Segment Reporting - Reconciliation of Segment Profits to Income before Taxes (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2024	Mar. 31, 2023
Segment Reporting Information [Line Items]
Profits	$ 5,670	$ 3,650
Interest income	73	112
Interest expense	(303)	(242)
Amortization	(473)	(543)
Depreciation	(511)	(448)
Research and development	(3,992)	(4,276)
Restructuring costs	(123)	(67)
Operating Segments
Segment Reporting Information [Line Items]
Profits	11,459	9,706
Operating Segments \| Pharmaceutical segment
Segment Reporting Information [Line Items]
Profits	10,904	9,140
Operating Segments \| Animal Health segment
Segment Reporting Information [Line Items]
Profits	555	566
Corporate, Non-Segment
Segment Reporting Information [Line Items]
Profits	146	164
Segment Reconciling Items
Segment Reporting Information [Line Items]
Interest income	73	112
Interest expense	(303)	(242)
Amortization	(473)	(543)
Depreciation	(452)	(398)
Research and development	(3,851)	(4,147)
Restructuring costs	(123)	(67)
Charge for Zetia antitrust litigation settlements	0	(573)
Other unallocated, net	$ (806)	$ (362)

Other net expenses not allocated to segments.

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Amount of gain (loss) recognized in settlement of litigation and insurance claims. Excludes claims within an insurance entity's normal claims settlement process.

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Amount of income (loss) from continuing operations, including income (loss) from equity method investments, before deduction of income tax expense (benefit), and income (loss) attributable to noncontrolling interest.

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Amount of the cost of borrowed funds accounted for as interest expense.

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The aggregate costs incurred (1) in a planned search or critical investigation aimed at discovery of new knowledge with the hope that such knowledge will be useful in developing a new product or service, a new process or technique, or in bringing about a significant improvement to an existing product or process; or (2) to translate research findings or other knowledge into a plan or design for a new product or process or for a significant improvement to an existing product or process whether intended for sale or the entity's use, during the reporting period charged to research and development projects, including the costs of developing computer software up to the point in time of achieving technological feasibility, and costs allocated in accounting for a business combination to in-process projects deemed to have no alternative future use.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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