Pension, Retiree Medical and Savings Plans (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 25, 2021	Dec. 26, 2020	Dec. 28, 2019	Dec. 29, 2018
Defined Benefit Plan Disclosure [Line Items]
Average remaining service period of active plan participants, pension expense		10 years
Defined Benefit Plan, Average Remaining Service Period of Active Plan Participants, Retiree Medical Expense		8 years
Defined Benefit Plan, Average remaining life expectancy of Inactive Plan Participants, Pension Expense		23 years
Pension strategy investment term, years		5 years
Defined Contribution Plan, Cost		$ 225	$ 197	$ 180
amortization corridor		10.00%
Domestic Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected return on plan assets		6.80%	7.10%	7.20%
Domestic - Plan A [Member]
Defined Benefit Plan Disclosure [Line Items]
Other Comprehensive Income (Loss), Defined Benefit Plan, Settlement and Curtailment Gain (Loss), before Tax		$ 205	$ 220
Pre-tax non-cash settlement charge, net of tax, per share		$ 0.11	$ 0.12
Other Comprehensive Income (Loss), Defined Benefit Plan, Settlement and Curtailment Gain (Loss), after Tax		$ 158	$ 170
Domestic-Plan I [Member]
Defined Benefit Plan Disclosure [Line Items]
Other Comprehensive Income (Loss), Defined Benefit Plan, Settlement and Curtailment Gain (Loss), before Tax			$ 53
Pre-tax non-cash settlement charge, net of tax, per share			$ 0.03
Other Comprehensive Income (Loss), Defined Benefit Plan, Settlement and Curtailment Gain (Loss), after Tax			$ 41
Defined benefit plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Other Comprehensive Income (Loss), Defined Benefit Plan, Settlement and Curtailment Gain (Loss), before Tax			$ 273
Pre-tax non-cash settlement charge, net of tax, per share		$ 0.11	$ 0.03
Other Comprehensive Income (Loss), Defined Benefit Plan, Settlement and Curtailment Gain (Loss), after Tax			$ 41
Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Pre-tax non-cash settlement charge, net of tax, per share			$ 0.12
Other Comprehensive Income (Loss), Defined Benefit Plan, Settlement and Curtailment Gain (Loss), after Tax			$ 170
Retiree Medical Plan
Defined Benefit Plan Disclosure [Line Items]
Expected return on plan assets		5.80%	6.60%	6.50%
Defined Benefit Plan, Funded Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Pre-tax non-cash settlement charge, net of tax, per share			$ 0.15
Other Comprehensive Income (Loss), Defined Benefit Plan, Settlement and Curtailment Gain (Loss), after Tax			$ 211
Forecast [Member] | Domestic Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected return on plan assets	6.40%
Pension Cost (Reversal of Cost)	$ 70
Forecast [Member] | Domestic - Plan A [Member]
Defined Benefit Plan Disclosure [Line Items]
Average remaining service period of active plan participants, pension expense	9 years
Forecast [Member] | Domestic-Plan I [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Average remaining life expectancy of Inactive Plan Participants, Pension Expense	27 years
Forecast [Member] | Domestic plan -Plan H [Member]
Defined Benefit Plan Disclosure [Line Items]
Average remaining service period of active plan participants, pension expense	11 years
Pension Cost (Reversal of Cost)	$ 45