Segment Information (Details 2) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Net sales to principal customers
Net sales	$ 15,169	$ 15,680	$ 15,615
U.S. Government agencies [Member]
Net sales to principal customers
Net sales	12,434	13,077	13,059
Commercial [Member]
Net sales to principal customers
Net sales	1,535	1,461	1,474
Allied foreign governments [Member]
Net sales to principal customers
Net sales	$ 1,200	$ 1,142	$ 1,082