Revenue - Revenue by Contract Type (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 27, 2020	Sep. 29, 2019	Sep. 27, 2020	Sep. 29, 2019
Revenue [Line Items]
Revenue	$ 9,431	$ 9,761	$ 27,444	$ 28,577
Fixed-price
Revenue [Line Items]
Revenue	6,514	6,867	18,891	19,865
Cost-reimbursement
Revenue [Line Items]
Revenue	2,318	2,242	6,820	6,705
Time-and-materials
Revenue [Line Items]
Revenue	599	652	1,733	2,007
Aerospace
Revenue [Line Items]
Revenue	1,975	2,495	5,640	6,871
Aerospace | Fixed-price
Revenue [Line Items]
Revenue	1,821	2,306	5,148	6,271
Aerospace | Cost-reimbursement
Revenue [Line Items]
Revenue	0	0	0	0
Aerospace | Time-and-materials
Revenue [Line Items]
Revenue	154	189	492	600
Combat Systems
Revenue [Line Items]
Revenue	1,801	1,740	5,263	5,035
Combat Systems | Fixed-price
Revenue [Line Items]
Revenue	1,552	1,501	4,524	4,344
Combat Systems | Cost-reimbursement
Revenue [Line Items]
Revenue	231	230	690	662
Combat Systems | Time-and-materials
Revenue [Line Items]
Revenue	18	9	49	29
Information Technology
Revenue [Line Items]
Revenue	2,029	2,071	5,901	6,398
Information Technology | Fixed-price
Revenue [Line Items]
Revenue	806	824	2,317	2,620
Information Technology | Cost-reimbursement
Revenue [Line Items]
Revenue	846	838	2,539	2,537
Information Technology | Time-and-materials
Revenue [Line Items]
Revenue	377	409	1,045	1,241
Mission Systems
Revenue [Line Items]
Revenue	1,221	1,220	3,518	3,655
Mission Systems | Fixed-price
Revenue [Line Items]
Revenue	694	719	1,976	2,122
Mission Systems | Cost-reimbursement
Revenue [Line Items]
Revenue	478	458	1,403	1,405
Mission Systems | Time-and-materials
Revenue [Line Items]
Revenue	49	43	139	128
Marine Systems
Revenue [Line Items]
Revenue	2,405	2,235	7,122	6,618
Marine Systems | Fixed-price
Revenue [Line Items]
Revenue	1,641	1,517	4,926	4,508
Marine Systems | Cost-reimbursement
Revenue [Line Items]
Revenue	763	716	2,188	2,101
Marine Systems | Time-and-materials
Revenue [Line Items]
Revenue	$ 1	$ 2	$ 8	$ 9