Basis of Presentation - Adoption on Consolidated Condensed Statement of Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Changes in: Net unrealized losses on other investments	$ (413)	$ (2,226)	$ 257	$ (4,869)
Total unrealized losses on investments	(414)	(2,228)	248	(4,875)
Impact of changes in discount rates used to measure long-duration contract liabilities	256	1,507	(140)	3,142
Other comprehensive (loss)	(109)	(778)	180	(1,780)
Comprehensive (loss)	279	(591)	972	(1,241)
Amounts attributable to noncontrolling interests	(17)	59	(77)	136
Total comprehensive (loss) attributable to Loews Corporation	$ 262	(532)	$ 895	(1,105)
As Reported
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Changes in: Net unrealized losses on other investments		(1,346)		(2,957)
Total unrealized losses on investments		(1,348)		(2,963)
Other comprehensive (loss)		(1,405)		(3,010)
Comprehensive (loss)		(1,203)		(2,438)
Amounts attributable to noncontrolling interests		124		260
Total comprehensive (loss) attributable to Loews Corporation		(1,079)		(2,178)
Effect of Adoption
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Changes in: Net unrealized losses on other investments		(880)		(1,912)
Total unrealized losses on investments		(880)		(1,912)
Impact of changes in discount rates used to measure long-duration contract liabilities		1,507		3,142
Other comprehensive (loss)		627		1,230
Comprehensive (loss)		612		1,197
Amounts attributable to noncontrolling interests		(65)		(124)
Total comprehensive (loss) attributable to Loews Corporation		$ 547		$ 1,073