Transactions With Affiliates (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020
Transactions With Affiliates [Abstract]
Borrowing and lending limit, percent of admitted assets	3.00%
Line of credit beneficiary amount	$ 1	$ 1

Borrowing and lending limit, percent of admitted assets

No definition available.

Name:	cik0000726865_BorrowingAndLendingLimitPercentOfAdmittedAssets
Namespace Prefix:	cik0000726865_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration