Retirement Plans (Details 9) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 29, 2012	Dec. 29, 2012 Fair Value, Inputs, Level 1	Dec. 31, 2011 Fair Value, Inputs, Level 1	Dec. 29, 2012 Fair Value, Inputs, Level 2	Dec. 31, 2011 Fair Value, Inputs, Level 2	Dec. 29, 2012 Unobservable Inputs (Level 3)	Dec. 31, 2011 Unobservable Inputs (Level 3)	Dec. 29, 2012 Cash and equivalents Fair Value, Inputs, Level 1	Dec. 31, 2011 Cash and equivalents Fair Value, Inputs, Level 1	Dec. 29, 2012 Cash and equivalents Fair Value, Inputs, Level 2	Dec. 31, 2011 Cash and equivalents Fair Value, Inputs, Level 2	Dec. 29, 2012 Domestic Equity Securities Fair Value, Inputs, Level 1	Dec. 31, 2011 Domestic Equity Securities Fair Value, Inputs, Level 1	Dec. 29, 2012 Domestic Equity Securities Fair Value, Inputs, Level 2	Dec. 31, 2011 Domestic Equity Securities Fair Value, Inputs, Level 2	Dec. 29, 2012 International Equity Securities Fair Value, Inputs, Level 1	Dec. 31, 2011 International Equity Securities Fair Value, Inputs, Level 1	Dec. 29, 2012 International Equity Securities Fair Value, Inputs, Level 2	Dec. 31, 2011 International Equity Securities Fair Value, Inputs, Level 2	Dec. 29, 2012 National, state and local governments debt securities Fair Value, Inputs, Level 1	Dec. 31, 2011 National, state and local governments debt securities Fair Value, Inputs, Level 1	Dec. 29, 2012 National, state and local governments debt securities Fair Value, Inputs, Level 2	Dec. 31, 2011 National, state and local governments debt securities Fair Value, Inputs, Level 2	Dec. 29, 2012 Corporate debt securities Fair Value, Inputs, Level 1	Dec. 31, 2011 Corporate debt securities Fair Value, Inputs, Level 1	Dec. 29, 2012 Corporate debt securities Fair Value, Inputs, Level 2	Dec. 31, 2011 Corporate debt securities Fair Value, Inputs, Level 2	Dec. 29, 2012 Asset-backed debt securities Fair Value, Inputs, Level 1	Dec. 31, 2011 Asset-backed debt securities Fair Value, Inputs, Level 1	Dec. 29, 2012 Asset-backed debt securities Fair Value, Inputs, Level 2	Dec. 31, 2011 Asset-backed debt securities Fair Value, Inputs, Level 2	Dec. 29, 2012 Private equity partnerships Unobservable Inputs (Level 3)	Dec. 31, 2011 Private equity partnerships Unobservable Inputs (Level 3)	Dec. 29, 2012 Real estate Unobservable Inputs (Level 3)	Dec. 31, 2011 Real estate Unobservable Inputs (Level 3)	Dec. 29, 2012 Hedge funds Unobservable Inputs (Level 3)	Dec. 31, 2011 Hedge funds Unobservable Inputs (Level 3)
Change in fair value of plan assets
Fair value of total pension plan assets		$ 2,754	$ 2,475	$ 2,041	$ 1,720	$ 920	$ 818	$ 16	$ 14	$ 157	$ 183	$ 1,149	$ 1,017	$ 560	$ 482	$ 981	$ 777	$ 268	$ 233	$ 594	$ 630	$ 318	$ 254	$ 13	$ 34	$ 647	$ 494	$ 1	$ 3	$ 91	$ 74	$ 308	$ 314	$ 508	$ 407	$ 104	$ 97
Valuation of owned properties period	3 years

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.

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