Property, Plant and Equipment - Depreciation Expense and Capital Expenditures (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Property, Plant and Equipment [Abstract]
Depreciation	$ 509	$ 503	$ 673
Capital Expend.	675	489	670
Interest costs capitalized	17	12	14
Operating Segments \| CNA Financial
Property, Plant and Equipment [Abstract]
Depreciation	49	51	56
Capital Expend.	50	26	25
Operating Segments \| Boardwalk Pipelines
Property, Plant and Equipment [Abstract]
Depreciation	394	368	361
Capital Expend.	352	340	415
Operating Segments \| Loews Hotels & Co
Property, Plant and Equipment [Abstract]
Depreciation	64	63	63
Capital Expend.	264	100	88
Operating Segments \| Diamond Offshore
Property, Plant and Equipment [Abstract]
Depreciation			119
Capital Expend.			52
Corporate
Property, Plant and Equipment [Abstract]
Depreciation	2	21	74
Capital Expend.	$ 9	$ 23	$ 90

The aggregate expense recognized in the current period that allocates the cost of tangible assets, intangible assets, or depleting assets to periods that benefit from use of the assets.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 22
-Subparagraph (e)
-URI https://asc.fasb.org/extlink&oid=126901519&loc=d3e8736-108599

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3602-108585

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- Definition

Amount of interest capitalized during the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=6450988&loc=d3e26243-108391

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

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- Definition

Amount of acquisition of long-lived, physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

+ References

No definition available.

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