Basis of Presentation (Unaudited) (Details 2) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Change in Accounting Estimate [Line Items]
Operating Income (Loss)	$ 794	$ 769	$ 2,387	$ 2,434
Net earnings	$ 516	$ 473	$ 1,531	$ 1,563
Diluted earnings per share	$ 2.75	$ 2.26	$ 7.89	$ 7.28
Contracts Accounted for under Percentage of Completion [Member]
Change in Accounting Estimate [Line Items]
Operating Income (Loss)	$ 112	$ 194	$ 461	$ 556
Net earnings	$ 73	$ 126	$ 300	$ 361
Diluted earnings per share	$ 0.39	$ 0.60	$ 1.55	$ 1.68