Receivables (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Accounts, Notes, Loans and Financing Receivable [Line Items]
Receivables, net	$ 6,563	$ 6,064
U.S. Government
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amounts billed	1,088	1,273
Unbilled costs and accrued profits	5,630	4,961
Less: customer advances and progress payments	(1,048)	(1,086)
Receivables, net	5,670	5,148
Other governments and commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amounts billed	376	396
Unbilled costs and accrued profits	789	774
Less: customer advances and progress payments	(272)	(254)
Receivables, net	$ 893	$ 916