Revenue - Revenue by Contract Type (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
Fixed-price
Revenue [Line Items]
Revenue	6,222	6,476	12,624	12,377
Cost-reimbursement
Revenue [Line Items]
Revenue	2,305	2,251	4,602	4,502
Time-and-materials
Revenue [Line Items]
Revenue	693	537	1,383	1,134
Aerospace
Revenue [Line Items]
Revenue	1,622	1,974	3,509	3,665
Aerospace | Fixed-price
Revenue [Line Items]
Revenue	1,440	1,849	3,149	3,327
Aerospace | Cost-reimbursement
Revenue [Line Items]
Revenue	0	0	0	0
Aerospace | Time-and-materials
Revenue [Line Items]
Revenue	182	125	360	338
Marine Systems
Revenue [Line Items]
Revenue	2,536	2,471	5,019	4,717
Marine Systems | Fixed-price
Revenue [Line Items]
Revenue	1,810	1,716	3,594	3,285
Marine Systems | Cost-reimbursement
Revenue [Line Items]
Revenue	726	750	1,425	1,425
Marine Systems | Time-and-materials
Revenue [Line Items]
Revenue	0	5	0	7
Combat Systems
Revenue [Line Items]
Revenue	1,899	1,754	3,719	3,462
Combat Systems | Fixed-price
Revenue [Line Items]
Revenue	1,668	1,507	3,237	2,972
Combat Systems | Cost-reimbursement
Revenue [Line Items]
Revenue	216	230	451	459
Combat Systems | Time-and-materials
Revenue [Line Items]
Revenue	15	17	31	31
Technologies
Revenue [Line Items]
Revenue	3,163	3,065	6,362	6,169
Technologies | Fixed-price
Revenue [Line Items]
Revenue	1,304	1,404	2,644	2,793
Technologies | Cost-reimbursement
Revenue [Line Items]
Revenue	1,363	1,271	2,726	2,618
Technologies | Time-and-materials
Revenue [Line Items]
Revenue	$ 496	$ 390	$ 992	$ 758