Business Combination, Acquisition Related Costs, Acceleration Of Costs Due To Termination Of Merger, Percentage

No definition available.

Name:	fron_BusinessCombinationAcquisitionRelatedCostsAccelerationOfCostsDueToTerminationOfMergerPercentage
Namespace Prefix:	fron_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Business Combination, Acquisition Related Costs, Expense To Be Paid By Acquiree Upon Termination Of Agreement

+ References

No definition available.

+ Details

Name:	fron_BusinessCombinationAcquisitionRelatedCostsExpenseToBePaidByAcquireeUponTerminationOfAgreement
Namespace Prefix:	fron_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Business Combination, Contingent Fee To Be Paid By Acquiree Upon Termination Of Agreement

+ References

No definition available.

+ Details

Name:	fron_BusinessCombinationContingentFeeToBePaidByAcquireeUponTerminationOfAgreement
Namespace Prefix:	fron_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- 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

No definition available.

+ Details

Name:	us-gaap_BusinessAcquisitionLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

This element represents acquisition-related costs incurred to effect a business combination which costs have been expensed during the period. Such costs include finder's fees; advisory, legal, accounting, valuation, and other professional or consulting fees; general administrative costs, including the costs of maintaining an internal acquisitions department; and may include costs of registering and issuing debt and equity securities.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 25
-Paragraph 23
-URI https://asc.fasb.org/extlink&oid=123586518&loc=d3e1043-128460

+ Details

Name:	us-gaap_BusinessCombinationAcquisitionRelatedCosts
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Sum of the carrying amounts as of the balance sheet date of deferred costs capitalized at the end of the reporting period that are expected to be charged against earnings within one year or the normal operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(8))
-URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

Name:	us-gaap_DeferredCostsCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The increase (decrease) during the reporting period in the value of expenditures made during the current reporting period for benefits that will be received over a period of years. Deferred charges differ from prepaid expenses in that they usually extend over a long period of time and may or may not be regularly recurring costs of operation.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3602-108585

+ Details

Name:	us-gaap_IncreaseDecreaseInDeferredCharges
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	us-gaap_BusinessAcquisitionAxis=fron_SpiritAirlinesIncMergerMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementScenarioAxis=srt_ScenarioForecastMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	fron_BusinessCombinationAcquisitionRelatedCostsAxis=fron_LegalAccountingAndOtherFeesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	fron_BusinessCombinationAcquisitionRelatedCostsAxis=fron_RetentionBonusMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	fron_BusinessCombinationAcquisitionRelatedCostsAxis=fron_EmployeeRetentionCostsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

The Proposed Merger with Spirit Airlines, Inc. (Details) - USD ($) $ in Millions		3 Months Ended			6 Months Ended
	Jul. 27, 2022	Sep. 30, 2022	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Business Acquisition [Line Items]
Transaction and merger-related costs			$ 9	$ 0	$ 20	$ 0
Spirit Airlines, Inc Merger
Business Acquisition [Line Items]
Transaction and merger-related costs			9		20
Capitalized costs incurred			2		2
Forecast \| Spirit Airlines, Inc Merger
Business Acquisition [Line Items]
Write-off of the capitalized deferred equity issuance costs	$ (2)
Merger-related expenses upon termination of agreement		$ 25
Termination fee	$ 69
Legal, Accounting and Other Fees \| Spirit Airlines, Inc Merger
Business Acquisition [Line Items]
Transaction and merger-related costs			4		12
Retention Bonus \| Spirit Airlines, Inc Merger
Business Acquisition [Line Items]
Transaction and merger-related costs			$ 5		$ 8
Employee Retention Costs \| Forecast \| Spirit Airlines, Inc Merger
Business Acquisition [Line Items]
Transaction and merger-related costs		$ 9
Acceleration of merger retention costs		50.00%