Inventories (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Schedule of Inventory [Line Items]
Work-in-process, primarily related to long-term contracts and programs in progress	$ 7,188	$ 7,000
Less: customer advances and progress payments	(5,124)	(4,932)
Inventory for long term contracts or programs net of customer advances and progress payments	2,064	2,068
Other inventories	831	869
Total inventories, net	$ 2,895	$ 2,937