| Document and Entity Information | Dec. 09, 2019 |
| Cover [Abstract] | |
| Entity Registrant Name | CENTURYLINK, INC |
| Amendment Flag | false |
| Entity Central Index Key | 0000018926 |
| Document Type | 8-K |
| Document Period End Date | Dec. 9, 2019 |
| Entity Incorporation State Country Code | LA |
| Entity File Number | 001-7784 |
| Entity Tax Identification Number | 72-0651161 |
| Entity Address, Address Line One | 100 CenturyLink Drive |
| Entity Address, City or Town | Monroe |
| Entity Address, State or Province | LA |
| Entity Address, Postal Zip Code | 71203 |
| City Area Code | (318) |
| Local Phone Number | 388-9000 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Security 12b Title | Common Stock, par value $1.00 per share |
| Trading Symbol | CTL |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
