XML 105 R93.htm IDEA: XBRL DOCUMENT
v3.24.0.1

Mortgage Servicing Rights - Summary of Adverse Changes to Weighted-Average Assumptions on the Fair Value of Servicing Rights (Details) - USD ($) | 12 Months Ended
--- | ---
Dec. 31, 2023 | Dec. 31, 2022
Actual |  |
Option adjusted spread (percent) | 5.40% | 5.90%
Constant prepayment rate (as a percent) | 7.90% | 7.90%
Weighted average cost to service (per loan) | $ 69 | $ 68
10% adverse change |  |
Option adjusted spread (percent) | 1,091,000,000 | 1,012,000,000
Constant prepayment rate (as a percent) | 1,073,000,000 | 1,000,000,000
Weighted average cost to service per loan | 1,100,000,000 | 1,023,000,000
20% adverse change |  |
Option adjusted spread (percent) | 1,072,000,000 | 992,000,000
Constant prepayment rate (as a percent) | 1,040,000,000 | 970,000,000
Weighted average cost to service per loan | $ 1,090,000,000 | $ 1,013,000,000

X
- Definition Sensitivity Analysis, Actual [Abstract] + References No definition available. + Details
Name: | fbc_SensitivityAnalysisActualAbstract
Namespace Prefix: | fbc_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Sensitivity Analysis, Adverse Change, Tranche 1 [Abstract] + References No definition available. + Details
Name: | fbc_SensitivityAnalysisAdverseChangeTranche1Abstract
Namespace Prefix: | fbc_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Sensitivity Analysis, Adverse Change, Tranche 2 [Abstract] + References No definition available. + Details
Name: | fbc_SensitivityAnalysisAdverseChangeTranche2Abstract
Namespace Prefix: | fbc_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Sensitivity Analysis of Fair Values, Transferor's Interests in Transferred Financial Assets, Impact of Other than 10 or 20 Percent Adverse Change in Other Assumption, Per Loan + References No definition available. + Details
Name: | fbc_SensitivityAnalysisOfFairValuesTransferorsInterestsInTransferredFinancialAssetsImpactOfOtherThan10Or20PercentAdverseChangeInOtherAssumptionPerLoan
Namespace Prefix: | fbc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Sensitivity Analysis of Fair Value, Transferor's Interests in Transferred Financial Assets, Impact of 10 Percent Adverse Change in Option Adjusted Spread + References No definition available. + Details
Name: | fbc_SensitivityAnalysisofFairValueTransferorsInterestsinTransferredFinancialAssetsImpactof10PercentAdverseChangeinOptionAdjustedSpread
Namespace Prefix: | fbc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Sensitivity Analysis of Fair Value, Transferor's Interests in Transferred Financial Assets, Impact of 20 Percent Adverse Change in Option Adjusted Spread + References No definition available. + Details
Name: | fbc_SensitivityAnalysisofFairValueTransferorsInterestsinTransferredFinancialAssetsImpactof20PercentAdverseChangeinOptionAdjustedSpread
Namespace Prefix: | fbc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Sensitivity Analysis of Fair Value, Transferor's Interests in Transferred Financial Assets, Impact of Other than 10 or 20 Percent Adverse Change in Option Adjusted Spread, Percent + References No definition available. + Details
Name: | fbc_SensitivityAnalysisofFairValueTransferorsInterestsinTransferredFinancialAssetsImpactofOtherthan10or20PercentAdverseChangeinOptionAdjustedSpreadPercent
Namespace Prefix: | fbc_
Data Type: | dtr-types1:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition The hypothetical financial impact of a 10 percent adverse change of the specified assumption on the fair value of transferor's interests in transferred financial assets (including any servicing assets or servicing liabilities) as of the balance sheet date. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 860 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481326/860-20-50-4 + Details
Name: | us-gaap_SensitivityAnalysisOfFairValueOfInterestsContinuedToBeHeldByTransferorServicingAssetsOrLiabilitiesImpactOf10PercentAdverseChangeInOtherAssumption
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The hypothetical financial impact of a 10 percent adverse change of prepayment speed on the fair value of transferor's interests in transferred financial assets (including any servicing assets or servicing liabilities) as of the balance sheet date. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 860 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481326/860-20-50-4 + Details
Name: | us-gaap_SensitivityAnalysisOfFairValueOfInterestsContinuedToBeHeldByTransferorServicingAssetsOrLiabilitiesImpactOf10PercentAdverseChangeInPrepaymentSpeed
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The hypothetical financial impact of a 20 percent adverse change of the specified assumption on the fair value of transferor's interests in transferred financial assets (including any servicing assets or servicing liabilities) as of the balance sheet date. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 860 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481326/860-20-50-4 + Details
Name: | us-gaap_SensitivityAnalysisOfFairValueOfInterestsContinuedToBeHeldByTransferorServicingAssetsOrLiabilitiesImpactOf20PercentAdverseChangeInOtherAssumption
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The hypothetical financial impact of a 20 percent adverse change of prepayment speed on the fair value of transferor's interests in transferred financial assets (including any servicing assets or servicing liabilities) as of the balance sheet date. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 860 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481326/860-20-50-4 + Details
Name: | us-gaap_SensitivityAnalysisOfFairValueOfInterestsContinuedToBeHeldByTransferorServicingAssetsOrLiabilitiesImpactOf20PercentAdverseChangeInPrepaymentSpeed
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition A specified percentage variance in the prepayment speed assumption in the determination of fair value of transferor's interests in transferred financial assets (including any servicing assets or servicing liabilities). + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 860 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481326/860-20-50-4 + Details
Name: | us-gaap_SensitivityAnalysisOfFairValueOfInterestsContinuedToBeHeldByTransferorServicingAssetsOrLiabilitiesImpactOfOtherThan10Or20PercentAdverseChangeInPrepaymentSpeedPercent
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration