| **Summary of Significant Accounting Policies (Details) (USD $)In Millions, unless otherwise specified** | 3 Months Ended | 9 Months Ended |
|---------------------------------------------------------------------------------------------------------|----------------|----------------|
||
| **Summary of Significant Accounting Policies [Abstract]**                                               |           |           |   |   |
| Customer surcharges                                                                                     | $ 29.0         | $ 24.5         | $ 87.5 | $ 78.7 |
| Number of reportable segments                                                                           |           |           | 1 |   |

| X                                                                                                                                                                                                                                                                                                               |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The amount of Universal Service Fund (USF) (primarily federal USF) surcharges collected from customers.
+ References
No definition available.
+ Details**Name:**ftr_CustomerSurcharges**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 |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                            |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Number of segments reported by the entity. A reportable segment is 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.
+ References
No definition available.
+ Details**Name:**us-gaap_NumberOfReportableSegments**Namespace Prefix:**us-gaap_**Data Type:**xbrli:integerItemType**Balance Type:**na**Period Type:**duration |