| **Summary of Significant Accounting Policies (Details) (USD $)In Millions, unless otherwise specified**         | 3 Months Ended | 9 Months Ended |
|-----------------------------------------------------------------------------------------------------------------|----------------|----------------|
||
| **Summary of Significant Accounting Policies [Abstract]**                                                       |           |           |   |   |
| Universal Service Fund (USF) surcharges from customers (primarily federal USF) included in revenue and expenses | $ 24.5         | $ 26.9         | $ 78.7 | $ 48.7 |
| Number of operating segments                                                                                    | 6              |           | 6 |   |
| Number of reportable segment                                                                                    | 1              |           | 1 |   |

| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
An operating segment is a component of an enterprise: (a) that engages in business activities from which it may earn revenues and incur expenses (including revenues and expenses relating to transactions with other components of the same enterprise), (b) whose operating results are regularly reviewed by the enterprise's chief operating decision maker to make decisions about resources to be allocated to the segment and assess its performance, and (c) for which discrete financial information is available.
+ Details**Name:**ftr_NumberOfOperatingSegments**Namespace Prefix:**ftr**Data Type:**xbrli:integerItemType**Balance Type:**na**Period Type:**instant |
| X                                                                                                                                                                                                                                                                                                                                         |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
A component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.
+ Details**Name:**ftr_NumberOfReportableSegments**Namespace Prefix:**ftr**Data Type:**xbrli:integerItemType**Balance Type:**na**Period Type:**instant |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                    |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Universal Service Fund (USF) surcharges collected from customers (primarily federal USF) which is recorded on a gross basis in consolidated statements of operations and included in revenue and other operating expenses.
+ Details**Name:**ftr_UniversalServiceFundUsfSurchargeIcludedInRevenueAndExpenses**Namespace Prefix:**ftr**Data Type:**xbrli:monetaryItemType**Balance Type:**credit**Period Type:**duration |
| X                                                                                                                                                             |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_AccountingPoliciesAbstract**Namespace Prefix:**us-gaap**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |