Collaborative Arrangements - AstraZeneca PLC - Narrative (Details) - USD ($)	6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024
Lynparza \| Licenses and Other
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Finite-lived intangible assets	$ 1,000,000,000.0
Koselugo \| Licenses and Other
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Finite-lived intangible assets	44,000,000
AstraZeneca \| Collaborative Arrangement, Transaction with Party to Collaborative Arrangement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Sales based milestone payments	700,000,000
AstraZeneca \| Collaborative Arrangement, Transaction with Party to Collaborative Arrangement \| Lynparza
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Sales based milestone payments	600,000,000
Eligible future contingent sales-based milestone payments (up to)	2,000,000,000.0
Regulatory milestone payments		$ 245,000,000
Eligible future contingent regulatory milestone payments (up to)	0
AstraZeneca \| Collaborative Arrangement, Transaction with Party to Collaborative Arrangement \| Koselugo
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Sales based milestone payments	$ 100,000,000

Merck & Co., Inc. 10-Q