| Cover Page | Apr. 28, 2020 |
| Entity Information [Line Items] | |
| Document Type | 8-K |
| Document Period End Date | Apr. 28, 2020 |
| Entity Registrant Name | PFIZER INC |
| Entity Incorporation, State or 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, Postal Zip Code | 10017 |
| Entity Address, City or Town | New York, |
| Entity Address, State or Province | NY |
| 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 |
| Amendment Flag | false |
| Entity Central Index Key | 0000078003 |
| Common Stock [Member] | |
| Entity Information [Line Items] | |
| Title of 12(b) Security | Common Stock, $.05 par value |
| Trading Symbol | PFE |
| Security Exchange Name | NYSE |
| Notes Due 2022, 0.250% [Member] | |
| Entity Information [Line Items] | |
| Title of 12(b) Security | 0.250% Notes due 2022 |
| Trading Symbol | PFE22 |
| Security Exchange Name | NYSE |
| Notes Due 2027, 1.000% [Member] | |
| Entity Information [Line Items] | |
| Title of 12(b) Security | 1.000% Notes due 2027 |
| Trading Symbol | PFE27 |
| Security Exchange Name | NYSE |
