Revenue from Contracts with Customers - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Disaggregation of Revenue [Line Items]
Revenues	$ 799	$ 688
Intersegment Sales
Disaggregation of Revenue [Line Items]
Revenues	(3)	(6)
ASC | Firm-Fixed Price
Disaggregation of Revenue [Line Items]
Revenues	437	350
ASC | Flexibly Priced
Disaggregation of Revenue [Line Items]
Revenues	71	77
ASC | Prime contractor
Disaggregation of Revenue [Line Items]
Revenues	224	163
ASC | Subcontractor
Disaggregation of Revenue [Line Items]
Revenues	284	264
ASC | Intersegment Sales
Disaggregation of Revenue [Line Items]
Revenues	(3)	(6)
ASC | Operating Segments
Disaggregation of Revenue [Line Items]
Revenues	511	433
ASC | United States
Disaggregation of Revenue [Line Items]
Revenues	446	337
ASC | International
Disaggregation of Revenue [Line Items]
Revenues	62	90
IMS | Firm-Fixed Price
Disaggregation of Revenue [Line Items]
Revenues	254	218
IMS | Flexibly Priced
Disaggregation of Revenue [Line Items]
Revenues	37	43
IMS | Prime contractor
Disaggregation of Revenue [Line Items]
Revenues	46	65
IMS | Subcontractor
Disaggregation of Revenue [Line Items]
Revenues	245	196
IMS | Intersegment Sales
Disaggregation of Revenue [Line Items]
Revenues	0	0
IMS | Operating Segments
Disaggregation of Revenue [Line Items]
Revenues	291	261
IMS | United States
Disaggregation of Revenue [Line Items]
Revenues	294	257
IMS | International
Disaggregation of Revenue [Line Items]
Revenues	$ (3)	$ 4