Income Taxes (Deferred Income Tax Assets and Liabilities) (Details) (USD $) In Millions, unless otherwise specified	Dec. 26, 2014	Dec. 27, 2013
Components of Deferred Tax Assets [Abstract]
Pension Plans	$ 188	$ 67
Other Employee Benefit Plans	306	299
Other	256us-gaap_DeferredTaxAssetsOther	257us-gaap_DeferredTaxAssetsOther
Total	750us-gaap_DeferredTaxAssetsNet	623us-gaap_DeferredTaxAssetsNet
Components of Deferred Tax Liabilities [Abstract]
Accelerated Depreciation	9,133	8,868
Other	334us-gaap_DeferredTaxLiabilitiesOther	262us-gaap_DeferredTaxLiabilitiesOther
Total	9,467us-gaap_DeferredTaxLiabilities	9,130us-gaap_DeferredTaxLiabilities
Net Deferred Income Tax Liabilities	$ 8,717us-gaap_DeferredTaxAssetsLiabilitiesNet	$ 8,507us-gaap_DeferredTaxAssetsLiabilitiesNet

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Amount after allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards, net of deferred tax liability attributable to taxable temporary differences.

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Amount after allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards.

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The tax effect as of the balance sheet date of the amount of the estimated future tax deductions arising from employee benefit costs not otherwise specified in the taxonomy, which can only be deducted for tax purposes when actual costs are incurred, and which can only be realized if sufficient tax-basis income is generated in future periods to enable the deduction to be taken.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from pension benefits.

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Amount of deferred tax liability attributable to taxable temporary differences net of deferred tax asset attributable to deductible temporary differences and carryforwards after valuation allowances.

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Amount of deferred tax liability attributable to taxable temporary differences not separately disclosed.

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Amount of deferred tax liability attributable to taxable temporary differences from property, plant, and equipment.

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