| Document and Entity Information | May 18, 2020 |
| Document And Entity Information [Line Items] | |
| Entity Registrant Name | PFIZER INC |
| Amendment Flag | false |
| Entity Central Index Key | 0000078003 |
| Document Type | 8-K |
| Document Period End Date | May 18, 2020 |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 1-3619 |
| Entity Tax Identification Number | 13-5315170 |
| Entity Address, Address Line One | 235 East 42nd Street |
| Entity Address, City or Town | New York |
| Entity Address, State or Province | NY |
| Entity Address, Postal Zip Code | 10017 |
| City Area Code | (212) |
| Local Phone Number | 733-2323 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Common Stock [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | Common Stock, $.05 par value |
| Trading Symbol | PFE |
| Security Exchange Name | NYSE |
| Notes Due 20220.250 [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | 0.250% Notes due 2022 |
| Trading Symbol | PFE22 |
| Security Exchange Name | NYSE |
| Notes Due 20271.000 [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | 1.000% Notes due 2027 |
| Trading Symbol | PFE27 |
| Security Exchange Name | NYSE |
