Revenue from Contracts with Customers (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disaggregation of Revenues [Abstract]
Revenues from contracts with customers	$ 2,005	$ 2,820	$ 3,870
Other revenues	128	113	68
Operating revenues and other	2,133	2,933	3,938
Deferred Revenue [Abstract]
Deferred revenue	4,503	4,023
Revenue recognized	1,200	1,100
Contract Costs [Abstract]
Capitalized Contract Cost, Net	3,476	3,068
Amortization of contract costs	1,100	907
Adjustments to deferred costs	0	0
Receivables
Receivables from Contracts with Customers [Abstract]
Receivables from contracts with customers	145	246
Other Liabilities
Deferred Revenue [Abstract]
Deferred revenue	4,600	4,100
Deferred Non-insurance Warranty Acquisition Expenses
Contract Costs [Abstract]
Capitalized Contract Cost, Net	3,500	3,100
Non-insurance warranty – CNA Financial | Non-insurance warranty – CNA Financial
Disaggregation of Revenues [Abstract]
Revenues from contracts with customers	1,430	1,252	1,161
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	1,306	1,264	1,266
Lodging and related services – Loews Hotels & Co | Lodging and related services – Loews Hotels & Co
Disaggregation of Revenues [Abstract]
Revenues from contracts with customers	419	234	691
Rigid plastic packaging and recycled resin - Corporate | Rigid plastic packaging and recycled resin - Corporate
Disaggregation of Revenues [Abstract]
Revenues from contracts with customers	280	1,022	932
Contract drilling - Diamond Offshore | Diamond Offshore Drilling Inc.
Disaggregation of Revenues [Abstract]
Revenues from contracts with customers		$ 300	$ 981