BUSINESS SEGMENT INFORMATION - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 29, 2024	Mar. 31, 2023
Disaggregation of Revenue [Line Items]
Revenue	$ 5,211	$ 4,471
SAS | United States
Disaggregation of Revenue [Line Items]
Revenue	1,507	1,454
SAS | International
Disaggregation of Revenue [Line Items]
Revenue	229	188
SAS | Fixed-price
Disaggregation of Revenue [Line Items]
Revenue	1,108	1,022
SAS | Cost-reimbursable
Disaggregation of Revenue [Line Items]
Revenue	628	620
SAS | Operating segments
Disaggregation of Revenue [Line Items]
Revenue	1,751	1,655
SAS | Intersegment
Disaggregation of Revenue [Line Items]
Revenue	(15)	(13)
IMS | United States
Disaggregation of Revenue [Line Items]
Revenue	1,203	1,257
IMS | International
Disaggregation of Revenue [Line Items]
Revenue	450	422
IMS | Fixed-price
Disaggregation of Revenue [Line Items]
Revenue	1,278	1,286
IMS | Cost-reimbursable
Disaggregation of Revenue [Line Items]
Revenue	375	393
IMS | Operating segments
Disaggregation of Revenue [Line Items]
Revenue	1,669	1,700
IMS | Intersegment
Disaggregation of Revenue [Line Items]
Revenue	(16)	(21)
CS | United States
Disaggregation of Revenue [Line Items]
Revenue	925	791
CS | International
Disaggregation of Revenue [Line Items]
Revenue	355	359
CS | Fixed-price
Disaggregation of Revenue [Line Items]
Revenue	1,065	978
CS | Cost-reimbursable
Disaggregation of Revenue [Line Items]
Revenue	215	172
CS | Operating segments
Disaggregation of Revenue [Line Items]
Revenue	1,294	1,163
CS | Intersegment
Disaggregation of Revenue [Line Items]
Revenue	(14)	(13)
AR | United States
Disaggregation of Revenue [Line Items]
Revenue	527
AR | International
Disaggregation of Revenue [Line Items]
Revenue	15
AR | Fixed-price
Disaggregation of Revenue [Line Items]
Revenue	302
AR | Cost-reimbursable
Disaggregation of Revenue [Line Items]
Revenue	240
AR | Operating segments
Disaggregation of Revenue [Line Items]
Revenue	542
AR | Intersegment
Disaggregation of Revenue [Line Items]
Revenue	0
Prime contractor | SAS
Disaggregation of Revenue [Line Items]
Revenue	1,108	1,010
Prime contractor | IMS
Disaggregation of Revenue [Line Items]
Revenue	1,066	1,154
Prime contractor | CS
Disaggregation of Revenue [Line Items]
Revenue	913	807
Prime contractor | AR
Disaggregation of Revenue [Line Items]
Revenue	153
Subcontractor | SAS
Disaggregation of Revenue [Line Items]
Revenue	628	632
Subcontractor | IMS
Disaggregation of Revenue [Line Items]
Revenue	587	525
Subcontractor | CS
Disaggregation of Revenue [Line Items]
Revenue	367	$ 343
Subcontractor | AR
Disaggregation of Revenue [Line Items]
Revenue	$ 389