Revenue from Contracts with Customers - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Disaggregation of Revenues [Abstract]
Revenues from contracts with customers	$ 505	$ 396	$ 1,020	$ 1,093
Other revenues	29	19	54	37
Operating revenues and other	534	415	1,074	1,130
Non-insurance warranty – CNA Financial | CNA Financial
Disaggregation of Revenues [Abstract]
Revenues from contracts with customers	392	359	774	697
Transportation and storage of natural gas and NGLs and other services – Boardwalk Pipelines | Transportation and storage of natural gas and NGLs and other services – Boardwalk Pipelines
Disaggregation of Revenues [Abstract]
Revenues from contracts with customers	315	302	684	663
Lodging and related services – Loews Hotels & Co | Lodging and related services – Loews Hotels & Co
Disaggregation of Revenues [Abstract]
Revenues from contracts with customers	190	94	336	150
Rigid plastic packaging and recycled resin - Corporate | Rigid plastic packaging and recycled resin - Corporate
Disaggregation of Revenues [Abstract]
Revenues from contracts with customers				$ 280