Revenue - Revenue by Contract Type (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 29, 2020	Mar. 31, 2019
Revenue [Line Items]
Revenue	$ 8,749	$ 9,261
Aerospace
Revenue [Line Items]
Revenue	1,691	2,240
Combat Systems
Revenue [Line Items]
Revenue	1,708	1,636
Information Technology
Revenue [Line Items]
Revenue	1,988	2,169
Mission Systems
Revenue [Line Items]
Revenue	1,116	1,158
Marine Systems
Revenue [Line Items]
Revenue	2,246	2,058
Fixed-price
Revenue [Line Items]
Revenue	5,901	6,444
Fixed-price | Aerospace
Revenue [Line Items]
Revenue	1,478	2,040
Fixed-price | Combat Systems
Revenue [Line Items]
Revenue	1,465	1,416
Fixed-price | Information Technology
Revenue [Line Items]
Revenue	769	921
Fixed-price | Mission Systems
Revenue [Line Items]
Revenue	620	651
Fixed-price | Marine Systems
Revenue [Line Items]
Revenue	1,569	1,416
Cost-reimbursement
Revenue [Line Items]
Revenue	2,251	2,155
Cost-reimbursement | Aerospace
Revenue [Line Items]
Revenue	0	0
Cost-reimbursement | Combat Systems
Revenue [Line Items]
Revenue	229	211
Cost-reimbursement | Information Technology
Revenue [Line Items]
Revenue	893	841
Cost-reimbursement | Mission Systems
Revenue [Line Items]
Revenue	454	463
Cost-reimbursement | Marine Systems
Revenue [Line Items]
Revenue	675	640
Time-and-materials
Revenue [Line Items]
Revenue	597	662
Time-and-materials | Aerospace
Revenue [Line Items]
Revenue	213	200
Time-and-materials | Combat Systems
Revenue [Line Items]
Revenue	14	9
Time-and-materials | Information Technology
Revenue [Line Items]
Revenue	326	407
Time-and-materials | Mission Systems
Revenue [Line Items]
Revenue	42	44
Time-and-materials | Marine Systems
Revenue [Line Items]
Revenue	$ 2	$ 2