Employee Benefit Plans (Tables)

12 Months Ended

Dec. 28, 2012

Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Abstract]

Schedule of summary of participants

The Company engages independent, external actuaries to compute the amounts of liabilities and expenses related to these plans subject to the assumptions that the Company selects. 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.

	Summary of Participants as of
	January 1, 2012
	Pension Plans	Post-retirement Medical Plan
Active Employees	4,993	2,488
Retirees and Beneficiaries	11,277	13,177
Other(a)	6,295	40
Total	22,565	15,705

(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 beneit payments

Future expected benefit payments are as follows:

	Expected Cash Flows
(Dollars in Millions)	Pension Benefits		Post-retirement Benefits
2013	$	173	$	41
2014	177		40
2015	178		38
2016	180		36
2017	181		34
2018-2022	916		143
Total	$	1,805	$	332

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 2012				December 2011
			Percent of				Percent of
(Dollars in Millions)	Amount		Total Assets		Amount		Total Assets
Equity	$	1,408	61	%	$	1,064	57	%
Fixed Income	829		36		755		41
Cash and Cash Equivalents	57		3		31		2
Total	$	2,294	100	%	$	1,850	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 2012 and 2011 calendar plan years are as follows:

	Pension Benefits						Post-retirement Benefits
	Plan Year			Plan Year			Plan Year			Plan Year
(Dollars in Millions)	2012			2011			2012			2011
Actuarial Present Value of Benefit Obligation
Accumulated Benefit Obligation	$	2,806		$	2,516		N/A			N/A
Projected Benefit Obligation	2,954			2,668			$	415		$	388
Change in Projected Benefit Obligation:
Projected Benefit Obligation atBeginning of Plan Year	$	2,668		$	2,487		$	388		$	383
Service Cost	44			40			4			2
Interest Cost	123			121			16			11
Plan Participants' Contributions	—			—			8			7
Plan Amendments	—			—			(1		)	—
Actuarial Loss	274			175			43			32
Benefits Paid	(155		)	(155		)	(43		)	(47		)
Benefit Obligation at End of Plan Year	$	2,954		$	2,668		$	415		$	388
Change in Plan Assets:
Fair Value of Plan Assets at Beginning of Plan Year	$	1,850		$	1,851		$	—		$	—
Actual Return on Plan Assets	311			141			—			—
Qualified Employer Contributions	275			—			—			—
Non-qualified Employer Contributions	13			13			35			40
Plan Participants' Contributions	—			—			8			7
Benefits Paid	(155		)	(155		)	(43		)	(47		)
Fair Value of Plan Assets at End of Plan Year	$	2,294		$	1,850		—			—
Funded Status at End of Plan Year	$	(660	)	$	(818	)	$	(415	)	$	(388	)

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:

	Pension Benefits						Post-retirement Benefits
	December			December			December			December
(Dollars in Millions)	2012			2011			2012			2011
Amounts Recorded in Consolidated
Balance Sheets:
Long-term Assets (a)	$	3		$	—		$	—		$	—
Current Liabilities	(15		)	(15		)	(41		)	(42		)
Long-term Liabilities	(648		)	(803		)	(374		)	(346		)
Net Amount Recognized in
Consolidated Balance Sheet	$	(660	)	$	(818	)	$	(415	)	$	(388	)

Benefit obligations in excess of plan assets

At December 2012, the status of CSX plans only with a net liability is disclosed below. The total fair value of all plans as of December 2012 was $2,294 million, which includes the qualified pension plan with a net asset.

	Aggregate		Aggregate
(Dollars in Millions)	Fair Value		Projected
Benefit Obligations in Excess of Plan Assets	of Plan Assets		Benefit Obligation
Projected Benefit Obligation	$	2,249	$	(2,912	)
Accumulated Benefit Obligation	$	2,249	$	(2,764	)

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)	2012			2011			2010			2012			2011			2010
Service Cost	$	44		$	40		$	41		$	4		$	2		$	5
Interest Cost	123			121			122			16			11			20
Expected Return on Plan Assets	(166		)	(157		)	(165		)	—			—			—
Amortization of Net Loss	82			71			58			9			7			7
Amortization of Prior Service Cost	—			—			—			(1		)	(1		)	—
Net Periodic Benefit Expense	$	83		$	75		$	56		$	28		$	19		$	32
Settlement Gain(a)	(2		)	(2		)	(2		)	—			—			—
Total Expense	$	81		$	73		$	54		$	28		$	19		$	32

(a) Settlement gains were recognized as one of the pension plan's lump-sum payments 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)	2012			2011			2012			2011
Recognized in the balance sheet
Losses	$	130		$	191		$	43		$	25
Prior service credits	$	—		$	—		$	(1	)	$	—
Expense (Income) recognized in the income statement
Amortization of net losses (a)	$	82		$	71		$	9		$	7
Settlement gain	$	(2	)	$	(2	)	$	—		$	—
Amortization of prior service costs (b)	$	—		$	—		$	(1	)	$	(1	)

(a) Amortization of net losses estimated to be expensed for 2013 is $101 million and $14 million for pension benefits and post-retirement benefits, respectively. The increase in the pension expense is largely related to the impact of decreasing discount rates and amortization of net losses.

(b) Amortization of prior service costs estimated to be expensed in 2013 are less than $1 million for pension benefits. The estimated post-retirement benefits amount to be credited to expense for 2013 is $1 million.

Schedule of pre-tax amounts to be amortized that included in accumulated other comprehensive loss

As of December 2012, 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	$	1,218	$	135
Prior Service Costs (Credits)	1		(4		)
Total	$	1,219	$	131

Schedule of weighted-average assumptions used

Weighted-average assumptions used in accounting for the plans were as follows:

	Pension Benefits				Post-retirement Benefits
	2012		2011		2012		2011
Expected Long-term Return on Plan Assets:
Benefit Cost for Plan Year	8.00	%	8.25	%	N/A		N/A
Benefit Obligation at End of Plan Year	7.75	%	8.00	%	N/A		N/A
Discount Rates:
Benefit Cost for Plan Year	4.75	%	5.00	%	4.25	%	4.50	%
Benefit Obligation at End of Plan Year	3.75	%	4.75	%	3.20	%	4.25	%
Salary Scale Inflation	3.75	%	4.00	%	N/A		N/A

Schedule of health care cost trend rates

Additionally, there are cost differentials between Medicare and Non-Medicare eligible individuals which are reflected below.

	Post-retirement Benefits
	2012	2011
Health Care Cost Trend Rate:
Components of Benefit Cost:  Non-Medicare Eligible	8.5%	8.5%
Components of Benefit Cost:  Medicare Eligible	8.0%	8.0%
Benefit Obligations:  Non-Medicare Eligible	8.5%	8.5%
Benefit Obligations:  Medicare Eligible	8.0%	8.0%