Long-Term Debt (Long-Term Debt) (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2022	Dec. 31, 2021
Debt Instrument [Line Items]
Less: Current Portion	$ (15)	$ (15)
Long-term debt	7,957	7,968
Long-term debt, fair value adjustment	236
Successor [Member]
Debt Instrument [Line Items]
Principal debt outstanding, beginning	7,777
Principal Payments and Retirements	(3)
Principal debt outstanding, ending	7,774
Less: Debt Issuance Costs	(13)	(13)
Less: Current Portion	(15)	(15)
Plus: Unamortized fair value adjustments	211	219
Long-term debt	7,957	$ 7,968
Successor [Member] \| Secured Debt Issued By Frontier [Member]
Debt Instrument [Line Items]
Principal debt outstanding, beginning	6,927
Principal Payments and Retirements	(3)
Principal debt outstanding, ending	6,924
Successor [Member] \| Secured Debt Issued By Subsidiaries [Member]
Debt Instrument [Line Items]
Principal debt outstanding, beginning	100
Principal debt outstanding, ending	100
Successor [Member] \| Unsecured Debt Issued By Subsidiaries [Member]
Debt Instrument [Line Items]
Principal debt outstanding, beginning	750
Principal debt outstanding, ending	750
Predecessor [Member]
Debt Instrument [Line Items]
Principal debt outstanding, beginning	$ 7,777

Debt Instrument Unamortized Fair Value Adjustment

No definition available.

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- Definition

Long Term Debt Fair Value Adjustment

+ References

No definition available.

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- Definition

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)(1)
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-Topic 942
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-Section S99
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-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878

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- 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

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- Definition

Amount of debt discount to be amortized within one year or within the normal operating cycle, if longer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 1A
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- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt, classified as current. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition

Amount after unamortized (discount) premium and debt issuance costs of long-term debt classified as noncurrent and excluding amounts to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition

The cash outflow during the period from the repayment of aggregate short-term and long-term debt. Excludes payment of capital lease obligations.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
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