Basis of Presentation - Adoption on Consolidated Condensed Statement of Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Changes in: Net unrealized losses on other investments	$ (1,084)	$ (1,735)	$ (827)	$ (6,604)
Total unrealized losses on investments	(1,085)	(1,737)	(837)	(6,612)
Impact of changes in discount rates used to measure long-duration contract liabilities	818	994	678	4,136
Other comprehensive (loss)	(283)	(839)	(103)	(2,619)
Comprehensive (loss)	(7)	(866)	965	(2,107)
Amounts attributable to noncontrolling interests	8	78	(69)	215
Total comprehensive (loss) attributable to Loews Corporation	$ 1	(788)	$ 896	(1,892)
As Reported
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Changes in: Net unrealized losses on other investments		(1,327)		(4,284)
Total unrealized losses on investments		(1,329)		(4,292)
Other comprehensive (loss)		(1,425)		(4,435)
Comprehensive (loss)		(1,282)		(3,720)
Amounts attributable to noncontrolling interests		119		379
Total comprehensive (loss) attributable to Loews Corporation		(1,163)		(3,341)
Effect of Adoption
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Changes in: Net unrealized losses on other investments		(408)		(2,320)
Total unrealized losses on investments		(408)		(2,320)
Impact of changes in discount rates used to measure long-duration contract liabilities		994		4,136
Other comprehensive (loss)		586		1,816
Comprehensive (loss)		416		1,613
Amounts attributable to noncontrolling interests		(41)		(164)
Total comprehensive (loss) attributable to Loews Corporation		$ 375		$ 1,449