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 atBeginning 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