Name:	l_AdvanceWrittenNoticePeriodForHedgeFundWithdrawals
Namespace Prefix:	l_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Carrying value of limited partnerships on the balance sheet as a percentage of the aggregate partnership equity.

No definition available.

Name:	l_CarryingValueOfLimitedPartnershipsAsPercentageOfAggregatePartnershipEquity
Namespace Prefix:	l_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

Income from limited partnerships reflected on the statement of operations as a percentage of changes in aggregate partnership equity.

No definition available.

Name:	l_IncomeFromLimitedPartnershipsAsPercentageOfChangesInAggregatePartnershipEquity
Namespace Prefix:	l_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Period of time to maintain liquidity under hedge fund withdrawal provisions, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Includes, but not limited to, weeks in a year or quarter.

No definition available.

Name:	l_LiquidityPeriodUnderHedgeFundWithdrawalProvisions
Namespace Prefix:	l_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Percentage of the carrying value of investments in limited partnerships.

No definition available.

Name:	l_PercentageOfCarryingValueOfInvestmentsInLimitedPartnerships
Namespace Prefix:	l_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

Percentage of the carrying value of investments in limited partnerships reported on a current basis.

No definition available.

Name:	l_PercentageOfCarryingValueOfInvestmentsInLimitedPartnershipsReportedOnCurrentBasis
Namespace Prefix:	l_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Percentage of the carrying value of investments in limited partnerships reported on a one-month lag.

No definition available.

Name:	l_PercentageOfCarryingValueOfInvestmentsInLimitedPartnershipsReportedOnOneMonthLag
Namespace Prefix:	l_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Threshold for the number of largest limited partnership positions held.

No definition available.

Name:	l_ThresholdForNumberOfLargestLimitedPartnershipPositionsHeld
Namespace Prefix:	l_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

Amount of investment in equity method investee and investment in and advance to affiliate.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(18))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Name:	us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

Name:	us-gaap_LimitedPartnersCapitalAccountValueAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Amount of undistributed earnings (loss) allocated to participating securities for the basic earnings (loss) per share or per unit calculation under the two-class method.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 480
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 4
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481679/480-10-45-4

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 65
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482689/260-10-45-65

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 66
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482689/260-10-45-66

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 60B
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482689/260-10-45-60B

Name:	us-gaap_UndistributedEarningsLossAllocatedToParticipatingSecuritiesBasic
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_InvestmentTypeAxis=l_PrivateDebtAndEquityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_InvestmentTypeAxis=us-gaap_HedgeFundsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: