Retirement Plans (Details 7) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 29, 2012	Dec. 31, 2011
Assumed healthcare cost trend rates
Rate to which medical and prescription drug cost trend rates will gradually decline (as a percent)	5.00%	5.00%
Year that the rates reach the rate where we assume they will remain	2021	2021
Effects of one-percentage-point change in assumed healthcare cost trend rates
Effect of One Percentage Point Increase on Service and Interest Cost Components	$ 3
Effect of One Percentage Point Decrease on Service and Interest Cost Components	(2)
Effect of One Percentage Point Increase on Accumulated Postretirement Benefit Obligation	41
Effect of One Percentage Point Decrease on Accumulated Postretirement Benefit Obligation	$ (36)
Medical Cost Trend Rate
Assumed healthcare cost trend rates
Cost trend rates (as a percent)	8.40%	9.00%
Prescription Drug Cost Trend Rate
Assumed healthcare cost trend rates
Cost trend rates (as a percent)	8.40%	9.00%

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Amount of effect of a one-percentage-point decrease in the assumed health care cost trend rates on the accumulated postretirement benefit obligation for health care benefits.

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Amount of effect of a one-percentage-point decrease in the assumed health care cost trend rates on the aggregate of the service and interest cost components of net periodic postretirement health care benefit costs.

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The effect of a one-percentage-point increase in the assumed health care cost trend rates on the accumulated postretirement benefit obligation for health care benefits.

+ References

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

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The effect of a one-percentage-point increase in the assumed health care cost trend rates on the aggregate of the service and interest cost components of net periodic postretirement health care benefit costs.

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The assumed health care cost trend rate for the next year used to measure the expected cost of benefits covered by the plan (gross eligible charges). This is based upon the annual rate of change in the cost of health care benefits currently provided by the postretirement benefit plan, due to factors other than changes in the composition of the plan population by age and dependency status.

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

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The ultimate trend rate for health care costs.

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Year the ultimate health care cost trend rate is expected to be reached, in CCYY format.

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