Segment Information - Revenues and Intersegment Revenues (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Segment Reporting Information [Line Items]
Total revenues	$ 812	$ 703	$ 2,253	$ 1,900
Operating Segments | ASC
Segment Reporting Information [Line Items]
Total revenues	533	431	1,458	1,226
Operating Segments | IMS
Segment Reporting Information [Line Items]
Total revenues	285	277	812	692
Corporate & Eliminations
Segment Reporting Information [Line Items]
Total revenues	(6)	(5)	(17)	(18)
Corporate & Eliminations | ASC
Segment Reporting Information [Line Items]
Total revenues	(6)	(5)	(17)	(18)
Corporate & Eliminations | IMS
Segment Reporting Information [Line Items]
Total revenues	$ 0	$ 0	$ 0	$ 0