Legal Proceedings And Contingencies (Details) (USD $)	3 Months Ended							3 Months Ended
	Mar. 25, 2012 Y	Mar. 25, 2012 N.Y. Metropolitan Transportation Authority [Member]	Apr. 24, 2009 N.Y. Metropolitan Transportation Authority [Member]	Mar. 25, 2012 Environmental Matters [Member]	Dec. 31, 2011 Environmental Matters [Member]	Mar. 25, 2012 Standby Letters Of Credit [Member]	Dec. 31, 2011 Standby Letters Of Credit [Member]	Mar. 25, 2012 United Launch Alliance [Member]	Mar. 25, 2012 Third-Party Guarantees [Member]	Dec. 31, 2011 Third-Party Guarantees [Member]	Mar. 25, 2012 Other Noncurrent Liabilities [Member]	Dec. 31, 2011 Other Noncurrent Liabilities [Member]	Mar. 25, 2012 Other Noncurrent Assets [Member] Environmental Matters [Member]	Dec. 31, 2011 Other Noncurrent Assets [Member] Environmental Matters [Member]
Loss Contingencies [Line Items]
Contract value			$ 323,000,000
Contract payments received to date		241,000,000
Liabilities recorded relative to environmental matters				966,000,000	932,000,000						848,000,000	814,000,000
Environmental costs eligible for future recovery				838,000,000	808,000,000								736,000,000	706,000,000
Time period environmental costs and recovery of environmental costs are projected over, years	20
Percentage of expenditures that are reimbursed for certain remediation activities	50.00%
Outstanding letters of credit, surety bonds and third-party guarantees						3,400,000,000	3,900,000,000
Third-party guarantees outstanding									894,000,000	907,000,000
Percentage of total guarantees that relate to guarantees of contractual performance of joint ventures									85.00%
Ownership interest in affiliated entity								50.00%
Dividends that are subject to contingency								380,000,000
Revolving line of credit								$ 400,000,000