CONSOLIDATED CONDENSED STATEMENTS OF OPERATIONS (Unaudited) (Parenthetical) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Income Statement [Abstract]
Re-measurement gain of insurance claims and policyholders’ benefits	$ (33)	$ 1	$ (34)	$ 6

Insurance Claims And Policyholders Benefits, Including Policyholders' Dividends, Remeasurement Impact

No definition available.

Name:	l_InsuranceClaimsAndPolicyholdersBenefitsIncludingPolicyholdersDividendsRemeasurementImpact
Namespace Prefix:	l_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration