Basis of Presentation - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 26, 2014	Sep. 27, 2013
Summary Of Significant Accounting Policies [Line Items]
Percentage of sales accounted for under contract accounting standards	47.00%
Percentage of fixed-price type contracts	38.00%
Percentage of cost-plus type contracts	9.00%
Period of performance for contracts accounted for under the percentage-of-completion method of accounting, minimum	1 year
Increase in operating income due to changes in contract estimates	$ 62	$ 92
Percentage of increase in operating income due to changes in contract estimates	8.00%	10.00%
CODES Due 2035 [Member]
Summary Of Significant Accounting Policies [Line Items]
Interest rate on debt instruments	3.00%
Debt instruments, maturity year	2035