Basis of Presentation (Details 2) (Contracts accounted for under percentage of completion method, USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended
	Apr. 04, 2015	Mar. 29, 2014
Contracts accounted for under percentage of completion method
Use of Estimates
Change in Accounting Estimate Financial Effect Increase in Income from Continuing Operations before Income Taxes	$ 18	$ 21
Change in Accounting Estimate Financial Effect Increase in Income from Continuing Operations after taxes	11	13
Change in Accounting Estimate Financial Effect Increase in Earnings Per Share Diluted	$ 0.04	$ 0.05
Gross Favorable Program Profit Adjustments	33	24
Gross Unfavorable Program Profit Adjustments	$ 15	$ 3