| **Other (Income)/Deductions - Net - Schedule of Other (Income)/Deductions - Net (Detail) - USD ($) $ in Millions**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    | 3 Months Ended | 6 Months Ended |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|----------------|----------------|
||
| **Other Income and Expenses [Abstract]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |                |           |   |   |   |
| Interest income                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |                | $ (30)         | $ (13) | $ (44) | $ (12) |
| Interest expense                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |                | 293            | 316 | 614 | 651 |
| Net interest expense                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |                | 263            | 303 | 571 | 639 |
| Royalty-related income                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                |                | (217)          | (212) | (389) | (388) |
| Net (gains)/losses on asset disposals                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |                | 0              | (58) | (1) | (98) |
| Net (gains)/losses recognized during the period on equity securities                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | [1],[2]        | 541            | (800) | 1,241 | (1,200) |
| Income from collaborations, out-licensing arrangements and sales of compound/product rights                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           | [3]            | (5)            | (21) | (14) | (252) |
| Net periodic benefit costs/(credits) other than service costs                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |                | 295            | (237) | 12 | (503) |
| Certain legal matters, net                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |                | 19             | 24 | 98 | 74 |
| Consumer Healthcare JV equity method (income)/loss                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    | [4]            | (149)          | (140) | (334) | (202) |
| Other, net                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |                | 26             | (201) | (62) | (417) |
| Other (income)/deductions––net                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |                | $ 772          | $ (1,343) | $ 1,122 | $ (2,347) |
|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |
| [1]Reported in Other (income)/deductions––net. See Note 4.[2]The losses in the second quarter and first six months of 2022 include, among other things, unrealized losses of $432 million and $776 million, respectively, related to investments in BioNTech and Cerevel Therapeutics Holdings, Inc. (Cerevel). The gains in the second quarter and first six months of 2021 included, among other things, unrealized gains of $917 million and $1.0 billion, respectively, related to investments in BioNTech and Cerevel.[3]The first six months of 2021 included, among other things, $188 million of net collaboration income from BioNTech in the first quarter of 2021 related to Comirnaty.[4]See Note 2C |

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Income (Loss) From Collaborations, Licensing Agreements And Sales Of Compound/Product Rights
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Income (Loss) From Equity Method Investments, Net Excess Basis Amortization
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Other Nonoperating Income (Expense), Net
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Amount of unrealized and realized gain (loss) on investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).
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| - Definition
Amount of gain (loss) on sale or disposal of assets, including but not limited to property plant and equipment, intangible assets and equity in securities of subsidiaries or equity method investee.
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| - Definition
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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| - Definition
Amount of the cost of borrowed funds accounted for as interest expense.
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Amount of interest revenue (income derived from investments in debt securities and on cash and cash equivalents) net of interest expense (cost of borrowed funds accounted for as interest).
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Amount before accretion (amortization) of purchase discount (premium) of interest income on nonoperating securities.
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Amount of expense (reversal of expense) for net periodic benefit cost components, excluding service cost component, of defined benefit plan. Amount includes, but is not limited to, interest cost, expected (return) loss on plan asset, amortization of prior service cost (credit), amortization of (gain) loss, amortization of transition (asset) obligation, settlement (gain) loss, curtailment (gain) loss and certain termination benefits.
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Amount of income (expense) related to nonoperating activities, classified as other.
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Ancillary revenue earned during the period from the consideration paid to the entity for the use of its rights and property by another party. Examples include licensing the use of copyrighted materials and leasing the extraction of natural resources.
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