| Document and Entity Information - USD ($) $ in Millions | Dec. 31, 2020 | Feb. 26, 2021 | Jun. 30, 2020 |
| Cover [Abstract] | |||
| Document Type | 10-K/A | ||
| Amendment Flag | true | ||
| Amendment Description | Amendment No. 1 | ||
| Document Period End Date | Dec. 31, 2020 | ||
| Current Fiscal Year End Date | --12-31 | ||
| Document Transition Report | false | ||
| Entity Registrant Name | FRONTIER COMMUNICATIONS CORP | ||
| Entity Incorporation, State or Country Code | DE | ||
| Entity File Number | 001-11001 | ||
| Entity Tax Identification Number | 06-0619596 | ||
| Entity Address, Address Line One | 401 MERRITT 7 | ||
| Entity Address, City or Town | NORWALK | ||
| Entity Address, State or Province | CT | ||
| Entity Address, Postal Zip Code | 06851 | ||
| City Area Code | 203 | ||
| Local Phone Number | 614-5600 | ||
| No Trading Symbol Flag | true | ||
| Entity Well-known Seasoned Issuer | No | ||
| Entity Voluntary Filers | No | ||
| Entity Filer Category | Non-accelerated Filer | ||
| Entity Current Reporting Status | Yes | ||
| Entity Interactive Data Current | Yes | ||
| Entity Emerging Growth Company | false | ||
| Entity Shell Company | false | ||
| Entity Small Business | true | ||
| Entity Public Float | $ 10.5 | ||
| Entity Common Stock, Shares Outstanding | 104,778,943 | ||
| Document Fiscal Year Focus | 2020 | ||
| Document Fiscal Period Focus | FY | ||
| Entity Central Index Key | 0000020520 | ||
| Document Annual Report | true | ||
| Title of 12(b) Security | Common Stock, par value $0.25 per share |
