XML 108 R80.htm IDEA: XBRL DOCUMENT
v3.25.4

Commitments and Contingencies - Schedule of Collective Bargaining Agreements (Details) - USD ($) $ in Millions |  |  | 12 Months Ended |
--- | --- | --- | --- | ---
Dec. 10, 2025 | Nov. 07, 2025 | Dec. 31, 2025 | Dec. 31, 2024
Multiemployer Plan [Line Items] |  |  |  |
Amount of employees represented by unions |  |  | 86.00% |
Accrued liabilities for health care claims |  |  | $ 7 | $ 6
Pilots |  |  |  |
Multiemployer Plan [Line Items] |  |  |  |
Amount of employees represented by unions |  |  | 29.00% |
Flight Attendants |  |  |  |
Multiemployer Plan [Line Items] |  |  |  |
Amount of employees represented by unions |  |  | 48.00% |
Aircraft Technicians |  |  |  |
Multiemployer Plan [Line Items] |  |  |  |
Amount of employees represented by unions |  |  | 6.00% |
Aircraft Appearance Agents |  |  |  |
Multiemployer Plan [Line Items] |  |  |  |
Amount of employees represented by unions |  |  | 1.00% |
Dispatchers |  |  |  |
Multiemployer Plan [Line Items] |  |  |  |
Amount of employees represented by unions |  |  | 1.00% |
Material Specialists |  |  |  |
Multiemployer Plan [Line Items] |  |  |  |
Contract term (in years) |  | 5 years |  |
Maintenance Controllers |  |  |  |
Multiemployer Plan [Line Items] |  |  |  |
Amount of employees represented by unions |  |  | 1.00% |
Contract term (in years) | 5 years |  |  |

X
- Definition Multiemployer Plan, Contract Term + References No definition available. + Details
Name: | fron_MultiemployerPlanContractTerm
Namespace Prefix: | fron_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of entity's employees covered by collective-bargaining arrangement (CBA) to all entity's employees in multiemployer pension plan determined to be individually significant. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 715 -SubTopic 80 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480576/715-80-50-5 + Details
Name: | us-gaap_MultiemployerPlanPensionSignificantEmployeesCoveredByCollectiveBargainingArrangementToAllEntitysEmployeesPercentage
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 715 -SubTopic 80 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480576/715-80-50-6 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Topic 715 -SubTopic 80 -Name Accounting Standards Codification -Section 50 -Paragraph 11 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480576/715-80-50-11 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 80 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480576/715-80-50-5 Reference 4: http://www.xbrl.org/2003/role/exampleRef -Topic 715 -SubTopic 80 -Name Accounting Standards Codification -Section 50 -Paragraph 11 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480576/715-80-50-11 Reference 5: http://www.xbrl.org/2003/role/exampleRef -Topic 715 -SubTopic 80 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480576/715-80-50-6 Reference 6: http://www.xbrl.org/2003/role/exampleRef -Topic 715 -SubTopic 80 -Name Accounting Standards Codification -Section 50 -Paragraph 11 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480576/715-80-50-11 Reference 7: http://www.xbrl.org/2003/role/exampleRef -Topic 715 -SubTopic 80 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480576/715-80-50-6 Reference 8: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 80 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (f)(3) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480576/715-80-50-5 Reference 9: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 80 -Name Accounting Standards Codification -Section 50 -Paragraph 11 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480576/715-80-50-11 Reference 10: http://www.xbrl.org/2003/role/exampleRef -Topic 715 -SubTopic 80 -Name Accounting Standards Codification -Section 55 -Paragraph 8 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480547/715-80-55-8 Reference 11: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 80 -Name Accounting Standards Codification -Section 35 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480606/715-80-35-1 Reference 12: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 80 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480576/715-80-50-5 Reference 13: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 80 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480576/715-80-50-5 Reference 14: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 80 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480576/715-80-50-5 Reference 15: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 80 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (e)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480576/715-80-50-5 Reference 16: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 80 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (e)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480576/715-80-50-5 Reference 17: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 80 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (f)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480576/715-80-50-5 Reference 18: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 80 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (f)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480576/715-80-50-5 Reference 19: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 80 -Name Accounting Standards Codification -Section 50 -Paragraph 9 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480576/715-80-50-9 + Details
Name: | us-gaap_MultiemployerPlansLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Carrying amount (including both current and noncurrent portions) of accrued known and estimated losses incurred as of the balance sheet date for which no insurance coverage exists, and for which a claim has been made or is probable of being asserted, typically arising from workmen's compensation-type of incidents and personal injury to nonemployees from accidents on the entity's property. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(24)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 + Details
Name: | us-gaap_SelfInsuranceReserve
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | us-gaap_CollectiveBargainingArrangementAxis=fron_CollectiveBargainingArrangementEmployeeGroupPilotsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CollectiveBargainingArrangementAxis=fron_CollectiveBargainingArrangementEmployeeGroupFlightAttendantsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CollectiveBargainingArrangementAxis=fron_CollectiveBargainingArrangementEmployeeGroupAircraftTechniciansMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CollectiveBargainingArrangementAxis=fron_CollectiveBargainingArrangementEmployeeGroupAircraftAppearanceMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CollectiveBargainingArrangementAxis=fron_CollectiveBargainingArrangementEmployeeGroupDispatchersMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CollectiveBargainingArrangementAxis=fron_CollectiveBargainingArrangementEmployeeGroupMaterialSpecialistsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CollectiveBargainingArrangementAxis=fron_CollectiveBargainingArrangementEmployeeGroupMaintenanceControllersMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |