Derivative Instruments (Schedule Of Collateral Amounts With Rights To Reclaim Or Obligation To Return Cash) (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Credit Derivatives [Line Items]
Collateral Posted by Counter-Party (Held by LNC)	$ 681	$ 765
Collateral Posted by LNC (Held by Counter-Party)	(158)	(581)
AA- [Member]
Credit Derivatives [Line Items]
Collateral Posted by Counter-Party (Held by LNC)	79	116
Collateral Posted by LNC (Held by Counter-Party)	(4)	(1)
A+ [Member]
Credit Derivatives [Line Items]
Collateral Posted by Counter-Party (Held by LNC)	181	242
Collateral Posted by LNC (Held by Counter-Party)	(109)	(453)
A [Member]
Credit Derivatives [Line Items]
Collateral Posted by Counter-Party (Held by LNC)	184	170
Collateral Posted by LNC (Held by Counter-Party)	(34)	(120)
A- [Member]
Credit Derivatives [Line Items]
Collateral Posted by Counter-Party (Held by LNC)	237	237
Collateral Posted by LNC (Held by Counter-Party)		(3)
BBB+ [Member]
Credit Derivatives [Line Items]
Collateral Posted by Counter-Party (Held by LNC)
Collateral Posted by LNC (Held by Counter-Party)	$ (11)	$ (4)