Revenue - Revenue by Contract Type (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jul. 01, 2018	Jul. 02, 2017	Jul. 01, 2018	Jul. 02, 2017
Revenue [Line Items]
Cost-reimbursement	$ 2,373	$ 2,038	$ 4,297	$ 4,056
Revenue	9,186	7,675	16,721	15,116
Aerospace
Revenue [Line Items]
Cost-reimbursement	0	0	0	0
Revenue	1,895	2,078	3,720	4,152
Combat Systems
Revenue [Line Items]
Cost-reimbursement	197	196	376	403
Revenue	1,534	1,414	2,974	2,701
Information Technology
Revenue [Line Items]
Cost-reimbursement	930	555	1,507	1,108
Revenue	2,442	1,052	3,580	2,110
Mission Systems
Revenue [Line Items]
Cost-reimbursement	451	463	891	920
Revenue	1,147	1,052	2,245	2,140
Marine Systems
Revenue [Line Items]
Cost-reimbursement	795	824	1,523	1,625
Revenue	2,168	2,079	4,202	4,013
Fixed-price
Revenue [Line Items]
Revenue	6,115	5,265	11,348	10,300
Fixed-price | Aerospace
Revenue [Line Items]
Revenue	1,696	1,913	3,364	3,815
Fixed-price | Combat Systems
Revenue [Line Items]
Revenue	1,330	1,207	2,583	2,280
Fixed-price | Information Technology
Revenue [Line Items]
Revenue	1,059	339	1,446	690
Fixed-price | Mission Systems
Revenue [Line Items]
Revenue	658	553	1,278	1,132
Fixed-price | Marine Systems
Revenue [Line Items]
Revenue	1,372	1,253	2,677	2,383
Time-and-materials
Revenue [Line Items]
Revenue	698	372	1,076	760
Time-and-materials | Aerospace
Revenue [Line Items]
Revenue	199	165	356	337
Time-and-materials | Combat Systems
Revenue [Line Items]
Revenue	7	11	15	18
Time-and-materials | Information Technology
Revenue [Line Items]
Revenue	453	158	627	312
Time-and-materials | Mission Systems
Revenue [Line Items]
Revenue	38	36	76	88
Time-and-materials | Marine Systems
Revenue [Line Items]
Revenue	$ 1	$ 2	$ 2	$ 5