Revenue from Contracts with Customers - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Disaggregation of Revenues [Abstract]
Revenues from contracts with customers	$ 571	$ 516
Other revenues	23	24
Operating revenues and other	594	540
CNA Financial | Non-insurance warranty
Disaggregation of Revenues [Abstract]
Revenues from contracts with customers	407	382
Boardwalk Pipelines | Transportation and storage of natural gas and NGLs and other services
Disaggregation of Revenues [Abstract]
Revenues from contracts with customers	386	370
Loews Hotels & Co | Lodging and related services
Disaggregation of Revenues [Abstract]
Revenues from contracts with customers	$ 185	$ 146