Revenue - Revenue by Products and Services (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jul. 04, 2021	Jun. 28, 2020	Jul. 04, 2021	Jun. 28, 2020
Revenue [Line Items]
Revenue		$ 9,220	$ 9,264	$ 18,609	$ 18,013
Aerospace
Revenue [Line Items]
Revenue		1,622	1,974	3,509	3,665
Aerospace | Aircraft manufacturing
Revenue [Line Items]
Revenue		1,072	1,532	2,444	2,697
Aerospace | Aircraft services and completions
Revenue [Line Items]
Revenue		550	442	1,065	968
Marine Systems
Revenue [Line Items]
Revenue		2,536	2,471	5,019	4,717
Marine Systems | Nuclear-powered submarines
Revenue [Line Items]
Revenue		1,679	1,708	3,398	3,268
Marine Systems | Surface ships
Revenue [Line Items]
Revenue		585	510	1,113	972
Marine Systems | Repair and other services
Revenue [Line Items]
Revenue		272	253	508	477
Combat Systems
Revenue [Line Items]
Revenue		1,899	1,754	3,719	3,462
Combat Systems | Military vehicles
Revenue [Line Items]
Revenue		1,231	1,103	2,434	2,249
Combat Systems | Weapons systems, armament and munitions
Revenue [Line Items]
Revenue		511	515	971	948
Combat Systems | Engineering and other services
Revenue [Line Items]
Revenue		157	136	314	265
Technologies
Revenue [Line Items]
Revenue		3,163	3,065	6,362	6,169
Technologies | Information Technology Services [Member]
Revenue [Line Items]
Revenue		2,071	1,884	4,156	3,872
Technologies | C4ISR* solutions
Revenue [Line Items]
Revenue	[1]	$ 1,092	$ 1,181	$ 2,206	$ 2,297

[1] Command, control, communications, computers, intelligence, surveillance and reconnaissance