Basis of Presentation (Details) (Unaudited) (USD $)	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Dec. 31, 2011
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Changes in contract estimates, increase in earnings from continuing operations	$ 265,000,000	$ 144,000,000
Changes in contract estimates, increase in earnings from continuing operations, per diluted share	$ 0.67	$ 0.32
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Unamortized benefit plan costs, tax benefit	2,252,000,000		2,289,000,000
Unamortized benefit plan costs, net of tax benefit of $2,252 as of March 31, 2012 and $2,289 as of December 31, 2011	(3,437,000,000)		(3,487,000,000)
Cumulative translation adjustment	2,000,000		(4,000,000)
Net unrealized gain on marketable securities and cash flow hedges, net of tax expense	1,000,000		1,000,000
Accumulated other comprehensive loss	(3,434,000,000)		(3,490,000,000)
Net after-tax actuarial loss amounts	$ 3,800,000,000		$ 3,900,000,000