Property, Plant and Equipment - Depreciation Expense and Capital Expenditures (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Abstract]
Depreciation	$ 580	$ 534	$ 509
Capital Expend.	585	693	675
Interest costs capitalized	27	32	17
Operating Segments | CNA Financial
Property, Plant and Equipment [Abstract]
Depreciation	59	54	49
Capital Expend.	105	97	50
Operating Segments | Boardwalk Pipelines
Property, Plant and Equipment [Abstract]
Depreciation	426	410	394
Capital Expend.	365	383	352
Operating Segments | Loews Hotels & Co
Property, Plant and Equipment [Abstract]
Depreciation	93	69	64
Capital Expend.	115	201	264
Corporate | Corporate
Property, Plant and Equipment [Abstract]
Depreciation	2	1	2
Capital Expend.		$ 12	$ 9