Derivative Instruments (Schedule Of Collateral Amounts With Rights To Reclaim Or Obligation To Return Cash) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Credit Derivatives [Line Items]
Collateral Posted by Counter-Party (Held by LNC)	$ 765	$ 894
Collateral Posted by LNC (Held by Counter-Party)	(581)	(630)
AA- [Member]
Credit Derivatives [Line Items]
Collateral Posted by Counter-Party (Held by LNC)	116	53
Collateral Posted by LNC (Held by Counter-Party)	(1)	(32)
A+ [Member]
Credit Derivatives [Line Items]
Collateral Posted by Counter-Party (Held by LNC)	242	10
Collateral Posted by LNC (Held by Counter-Party)	(453)	(217)
A [Member]
Credit Derivatives [Line Items]
Collateral Posted by Counter-Party (Held by LNC)	170	466
Collateral Posted by LNC (Held by Counter-Party)	(120)	(381)
A- [Member]
Credit Derivatives [Line Items]
Collateral Posted by Counter-Party (Held by LNC)	237	67
Collateral Posted by LNC (Held by Counter-Party)	(3)
BBB+ [Member]
Credit Derivatives [Line Items]
Collateral Posted by Counter-Party (Held by LNC)		298
Collateral Posted by LNC (Held by Counter-Party)	$ (4)