Basis of Presentation (Unaudited) (Details) (USD $)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Changes in contract estimates, increase in earnings from continuing operations	$ 247,000,000	$ 222,000,000	$ 421,000,000	$ 487,000,000
Changes in contract estimates, increase in earnings from continuing operations, per diluted share	$ 0.68	$ 0.57	$ 1.15	$ 1.24
Accumulated Other Comprehensive Loss
Unamortized benefit plan costs, net of tax benefit of $3,044 as of June 30, 2013, and $3,149 as of December 31, 2012	(4,631,000,000)		(4,631,000,000)		(4,790,000,000)
Cumulative translation adjustment	(3,000,000)		(3,000,000)		4,000,000
Net unrealized loss on marketable securities and cash flow hedges, net of tax benefit	(1,000,000)		(1,000,000)		(1,000,000)
Total accumulated other comprehensive loss	(4,635,000,000)		(4,635,000,000)		(4,787,000,000)
Unamortized benefit plan cost, tax benefit			3,044,000,000		3,149,000,000
Unamortized benefit plan costs, net actuarial losses, after-tax	4,900,000,000		4,900,000,000		5,100,000,000
Unamortized benefit plan costs, reclassified from other comprehensive income to net earnings	$ 79,000,000	$ 54,000,000	$ 159,000,000	$ 104,000,000