|**Basis of Presentation and Significant Accounting Policies (Policies)**                           | 3 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       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|**Organization, Consolidation and Presentation of Financial Statements [Abstract]**                |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   
|Basis of Presentation                                                                              | Basis of PresentationSee the Glossary of Defined Terms at the beginning of this Quarterly Report on Form 10-Q for terms used throughout the condensed consolidated financial statements and related notes in this Quarterly Report on Form 10-Q.We prepared the condensed consolidated financial statements following the requirements of the SEC for interim reporting. As permitted under those rules, certain footnotes or other financial information that are normally required by U.S. GAAP can be condensed or omitted.The financial information included in our condensed consolidated financial statements for subsidiaries operating outside the U.S. is as of and for thethree monthsendedFebruary 23, 2020andFebruary 24, 2019. The financial information included in our condensed consolidated financial statements for U.S. subsidiaries is as of and for thethree monthsendedMarch 29, 2020andMarch 31, 2019.Revenues, expenses, assets and liabilities can vary during each quarter of the year. Therefore, the results and trends in these interim financial statements may not be representative of those for the full year.We are responsible for the unaudited financial statements included in this Quarterly Report on Form 10-Q. The interim financial statements include all normal and recurring adjustments that are considered necessary for the fair statement of results for the interim periods presented. The information included in this Quarterly Report on Form 10-Q should be read in conjunction with the consolidated financial statements and accompanying notes included in our2019Financial Report.At the beginning of our 2019 fiscal year, we began to manage our commercial operations through a new global structure consisting ofthreebusiness segments––Pfizer Biopharmaceuticals Group (Biopharma), Upjohn and throughJuly 31, 2019, Consumer Healthcare. Biopharma and Upjohn are the only reportable segments. For additional information, seeNote 13.Beginning in 2020, Upjohn began managing our Meridian subsidiary, the manufacturer of EpiPen and other auto-injector products, and a pre-existing strategic collaboration between Pfizer and Mylan for generic drugs in Japan (Mylan-Japan).As a result, revenues and expenses associated with Meridian and Mylan-Japan are reported in our Upjohn business beginning in the first quarter of 2020. In 2019, revenues and expenses from Meridian and Mylan-Japan were recorded in our Biopharma business. We performed certain reclassifications between the Biopharma and Upjohn segments to conform 2019 segment revenues and expenses associated with Meridian and Mylan-Japan to the current presentation. There was no impact to our consolidated financial statements.For additional information, seeNote 13.As described in Notes to Consolidated Financial Statements—Note 1A. Basis of Presentation and Significant Accounting Policies: Basis of Presentationin our 2019 Financial Report, recent acquisitions and the contribution of our Consumer Healthcare business to the GSK Consumer Healthcare joint venture have impacted our results of operations. For additional information on the GSK Consumer Healthcare joint venture, seeNote 2.Certain amounts in the condensed consolidated financial statements and associated notes may not add due to rounding. All percentages have been calculated using unrounded amounts.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            
|Adoption of New Accounting Standards                                                               | Adoption of New Accounting Standards in 2020On January 1,2020, we adoptedfournew accounting standards.Credit Losses on Financial Instruments––We adopted a new accounting standard for credit losses on financial instruments, which replaces the probable initial recognition threshold for incurred loss estimates under prior guidance with a methodology that reflects expected credit loss estimates. The standard generally impacts financial assets that have a contractual right to receive cash and are not accounted for at fair value through net income, such as accounts receivable and held-to-maturity debt securities. The new guidance requires us to identify, analyze, document and support new methodologies for quantifying expected credit loss estimates for certain financial instruments, using information such as historical experience, current economic conditions and information, and the use of reasonable and supportable forecasted information. The standard alsoamends existing impairment guidance for available-for-sale debt securities to incorporate a credit loss allowance and allows for reversals of credit impairments in the event the issuer’s credit improves.We adopted the new accounting standard utilizing the modified retrospective method and, therefore, no adjustments were made to amounts in our prior period financial statements. The cumulative effect of adopting the standard as an adjustment to the opening balance ofRetained earningswas not material. The impact of adoption did not have a material impact on our condensed consolidated statement of income or condensed consolidated statement of cash flows for thethree monthsendedMarch 29, 2020, nor on our condensed consolidated balance sheet as ofMarch 29, 2020. For additional information, seeNote 1C.Goodwill Impairment Testing––We prospectively adopted the new standard, which eliminates the requirement to perform a hypothetical purchase price allocation to measure goodwill impairment. Under the new guidance, the goodwill impairment test is performed by comparing the fair value of a reporting unit with its carrying amount, and recognizing an impairment charge for the amount by which the carrying amount of the reporting unit exceeds its fair value. There was no impact to our condensed consolidated financial statements from the adoption of this new standard.Implementation Costs in a Cloud Computing Arrangement––We prospectively adopted the new standard related to customers’ accounting for implementation costs incurred in a cloud computing arrangement that is considered a service contract. The new guidance aligns the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software. The adoption of this guidance did not have a material impact on our condensed consolidated financial statements.Collaboration Agreements––We prospectively adopted the new standard, which provides new guidance clarifying the interaction between the accounting for collaborative arrangements and revenue from contracts with customers. There was no impact to our condensed consolidated financial statements from the adoption of this new standard.On January 1, 2019, we adoptedfournew accounting standards. For additional information, see Notes to Consolidated Financial Statements––Note 1B. Basis of Presentation and Significant Accounting Policies: Adoption of New Accounting Standards in 2019included in our 2019 Financial Report.C. Revenues and Trade Accounts ReceivableDeductions from Revenues––Our accruals for Medicare rebates, Medicaid and related state program rebates, performance-based contract rebates, chargebacks, sales allowances and sales returns and cash discounts totaled$5.6 billionas ofMarch 29, 2020and$5.7 billionas ofDecember 31, 2019.The following table provides information about the balance sheet classification of these accruals:(MILLIONS OF DOLLARS)March 29, 2020December 31, 2019Reserve againstTrade accounts receivable, less allowance for doubtful accounts$1,107$1,257Other current liabilities:Accrued rebates3,4083,285Other accruals553581Other noncurrent liabilities577565Total accrued rebates and other accruals$5,645$5,689Trade Accounts Receivable––Trade accounts receivable are stated at their net realizable value. The allowance for credit losses against gross trade accounts receivable reflects the best estimate of expected credit losses of the receivables portfolio determined on the basis of historical experience, current information, and forecasts of future economic conditions. In developing the estimate for expected credit losses, trade accounts receivables are segmented into pools of assets depending on market (U.S. versus international), delinquency status, and customer type (high risk versus low risk and government versus non-government), and fixed reserve percentages are established for each pool of trade accounts receivables.In determining the reserve percentages for each pool of trade accounts receivables, we considered our historical experience with certain customers and customer types, regulatory and legal environments, country and political risk, and other relevant current and future forecasted macroeconomic factors. These credit risk indicators are monitored on a quarterly basis to determine whether there have been any changes in the economic environment that would indicate the established reserve percentages should be adjusted, and are considered on a regional basis to reflect more geographic-specific metrics. Additionally, write-offs and recoveries of customer receivables are tracked against collections on a quarterly basis to determine whether the reserve percentages remain appropriate. When management becomes aware of certain customer-specific factors that impact credit risk,specific allowances for these known troubled accounts are recorded. Trade accounts receivable are written off after all reasonable means to collect the full amount (including litigation, where appropriate) have been exhausted.During thefirst quarterof2020, additions to the allowance for credit losses, write-offs and recoveries of customer receivables were not material to our condensed consolidated financial statements.
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                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      
|The following table provides information about the balance sheet classification of these accruals:
|(MILLIONS OF DOLLARS)                                                                              |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   
|Reserve againstTrade accounts receivable, less allowance for doubtful accounts                     |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   
|Other current liabilities:                                                                         |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   
|Accrued rebates                                                                                    |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   
|Other accruals                                                                                     |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   
|Other noncurrent liabilities                                                                       |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   
|Total accrued rebates and other accruals                                                           |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   

X- DefinitionDisclosure of accounting policy for basis of accounting, or basis of presentation, used to prepare the financial statements (for example, US Generally Accepted Accounting Principles, Other Comprehensive Basis of Accounting, IFRS).
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