Contracts in Process - General and Administrative, Independent Research and Development and Bids and Proposal Costs (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 25, 2015	Sep. 26, 2014	Sep. 25, 2015	Sep. 26, 2014
Inventory Disclosure [Abstract]
Amounts included in inventoried contract costs at beginning of the period	$ 149	$ 146	$ 138	$ 133
Contract costs incurred:
IRAD and B&P	70	70	210	213
Other G&A	219	230	640	645
Total	289	300	850	858
Amounts charged to cost of sales	(269)	(300)	(819)	(845)
Amounts included in inventoried contract costs at end of the period	$ 169	$ 146	$ 169	$ 146