Investments (Schedule Of Increase (Decrease) In Payables For Collateral On Investments) (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Increase (decrease) in payables for collateral on investments
Collateral payable for derivative investments	$ (83)	$ 29
Securities pledged under securities lending agreements	(68)	(89)
Securities pledged under repurchase agreements	(1)	1
Investments pledged for FHLBI		150
Total increase (decrease) in payables for collateral on investments	$ (152)	$ 91

- 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

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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

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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

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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

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- 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

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