Summary of Accounting Policies (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Intangible Assets Excluding Goodwill [Line Items]
Customer discounts	$ 13,300	$ 12,500	$ 12,300
Accrual for chargebacks reflected as direct reduction to accounts receivable	293	188
Accrual for rebates included in accrued and other current liabilities	$ 2,200	2,300
Product return period and expiration	12 months
Depreciation	$ 2,104	1,828	1,824
Advertising and promotion costs	$ 2,400	$ 2,300	$ 2,200
Minimum
Intangible Assets Excluding Goodwill [Line Items]
Product return period	3 months
Estimated useful life of intangible assets	2 years
Minimum | Capitalized Software
Intangible Assets Excluding Goodwill [Line Items]
Estimated useful life of intangible assets	2 years
Minimum | Buildings
Intangible Assets Excluding Goodwill [Line Items]
Estimated useful life of property, plant and equipment	25 years
Minimum | Machinery, equipment and office furnishings
Intangible Assets Excluding Goodwill [Line Items]
Estimated useful life of property, plant and equipment	3 years
Minimum | United States
Intangible Assets Excluding Goodwill [Line Items]
Payment terms, vaccine sales	30 days
Minimum | United States | Pharmaceutical
Intangible Assets Excluding Goodwill [Line Items]
Payment terms	36 days
Minimum | United States | Animal Health
Intangible Assets Excluding Goodwill [Line Items]
Payment terms	30 days
Minimum | Outside of the United States
Intangible Assets Excluding Goodwill [Line Items]
Payment terms	30 days
Maximum
Intangible Assets Excluding Goodwill [Line Items]
Product return period	6 months
Estimated useful life of intangible assets	24 years
Maximum | Capitalized Software
Intangible Assets Excluding Goodwill [Line Items]
Estimated useful life of intangible assets	10 years
Maximum | Buildings
Intangible Assets Excluding Goodwill [Line Items]
Estimated useful life of property, plant and equipment	45 years
Maximum | Machinery, equipment and office furnishings
Intangible Assets Excluding Goodwill [Line Items]
Estimated useful life of property, plant and equipment	15 years
Maximum | United States
Intangible Assets Excluding Goodwill [Line Items]
Payment terms	90 days
Payment terms, vaccine sales	60 days
Maximum | Outside of the United States
Intangible Assets Excluding Goodwill [Line Items]
Payment terms	90 days