License and Collaborations - Additional Information (Details) - USD ($) $ in Millions		12 Months Ended
	Jan. 01, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2017
License and Collaboration Agreements [Line Items]
Revenue from contract with customer, excluding assessed tax		$ 117	$ 112	$ 383
Other noncurrent liabilities		142	140
Other noncurrent assets		106	114
Development expense		340	288	257
AstraZeneca Agreement
License and Collaboration Agreements [Line Items]
Milestone payments					$ 24
Development cost recorded within research and development expenses		6	4	1
Other noncurrent liabilities		11	5
Gilead Collaboration Agreement
License and Collaboration Agreements [Line Items]
Development cost recorded within research and development expenses		6
Other noncurrent assets		6	2
Exelixis Collaboration
License and Collaboration Agreements [Line Items]
Development expense		3
Taiho Pharmaceutical Co., Ltd | Taiho Agreement
License and Collaboration Agreements [Line Items]
Option period						5 years
Non refundable and non creditable cash payments						$ 35
Payment for option exercise		28
Royalties payable term						10 years
Revenue from contract with customer, excluding assessed tax		5	5	22
Reimbursement of research and development expense		8
Taiho Pharmaceutical Co., Ltd | Taiho Agreement | Subsequent Event
License and Collaboration Agreements [Line Items]
Payment for option exercise	$ 26
Taiho Pharmaceutical Co., Ltd | Taiho Agreement | Minimum
License and Collaboration Agreements [Line Items]
Payment for option exercise						$ 3
Taiho Pharmaceutical Co., Ltd | Taiho Agreement | Maximum
License and Collaboration Agreements [Line Items]
Payment for option exercise						15
Additional clinical and regulatory milestone payments receivable						130
Contingent milestone payments receivable						$ 145
WuXi Biologics License Agreement | anti-CD39 | Research and Development
License and Collaboration Agreements [Line Items]
Milestone payments		1	2
WuXi Biologics License Agreement | Maximum | anti-PD-1
License and Collaboration Agreements [Line Items]
Milestone payments				10
Clinical regulatory milestone payments		50
Commercialization milestone payments		375
WuXi Biologics License Agreement | Maximum | anti-CD39
License and Collaboration Agreements [Line Items]
Additional clinical, regulatory and commercialization milestone payments		14
Abmuno License Agreement
License and Collaboration Agreements [Line Items]
Additional clinical, regulatory and commercialization milestone payments		$ 88
Abmuno License Agreement | Research and Development
License and Collaboration Agreements [Line Items]
Development milestone expense			$ 5	$ 5