Guaranteed Benefit Features (Narrative) (Details)	9 Months Ended	12 Months Ended
Sep. 30, 2022	Dec. 31, 2021
Guaranteed Benefit Features [Abstract]
Percent of permanent life insurance sales	38.00%	37.00%

Sales of universal life and variable universal life products with secondary guarantees as a percentage of total sales of permanent life insurance.

No definition available.

Name:	cik0000726865_PercentOfPermanentLifeInsuranceSales
Namespace Prefix:	cik0000726865_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration