Revenue from Contracts with Customers - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Disaggregation of Revenues [Abstract]
Revenues from contracts with customers	$ 552	$ 505	$ 1,123	$ 1,020
Other revenues	22	29	45	54
Operating revenues and other	574	534	1,168	1,074
CNA Financial | Non-insurance warranty
Disaggregation of Revenues [Abstract]
Revenues from contracts with customers	407	392	814	774
Boardwalk Pipelines | Transportation and storage of natural gas and NGLs and other services
Disaggregation of Revenues [Abstract]
Revenues from contracts with customers	350	315	736	684
Loews Hotels & Co | Lodging and related services
Disaggregation of Revenues [Abstract]
Revenues from contracts with customers	$ 202	$ 190	$ 387	$ 336