Revenue from Contracts with Customers - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Disaggregation of Revenue [Line Items]
Total revenues	$ 569	$ 612
Intersegment Sales
Disaggregation of Revenue [Line Items]
Total revenues	(11)	(2)
ASC | Prime contractor
Disaggregation of Revenue [Line Items]
Total revenues	162	232
ASC | Subcontractor
Disaggregation of Revenue [Line Items]
Total revenues	218	162
ASC | Firm Fixed Price
Disaggregation of Revenue [Line Items]
Total revenues	324	342
ASC | Flexibly Priced
Disaggregation of Revenue [Line Items]
Total revenues	56	52
ASC | Intersegment Sales
Disaggregation of Revenue [Line Items]
Total revenues	11	2
ASC | Operating Segments
Disaggregation of Revenue [Line Items]
Total revenues	391	396
IMS | Prime contractor
Disaggregation of Revenue [Line Items]
Total revenues	46	33
IMS | Subcontractor
Disaggregation of Revenue [Line Items]
Total revenues	143	185
IMS | Firm Fixed Price
Disaggregation of Revenue [Line Items]
Total revenues	155	193
IMS | Flexibly Priced
Disaggregation of Revenue [Line Items]
Total revenues	34	25
IMS | Intersegment Sales
Disaggregation of Revenue [Line Items]
Total revenues	0	0
IMS | Operating Segments
Disaggregation of Revenue [Line Items]
Total revenues	189	218
United States | ASC
Disaggregation of Revenue [Line Items]
Total revenues	330	372
United States | IMS
Disaggregation of Revenue [Line Items]
Total revenues	186	212
International | ASC
Disaggregation of Revenue [Line Items]
Total revenues	50	22
International | IMS
Disaggregation of Revenue [Line Items]
Total revenues	$ 3	$ 6