Segment Information (Details 5) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting Information [Line Items]
Sales	$ 6,108	$ 5,984	$ 6,039	$ 5,848	$ 6,157	$ 6,106	$ 6,294	$ 6,104	$ 23,979	$ 24,661	$ 25,218
U.S. Government
Segment Reporting Information [Line Items]
Sales									20,100	21,300	22,300
Percentage of total sales									84.00%	86.00%	88.00%
International Customer
Segment Reporting Information [Line Items]
Sales									$ 3,000	$ 2,500	$ 2,100
Percentage of total sales									13.00%	10.00%	8.00%