Acquisitions - Loews Hotels & Co (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2023	Jun. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Subsidiary, Sale of Stock [Line Items]
Investment gains (losses)	$ (38)		$ (96)	$ (59)	$ (166)
Total assets	76,469			76,469		$ 75,567
Total liabilities	$ 61,311			61,311		$ 60,366
Joint Venture
Subsidiary, Sale of Stock [Line Items]
Investment gains (losses)				$ 46
Loews Hotels And Co
Subsidiary, Sale of Stock [Line Items]
Payments to acquire an additional equity interest in joint venture property		$ 46
Loews Hotels And Co | Joint Venture
Subsidiary, Sale of Stock [Line Items]
Investment gains (losses)		46
Gain on investments, net of tax		36
Total assets		232
Total liabilities		$ 120