Summary of Financial Information for Each Business Segment (Parenthetical) (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Segment Reporting Information [Line Items]
Non-cash FAS/CAS pension adjustment	$ (830)		$ (922)		$ (454)
Stock-based compensation	(167)		(157)		(168)
Other, net	(104)		(46)		(81)
Other unallocated expense, net	(1,101)	[1]	(1,125)	[1]	(703)	[1]
The increase in goodwill during the year			$ 543

[1] Other unallocated expenses, net included the following (in millions): 2012 2011 2010 Non-cash FAS/CAS pension adjustment $ (830 ) $ (922 ) $ (454 ) Stock-based compensation (167 ) (157 ) (168 ) Other, net (104 ) (46 ) (81 ) Total $ (1,101 ) $ (1,125 ) $ (703 )