Revenue from Contracts with Customers - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Disaggregation of Revenue [Line Items]
Revenues	$ 846	$ 799
Intersegment sales
Disaggregation of Revenue [Line Items]
Revenues	(8)	(3)
ASC \| Fixed-price
Disaggregation of Revenue [Line Items]
Revenues	491	437
ASC \| Flexibly Priced
Disaggregation of Revenue [Line Items]
Revenues	61	71
ASC \| Prime contractor
Disaggregation of Revenue [Line Items]
Revenues	261	224
ASC \| Subcontractor
Disaggregation of Revenue [Line Items]
Revenues	291	284
ASC \| Intersegment sales
Disaggregation of Revenue [Line Items]
Revenues	(7)	(3)
ASC \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenues	559	511
ASC \| United States
Disaggregation of Revenue [Line Items]
Revenues	471	446
ASC \| International
Disaggregation of Revenue [Line Items]
Revenues	81	62
IMS \| Fixed-price
Disaggregation of Revenue [Line Items]
Revenues	242	254
IMS \| Flexibly Priced
Disaggregation of Revenue [Line Items]
Revenues	52	37
IMS \| Prime contractor
Disaggregation of Revenue [Line Items]
Revenues	62	46
IMS \| Subcontractor
Disaggregation of Revenue [Line Items]
Revenues	232	245
IMS \| Intersegment sales
Disaggregation of Revenue [Line Items]
Revenues	(1)	0
IMS \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenues	295	291
IMS \| United States
Disaggregation of Revenue [Line Items]
Revenues	277	294
IMS \| International
Disaggregation of Revenue [Line Items]
Revenues	$ 17	$ (3)