Business Segment - Schedule of Segment Reporting Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Segment Reporting, Asset Reconciling Item [Line Items]
Total revenues	$ 28	$ 145
Less:
Impairment of long-lived assets	0	20
Interest income, net	1	1
Income tax expense	0	0
Net loss	(112)	(4)
Reportable segment
Segment Reporting, Asset Reconciling Item [Line Items]
Total revenues	28	145
Less:
Late-stage development programs	55	63
Early-stage development and preclinical programs	42	25
Compensation and personnel costs	66	64
Depreciation and amortization	3	3
Impairment of long-lived assets	0	20
Interest income, net	(10)	(12)
Income tax expense	0	0
Other segment items	22	23
Partnership reimbursements	(38)	(37)
Net loss	$ (112)	$ (4)