Investments (Schedule Of Increase (Decrease) In Payables For Collateral On Investments) (Details) - USD ($) $ in Millions	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017
Increase (decrease) in payables for collateral on investments
Collateral payable for derivative investments	$ (297)	$ 160
Securities pledged under securities lending agreements	(80)	(8)
Securities pledged under repurchase agreements	379	5
Investments pledged for FHLBI	280	(200)
Total increase (decrease) in payables for collateral on investments	$ 282	$ (43)

- Definition

The net change during the reporting period in the amount of cash that is received related to collateral payable held for derivative instruments.

+ References

No definition available.

+ Details

Name:	lnc_IncreaseDecreaseInCashCollateralForDerivativeInvestments
Namespace Prefix:	lnc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The net change during the reporting period in the amount of cash that is received related to securities pledged under reverse repurchase agreements

+ References

No definition available.

+ Details

Name:	lnc_IncreaseDecreaseInCashCollateralForReverseRepurchaseAgreements
Namespace Prefix:	lnc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The net change during the reporting period in the amount of cash that is received related to securities pledged under securities lending agreements.

+ References

No definition available.

+ Details

Name:	lnc_IncreaseDecreaseInCashCollateralForSecuritiesLendingAgreements
Namespace Prefix:	lnc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The net change during the reporting period in the amount of cash that is received related to securities pledged for Federal Home Loan Bank of Indianapolis.

+ References

No definition available.

+ Details

Name:	lnc_IncreaseDecreaseInCashCollateralForSecuritiesPledgedForFhlbi
Namespace Prefix:	lnc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The increase (decrease) during the reporting period in the amount that is received as security when loaning securities.

+ References

No definition available.

+ Details

Name:	lnc_IncreaseDecreaseInCollateralForLoanedSecurities
Namespace Prefix:	lnc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- References

No definition available.

+ Details

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