BUSINESS SEGMENT INFORMATION - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 28, 2024	Jun. 30, 2023	Jun. 28, 2024	Jun. 30, 2023
Disaggregation of Revenue [Line Items]
Revenue	$ 5,299	$ 4,693	$ 10,510	$ 9,164
Intersegment
Disaggregation of Revenue [Line Items]
Revenue	(64)	(46)	(109)	(93)
SAS | United States
Disaggregation of Revenue [Line Items]
Revenue	1,488	1,475	2,995	2,929
SAS | International
Disaggregation of Revenue [Line Items]
Revenue	206	230	435	418
SAS | Fixed-price
Disaggregation of Revenue [Line Items]
Revenue	1,072	1,099	2,180	2,121
SAS | Cost-reimbursable
Disaggregation of Revenue [Line Items]
Revenue	622	606	1,250	1,226
SAS | Operating segments
Disaggregation of Revenue [Line Items]
Revenue	1,707	1,715	3,458	3,370
SAS | Intersegment
Disaggregation of Revenue [Line Items]
Revenue	(13)	(10)	(28)	(23)
IMS | United States
Disaggregation of Revenue [Line Items]
Revenue	1,263	1,281	2,466	2,538
IMS | International
Disaggregation of Revenue [Line Items]
Revenue	437	430	887	852
IMS | Fixed-price
Disaggregation of Revenue [Line Items]
Revenue	1,340	1,317	2,618	2,603
IMS | Cost-reimbursable
Disaggregation of Revenue [Line Items]
Revenue	360	394	735	787
IMS | Operating segments
Disaggregation of Revenue [Line Items]
Revenue	1,729	1,735	3,398	3,435
IMS | Intersegment
Disaggregation of Revenue [Line Items]
Revenue	(29)	(24)	(45)	(45)
CS | United States
Disaggregation of Revenue [Line Items]
Revenue	886	834	1,811	1,625
CS | International
Disaggregation of Revenue [Line Items]
Revenue	438	443	793	802
CS | Fixed-price
Disaggregation of Revenue [Line Items]
Revenue	1,118	1,102	2,183	2,080
CS | Cost-reimbursable
Disaggregation of Revenue [Line Items]
Revenue	206	175	421	347
CS | Operating segments
Disaggregation of Revenue [Line Items]
Revenue	1,346	1,289	2,640	2,452
CS | Intersegment
Disaggregation of Revenue [Line Items]
Revenue	(22)	(12)	(36)	(25)
AR | United States
Disaggregation of Revenue [Line Items]
Revenue	571		1,098
AR | International
Disaggregation of Revenue [Line Items]
Revenue	10		25
AR | Fixed-price
Disaggregation of Revenue [Line Items]
Revenue	344		646
AR | Cost-reimbursable
Disaggregation of Revenue [Line Items]
Revenue	237		477
AR | Operating segments
Disaggregation of Revenue [Line Items]
Revenue	581		1,123
AR | Intersegment
Disaggregation of Revenue [Line Items]
Revenue	0		0
Prime contractor | SAS
Disaggregation of Revenue [Line Items]
Revenue	1,076	1,084	2,184	2,094
Prime contractor | IMS
Disaggregation of Revenue [Line Items]
Revenue	1,097	1,127	2,163	2,281
Prime contractor | CS
Disaggregation of Revenue [Line Items]
Revenue	915	798	1,828	1,605
Prime contractor | AR
Disaggregation of Revenue [Line Items]
Revenue	155		308
Subcontractor | SAS
Disaggregation of Revenue [Line Items]
Revenue	618	621	1,246	1,253
Subcontractor | IMS
Disaggregation of Revenue [Line Items]
Revenue	603	584	1,190	1,109
Subcontractor | CS
Disaggregation of Revenue [Line Items]
Revenue	409	$ 479	776	$ 822
Subcontractor | AR
Disaggregation of Revenue [Line Items]
Revenue	$ 426		$ 815