Summary Of Significant Accounting Policies - Additional Information (Detail) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jul. 01, 2012	Jun. 30, 2013	Jul. 01, 2012
Accounting Policies [Abstract]
Length of fiscal quarters, weeks			P13W
Net increase in operating earnings from the quarterly impact of revisions in contract	$ 83	$ 90	$ 191	$ 158
Net increase in operating earnings per share from the quarterly impact of revisions in contract	$ 0.15	$ 0.17	$ 0.35	$ 0.30