Pension, Retiree Medical And Savings Plans (Narrative) (Details) (USD $)	12 Months Ended	3 Months Ended	12 Months Ended
	Dec. 31, 2011 years	Sep. 04, 2010 Retiree Medical Plan [Member]	Dec. 31, 2011 U.S. Equity Allocations [Member]	Dec. 31, 2011 International Equity Allocation [Member]	Dec. 31, 2011 Fixed Income Allocations [Member]	Dec. 31, 2011 2020 And Thereafter [Member]	Dec. 31, 2011 U.S. Savings Plan [Member]	Dec. 25, 2010 U.S. Savings Plan [Member]	Dec. 31, 2011 2012 [Member]	Dec. 31, 2011 2012 [Member] U.S. Equity Allocations [Member]	Dec. 31, 2011 2012 [Member] International Equity Allocation [Member]	Dec. 31, 2011 2012 [Member] Fixed Income Allocations [Member]	Dec. 25, 2010 Discretionary [Member] 2012 [Member]	Dec. 24, 2011 Non-Discretionary [Member]	Dec. 25, 2010 Non-Discretionary [Member]	Dec. 31, 2011 Real Estate [Member] 2012 [Member]
Defined Benefit Plan Disclosure [Line Items]
Lower limit of net accumulated gain or loss	10.00%
Average remaining service period of active plan participants for pension expense, years	10
Average remaining service period of active plan participants for retiree medical expense, years	8
Unfunded plans included in total projected benefit liability	$ 787,000,000
Pension contributions									1,300,000,000
Discretionary, pension contributions									1,000,000,000
Expected long-term rate of return on U.S. plan assets	7.80%
Target investment allocation, for fixed income allocations					40.00%							40.00%
Pension strategy investment term, years	5
Contribution retiree medical plan	124,000,000						144,000,000	135,000,000					170,000,000	110,000,000	100,000,000
Average increase in the cost of covered retiree medical benefits	7.00%
Pre-tax curtailment gain		$ 62,000,000
Target investment allocation			40.00%	20.00%						33.00%	22.00%
Average increase is then projected to decline						5.00%
Target investment allocation, Real estate																5.00%