Contracts in Process (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended		12 Months Ended
		Sep. 29, 2017	Sep. 23, 2016	Sep. 29, 2017	Sep. 23, 2016	Dec. 31, 2016
Contracts Receivable [Abstract]
Unbilled contract receivables, gross		$ 1,965		$ 1,965		$ 2,020
Unliquidated progress payments		(710)		(710)		(827)
Unbilled contract receivables, net		1,255		1,255		1,193
Inventoried contract costs, gross		1,101		1,101		1,065
Unliquidated progress payments		(83)		(83)		(203)
Inventoried contract costs, net		1,018		1,018		862
Total contracts in process		2,273		2,273		2,055
Summary of Inventory for Long Term Contracts or Programs [Roll Forward]
Amounts included in inventoried contract costs at beginning of the period		174	$ 163	173	$ 137	137
Contract costs incurred [Abstract]
IRAD and B&P		89	76	246	213
Other G&A	[1]	219	201	671	611
Total		308	277	917	824
Amounts charged to cost of sales		(303)	(270)	(911)	(791)
Amounts included in inventoried contract costs at end of the period		179	170	179	170	173
Severance and restructuring costs		31	4	54	9	$ 17
Operating Expenses [Abstract]
Selling, general and administrative expenses		71	53	205	164
Research and development expenses		15	16	47	40
Total		$ 86	$ 69	$ 252	$ 204

[1] Amounts include severance and restructuring related costs of $31 million and $4 million for the quarterly periods ended September 29, 2017 and September 23, 2016, respectively, and $54 million and $9 million for the year-to-date periods ended September 29, 2017 and September 23, 2016, respectively.