Investments (Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2015 item	Dec. 31, 2014 item
Increase (decrease) in gross AFS securities unrealized losses	$ (84)
Number of partnerships in alternative investment portfolio	171	156
Alternative investments as a percentage of overall invested assets	1.00%	1.00%
Investment commitments	1,700lnc_InvestmentCommitments
Investment commitments for limited partnerships	675
Investment commitments for private placements	275
Investment commitments for mortgage loans on real estate	717lnc_InvestmentCommitmentsMortgageLoans
California and Texas [Member]
Largest mortgage loan concentration in geographic region	23.00%	9.00%
Federal Home Loan Mortgage Corporation
Fair value	2,200	2,200
Concentration risk, percentage	2.00%	2.00%
Fannie Mae
Fair value	1,400	1,400
Concentration risk, percentage	1.00%	1.00%
Electric Industry [Member]
Fair value	13,200	12,800
Concentration risk, percentage	12.00%	13.00%
Consumer Non-Cyclical Industry [Member]
Fair value	12,300	11,700
Concentration risk, percentage	12.00%	11.00%
Corporate Bonds [Member]
Percentage of fair value rated as investment grade	95.00%	96.00%
Amortized cost of portfolio rated below investment grade	3,500	3,300
Fair value of portfolio rated below investment grade	3,500	3,200
Asset-backed Securities [Member]
Percentage of fair value rated as investment grade	92.00%	88.00%
Amortized cost of portfolio rated below investment grade	191	193
Fair value of portfolio rated below investment grade	$ 178	176
MBS [Member]
Projected default rate on existing delinquencies on MBS (low end of range)	10.00%	10.00%
Projected default rate on existing delinquencies on MBS (high end of range)	100.00%	100.00%
Severity of second lien loans	100.00%	100.00%
Severity of first lien loans	30.00%	30.00%

Alternative investments as a percentage of overall invested assets.

No definition available.

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- Definition

Amortized cost of portfolio rated below investment grade.

+ References

No definition available.

+ Details

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Namespace Prefix:	lnc_
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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
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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- Definition

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

+ References

No definition available.

+ Details

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Namespace Prefix:	lnc_
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- Definition

Fair value of portfolio rated below investment grade.

+ References

No definition available.

+ Details

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- 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

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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

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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

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Data Type:	xbrli:monetaryItemType
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Period Type:	instant

- Definition

Largest concentration percentage of mortgage loans on commercial real estate throughout the U.S.

+ References

No definition available.

+ Details

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

- Definition

Number of partnerships represented in alternative investment portfolio.

+ References

No definition available.

+ Details

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Namespace Prefix:	lnc_
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Balance Type:	na
Period Type:	instant

- Definition

This item represents the default rate (as a percentage) of the underlying assets in the security 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 (high end of range).

+ References

No definition available.

+ Details

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

- Definition

+ References

No definition available.

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Name:	lnc_ProjectedDefaultRateOnExistingDeliquenciesPercentLowEndOfRange
Namespace Prefix:	lnc_
Data Type:	num:percentItemType
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

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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

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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://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 21

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=28364263&loc=d3e13537-108611

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 275

-SubTopic 10

-Section 50

-Paragraph 20

-URI http://asc.fasb.org/extlink&oid=6927468&loc=d3e6404-108592

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 20

-URI http://asc.fasb.org/extlink&oid=28364263&loc=d3e13531-108611

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 275

-SubTopic 10

-Section 50

-Paragraph 18

-URI http://asc.fasb.org/extlink&oid=6927468&loc=d3e6351-108592

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- 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/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Available-for-Sale Securities

-URI http://asc.fasb.org/extlink&oid=6505594

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Trading Securities

-URI http://asc.fasb.org/extlink&oid=6526789

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 25

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=28360136&loc=d3e22054-111558

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Subparagraph a, f, g

-Article 7

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- Details

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