Pension and Retiree Medical Benefits Narrative (Details) - USD ($) $ in Millions	6 Months Ended
Jun. 16, 2018	Jun. 17, 2017
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Contributions by Employer, Discretionary	$ 1,400
International [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Contributions by Employer, Discretionary	$ 17	$ 6

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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