Federal Income Taxes - Federal Income Tax Asset (Liability) (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Current	$ 546	$ 353
Deferred	49	734
Total federal income tax asset (liability)	$ 595	$ 1,087

Carrying amount as of the balance sheet date of income taxes previously overpaid to tax authorities (such as U.S. Federal, state and local tax authorities) representing refunds of overpayments or recoveries based on agreed-upon resolutions of disputes, net of the unpaid sum of the known and estimated amounts payable to satisfy all domestic and foreign income tax obligations due.

No definition available.

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Namespace Prefix:	cik0000726865_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant