Employee Benefit Plans (Benefit Obligation, Plan Assets and Funded Status) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 26, 2014	Dec. 27, 2013	Dec. 28, 2012
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets at End of Plan Year	$ 2,504	$ 2,500
Pension Benefits [Member]
Actuarial Present Value of Benefit Obligation [Abstract]
Accumulated Benefit Obligation	2,849	2,538
Projected Benefit Obligation	3,002	2,679	2,954
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Projected Benefit Obligation at Beginning of Year	2,679	2,954
Service Cost	44	49	44
Interest Cost	123	108	123
Plan Participants' Contributions	0	0
Workforce Reduction Program/Curtailment	27	0
Actuarial Loss (Gain)	333	(275)
Benefits Paid	(204)	(157)
Benefit Obligation at End of Plan Year	3,002	2,679	2,954
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair Value of Plan Assets at Beginning of Plan Year	2,500	2,294
Actual Return on Plan Assets	195	350
Plan Participants' Contributions	0	0
Benefits Paid	(204)	(157)
Fair Value of Plan Assets at End of Plan Year	2,504	2,500	2,294
Funded Status at End of Plan Year	(498)	(179)
Post-retirement Benefits [Member]
Actuarial Present Value of Benefit Obligation [Abstract]
Projected Benefit Obligation	340	350	415
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Projected Benefit Obligation at Beginning of Year	350	415
Service Cost	3	3	4
Interest Cost	13	13	16
Plan Participants' Contributions	7	8
Workforce Reduction Program/Curtailment	8	0
Actuarial Loss (Gain)	(8)	(49)
Benefits Paid	(33)	(40)
Benefit Obligation at End of Plan Year	340	350	415
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	8
Benefits Paid	(33)	(40)
Fair Value of Plan Assets at End of Plan Year	0	0	0
Funded Status at End of Plan Year	(340)	(350)
Qualified Employer Contributions [Member] \| Pension Benefits [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Employer Contributions			275
Non-qualified Employer Contributions [Member] \| Pension Benefits [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Employer Contributions	13	13
Non-qualified Employer Contributions [Member] \| Post-retirement Benefits [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Employer Contributions	$ 26	$ 32

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For defined benefit pension plans, the actuarial present value of benefits (whether vested or nonvested) attributed by the pension benefit formula to employee service rendered before a specified date and based on employee service and compensation (if applicable) before that date. The accumulated benefit obligation differs from the projected benefit obligation in that it includes no assumption about future compensation levels. For plans with flat-benefit or nonpay-related pension benefit formulas, the accumulated benefit obligation and the projected benefit obligation are the same.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Accumulated Benefit Obligation

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Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

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- Definition

The difference between fair value of plan assets at the end of the period and the fair value at the beginning of the period, adjusted for contributions and payments of benefits during the period, and after adjusting for taxes and other expenses, as applicable.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Actual Return on Plan Assets (Component of Net Periodic Postretirement Benefit Cost)

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-Glossary Actual Return on Plan Assets (Component of Net Periodic Pension Cost)

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- Definition

Amount of gain (loss) related to change in benefit obligation resulting from changes in actuarial assumptions, for example, but not limited to, interest, mortality, employee turnover, salary, and temporary deviation from the substantive plan.

+ References

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-Publisher FASB

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-Glossary Gain or Loss

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- Definition

1) For defined benefit pension plans, the benefit obligation is the projected benefit obligation, which is the actuarial present value as of a date of all benefits attributed by the pension benefit formula to employee service rendered prior to that date. 2) For other postretirement defined benefit plans, the benefit obligation is the accumulated postretirement benefit obligation, which is the actuarial present value of benefits attributed to employee service rendered to a particular date.

+ References

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-Glossary Projected Benefit Obligation

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-Publisher FASB

-Name Accounting Standards Codification

-Glossary Accumulated Postretirement Benefit Obligation

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- Definition

The amount of payments made for which participants are entitled under a pension plan, including pension benefits, death benefits, and benefits due on termination of employment. Also includes payments made under a postretirement benefit plan, including prescription drug benefits, health care benefits, life insurance benefits, and legal, educational and advisory services. This item represents a periodic decrease to the plan obligations and a decrease to plan assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Postretirement Benefits

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The increase in the fair value of plan assets from contributions made by the employer.

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The amount of contributions made by plan participants. This item represents a periodic increase to the plan obligation and an increase to plan assets.

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Assets, usually stocks, bonds, and other investments, that have been segregated and restricted (usually in a trust) to provide benefits, at their fair value as of the measurement date. Plan assets include amounts contributed by the employer (and by employees for a contributory plan) and amounts earned from investing the contributions, less benefits paid. If a plan has liabilities other than for benefits, those non-benefit obligations may be considered as reductions of plan assets.

+ References

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The funded status is measured as the difference between the fair value of plan assets and the benefit obligation. Will normally be the same as the net Defined Benefit Plan, Amounts Recognized in Balance Sheet, Total.

+ References

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The increase in a defined benefit pension plan's projected benefit obligation or a defined benefit postretirement plan's accumulated postretirement benefit obligation due to the passage of time.

+ References

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The amount of increase or decrease due to a change in the terms of an existing plan or the initiation of a new plan. A plan amendment may increase or decrease benefits, including those attributed to years of service already rendered.

+ References

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-Publisher FASB

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The actuarial present value of benefits attributed by the pension benefit formula to services rendered by employees during the period. The portion of the expected postretirement benefit obligation attributed to employee service during the period. The service cost component is a portion of the benefit obligation and is unaffected by the funded status of the plan.

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