Commercial Mortgage Loans, Percentage of Investments

No definition available.

Name:	fnf_CommercialMortgageLoansPercentageOfInvestments
Namespace Prefix:	fnf_
Data Type:	dtr-types1:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Debt Securities, Available-For-Sale, Unrealized Loss Position, Allowance For Credit Loss, Excluding Accrued Interest

+ References

No definition available.

+ Details

Name:	fnf_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAllowanceForCreditLossExcludingAccruedInterest
Namespace Prefix:	fnf_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Debt Service Coverage Ratio, Amortization Period

+ References

No definition available.

+ Details

Name:	fnf_DebtServiceCoverageRatioAmortizationPeriod
Namespace Prefix:	fnf_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Financing Receivable, Allowance For Credit Loss, Probability of Loss, Default Model, Projected Loss, Using Reasonable And Supportable Forecast Period

+ References

No definition available.

+ Details

Name:	fnf_FinancingReceivableAllowanceForCreditLossProbabilityOfLossDefaultModelProjectedLossUsingReasonableAndSupportableForecastPeriod
Namespace Prefix:	fnf_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Financing Receivable, Allowance For Credit Loss, Probability of Projected Loss, Default, Projection Model, Using Market Historical Loss, Period

+ References

No definition available.

+ Details

Name:	fnf_FinancingReceivableAllowanceForCreditLossProbabilityOfProjectedLossDefaultProjectionModelUsingMarketHistoricalLossPeriod
Namespace Prefix:	fnf_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Number Of Mortgage Loans Delinquent In Principal Or Interest

+ References

No definition available.

+ Details

Name:	fnf_NumberOfMortgageLoansDelinquentInPrincipalOrInterest
Namespace Prefix:	fnf_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Reinsurance Agreement, Recognized Gains (Losses)

+ References

No definition available.

+ Details

Name:	fnf_ReinsuranceAgreementRecognizedGainsLosses
Namespace Prefix:	fnf_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Residential Mortgage Loans, Location Percentage

+ References

No definition available.

+ Details

Name:	fnf_ResidentialMortgageLoansLocationPercentage
Namespace Prefix:	fnf_
Data Type:	dtr-types1:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of the total residential loan portfolio

+ References

No definition available.

+ Details

Name:	fnf_ResidentialMortgageReceivablePercentageofTotal
Namespace Prefix:	fnf_
Data Type:	dtr-types1:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Carrying amount of cash and investment securities on deposit with state regulatory authorities in connection with capital requirements.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 825
-Name Accounting Standards Codification
-Section 50
-Paragraph 1A
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479383/944-825-50-1A

+ Details

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

- Definition

Amount, after allowance for credit loss, of accrued interest on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2A
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-2A

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479130/326-30-45-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 3A
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479106/326-30-50-3A

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 3B
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479106/326-30-50-3B

+ Details

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

- Definition

Amount excluding accrued interest, of allowance for credit loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479130/326-30-45-1

+ Details

Name:	us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostAllowanceForCreditLossExcludingAccruedInterest
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount at purchase price of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), purchased with credit deterioration.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 10
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479106/326-30-50-10

+ Details

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

- Definition

Amount of the collateral pledged in support of federal home loan bank advances outstanding.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 942
-SubTopic 470
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480876/942-470-45-1

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480848/942-470-50-3

+ Details

Name:	us-gaap_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresCollateralPledged1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amortized cost excluding accrued interest, of financing receivable on nonaccrual status. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 16
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479319/326-20-50-16

+ Details

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

- Definition

Amount, before investment expense, of income earned from investments in securities and real estate. Includes, but is not limited to, real estate investment, policy loans, dividends, and interest. Excludes realized gain (loss) on investments.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 946
-SubTopic 830
-Name Accounting Standards Codification
-Section 55
-Paragraph 10
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480167/946-830-55-10

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(2)(b))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483586/944-220-S99-1

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-07(1))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483575/946-220-S99-1

+ Details

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

- Definition

Recorded investment of consumer mortgage loan receivables secured by residential real estate properties for which formal foreclosure proceedings are in process.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 35
-SubTopic 10
-Topic 310
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481962/310-10-50-35

+ Details

Name:	us-gaap_MortgageLoansInProcessOfForeclosureAmount
Namespace Prefix:	us-gaap_
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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-2

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (aa)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-2

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (aaa)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-2

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-2

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-2

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-2

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-3

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-3

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-3

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-3

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-3

+ Details

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

- Details

Name:	us-gaap_InvestmentTypeAxis=fnf_FundsWithheldReinsuranceAgreementsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementGeographicalAxis=country_US
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis=fnf_MortgageLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ResidentialPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_DebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Investments - Narrative (Details)	3 Months Ended		9 Months Ended
Investments - Narrative (Details)	Sep. 30, 2023 USD ($) loan	Sep. 30, 2022 USD ($)	Sep. 30, 2023 USD ($) loan	Sep. 30, 2022 USD ($)	Dec. 31, 2022 USD ($) loan
Debt Securities, Available-for-sale [Line Items]
Accrued interest receivable	$ 474,000,000		$ 474,000,000		$ 365,000,000
FHLB collateral pledged	3,840,000,000		3,840,000,000		3,387,000,000
Fixed maturity securities, available-for-sale securities, allowance for credit losses	44,000,000		44,000,000		39,000,000
Purchases of PCD AFS securities			0	$ 0
Allowance for credit loss for securities in an unrealized loss position	$ 0		$ 0
DSC ratio, amortization period			25 years
Mortgage loans delinquent in principal or interest \| loan	1		1
Amortized cost of loans on non-accrual	$ 76,000,000		$ 76,000,000		$ 71,000,000
Gross investment income	749,000,000	$ 461,000,000	2,103,000,000	1,497,000,000
Reinsurance agreement, recognized gains (losses)	43,000,000	105,000,000	42,000,000	384,000,000
Funds Withheld, Reinsurance Agreements
Debt Securities, Available-for-sale [Line Items]
Gross investment income	$ 102,000,000	$ 29,000,000	$ 236,000,000	$ 67,000,000
United States
Debt Securities, Available-for-sale [Line Items]
Residential mortgage loans, location percentage			100.00%
Commercial mortgage loans
Debt Securities, Available-for-sale [Line Items]
Commercial mortgage loans, percentage of investments	6.00%		6.00%		6.00%
Mortgage loans delinquent in principal or interest \| loan					1
Amortized cost of loans on non-accrual	$ 9,000,000		$ 9,000,000		$ 9,000,000
Commercial mortgage loans \| Mortgage loans
Debt Securities, Available-for-sale [Line Items]
Allowance for expected credit loss, probability of loss/default model, projected loss, using reasonable forecast period			2 years
Allowance for credit loss, probability of loss/default, using market historical loss experience, period			3 years
Residential mortgage loans
Debt Securities, Available-for-sale [Line Items]
Residential mortgage loans, percentage of total investments	6.00%		6.00%		5.00%
Amortized cost of loans on non-accrual	$ 67,000,000		$ 67,000,000		$ 62,000,000
Loans in process of foreclosure	37,000,000		$ 37,000,000		38,000,000
Residential mortgage loans \| Mortgage loans
Debt Securities, Available-for-sale [Line Items]
Allowance for expected credit loss, probability of loss/default model, projected loss, using reasonable forecast period			2 years
Allowance for credit loss, probability of loss/default, using market historical loss experience, period			3 years
Fixed maturity securities, available-for-sale
Debt Securities, Available-for-sale [Line Items]
Assets held by insurance regulators	$ 141,000,000		$ 141,000,000		$ 17,870,000,000