Inventories (Detail) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Schedule of Inventory [Line Items]
Work-in-process, primarily related to long-term contracts and programs in progress	$ 7,000	$ 7,129
Less: customer advances and progress payments	(4,944)	(5,425)
Inventory for Long Term Contracts or Programs Net of Customer Advances and Progress Payments, Total	2,056	1,704
Other inventories	822	777
Total inventories, net	$ 2,878	$ 2,481