Retirement Plans (Details 9) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 28, 2013	Dec. 28, 2013 Fair Value, Inputs, Level 1	Dec. 29, 2012 Fair Value, Inputs, Level 1	Dec. 28, 2013 Fair Value, Inputs, Level 2	Dec. 29, 2012 Fair Value, Inputs, Level 2	Dec. 28, 2013 Unobservable Inputs (Level 3)	Dec. 29, 2012 Unobservable Inputs (Level 3)	Dec. 28, 2013 Cash and equivalents Fair Value, Inputs, Level 1	Dec. 29, 2012 Cash and equivalents Fair Value, Inputs, Level 1	Dec. 28, 2013 Cash and equivalents Fair Value, Inputs, Level 2	Dec. 29, 2012 Cash and equivalents Fair Value, Inputs, Level 2	Dec. 28, 2013 Domestic Equity Securities Fair Value, Inputs, Level 1	Dec. 29, 2012 Domestic Equity Securities Fair Value, Inputs, Level 1	Dec. 28, 2013 Domestic Equity Securities Fair Value, Inputs, Level 2	Dec. 29, 2012 Domestic Equity Securities Fair Value, Inputs, Level 2	Dec. 28, 2013 International Equity Securities Fair Value, Inputs, Level 1	Dec. 29, 2012 International Equity Securities Fair Value, Inputs, Level 1	Dec. 28, 2013 International Equity Securities Fair Value, Inputs, Level 2	Dec. 29, 2012 International Equity Securities Fair Value, Inputs, Level 2	Dec. 28, 2013 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 1	Dec. 28, 2013 National, state and local governments debt securities Fair Value, Inputs, Level 2	Dec. 29, 2012 National, state and local governments debt securities Fair Value, Inputs, Level 2	Dec. 29, 2012 Corporate debt securities Fair Value, Inputs, Level 1	Dec. 28, 2013 Corporate debt securities Fair Value, Inputs, Level 2	Dec. 29, 2012 Corporate debt securities Fair Value, Inputs, Level 2	Dec. 29, 2012 Asset-backed debt securities Fair Value, Inputs, Level 1	Dec. 28, 2013 Asset-backed debt securities Fair Value, Inputs, Level 2	Dec. 29, 2012 Asset-backed debt securities Fair Value, Inputs, Level 2	Dec. 28, 2013 Private equity partnerships Unobservable Inputs (Level 3)	Dec. 29, 2012 Private equity partnerships Unobservable Inputs (Level 3)	Dec. 28, 2013 Real estate Unobservable Inputs (Level 3)	Dec. 29, 2012 Real estate Unobservable Inputs (Level 3)	Dec. 28, 2013 Hedge funds Unobservable Inputs (Level 3)	Dec. 29, 2012 Hedge funds Unobservable Inputs (Level 3)
Change in fair value of plan assets
Fair value of total pension plan assets		$ 2,842	$ 2,754	$ 2,470	$ 2,041	$ 1,033	$ 920	$ 17	$ 16	$ 144	$ 157	$ 1,179	$ 1,149	$ 866	$ 560	$ 1,140	$ 981	$ 258	$ 268	$ 506	$ 594	$ 411	$ 318	$ 13	$ 638	$ 647	$ 1	$ 153	$ 91	$ 305	$ 308	$ 553	$ 508	$ 175	$ 104
Valuation of owned properties period	3 years