Segment Information (Details 6) (USD $)	12 Months Ended
	Dec. 31, 2011 Segment	Dec. 31, 2010	Dec. 31, 2009
Segment Information (Amounts in paragraph)
Number of reportable segments	4
Net pension adjustment	$ 400,000,000	$ 10,000,000	$ (237,000,000)
Intersegment Elimination [Member]
Segment Reporting Information [Line Items]
Cost of product sales		746,000,000	318,000,000
Cost of service revenues		(746,000,000)	(318,000,000)
U.S. Government Sales including Foreign Military Sales
Revenue, Major Customer [Line Items]
Total sales and service revenues	23,900,000,000	25,500,000,000	25,000,000,000
Percent of total sales	90.50%	90.60%	90.30%
Direct Foreign
Revenue, Major Customer [Line Items]
Total sales and service revenues	$ 1,600,000,000	$ 1,600,000,000	$ 1,600,000,000
Percent of total sales	6.00%	6.00%	6.00%