| Cover | Apr. 19, 2021 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Apr. 19, 2021 |
| Entity File Number | 000-26301 |
| Entity Registrant Name | United Therapeutics Corporation |
| Entity Central Index Key | 0001082554 |
| Entity Tax Identification Number | 52-1984749 |
| Entity Incorporation, State or Country Code | DE |
| Entity Address, Address Line One | 1040 Spring Street |
| Entity Address, City or Town | Silver Spring |
| Entity Address, State or Province | MD |
| Entity Address, Postal Zip Code | 20910 |
| City Area Code | 301 |
| Local Phone Number | 608-9292 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, par value $0.01 per share |
| Trading Symbol | UTHR |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
