Revenue - Revenue by Contract Type (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jul. 01, 2018	Jun. 30, 2019	Jul. 01, 2018
Revenue [Line Items]
Revenue	$ 9,555	$ 9,186	$ 18,816	$ 16,721
Aerospace
Revenue [Line Items]
Revenue	2,136	1,895	4,376	3,720
Combat Systems
Revenue [Line Items]
Revenue	1,659	1,534	3,295	2,974
Information Technology
Revenue [Line Items]
Revenue	2,158	2,442	4,327	3,580
Mission Systems
Revenue [Line Items]
Revenue	1,277	1,147	2,435	2,245
Marine Systems
Revenue [Line Items]
Revenue	2,325	2,168	4,383	4,202
Fixed-price
Revenue [Line Items]
Revenue	6,554	6,115	12,998	11,348
Fixed-price | Aerospace
Revenue [Line Items]
Revenue	1,925	1,696	3,965	3,364
Fixed-price | Combat Systems
Revenue [Line Items]
Revenue	1,427	1,330	2,843	2,583
Fixed-price | Information Technology
Revenue [Line Items]
Revenue	875	1,059	1,796	1,446
Fixed-price | Mission Systems
Revenue [Line Items]
Revenue	752	658	1,403	1,278
Fixed-price | Marine Systems
Revenue [Line Items]
Revenue	1,575	1,372	2,991	2,677
Cost-reimbursement
Revenue [Line Items]
Revenue	2,308	2,373	4,463	4,297
Cost-reimbursement | Aerospace
Revenue [Line Items]
Revenue	0	0	0	0
Cost-reimbursement | Combat Systems
Revenue [Line Items]
Revenue	221	197	432	376
Cost-reimbursement | Information Technology
Revenue [Line Items]
Revenue	858	930	1,699	1,507
Cost-reimbursement | Mission Systems
Revenue [Line Items]
Revenue	484	451	947	891
Cost-reimbursement | Marine Systems
Revenue [Line Items]
Revenue	745	795	1,385	1,523
Time-and-materials
Revenue [Line Items]
Revenue	693	698	1,355	1,076
Time-and-materials | Aerospace
Revenue [Line Items]
Revenue	211	199	411	356
Time-and-materials | Combat Systems
Revenue [Line Items]
Revenue	11	7	20	15
Time-and-materials | Information Technology
Revenue [Line Items]
Revenue	425	453	832	627
Time-and-materials | Mission Systems
Revenue [Line Items]
Revenue	41	38	85	76
Time-and-materials | Marine Systems
Revenue [Line Items]
Revenue	$ 5	$ 1	$ 7	$ 2