| Cover | Nov. 25, 2020 | Nov. 02, 2020 |
| Cover [Abstract] | ||
| Document Type | 8-K | |
| Document Period End Date | Nov. 25, 2020 | |
| Entity Registrant Name | LABORATORY CORPORATION OF AMERICA HOLDINGS | |
| Entity Incorporation, State or Country Code | DE | |
| Entity File Number | 1-11353 | |
| Entity Tax Identification Number | 13-3757370 | |
| Entity Address, Address Line One | 358 South Main Street | |
| Entity Address, City or Town | Burlington, | |
| Entity Address, State or Province | NC | |
| Entity Address, Postal Zip Code | 27215 | |
| Local Phone Number | 229-1127 | |
| Written Communications | false | |
| Soliciting Material | false | |
| Pre-commencement Tender Offer | false | |
| Pre-commencement Issuer Tender Offer | false | |
| Title of 12(b) Security | Common Stock, $0.10 par value | |
| Trading Symbol | LH | |
| Amendment Flag | false | |
| Security Exchange Name | NYSE | |
| Entity Emerging Growth Company | false | |
| City Area Code | 336 | |
| Entity Central Index Key | 0000920148 |
