsidiaries and Other	0	0
CSX Corporation | Affiliates and Other Companies
Current Assets:
Investment in Affiliates, Subsidiaries and Other	(39)	(39)
CSX Corporation | Investment in Consolidated Subsidiaries
Current Assets:
Investment in Affiliates, Subsidiaries and Other	22,755	21,570
CSX Transportation
Current Assets:
Cash and Cash Equivalents	175	100	91	235
Short-term Investments	0	0
Accounts Receivable - Net	198	206
Receivable from Affiliates	2,038	2,418
Materials and Supplies	350	272
Deferred Income Taxes	117	139
Other Current Assets	120	61
Total Current Assets	2,998	3,196
Properties	38,964	36,888
Accumulated Depreciation	(10,016)	(9,516)
Properties - Net	28,948	27,372
Other Long-term Assets	399	387
Total Assets	33,003	31,599
Current Liabilities:
Accounts Payable	626	707
Labor and Fringe Benefits Payable	407	511
Payable to Affiliates	437	514
Casualty, Environmental and Other Reserves	115	126
Current Maturities of Long-term Debt	19	29
Income and Other Taxes Payable	183	293
Other Current Liabilities	437	111
Total Current Liabilities	2,224	2,291
Casualty, Environmental and Other Reserves	219	213
Long-term Debt	783	809
Deferred Income Taxes	9,258	8,827
Other Long-term Liabilities	484	487
Total Liabilities	12,968	12,627
Shareholders' Equity:
Common Stock, $1 Par Value	181	181
Other Capital	5,091	5,077
Retained Earnings	14,774	13,717
Accumulated Other Comprehensive Loss	(31)	(31)
Noncontrolling Minority Interest	20	28
Total Shareholders' Equity	20,035	18,972
Total Liabilities and Shareholders' Equity	33,003	31,599
CSX Transportation | Investments in Conrail
Current Assets:
Investment in Affiliates, Subsidiaries and Other	0	0
CSX Transportation | Affiliates and Other Companies
Current Assets:
Investment in Affiliates, Subsidiaries and Other	658	644
CSX Transportation | Investment in Consolidated Subsidiaries
Current Assets:
Investment in Affiliates, Subsidiaries and Other	0	0
Eliminations and Other
Current Assets:
Cash and Cash Equivalents	9	59	$ 62	$ 68
Short-term Investments	0	42
Accounts Receivable - Net	783	921
Receivable from Affiliates	(3,130)	(3,629)
Materials and Supplies	0	1
Deferred Income Taxes	(1)	(1)
Other Current Assets	9	7
Total Current Assets	(2,330)	(2,600)
Properties	2,609	2,454
Accumulated Depreciation	(1,383)	(1,242)
Properties - Net	1,226	1,212
Other Long-term Assets	(70)	(24)
Total Assets	(23,154)	(22,231)
Current Liabilities:
Accounts Payable	30	32
Labor and Fringe Benefits Payable	47	64
Payable to Affiliates	(3,391)	(3,567)
Casualty, Environmental and Other Reserves	16	16
Current Maturities of Long-term Debt	0	(1)
Income and Other Taxes Payable	12	20
Other Current Liabilities	2	5
Total Current Liabilities	(3,284)	(3,431)
Casualty, Environmental and Other Reserves	50	63
Long-term Debt	0	0
Deferred Income Taxes	225	203
Other Long-term Liabilities	(126)	(118)
Total Liabilities	(3,135)	(3,283)
Shareholders' Equity:
Common Stock, $1 Par Value	(181)	(181)
Other Capital	(5,091)	(5,077)
Retained Earnings	(14,774)	(13,717)
Accumulated Other Comprehensive Loss	31	31
Noncontrolling Minority Interest	(4)	(4)
Total Shareholders' Equity	(20,019)	(18,948)
Total Liabilities and Shareholders' Equity	(23,154)	(22,231)
Eliminations and Other | Investments in Conrail
Current Assets:
Investment in Affiliates, Subsidiaries and Other	803	779
Eliminations and Other | Affiliates and Other Companies
Current Assets:
Investment in Affiliates, Subsidiaries and Other	(28)	(28)
Eliminations and Other | Investment in Consolidated Subsidiaries
Current Assets:
Investment in Affiliates, Subsidiaries and Other	$ (22,755)	$ (21,570)

Summarized Consolidating Fina94

Summarized Consolidating Financial Data (Cash Flow Statements) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 25, 2015	Dec. 26, 2014	Dec. 27, 2013
Operating Activities
Net Cash Provided by (Used in) Operating Activities	$ 3,370	$ 3,343	$ 3,267
Investing Activities
Property Additions	(2,562)	(2,449)	(2,313)
Purchase of Short-term Investments	(1,739)	(1,433)	(1,256)
Proceeds from Sales of Short-term Investments	1,225	1,674	1,401
Proceeds from Property Dispositions	147	62	53
Other Investing Activities	37	(37)	(112)
Net Cash Used in Investing Activities	(2,892)	(2,183)	(2,227)
Financing Activities
Long-term Debt Issued	1,200	1,000	500
Long-term Debt Repaid	(229)	(933)	(780)
Dividends Paid	(686)	(629)	(600)
Stock Options Exercised	0	0	9
Shares Repurchased	(804)	(517)	(353)
Other Financing Activities	0	(4)	(8)
Net Cash Used in Financing Activities	(519)	(1,083)	(1,232)
Net (Decrease) Increase in Cash and Cash Equivalents	(41)	77	(192)
Cash and Cash Equivalents at Beginning of Period	669	592	784
Cash and Cash Equivalents at End of Period	628	669	592
CSX Corporation
Operating Activities
Net Cash Provided by (Used in) Operating Activities	983	583	1,004
Investing Activities
Property Additions	0	0	0
Purchase of Short-term Investments	(1,734)	(1,419)	(1,251)
Proceeds from Sales of Short-term Investments	1,175	1,642	1,335
Proceeds from Property Dispositions	0	0	0
Other Investing Activities	(10)	0	(134)
Net Cash Used in Investing Activities	(569)	223	(50)
Financing Activities
Long-term Debt Issued	1,200	1,000	500
Long-term Debt Repaid	(200)	(600)	(700)
Dividends Paid	(686)	(629)	(600)
Stock Options Exercised	0	0	9
Shares Repurchased	(804)	(517)	(353)
Other Financing Activities	10	11	148
Net Cash Used in Financing Activities	(480)	(735)	(996)
Net (Decrease) Increase in Cash and Cash Equivalents	(66)	71	(42)
Cash and Cash Equivalents at Beginning of Period	510	439	481
Cash and Cash Equivalents at End of Period	444	510	439
CSX Transportation
Operating Activities
Net Cash Provided by (Used in) Operating Activities	2,974	3,278	3,005
Investing Activities
Property Additions	(2,400)	(2,192)	(2,053)
Purchase of Short-term Investments	0	0	0
Proceeds from Sales of Short-term Investments	0	0	0
Proceeds from Property Dispositions	147	62	53
Other Investing Activities	132	(128)	(315)
Net Cash Used in Investing Activities	(2,121)	(2,258)	(2,315)
Financing Activities
Long-term Debt Issued	0	0	0
Long-term Debt Repaid	(29)	(333)	(80)
Dividends Paid	(750)	(660)	(730)
Stock Options Exercised	0	0	0
Shares Repurchased	0	0	0
Other Financing Activities	1	(18)	(24)
Net Cash Used in Financing Activities	(778)	(1,011)	(834)
Net (Decrease) Increase in Cash and Cash Equivalents	75	9	(144)
Cash and Cash Equivalents at Beginning of Period	100	91	235
Cash and Cash Equivalents at End of Period	175	100	91
Eliminations and Other
Operating Activities
Net Cash Provided by (Used in) Operating Activities	(587)	(518)	(742)
Investing Activities
Property Additions	(162)	(257)	(260)
Purchase of Short-term Investments	(5)	(14)	(5)
Proceeds from Sales of Short-term Investments	50	32	66
Proceeds from Property Dispositions	0	0	0
Other Investing Activities	(85)	91	337
Net Cash Used in Investing Activities	(202)	(148)	138
Financing Activities
Long-term Debt Issued	0	0	0
Long-term Debt Repaid	0	0	0
Dividends Paid	750	660	730
Stock Options Exercised	0	0	0
Shares Repurchased	0	0	0
Other Financing Activities	(11)	3	(132)
Net Cash Used in Financing Activities	739	663	598
Net (Decrease) Increase in Cash and Cash Equivalents	(50)	(3)	(6)
Cash and Cash Equivalents at Beginning of Period	59	62	68
Cash and Cash Equivalents at End of Period	$ 9	$ 59	$ 62