Line Of Credit Facility, Number Of Extensions

No definition available.

Name:	l_LineOfCreditFacilityNumberOfExtensions
Namespace Prefix:	l_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

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+ Details

Name:	us-gaap_DebtInstrumentFaceAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (b)
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-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- References

No definition available.

+ Details

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

- Definition

Period remaining on line of credit facility before it terminates, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	us-gaap_LineOfCreditFacilityExpirationPeriod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
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+ Details

Name:	us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_DebtInstrumentAxis=l_SeniorNotesDue2023Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_SeniorNotesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ConsolidatedEntitiesAxis=l_BoardwalkPipelinePartnersLpMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=l_SeniorVariableRateRevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ConsolidatedEntitiesAxis=l_CnaFinancialCorporationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=l_SeniorNotesDue2033Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Debt (Details) $ in Millions	9 Months Ended
Debt (Details) $ in Millions	Sep. 30, 2023 USD ($) Extension	Aug. 31, 2023 USD ($)	May 31, 2023 USD ($)
2.6% Senior Notes Due 2023 \| Senior Notes
Debt [Abstract]
Face amount			$ 500
Interest rate			2.60%
Transportation and storage of natural gas and NGLs and other services – Boardwalk Pipelines \| Senior Variable Rate Revolving Credit Facility
Debt [Abstract]
Number of extensions \| Extension	2
Term of extension	1 year
Remaining borrowing capacity	$ 912		$ 1,000
CNA Financial \| 5.5% Senior Notes Due 2033 \| Senior Notes
Debt [Abstract]
Face amount		$ 100	$ 400
Interest rate		5.50%	5.50%