Alternative investments as a percentage of overall invested assets.

No definition available.

Name:	lnc_AlternativeInvestmentsAsPercentageOfOverallInvestedAssets
Namespace Prefix:	lnc_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amortized cost of portfolio rated below investment grade.

+ References

No definition available.

+ Details

Name:	lnc_AmortizedCostOfPortfolioRatedBelowInvestmentGrade
Namespace Prefix:	lnc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

This item represents the change in gross unrealized holding gain or loss on available-for-sale securities that has been included in accumulated other comprehensive income, a separate component of shareholders' equity, during the period.

+ References

No definition available.

+ Details

Name:	lnc_AvailableForSaleSecuritiesChangeInGrossUnrealizedHoldingGainLoss
Namespace Prefix:	lnc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Percentage of the fair value of portfolio that was rated investment grade as of balance sheet date.

+ References

No definition available.

+ Details

Name:	lnc_AvailableForSaleSecuritiesFairValueDisclosurePercentInvestmentGrade
Namespace Prefix:	lnc_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Fair value of portfolio rated below investment grade.

+ References

No definition available.

+ Details

Name:	lnc_FairValueOfPortfolioRatedBelowInvestmentGrade
Namespace Prefix:	lnc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Debt-service coverage ratio threshold indicating property operations do not generate enough income to cover payments.

+ References

No definition available.

+ Details

Name:	lnc_FinancingReceivableCreditQuailtyIndicatorDebtServiceCoverageRatioThreshold
Namespace Prefix:	lnc_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	duration

- Definition

Financing receivable, Number of loans past due

+ References

No definition available.

+ Details

Name:	lnc_FinancingReceivableNumberOfLoansPastDue
Namespace Prefix:	lnc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage threshold of loan-to-value ratios indicating principal is greater than collateral value.

+ References

No definition available.

+ Details

Name:	lnc_FinancingReceivablePercentageThresholdOfLoanToValueRatioQualityIndicator
Namespace Prefix:	lnc_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Impaired financing receivable, number of impaired loans

+ References

No definition available.

+ Details

Name:	lnc_ImpairedFinancingReceivableNumberOfImpairedLoans
Namespace Prefix:	lnc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Impaired Financing Receivable, Related Allowance, Increase (decrease)

+ References

No definition available.

+ Details

Name:	lnc_ImpairedFinancingReceivableRelatedAllowanceIncreaseDecrease
Namespace Prefix:	lnc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

This item represents total investment commitments as of the balance sheet date for fixed maturity available-for-sale securities, limited partnerships, real estate and mortgage loans on real estate.

+ References

No definition available.

+ Details

Name:	lnc_InvestmentCommitments
Namespace Prefix:	lnc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

This item represents investment commitments as of the balance sheet date for limited partnerships.

+ References

No definition available.

+ Details

Name:	lnc_InvestmentCommitmentsLimitedPartnerships
Namespace Prefix:	lnc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

This item represents investment commitments as of the balance sheet date for private placements.

+ References

No definition available.

+ Details

Name:	lnc_InvestmentCommitmentsLimitedPrivatePlacements
Namespace Prefix:	lnc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

This item represents investment commitments as of the balance sheet date for mortgage loans.

+ References

No definition available.

+ Details

Name:	lnc_InvestmentCommitmentsMortgageLoans
Namespace Prefix:	lnc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Investments [Line Items]

+ References

No definition available.

+ Details

Name:	lnc_InvestmentsLineItems
Namespace Prefix:	lnc_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of partnerships represented in alternative investment portfolio.

+ References

No definition available.

+ Details

Name:	lnc_NumberOfPartnershipsInAlternativeInvestmentPortfolio
Namespace Prefix:	lnc_
Data Type:	xbrli:positiveIntegerItemType
Balance Type:	na
Period Type:	instant

- Definition

This item represents the loss severity as a percentage of first lien loans that was considered as one of the potential factors in reaching a conclusion that the available-for-sale investments are other than temporarily impaired and the amount of such impairment determined to be related to credit loss recognized in earnings.

+ References

No definition available.

+ Details

Name:	lnc_SeverityOfFirstLienLoansAssumedMimimumPercent
Namespace Prefix:	lnc_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

This item represents the loss severity as a percentage of defaulted second lien loans that was considered as one of the potential factors in reaching a conclusion that the available-for-sale investments are other than temporarily impaired and the amount of such impairment determined to be related to credit loss recognized in earnings.

+ References

No definition available.

+ Details

Name:	lnc_SeverityOfSecondLienDefaultedLoans
Namespace Prefix:	lnc_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 18
-URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6351-108592

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=118260190&loc=d3e13531-108611

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 21
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118260190&loc=d3e13537-108611

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6404-108592

+ Details

Name:	us-gaap_ConcentrationRiskPercentage1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

This item represents disclosure of all significant concentrations of credit risk or market risk arising from the subject financial instrument (as defined), whether from an individual counterparty or groups of counterparties.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=118260190&loc=d3e13531-108611

+ Details

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

- Definition

Fair value of collateral permitted, by contact or custom, to be sold or re-pledged.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 30
-Section 50
-Paragraph 1A
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=109249958&loc=SL6224234-111729

+ Details

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

- Definition

Fair value of the collateral, or portion thereof, that has been re-pledged, delivered, or otherwise used.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 30
-Section 50
-Paragraph 1A
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=109249958&loc=SL6224234-111729

+ Details

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

- Definition

Unpaid principal balance of impaired financing receivables for which there is a related allowance for credit losses.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (a)(4)
-URI http://asc.fasb.org/extlink&oid=118936363&loc=d3e5212-111524

+ Details

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

- Definition

Amount before tax of other than temporary impairment (OTTI) loss on investments in available-for-sale and held-to-maturity debt securities, recognized in other comprehensive loss.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 35
-Paragraph 35
-URI http://asc.fasb.org/extlink&oid=118985780&loc=d3e25362-111560

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 10A
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=118930883&loc=SL7669646-108580

+ Details

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

- Details

Name:	us-gaap_ConcentrationRiskByTypeAxis=us-gaap_FederalHomeLoanMortgageCorporationCertificatesAndObligationsFHLMCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ConcentrationRiskByBenchmarkAxis=lnc_InvestedAssetsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ConcentrationRiskByTypeAxis=us-gaap_FederalNationalMortgageAssociationCertificatesAndObligationsFNMAMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ConcentrationRiskByTypeAxis=lnc_ConsumerNonCyclicalIndustryMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ConcentrationRiskByTypeAxis=us-gaap_FinancialServiceMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

- Details

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

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ConcentrationRiskByTypeAxis=us-gaap_MortgagesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ConcentrationRiskByBenchmarkAxis=us-gaap_GeographicConcentrationRiskMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	srt_StatementGeographicalAxis=stpr_TX
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:	srt_StatementGeographicalAxis=stpr_FL
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Investments (Narrative) (Details) $ in Millions	3 Months Ended		12 Months Ended
Investments (Narrative) (Details) $ in Millions	Mar. 31, 2020 USD ($) item security loan	Mar. 31, 2019 USD ($)	Dec. 31, 2019 USD ($) security loan item
Investments [Line Items]
Increase (decrease) in gross AFS securities unrealized losses	$ 2,100
Impaired financing receivable, change in recorded allowance		$ 0
Number of partnerships in alternative investment portfolio \| item	260		258
Alternative investments as a percentage of overall invested assets	1.00%		1.00%
Net portion of OTTI recognized in OCI, pre-tax		$ 15
Fair value of collateral received that we are permitted to sell or re-pledge	25
Securities that have been re-pledged	25
Investment commitments	1,600
Investment commitments for limited partnerships	1,000
Investment commitments for mortgage loans on real estate	365
Investment commitments for private placements	197
Federal Home Loan Mortgage Corporation [Member] \| Investments [Member]
Investments [Line Items]
Fair value	$ 1,400		$ 1,300
Concentration risk, percentage	1.00%		1.00%
Federal National Mortgage Association [Member] \| Investments [Member]
Investments [Line Items]
Fair value	$ 1,100		$ 1,000
Concentration risk, percentage	1.00%		1.00%
Consumer Non-Cyclical Industry [Member] \| Investments [Member]
Investments [Line Items]
Fair value	$ 16,400		$ 16,300
Concentration risk, percentage	12.00%		12.00%
Financial Service [Member] \| Investments [Member]
Investments [Line Items]
Fair value	$ 15,700		$ 16,400
Concentration risk, percentage	12.00%		12.00%
Corporate Bonds [Member]
Investments [Line Items]
Percentage of fair value rated as investment grade	96.00%		96.00%
Amortized cost of portfolio rated below investment grade	$ 3,900		$ 3,200
Fair value of portfolio rated below investment grade	$ 3,500		$ 3,300
MBS [Member]
Investments [Line Items]
Severity of second lien loans	100.00%
Severity of first lien loans	30.00%
Commercial [Member]
Investments [Line Items]
Number of impaired loans \| security	2		1
Percentage threshold of loan-to-value ratios indicating principal is greater than collateral value	100.00%
Debt-service coverage ratio threshold \| item	1.0
Commercial [Member] \| Maximum [Member]
Investments [Line Items]
Impaired financing receivable, principal balance	$ 1		$ 1
Commercial [Member] \| Mortgage Loans On Real Estate [Member] \| Geographic Concentration Risk [Member] \| California [Member]
Investments [Line Items]
Concentration risk, percentage	24.00%		24.00%
Commercial [Member] \| Mortgage Loans On Real Estate [Member] \| Geographic Concentration Risk [Member] \| Texas [Member]
Investments [Line Items]
Concentration risk, percentage	11.00%		11.00%
Residential [Member]
Investments [Line Items]
Number of loans past due \| loan	44		38
Number of impaired loans \| security	24		4
Impaired financing receivable, principal balance	$ 6		$ 1
Residential [Member] \| Mortgage Loans On Real Estate [Member] \| Geographic Concentration Risk [Member] \| California [Member]
Investments [Line Items]
Concentration risk, percentage	34.00%		34.00%
Residential [Member] \| Mortgage Loans On Real Estate [Member] \| Geographic Concentration Risk [Member] \| Florida [Member]
Investments [Line Items]
Concentration risk, percentage	18.00%		20.00%