| Document and Entity Information Document | Feb. 01, 2021 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | Feb. 1, 2021 |
| Entity Registrant Name | VERTEX PHARMACEUTICALS INC / MA |
| Entity Central Index Key | 0000875320 |
| Amendment Flag | false |
| Entity Incorporation, State or Country Code | MA |
| Entity File Number | 000-19319 |
| Entity Tax Identification Number | 04-3039129 |
| Entity Address, Address Line One | 50 Northern Avenue |
| Entity Address, City or Town | Boston |
| Entity Address, State or Province | MA |
| Entity Address, Postal Zip Code | 02210 |
| City Area Code | 617 |
| Local Phone Number | 341-6100 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, $0.01 Par Value Per Share |
| Trading Symbol | VRTX |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
