Summary of Significant Accounting Policies - Contracts accounted for under percentage of completion method (Details) - Contracts accounted for under percentage of completion method - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2016	Jan. 02, 2016	Jan. 03, 2015
Use of Estimates
Change in Accounting Estimate Financial Effect Increase in Income from Continuing Operations before Income Taxes	$ 83	$ 78	$ 95
Change in Accounting Estimate Financial Effect Increase in Income from Continuing Operations after taxes	$ 52	$ 49	$ 60
Change in Accounting Estimate Financial Effect Increase in Earnings Per Share Diluted	$ 0.19	$ 0.18	$ 0.21
Gross Favorable Program Profit Adjustments	$ 106	$ 111	$ 132
Gross Unfavorable Program Profit Adjustments	$ 23	$ 33	$ 37