Revenue from Contracts with Customers - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Disaggregation of Revenues
Total revenues from contracts with customers	$ 843	$ 732	$ 2,529	$ 2,347
Other revenues	26	27	81	79
Operating revenues and other	869	759	2,610	2,426
CNA Financial \| Non-insurance warranty – CNA Financial
Disaggregation of Revenues
Total revenues from contracts with customers	357	393	1,098	1,188
Boardwalk Pipelines \| Transportation and storage of natural gas and NGLs and ethane supply and transportation services – Boardwalk Pipelines
Disaggregation of Revenues
Total revenues from contracts with customers	602	530	1,776	1,662
Loews Hotels & Co \| Lodging and related services – Loews Hotels & Co
Disaggregation of Revenues
Total revenues from contracts with customers	$ 241	$ 202	$ 753	$ 685

Amount of revenue and income classified as other.

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